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2021-02-03 Architectural Design Board Packet
�C)F F.°1[10 Architectural Design Board Remote Zoom Meeting Agenda �c. 1 R90 121 5th Ave. N. Edmonds, WA 98020 www.edmondswa.gov Michelle Martin 425-771-0220 Wednesday, February 3, 2021 7:00 PM Virtual Online Meeting Remote Meeting Information Join Zoom Meeting at: https://zoom.us/j/96385160252?pwd=OGtCN DNGQkl lMzVNZjJgMkNJYlZGQT09 Meeting ID: 963 8516 0252. Password: 944947 Call into the meeting by dialing: 253-215-8782 I. Call to Order Attendee Name Present Absent Late Arrived II. Approval of Agenda III. Approval of Minutes 1. Generic Agenda Item (ID # 5269) Approval of Minutes Background/History N/A Staff Recommendation Approve meetings minutes of the December 2, 2020 ADB meeting. ATTACHMENTS: • Draft December 2, 2020 meeting minutes (PDF) IV. Audience Comment V. Public Hearing 1. Generic Agenda Item (ID # 5268) PLN2020-0040 Woodway Station: The applicant is proposing to demolish the existing structure that was formerly used as a convenience store and gas station and construct a new two-story, approximately 11,000 square foot commercial building. The project will also provide 22 parking spaces and new landscaping . The site is zoned Neighborhood Business (BN). The proposed development is subject to Architectural Design Board Page 1 Printed 112812021 Remote Zoom Meeting Agenda February 3, 2021 the zoning standards in Chapter 16.45 Edmonds Community Development Code (ECDC) and general design standards in Chapter 20.11 ECDC. Background/History N/A Staff Recommendation Staff recommends approval with conditions. ATTACHMENTS: • PLN2020-0040 Staff Report with Attachments (PDF) VI. ADB Member Comments VII. Adjournment Architectural Design Board Page 2 Printed 112812021 3.1 Architectural Design Board Agenda Item Meeting Date: 02/3/2021 Approval of Minutes Staff Lead: Kernen Lien Department: Planning Division Prepared By: Kernen Lien Background/History N/A Staff Recommendation Approve meetings minutes of the December 2, 2020 ADB meeting. Narrative Draft December 2, 2020 meeting minutes attached. Attachments: Draft December 2, 2020 meeting minutes Packet Pg. 3 3.1.a CITY OF EDMONDS ARCHITECTURAL DESIGN BOARD Minutes of Virtual Meeting December 2, 2020 Board Member Owenby called the meeting of the Architectural Design Board to order at 7:00 p.m., at the City Council Chambers, 250 - 5' Avenue North, Edmonds, Washington. Board Members Present Laurie Strauss, Chair (joined at 7:05) Bruce Owensby, Vice Chair Kim Bayer Cary Guenther Joe Herr Maurine Jeude Board Members Absent PRESENTATION BY MAYOR NELSON Staff Present Mike Clugston, Senior Planner Mayor Nelson thanked Board Member Guenther for his 8 years of service on the Architectural Design Board. He also voiced appreciation for the Board's work to shape the City building -by -building. On behalf of the City, he presented a paper weight gift to Board Member Guenther. ELECTION OF OFFICERS THE BOARD UNANIMOUSLY SELECTED BOARD MEMBER STRAUSS TO SERVE AS CHAIR AND BOARD MEMBER OWENSBY TO SERVE AS VICE CHAIR IN 2021. REQUESTS FROM THE AUDIENCE: There were no audience comments during this part of the agenda. APPROVAL OF MINUTES BOARD MEMBER BAYER MOVED THAT THE MINUTES OF AUGUST 5, 2020 BE APPROVED AS AMENDED. VICE CHAIR OWENSBY SECONDED THE MOTION, WHICH CARRIED UNANIMOUSLY. APPROVAL OF AGENDA The agenda was accepted as presented. MINOR PROJECTS: No minor projects were scheduled on the agenda. Architectural Design Board Meeting Minutes of Virtual Meeting December 2, 2020 Page 1 of 2 Packet Pg. 4 to r 7 C 0 0 0. 0. a 3.1.a I141 : a I I BI\ :710[iff There was no public hearing. CONSOLIDATED PERMIT APPLICATIONS (No Public Participation): There were no consolidated permit applications. ADMINISTRATIVE REPORTS/ITEMS FOR DISCUSSION Board Member Herr shared an experience he had in the City of Redmond. He estimated his company spent over $30,000 in extra costs to design a house to save a tree that was rather sickly and unattractive and needed to be taken down. Board Member Guenther observed that the City of Seattle has similar tree retention requirements. Mr. Clugston announced that the Planning Board will have a public hearing on the new draft Tree Code on December 9'''. He encouraged the Board Members to review their agenda and provide some comments. The Board Members asked Mr. Clugston to send them a reminder email. o Mr. Clugston advised that the positions vacated by Board Members Walker and Guenther will be advertised soon. o a a ARCHITECTURAL DESIGN BOARD MEMBER COMMENTS: Q Board Member Guenther said he was disappointed that, due to the pandemic, the Board was unable to make progress in redefining its role. He was hoping the Board's role could be modified to allow an opportunity to provide more direction to applicants. He was also hoping the Board could have drafted a proposed amendment that allows exceptions to the Design Guidelines. He recalled that this opportunity would have been helpful for a few recent projects. Board Member Jeude said her understanding was that, following joint meetings with the Planning Board to discuss the changes, the Architectural Design Board indicated support and asked the staff and Planning Board to work on proposed amendments to implement the concepts. Mr. Clugston reviewed that there was a general discussion about the proposed changes when the Planning Board met jointly with the City Council earlier in the year, but the pandemic stalled the process. The concept can be reintroduced to the Mayor and City Council as they work on setting the 2021 Work Program. Chair Strauss suggested that, when there are no projects to review, the Board could use their regular meeting dates to discuss their ideas and the best way forward. She stressed the need to keep the momentum going, and the remainder of the Board concurred. Board Member Bayer requested an update on the Westgate Station Project. Mr. Clugston said he recently spoke with the developer a few months ago and was advised that he would likely submit a building permit application before the end of the year. Board Member Bayer noted that a "for sale" sign was recently posted on the property. Mr. Clugston said he is not aware of any recent changes. Board Member Bayer requested an update on the Main Street Commons Project, as well. Mr. Clugston reported that the project is currently in building permit review. Vice Chair Owenby asked if building permit reviews have been slower. Mr. Clugston responded that some of the larger projects have slowed down a bit. However, there have been a number of permits issued for single-family residential development and remodels. Staff s level of work has remained constant. ADJOURNMENT: The meeting was adjourned at 7:27 p.m. Architectural Design Board Meeting Minutes of virtual Meeting December 2, 2020 Page 2 of 2 Packet Pg. 5 5.1 Architectural Design Board Agenda Item Meeting Date: 02/3/2021 PLN2020-0040 Woodway Station: The applicant is proposing to demolish the existing structure that was formerly used as a convenience store and gas station and construct a new two-story, approximately 11,000 square foot commercial building. The project will also provide 22 parking spaces and new landscaping. The site is zoned Neighborhood Business (BN). The proposed development is subject to the zoning standards in Chapter 16.45 Edmonds Community Development Code (ECDC) and general design standards in Chapter 20.11 ECDC. Staff Lead: Kernen Lien Department: Planning Division Prepared By: Kernen Lien Background/History N/A Staff Recommendation Staff recommends approval with conditions. Narrative The applicant is proposing to demolish the existing structure that was formerly used as a convenience store and gas station and construct a new two-story, approximately 11,000 square foot commercial building. The project will also provide 22 parking spaces and new landscaping. The site is zoned Neighborhood Business (BN). The proposed development is subject to the zoning standards in Chapter 16.45 Edmonds Community Development Code (ECDC) and general design standards in Chapter 20.11 ECDC. Pursuant to ECDC 20.11.010, proposed developments that require a State Environmental Policy Act (SEPA) threshold determination are reviewed by the ADB in a public hearing. According to ECDC 20.01.003, review by the ADB in a public hearing format is a Type III -A decision. Attachments: PLN2020-0040 Staff Report with Attachments Packet Pg. 6 5.1.a CITY OF EDMONDS 121 51h Avenue North, Edmonds WA 98020 Phone: 425.771.0220 • Fax: 425.771.0221 • Web: www.edmondswa.gov DEVELOPMENT SERVICES DEPARTMENT • PLANNING DIVISION PLANNING DIVISION REPORT AND RECOMMENDATION ARCHITECTURAL DESIGN BOARD Project: Woodway Station File Number: PLN2020-0040 Date of Report: January 27, 2021 90 Staff Contact: � Kernen Lien, Environmental Programs Manager Public Hearing: Wednesday — February 3, 2021 at 7:00 P.M. Due to COVID-19, a virtual public will be held via Zoom. The Zoom meeting may be joined at: https://zoom.us/i/96385160252?pwd=OGtCNDNGQkllMzVNZgJgMkNJY1 ZGQT09 Or via phone by dialing 253-215-8782 Meeting ID: 963 8516 0252 Password: 944947 I. SUMMARY OF PROPOSAL The applicant is proposing to demolish the existing structure that was formerly uses as a convenience store and gas station and construct a new two-story, approximately 11,000 square foot commercial building. The project will also provide 22 parking spaces and new landscaping (Attachments 1 - 6). The site is zoned Neighborhood Business (BN). The proposed development is subject to the zoning standards in Chapter 16.45 Edmonds Community Development Code (ECDC) and general design standards in Chapter 20.11 ECDC. Packet Pg. 7 5.1.a II. GENERAL INFORMATION 1. Owner: Red Sea Properties, LLC 2. Applicant: CDA Pirscher Architects 3. Tax Parcel Number: 27033600400500 4. Location: 23726 100th Avenue West, Edmonds WA 98020 (Attachment 12) 5. Size: The subject property contains 21,506 square feet. 6. Zoning: The subject property is zoned Neighborhood Business (BN). 7. Existing Use: The existing structure on the site has been used as gas station and convenience store over the years. Currently the site is being used by Sound Disposal a waste collection company. 8. Proposed Use: The applicant is proposing to construct an approximately 11,000 square foot commercial building. Businesses that will use the building have not been identified. 9. Process: Pursuant to ECDC 20.11.010, proposed developments that require a State Environmental Policy Act (SEPA) threshold determination (those that are not categorically exempt from SEPA) are reviewed by the ADB in a public hearing. According to ECDC 20.01.003, review by the ADB in a public hearing format is a Type III -A decision. III. ATTACHMENTS 1. Land Use Application 2. Application Cover Letter 3. Site Plan 4. ADB Plan Set 5. Preliminary Civil Plans 6. Landscape Plan 7. Gibson Traffic Consultants November 18, 2020 Traffic Memorandum 8. Cobalt Sciences Geotechnical Report July 31, 2020 Geotechnical Report 9. Preliminary Stormwater Plan 10. SEPA Checklist 11. SEPA Determination of Nonsignificance 12. Zoning and Vicinity Map 13. Public Notice Documentation - September 10, 2020 Notice of Application 14. Public Notice Documentation — September 25, 2020 Revised Notice of Application 15. Public Notice Documentation — January 7, 2020 Notice of Public Hearing and SEPA Determination 16. Susan Frodsham September 23, 2020 Email 17. Danielle Hursh September 22, 2020 Email PLN2020-0040 Woodway Station Design Review Page 2 of 18 Packet Pg. 8 5.1.a 18. Killy Keefe September 22, 2020 Email 19. Vanessa Mark September 22, 2020 Email 20. Kristine Wear October 8, 2020 Email 21. Chris Johnson September 23, 2020 Email and Petition 22. Department of Ecology January 21, 2021 Letter 23. South County Fire Review Memorandum 24. City of Edmonds Engineering Division Memorandum of Compliance IV. SEPA THRESHOLD DETERMINATION Review under SEPA is required for this project because the project is a commercial development that exceeds 4,000 square feet and 20 parking spaces. The applicant submitted a SEPA Checklist for the project which is included in Attachment 10. The City of Edmonds determined that the requirements for environmental analysis and protection have been adequately addressed in the development regulations and comprehensive plan adopted under chapter 36.70A RCW, and in other local, state, or federal laws or rules, as provided by RCW 43.21C.240 and WAC 197-11-158 and issued SEPA Determination of Nonsignificance on January 7, 2021(Attachment 11). As of the drafting of this staff report, the City has not received any appeals of the SEPA determination. V. PUBLIC NOTICE AND COMMENTS A "Notice of Application" was published in the Herald Newspaper, posted at the subject site, as well as the Public Safety Complex, the Community Development Department and mailed to properties owners within 300 feet of the site on September 10, 2020 (Attachment 13). During review of an unrelated project, questions were raised about how adjacent property owners' lists were generated for mailing public notices. To ensure compliance with the City's notice requirements, a "Revised Notice of Application" was published in the Herald Newspaper, posted at the subject site, as well as the Public Safety Complex, the Community Development Department and mailed to properties owners within 300 feet (via an adjacent property owner's list generated by City staff) of the site on September 25, 2020 (Attachment 14). The "Notice Public Hearing and SEPA Threshold Determination" was published in the Herald Newspaper, posted at the subject site, as well as the Public Safety Complex, and Community Development Department, January 7, 2020. Notices were also mailed to property owners within 300 feet of the site and parties of record. See Attachment 15 for public notice documentation regarding the Notice of Public and SEPA determination. The City has complied with the noticing provisions of ECDC 20.03 (Public Notice). Five individual written comments have been submitted on the proposal as well as a petition signed by many of the residents located in the neighborhood along 101s' Avenue W. Public comments were concerned with the scale of development adjacent to a PLN2020-0040 Woodway Station Design Review Page 3 of 18 Packet Pg. 9 5.1.a residential area, traffic impacts, parking (on site and within the neighborhood), landscaping and disruption during development (Attachments 16 — 21). Additionally, during the SEPA comment period the Department of Ecology submit comments regarding further documentation needed for potential contamination issues that will need to be addressed during site development (Attachment 22). Below are staff responses to the public comments. Scale of Development: The comments related to the scale of development were mostly related to the new building being two stories tall while other structures in the area are primarily single -story. Staff Response: The maximum height in the BN and RS-8 zones (the zone of the adjacent residential properties) are both 25 feet. The proposed structure is 24' — 6" which is compliant with the height limit of the BN zone. Traffic Impacts: Traffic comments were related to the number of trips, safety concerns with access points near the intersection of 1001h Avenue W and 2381h Street SW, potential access to 10151 Avenue W and site distance concerns with fencing and landscaping along 101st Avenue W. Staff Response: A traffic impact analysis for the proposal was prepared by Gibson Traffic Consultants and reviewed by the City of Edmonds' Traffic Engineer. Regarding the number of trips generated by the development, the project would not alter the level of service (a measure used to evaluate traffic impacts in the City's Transportation Plan) of the intersection at 100th Avenue W and 238th Street SW, which is at a LOS A the best rating for intersections. The access points on 100th Avenue W and 238th Street SW were also evaluated and determined to be appropriate and would improve safety with the removal of the driveway cut along 238th Street SW closest to 100th Avenue W. To minimize impacts to the residential neighborhood along 101St Avenue W, the development will not have vehicular access from 101St Avenue W. During building permit review, fencing and vegetation will be reviewed to ensure proposed located do not create sight distance issues for vehicles exiting 1015t Avenue W. Parking: Parking concerns were regarding both the amount of parking provided with the development and potential impacts of other developments in the area no longer being able to use the site for parking. Staff Response: Off-street parking requirements are established in Chapter 17.50 ECDC. There is sufficient parking provided to meet the requirements of Chapter 17.50 ECDC for an office building with a mixed of uses that provide on -site customer service and office uses which do not provide on -site customer service. See Section VIII.B of this staff report for an analysis of the parking requirements. The project site is not required to provide parking for other off -site uses in the neighborhood. Landscaping: Comments on landscaping questioned whether the proposed landscaping provided sufficient screening for the neighborhood and lack of native plants. PLN2020-0040 Woodway Station Design Review Page 4 of 18 Packet Pg. 10 5.1.a Staff Response: Landscaping requirements are provided in Chapter 20.13 ECDC. The BN zone requires the setback from residential zoned property to be fully landscaped and Type I landscaping, which is intended to provide a dense site barrier is provided along the northern property boundary. Type IV landscaping is generally required along commercial street frontages to provide visual relief. Three trees are proposed along the western side of the building to screen the building from the neighborhood. Staff will add a suggested condition of approval that these trees be evergreen trees to provide a greater screening function from the neighborhood. Development Impacts: The development impacts comments were focused on the disruption to the neighborhood during construction of the site. Staff Response: City regulations restrict construction related noise to the hours of 7am- 6pm M-F and 10am-6pm on Saturdays. Activity that exceeds allowable noise levels is not permissible on Sundays and Federal Holidays. A pre -construction meeting will be held with the developer prior to the start of construction. Discussions will be had at that time to help minimize impacts to the neighborhood and ensure proper coordination/communication for any street or utility disturbances. Contamination: During the SEPA comment period, the Department of Ecology noted potential for contamination at the site. In support of the SEPA documentation, the applicants submitted a no further action required letter from Ecology, but this was only addressed the removal of the underground storage tanks used for the former gas station. Ecology noted there may be other contamination on the site (Attachment 22). Staff Response: The comment from Ecology has been provided to the applicant and it will be the responsibility of the applicant to comply with Model Toxics Control Act and providing documentation to Ecology during development of the site. VI. TECHNICAL COMMITTEE This application was reviewed by South County Fire and the Engineering and Building Divisions of the Development Services Department. The Building Division did not have any specific comments on the design review application. Compliance with all applicable building codes will be reviewed under the building permit application review. South County approved the design review of the project and provided the following additional comments which will be reviewed with the building permit review (Attachment 23): 1. Fire Sprinkler and Fire Alarm required, separate permits. 2. Required an additional hydrant at site and within 50 feet of new FDC 3. Riser room needs an outside entrance, FDC within 50 feet of hydrant 4. Signing and/or stripping "NO PARKING FIRE LANE" in parking area PLN2020-0040 Woodway Station Design Review Page 5 of 18 Packet Pg. 11 5.1.a 5. Knox key box entry The Engineering Division noted that the proposal is consistent with Title 18 ECDC and the City's Engineering Standards (Attachment 24). Compliance with Engineering codes and construction standards will be further reviewed with the building permit application for development of the site. Approval of the design review phase of the project does not constitute approval of the improvements as shown on the submitted plans. Additional comments are provided in Engineering's memorandum to provide guidance to the application when construction plans are prepared. VII. COMPREHENSIVE PLAN The Comprehensive Plan designation for the site is "Neighborhood Commercial." Neighborhood Commercial areas are intended to provide a mix of services, shopping, gathering places, office space and housing for local neighborhoods. The current project is subject to General Design Review as outlined in Chapter 20.11 ECDC. One of the findings required by ECDC 20.11.020 is that the proposal is consistent with the design guidelines provide in the Urban Design Chapter of the Comprehensive Plan. Below is a detailed analysis on how the proposal complies with the goals and objectives for site design, building form, and building facade contained in the Comprehensive Plan's Urban Design Chapter. Comprehensive Plan Urban Design Objectives Design Objectives for Site Design. The development of parking lots, pedestrian walkways and landscaping features is an integral part of how a building interacts with its site and its surrounding environment. Good design and site planning improves access by pedestrians, bicycles and automobiles, minimizes potential negative impacts to adjacent development, reinforces the character and activities within a district and builds a more cohesive and coherent physical environment. A.1 Vehicular Access. Reduce the numbers and width of driveways (curb cuts) in order to improve pedestrian, bicycle and auto safety. Staff Findings: The are currently three driveways which provide access to the site two on 238th Street SW and one from 100th Avenue W. Additionally, the property can currently be accessed from 101St Avenue W along the entire length of the property. The proposed development will provide two vehicle access points, one off 238th Street SW and one off 100th Avenue W. Vehicle access along 101St Avenue W will be eliminated. A.2 Layout of Parking. Locating buildings in proximity to the street to facilitate direct pedestrian access and help define the street edge. Parking should be placed to the side and rear. Staff Findings: The property is surrounded by streets on three sides and residential property on the fourth. To facilitate safe and efficient traffic flow while minimizing impact to the residential neighborhood on 101st Avenue W, the parking lot and access points are PLN2020-0040 Woodway Station Design Review Page 6 of 18 Packet Pg. 12 5.1.a placed along 2381" Street SW and 100t" Avenue W. The building placement complies with the required zoning setbacks. A.3 Connections On- and Offsite. Design site access and circulation within and between sites to encourage linkages for pedestrians, vehicles, and bicycles. Special attention should be paid to providing and improving connections to transit. Staff Findings: The subject property is one of three disconnected commercial properties in the area (Attachment 12). Connection between the commercial properties is not possible and connection the single-family neighborhood not desirable. A pedestrian connection to the 100t" Avenue W sidewalk is provided which will allow easy access to and from the bus stop located just north of the site on 100t" Avenue W. A.4 Building Entry Location. Building entries should be configured to provide clear entry points to buildings, be oriented to pedestrian walkways/pathways, and support the overall intent of the streetscape environment. Space at the entry for gathering or seating is desirable for residential or mixed -use buildings. Staff Findings: Clear entry points are provided directly from the parking lot and pedestrian path from 1001" Avenue W. While not a mixed -use building, space is provided at the entry for gathering or seating. A.5 Setbacks. Create and maintain the landscape and site characteristics of each neighborhood area and provide a common street frontage tying each site to its neighbor. Setbacks should be appropriate to the desired streetscape, providing for transition areas between public streets and private building entries where a variety of activities and amenities can occur. Staff Findings: Project meets the setbacks requirements for the zone and landscaping is provided within and around the perimeter of the development consistent with the requirements of Chapter 20.13 ECDC. A.6 Open Space. For residential settings, create green spaces to enhance the visual attributes of the development and provide places for interaction, play, seating, and other activities. Staff Findings: The proposed development is not a residential development. Landscaping adjacent to the residential neighborhood is intended to screen the development from the residential properties. The addition of landscaping to the site, which currently is nearly 100% hardscape, will help soften the appearance of the by creating some green spaces. A.7 Building/Site Identity. Improve pedestrian access and way finding by providing variety in building forms, colors, materials and individuality of buildings. Staff Findings: One building is proposed on the side. Way -finding is enhanced by the color scheme of the building with red entry canopy over the primary entrance to the building. A.8 Weather Protection. Provide covered walkways and entries for pedestrian weather protection. PLN2020-0040 Woodway Station Design Review Page 7 of 18 Packet Pg. 13 5.1.a Staff Findings: Covered entries are provided. A.9 Lighting. Provide adequate and appropriate illumination in all areas used by automobiles, bicycles and pedestrians — including building entries, walkways, parking areas, circulation areas and other open spaces — to support activity and security. Staff Findings: Site lighting details were not provided with the application materials. A.10 Signage. Encourage signage that provides clear information and direction for properties and businesses while preventing the streetscape from becoming cluttered. Encourage the use of graphics and symbols in signage to support the city's emphasis on uniqueness and the arts. Staff Findings: No signage proposed at this time. Signs will be subject to building permit review and compliance with Chapter 20.60 ECDC. A.11 Site Utilities, Storage, Trash and Mechanical Systems. Minimize the noise, odor and visual impacts of utility systems using such features as landscaping, building forms, or integrated design. Staff Findings: A trash enclosure with six-foot tall fence is provided on the western side of the property. A.12 Integrating Site Features. Integrate natural landscape features and unique landforms — such as rocky outcroppings or significant trees — into site design whenever possible. Staff Findings: No significant features exist on the site. A.13 Landscape Buffers. Use landscaping and/or other features such as fences to maintain privacy and create a visual barrier between incompatible uses. These buffering techniques should also be used to soften hard edges (such as the perimeters of parking lots) and reinforce pedestrian ways and circulation routes. Native plants and rain gardens should be promoted as alternatives to lawns and runoff retention areas. Staff Findings: Landscaping is provided consistent with the requirements of Chapter 20.13 ECDC. See the discussion on landscaping in Section VIII.D below. A new six-foot fence will be provided along the western and northern property boundaries and landscaping with further help screen the screen and soften its appearance. The project also includes a rain garden in the southeast corner of the development. Design Objectives for Building Form. Building height and modulation guidelines are essential to create diversity in building forms, minimize shadows cast by taller buildings upon the pedestrian areas and to ensure compliance with policies in the city's Comprehensive Plan. Protecting views from public parks and building entries as well as street views to the mountains and Puget Sound are an important part of Edmonds character and urban form. PLN2020-0040 Woodway Station Design Review Page 8 of 18 Packet Pg. 14 5.1.a A.14 Building Form. Encourage new construction to avoid repetitive, monotonous building forms. Staff Findings: The proposed building is not repetitive or monotonous. Varying colors and materials help break up the building form. A.15 Massing. Reduce the apparent bulk and mass of buildings by encouraging human scale elements in building design and/or by subdividing building masses vertically or horizontally. Staff Findings: Bulk and mass of the building is reduced through use of materials, colors, and building form subdividing the building both vertically and horizontally. A.16 Roof Modulation. Use roof forms to help identify different programs or functional areas within the building and support differentiation of building form and massing. Roof design, in combination with wall modulation, can allow for additional light to enter buildings or pedestrian spaces. Staff Findings: The building's roofline while not modulated vertically, but some variation to the roofline is provided by wall modulation. The roof overhangs the eastern and southern facades providing weather protection and juts out with the second story cantilever on the eastern facade. The roofline also has a notch in the southwest corner behind the stairwell on the southern facade. A.17 Wall Modulation. Variation in materials, decorative elements, or other features should be employed to support pedestrian scale environments and streetscapes, or to help break up large building masses to keep in scale with the surrounding environment. Staff Findings: The proposed buildings provide variation in colors, materials and projections that help break of the masses of the buildings both vertically and horizontally. Design Objectives for Building FaVade. Building facade objectives ensure that the exterior of a building — the portion of a building that defines the character and visual appearance of a place — is of high quality and demonstrates the strong sense of place and integrity valued by the residents of the City of Edmonds. A.18 Building Fagade Design. Encourage building fagades that reinforce the appearance and consistency of streetscape patterns while supporting diversity and identity in building design. Staff Findings: The proposed building will add some diversity to the small neighborhood commercial area which currently consists of a commercial garage, a single-family structure converted to a hair salon, and the existing former gas station/convenience store. A.19 Window Variety and Articulation. Use window size and placement to help define the scale and character of the building. Use the organization and combinations of window types to reinforce the streetscape character or to provide variation in a fagade, as well as provide light and air to the building interior. PLN2020-0040 Woodway Station Design Review Page 9 of 18 Packet Pg. 15 5.1.a Staff Findings: The eastern and southern facade contain a significant expanse of windows. The ground floor commercial space has windows that extend from the floor to the ceiling. Windows on the second floor extend up to the roof line above a horizontal band of metal side that separates the ground floor from the second story. Less expansive, but still significant fenestration is provided on the eastern and north facades of the building. A.20 Variation in Facade Materials. Employ variation in materials, colors or design elements on building fagades to help define the scale and style of the structure. Variation in fagade materials can help reduce the apparent bulk of larger buildings while allowing variety and individuality of building design. Staff Findings: The proposed buildings provide variation in colors, materials and projections that help break of the bulk of the buildings both vertically and horizontally. A. Chapter 16.45 ECDC — Neighborhood Business: The subject property is located with the Neighborhood Business zone and subject to the development standards of Chapter 16.45 ECDC. ECDC 16.45.010 Uses Staff Findings: Allowed uses in the BN are identified in ECDC 16.45.010. While specific uses have not been identified in the application, the proposal is for the construction of an office building. Office uses are listed as a permitted primary use pursuant to ECDC 16.45.010.A.3, so the proposed development is consistent with the allowed uses of the BN zone. The specific uses will be reviewed for compliance with BN use requirements with business licenses and tenant improvement applications. ECDC 16.45.020 Development Standards Minimum Minimum Minimum Maximum Maximum Floor Area Zone Street Side Rear Height Setback Setback Setback BN 20' None' None' 25' 3 sq. ft. per sq. ft. of lot area 'Fifteen feet from lot lines adjacent to R-zoned property. Staff Findings — Setbacks: The subject property is a corner lot with street setbacks on three sides from 10151 Avenue W, 238t" Street SW, and 1001" Avenue West. The northern property line is adjacent to RS-8 zoned property (Attachment 12) that will require a 15-foot setback according to footnote 1 in the ECDC 16.45.020 Development Standards table. The proposed building is at least 20 feet from all property lines fronting the streets and 15 feet from the adjacent RS-8 zoned property to the north. ECDC 16.45.020.D also notes the required setback from R-zoned property shall be permanently landscaped with trees and ground cover and permanently maintained PLN2020-0040 Woodway Station Design Review Page 10 of 18 Packet Pg. 16 5.1.a by the owner of the BN lot. A six-foot minimum height fence, wall or solid hedge shall be provided at some point in the setback. See Section VIII.D of this staff report of a discussion of the required landscaping. Staff Findings — Height: The building is proposed to be 24'-6" in height (Attachment 4, Sheets 13 and 14). The elevation views show an elevator overrun extending above the 25-foot height limit. A height exception is provided for elevator overruns in the definition of height in ECDC 21.40.030 that are not exceed 72 square feet in horizontal section or three feet in height for that portion above the height limit. The proposal appears to comply with the height requirements and height will be verified at building permit application review. Staff Findings — Maximum Floor Area: With a lot area of 21,506 square feet, the maximum floor area allowed on the property is 64,518 square feet. At approximately 11, 000 square feet the proposed building will be well below the maximum floor area. B. ECDC 17.50.020 — Off -Street Parking Regulations Off-street parking requirements for business uses are provided in ECDC 17.50.020. Office uses have two potential parking requirements. For business and professional offices with on -site customer service, one space per 400 square feet is required. For offices not providing on -site customer service, one space per 800 square feet is required. In accordance with ECDC 17.50.030 (Parking Calculations), when there are different uses on the same site, when calculating the park requirements for different uses on the same site, the parking requirements is the sum of all requirements for the individual uses, reduced by any applicable joint use provisions. At 11,000 the total number of spaces required if the site were occupied by businesses is 28 parking spaces (11,000 sq. ft./400). Since only 22 parking spaces will be provided with the development, the office space in the building cannot be rented out entirely to businesses providing on -site customer service. However, the office space may be rented to a mix of offices that provide on -site customer service and offices that do not or completing to office uses that do not provide on -site customer service. Compliance with overall parking requirements will be conducted with business license review. For the purposes of this design review application, it appears adequate parking is provide for a mixed use office building. The proposal is consistent with the off-street parking requirements of Chapter 17.50 ECDC. C. Chapter 20.11 ECDC —General Design Review ECDC 20.11.010 requires the ADB to review general design review applications that trigger SEPA. ECDC 20.11.030 lists the criteria for Building Design and Site Treatment that must be met. ECDC 20.11.030.A Building Design. No one architectural style is required. The building shall be designed to comply with the purposes of this chapter and to avoid conflict with PLN2020-0040 Woodway Station Design Review Page 11 of 18 Packet Pg. 17 5.1.a the existing and planned character of the nearby area. All elements of building design shall form an integrated development, harmonious in scale, line and mass. The following are included as elements of building design: 1. All exterior building components, including windows, doors, eaves, and parapets, 2. Colors, which should avoid excessive brilliance or brightness except where that would enhance the character of the area, Staff Findings: The proposed colors scheme avoids excessive brilliance or brightness (Attachment 4). 3. Mechanical equipment or other utility hardware on the roof, grounds or buildings should be screened from view from the street level; Staff Findings: Mechanical equipment is not depicted in the design review packet. This criterion is added as a suggest condition of approval. 4. Long, massive, unbroken or monotonous buildings shall be avoided in order to comply with the purposes of this chapter and the design objectives of the comprehensive plan. Staff Findings: The proposed buildings provide variation in colors, materials and projections that help break of the bulk of the buildings both vertically and horizontally. 5. All signs should conform to the general design theme of the development. Staff Findings: The proposed development does not currently propose any signage. Any signage will be reviewed under a subsequent building permit application for compliance with Chapter 20.60 ECDC. ECDC 20.11.030.8 Site Treatment. The existing character of the site and the nearby area should be the starting point for the design of the building and all site treatment. The following are elements of site treatment: 1. Grading, vegetation removal and other changes to the site shall be minimized where natural beauty exists. Large cut and fill and impervious surfaces should be avoided. Staff Findings: The site is relatively flat and with little vegetation or any natural beauty. Little grading should be required with the development and installation of the landscape will decrease impervious surface from existing conditions. 2. Landscape treatment shall be provided to enhance the building design and other site improvements. Staff Findings: Landscaping consistent with the requirements of Chapter 20.13 ECDC is being provided with the development. See the discussion on landscaping requirements in Section VIILD below and Attachment 6. PLN2020-0040 Woodway Station Design Review Page 12 of 18 Packet Pg. 18 5.1.a 3. Landscape treatment shall be provided to buffer the development from surrounding property where conflict may result, such as parking facilities near yard spaces, streets or residential units, and different building heights, design or color. Staff Findings: Landscaping is being provided consistent with Chapter 20.13 ECDC and will provide buffers from surrounding properties and soften and shade the parking area. The site is located next to a residential neighborhood. While dense Type I landscaping is provided along the northern property line to screen the developed from the adjacent single-family property, the landscaping along the western side of the building should also provide evergreen trees to help screen the building from the residential street. This has been added as a recommended condition of approval. 4. Landscaping that could be damaged by pedestrians or vehicles should be protected by curbing or similar devices. Staff Findings: Landscaping within the surface parking area will be protected by curbing. 5. Service yards, and other areas where trash or litter may accumulate, shall be screened with planting or fences or walls which are compatible with natural materials. Staff Findings: There proposal includes a trash enclosure one the western side of the development which will be screen by a six-foot fence. 6. All screening should be effective in the winter as well as the summer. Staff Findings: The primary screening portion of the landscaping is along the northern property boundary separating the commercial site from the single-family zoned property. Landscaping along this border consists of two rows of evergreen trees as well as a six-foot fence all of which will provide year-round screening. Additionally, the six-foot fence on 101st Avenue W will provide further screening of the site from the residential neighborhood. 7. Materials such as wood, brick, stone and gravel (as opposed to asphalt or concrete) maybe substituted for planting in areas unsuitable for plant growth. Staff Findings: Not applicable. 8. Exterior lighting shall be the minimum necessary for safety and security. Excessive brightness shall be avoided. All lighting shall be low-rise and directed downward onto the site. Lighting standards and patterns shall be compatible with the overall design theme. Staff Findings: Site lighting details were not provided with the application materials. PLN2020-0040 Woodway Station Design Review Page 13 of 18 Packet Pg. 19 5.1.a ECDC 20.11.030(C) Other Criteria. 1. Community facilities and public or quasi -public improvements should not conflict with the existing and planned character of the nearby area. Staff Findings: The proposed building is not a community facility. 2. Street furniture (including but not limited to benches, light standards, utility poles, newspaper stands, bus shelters, planters, traffic signs and signals, guardrails, rockeries, walls, mail boxes, fire hydrants and garbage cans) should be compatible with the existing and planned character of the nearby area. Staff Findings: No specific street furniture is proposed or required. Staff finds the proposal is consistent with the design standards of ECDC 20.11.030. D. Chapter 20.13 ECDC — Landscape Requirements Chapter 20.13 ECDC contains specific landscaping requirements for new developments, which the ADB and Hearing Examiner are allowed to interpret and modify according to ECDC 20.13.000. Three types of landscaping are required for the proposed develop. Type I landscaping is required along the northern property boundary to screen the development from the adjacent residential property; Type IV landscaping is required along the street frontages and Type V landscaping is required within the surface parking area. ECDC 20.13.030 provides the requirements for each landscaping type. The landscaping plan is provided in Attachment 6. Type 1 Landscaping. Type 1 landscaping is intended to provide a very dense sight barrier to significantly separate uses and land use districts. 1. Two rows of evergreen trees, a minimum of 10 feet in height and planted at intervals of no greater than 20 feet on center. The trees must be backed by a sight - obscuring fence a minimum of five feet high or the required width of the planting area must be increased by 10 feet; and 2. Shrubs a minimum of three and one-half feet in height planted in an area at least five feet in width, and other plant materials, planted so that the ground will be covered within three years, 3. Alternatively, the trees and shrubs may be planted on an earthen berm at least 15 feet in width and an average of five feet high along its midline. Staff Findings: Type I landscaping is required along the northern property boundary to provide a dense barrier between the subject property and the residentially zoned property to the north. ECDC 16.45.020 requires a 15-foot setback from residentially zoned properties and ECDC 16.45.020 notes that the setback shall be permeantnely landscaped within trees and ground cover and that a wall, hedge or fence shall be provided at some point in the setback. A six-foot fence is provide at the property boundary and landscaping in the setback is consistent with the Type I landscaping requirements. PLN2020-0040 Woodway Station Design Review Page 14 of 18 Packet Pg. 20 5.1.a Type IV Landscaping. Type IV landscaping is intended to provide visual relief where clear sight is desired to see signage or into adjacent space for safety concerns. 1. Trees shall be deciduous and planted 25 feet on center and the trunk shall be free of branches below six feet in height. 2. Plant materials which will cover the ground within three years, and which will not exceed three and one-half feet in height. Staff Findings: Landscaping consistent with the requirements of Type IV landscaping is provided along the eastern, western, and southern property boundaries. Also consistent with ECDC 20.13.020.J, landscaping is provided between the property line and street edge along 10151 Avenue W. To provide greater screening function from 101st Avenue W, the trees along the western side of the building should be evergreen species. Type V Landscaping. Type V landscaping is intended to provide visual relief and shade in parking areas. 1. Required Amount. a. If the parking area contains no more than 50 parking spaces, at least 17.5 square feet of landscape development must be provided as described in subsection (E)(2) of this section for each parking stall proposed. b. If the parking area contains more than 99 parking spaces, at least 35 square feet of landscape development must be provided as described in subsection (E)(2) of this section for each parking stall proposed. c. If the parking area contains more than 50 but less than 100 parking spaces, the director— or his designee —shall determine the required amount of landscaping by interpolating between 17.5 and 35 square feet for each parking stall proposed. The area must be landscaped as described in subsection (E)(2) of this section. 2. Design. a. Each area of landscaping must contain at least 150 square feet of area and must be at least four feet in any direction exclusive of vehicle overhang. The area must contain at least one tree a minimum of six feet in height and with a minimum size of one and one-half inches in caliper if deciduous. The remaining ground area must be landscaped with plant materials, decorative mulch or unit pavers. b. A landscaped area must be placed at the interior ends of each parking row in a multiple lane parking area. This area must be at least four feet wide and must extend the length of the adjacent parking stall. c. Up to 100 percent of the trees proposed for the parking area maybe deciduous. d. Bioswales integrated into parking lot designs are strongly encouraged. PLN2020-0040 Woodway Station Design Review Page 15 of 18 Packet Pg. 21 5.1.a e. The minimum area per planter is 64 square feet. f. The maximum area per planter is 1,500 square feet for parking lots greater than 12,000 square feet. Planters shall be spread throughout the parking lot. g. Shade trees are required at the rate of a minimum of one per planter and/or one per 150 square feet of planter. Staff Findings: With 22 parking spaces provided in the surface parking area 385 square feet of Type V landscaping is required. The proposal includes 562 square feet of landscaping meeting the Type V landscape requirements in seven landscaping islands within the surface parking area. Staff finds the proposal is consistent with the intent and requirements of the landscaping requirements of ECDC 20.13. IX. CONCLUSION AND RECOMMENDATION Pursuant to ECDC 20.11.020, when recommending approval of proposed development applications, the ADB must find that the proposed development is consistent with the criteria listed in ECDC 20.11.030 (General Design Review), the Comprehensive Plan, and the zoning ordinance. Based on findings, analysis, conclusions, and attachments within this report, staff recommends that the ADB APPROVE the design for the proposed development under file number PLN2020-0040 with the following motion and recommended conditions of approval: THE ARCHITECTURAL DESIGN BOARD ADOPTS THE FINDINGS, CONCLUSION, AND ANALYSIS OF THE STAFF REPORT AND FINDS THE PROPOSAL IS CONSISTENT WITH THE COMPREHENSIVE PLAN, POLICIES OF ECDC 20.10, DESIGN CRITERIA OF ECDC 20.11.030, AND ZONING REGIULATIONS AND APPROVES THE DESIGN OF THE PROPOSED SINGLE- FAMILY HOMES WITH THE FOLLOWING CONDITIONS: 1. THE APPLICANT MUST OBTAIN ALL NECESSARY PERMITS. THIS APPLICATION IS SUBJECT TO THE REQUIREMENTS IN THE EDMONDS COMMUNITY DEVELOPMENT CODE AND IT IS UP TO THE APPLICANT TO ENSURE COMPLIANCE WITH VARIOUS PROVISIONS CONTAINED IN THESE CODES. 2. STAFF WILL VERIFY COMPLIANCE OF THE PROPOSAL WITH ALL RELEVANT CODES AND LAND USE PERMIT CONDITIONS THROUGH REVIEW OF BUILDING AND ENGINEERING PERMITS. MINOR CHANGES TO THE APPROVED DESIGN MAY BE APPROVED BY STAFF AT THE TIME OF BUILDING PERMIT WITHOUT FURTHER DESIGN REVIEW BY THE BOARD AS LONG AS THE DESIGN IS SUBSTANTIALLY SIMILAR TO THAT ORIGINALLY APPROVED. 3. TO PROVIDE A MORE EFFECTIVE SCREEN FOR THE RESIDENTIAL NEIGHBORHOOD ON THE WEST SIDE OF THE DEVELOPMENT, THE PROPOSED TREES ON THE WEST SIDE OF THE BUILDING MUST BE EVERGREEN SPECIES. PLN2020-0040 Woodway Station Design Review Page 16 of 18 Packet Pg. 22 5.1.a XI. 4. MECHANICAL EQUIPMENT OR OTHER UTILITY HARDWARE ON THE ROOF, GROUNDS OR BUILDINGS SHOULD BE SCREENED FROM VIEW FROM THE STREET LEVEL. APPEALS According to ECDC 20.01.003.13 and 20.06.150, Type III -A decisions are not administratively appealable but rather subject to LUPA appeal at Snohomish County superior court pursuant to Chapter 36.70C RCW. LAPSE OF APPROVAL According to ECDC 20.11.050.A, unless the owner submits a fully completed building permit application necessary to bring about the approved alterations, or, if no building permit application is required, substantially commences the use allowed within 18 months from the date of approval, ADB or hearing examiner approval shall expire and be null and void, unless the owner files a fully completed application for an extension of time prior to the expiration date. For the purposes of this section the date of approval shall be the date on which the ADB's or hearing examiner's minutes or other method of conveying the final written decision of the ADB or hearing examiner as adopted are mailed to the applicant. In the event of appeal, the date of approval shall be the date on which a final decision is entered by the city council or court of competent jurisdiction. XII. PARTIES OF RECORD City of Edmonds 121— 5tn Ave N. Edmonds, WA 98020 Carl Pirscher CDA Pirscher Architects 23114 100t" Avenue Edmonds, WA 98020 Danielle Hursh 23627 1015t Avenue W Edmonds, WA 98020 Vanessa Mark sessamark@gmail.com Red Sea Properties, LLC 15423 36th Ave SE Bothel, WA 98012 Sue Frodsham 23626 101St Avenue W Edmonds, WA 98020 Chris Johnson chrisi4@frontier.com Killy Keefe 23627 10151 Avenue W Edmonds, WA 98020 PLN2020-0040 Woodway Station Design Review Page 17 of 18 Packet Pg. 23 5.1.a Kristine Wear 23633 101s' Avenue W Edmonds, WA 98220 PLN2020-0040 Woodway Station Design Review Page 18 of 18 Packet Pg. 24 5.1.a City of Edmonds RECEIVED Land Use Application ARCHITECTURAL DESIGN REVIEW COMPREHENSIVE PLAN AMENDMENT CONDITIONAL USE PERMIT HOME OCCUPATION FORMAL SUBDIVISION SHORT SUBDIVISION LOT LINE ADJUSTMENT PLANNED RESIDENTIAL DEVELOPMENT OFFICIAL STREET MAP AMENDMENT STREET VACATION REzoNE SHORELINE PERMIT VARIANCE / REASONABLE USE EXCEPTION OTHER: FILE # PLN2020-0040 DATE August 4, 2020 LONE IN REC'DBY Kernen FEE $2,780 RECEIPT # HEARING DATE. ❑ HL ❑ STAFF ❑ PB 0 ADB ❑ CC e PLEASE NOTE THAT ALL INFORMATI DA' CONTAINED WITHIN THE APPLI CATION IS A PUBLIC RECORD • PROPERTY ADDRESS OR LOCATION 23726 100th Ave W EDMONDS WA 98020 PROJECT NAME (IFAPPLICABLE) WOODWAY STATION PROPERTYOWNER RED SEA PROPERTIES, LLC PHONE# 206-391-0529 ADDRESS 15423 36TH AVE SE BOTHELL, WA 98012 E-mAI, AMCHE BINI@HOTMAIL.COM FAx# TAx ACCOUNT # 27033600400500 SEC. TWP. RNG. DESCRIPTION OF PROJECT OR PROPOSED USE (ATTACH COVER LETTER AS NECESSARY) Demolish existing_gas station convenience store and construct a new approximately 11 188 GSF (2) story structure devoted primarily to general office uses. DESCRIBE HOW THE PROJECT IhtEETS APPLICABLE CODES (ATTACH COVER LETTER AS NECESSARY) CONFORMS WITH ALL ZONING AND DESIGN GUIDELINES INCLUDING HEIGHT SETBACKS, PARKING, ETC APPLICANT CARL PIRSCHER PHONE 206-368-9668 ADDRESS 23114 100TH AVE W EDMONDS, WA 98020 E-MAIL CARLP@CDAARCH.COM FAx# CONTACT PERSON/AGENT CARL PIRSCHER PHONE# ADDRESS 23114 100TH AVE W EDMONDS, WA 98020 E-MAIL CARLP@CDAARCH.COM FAx# 206-368-9668 The undersigned applicant, and his/her/its heirs, and assigns, in consideration on the processing of the application agrees to release, indemnify, defend and hold the City of Edmonds harmless from any and all damages, including reasonable attorney's fees, arising from any action or infraction based in whole or part upon false, misleading, inaccurate or incomplete information furnished by the applicant, his/her/its agents or employees. By my signature, I certify that the information and exhibits herewith submitted are true and correct to the best of my knowledge and that I am authorized to file this application on the behalf of the owner as listed below. 8/4/20 SIGNATURE. OF APPLICANT/AGENT t' h DATE Property Owner's Authorisation I certify under the penalty of perjury under the laws of the State of Washington that the following is a true and correct statement: I have authorized the above Applicant/Agent to apply for the subject land use application, and grant my permission for the public offioials and the staff of the City of Edmonds to enter the subject property for the p spcction and pos ' g attendant to this application. SIGNATURE OF OWNER DATE Questions? Call (425) 771-0220. Revised on 8122112 B - Land Use Application Pas e I r l' I Attachment 1 Packet Pg. 25 5.1.a P I R S C H E R ARCHITECTS A R C H I T E C T S I August 4, 2020 City of Edmonds Development Services Department Attn: Kernen Lien 121 5th Ave N Edmonds, WA 98020 PROJECT: Woodway Station CDA# 20016 N T E R 1 O R S P L A N N E R S SUBJECT: Project Description/ Cover letter Dear Kernen Lien: PROJECT DESCRIPTION EXISTING SITE & CONTEXT: The subject property is located at 23726 100th Avenue West in Edmonds, Washington. The property consists of one nearly rectangular parcel (no. 27033600400500) with a total area of about 21,506 square feet. The central portion of the property is developed with a former convenience store/gas station building with asphalt and concrete paved areas surrounding the building. The site has local vegetated and graveled areas along some of the property margins. The site is nearly level to very slightly sloping downward from north to south with relief of about 4 feet. The western margin slopes downward to the west. F:\JOBS\20016 Woodway Station H-Edmonds\Word\City\Application\Woodway Project Description.doc Carl F. Pirscher, ALA principal 23114100 AVE Edmonds, Washington 98020 Tel: (206)-368-9668 c 0 �a �a 3 0 0 0 v 0 0 0 N O N Z J a Attachment 2 Packet Pg. 26 5.1.a There has been underground storage tank (ust) removal near the building (east side). Environmental assessment reports have been provided as part of this design review packet. The site is bordered to the North by a residential property, to the West by 101 st Avenue West, to the East by 100th Avenue West, and to the South by 238th Street SW. THE PROPOSED PROJECT DESCRIPTION - SITE The proposed project is to consist of a two (2) story office building with at -grade parking for 23 stalls. The overall building occupied square footage is broken down as follows: 1. First floor = 5,353 gsf (footprint) 2. Second floor = 5,613 gsf Total = 10,966 gsf As noted earlier, the site area is 21,506 sf. The coverage ratio of building to site area is (10,966 / 21,506) 51%. The ratio of pervious area to impervious area (16,271 sf of building footprint plus "hard" surfaces to 5,235 sf of landscaped surfaces) is 76% impervious surface area and 24% landscape area. As noted above, the site is nearly level and we are proposing to locate the new building in a similar location to the existing structure that is to be demolished. We are proposing extensive enhancement to the proposed site landscaping which will exceed that of most neighboring properties. This will include pedestrian scale landscaping along 100th ave w (see attached landscape plan), and proper screening of refuse at the rear. THE PROPOSED PROJECT DESCRIPTION - BUILDING The design of the building exterior seeks to compliment nearby structures and at the same time is consistent with the site development standards for the Neighborhood Business zone within the ECDC. The proposed two story building stays below the maximum 25' height limit. The building proposes materials of brick veneer cladding, horizontal metal siding, extensive storefront glazing and accents of metal panel siding as noted in the color renderings. F:\JOBS\20016 Woodway Station H-Edmonds\Word\City\Application\Woodway Project Description.doc Carl F. Pirscher, ALA principal 23114100 AVE Edmonds, Washington 98020 Tel: (206)-368-9668 Attachment 2 Packet Pg. 27 5.1.a Pedestrian views into the ground floor commercial space are considered important therefore a large portion of it is comprised of storefront. The main entrance along the frontage are weather protected by a 4' deep overhang. Window frames are proposed to be anodized aluminum and all window and door frames will be trimmed with metal trim pieces. Please do not hesitate to call if you have any questions. Sincerely, CDA + PIRSCHER ARCHITECTS, INC. Michael DeMarco Associate Architect F:\JOBS\20016 Woodway Station H-Edmonds\Word\City\Application\Woodway Project Description.doc Carl F. Pirscher, ALA principal 23114100 AVE Edmonds, Washington 98020 Tel: (206)-368-9668 Attachment 2 Packet Pg. 28 5.1.a R ZONING;r [DATA SITE ADDRESS: PARCEL ID: LEGAL DESCRIPTION: 23126 100TH AVE. W EDMONDS, WA SW20 0210336-004-005-00 PRESENT ZONING- BN - NEIGHBORHOOD BUSINESS COMP. PLAN DESIGNATION COMMERCIAL SITE AREA: EXISTING USE: PROPOSED USE: MIN STREET SETBACK: REAR YARD SETBACK: SIDE YARD SETBACK: MAX FLOOR AREA: FLOOR AREA PROPOSED: BUILDING HEIGHT (MAX.): STORIES (MAX): - ..7012291 STANDARD STALL = COMPACT STALL = PROVIDED: 22 STALLS 21,506 SF (PER SURVEY) GAS STATION/ RETAIL COMMERCIAL NEIGHBORHOOD BUSINESS 20' 0' (MIN 15' ADJACENT TO R-ZONING) 0' (MIN 15' ADJACENT TO R-ZONING) 3 SF PER SF OF LOT AREA = 64,518 SF FIRST FLOOR 5,434 GSF SECOND FLOOR 5,134 GSF TOTAL 25' 2 8.5'x16.5' 8'x16' Sf TE a 238TH ST SW D r m m A 11,168 GSF 23 -7rN A sw 238TH ST SW N I T �'AP I I I I I )446700000300 I I I I I I -----------� I I I® I I I 446700000200 I, I I I I I I I I )446700000100 I® I I I I I�— CB RIM=352.34 IE 12' CPP E =-W.14 IE 12' CPP((S)=348.14 a 16' 30' 0044 I 1 / I .00 123715 HOUSE J y ► I• DISK & PUNCH AT I l,/ \:�� .7 I 1141 �� `r— / I ► • y: �� a► I a1, • 731 ` lJ�di®ewNowr fiw��� j� .! 1 i i1 ���I � I I�� •-� y Off] I I ,_ 11111111111 -�--. . All 1 1 1 I /IIII i 1 ��©ate �`' ..,_ ����.� �: :H�,►� ,r afu Ia N�/WDIr{inG/G WALK. .°. I g EXIST. ADA RAMP d 25. N 88'13'02' W(C)(R1) 193.-2' — — — / -------EH---------- rFOUN0 1' IRON PIPE FOUND RE84R W/ILLEGIBLE 10.2'(S) OF CORNER CAP 0.2'(S) OF CORNER / I � I � I � 00615800000100 / SITS PLAN 6cALE: P = 20' -011 SCALE: 1 " = 20' 0 10' 20' 40' �� 60' SDMH RIM=36I.15 I IE 12' RCP(S)=354.65 IE IE 8' RCP(W)) 354.90 I I 237Ty W-79.00. PL. S. W. J I� v v ° c c c o� �o U U Z W Q a_ 3-- w �o N J W Q Q U v~i zf F- w N m 0 a z 0 O F- W F- F- U m U) W U) w 0 N 0 W N Q N 0 U Y Q DRAWN: N CHECK: CFF JOB NO: 1902C z O Q w C/O Q %1 OL 3 Z O 0 w of Ld N , C' V J PIRSCHER ARCH I TECT� CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 0 3 0 0 IRT CD 0 0 N Co N Z J a Attachment 3 Packet Pg. 29 5.1.a PR(DJECT OWNER/ CLIENT: RED SEA PROPERTIES, LLC 15423 3(oTH AVE SE BOTHELL, WA 58012 PHN: (20ro) 3S1-052S CONTACT: BINIAMI HASTE ARCM TECT: CDA + PIRSCHER ARCHITECTS, INC. 23114 100TH AVE L EDMONDS, WA 58155 PHN: C20(o) 368-5(o(o8 CONTACT: CARL PIRSCHER EMAIL -- CIVIL" FURR ENG31NEERING SERVICES 4-115 142ND PL SUJ #B EDMONDS, WA 5802& PHN: C20(o) 850-8251 CONTACT: DEAN FURR EMAIL: FURRENGINEERINGeGC IAIL.COM LANDSCAPE: MAIN STREET DESIGN 211 MADISON AVENUE S., SUITE 201 BAINBRIDC�E ISLAND, WA 58011 PHN: (2 00) 842 -I aa& CONTACT: KEN LONET' EMAIL: MAIN STREET�EARTHLINK.NET &URVE"�: PACIFIC COAST SURVE,I'S, INC PO BOX 13(o15 MILL CREEK, UJA DARKEN RIDDLE PHN: (425) 512 --1055 EXT 2112 CONTACT: DARKEN RIDDLE EMAIL: DARRENaPCSURVE'I'S.NET SOILS ENGR: COBALT GEOSCIENCES PO BOX 82243 KENMORE, WA Sa028 PHN: C20(o) 331-109T CONTACT: PHIL HABERMAN EMAIL: COBALTGEOeGMAIL.COM 23726 100TH AVE W EDMONDS, WA 98020 ARCce-la G-J�N'-N -OD30ARDD _Amu I BD (AD =D REV-, EW for: RED SEA PROPERTIES, LLC ..rS�r . a .' -r - :4' +£', �" ' ' :5 --- --- -_. - -i ;ai' +�c,' •c l 'ill' ) -y 3'r'' ~`+" �','r•{ I... � S r- �[]y■}�k � 1� d+ -y�' �.�4 'h'7l* i! 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'; � 'r ,l ,'.•+,r5�,,, 'li .i;: �l } - j , s� i�.'i.' 3 � ,�}.� j I :q•� i'I' ,�'. r., . • : . �„ ,�,y:a, �� _ - PIRSCHER �,� ' �I � , i' r ". ;'�-� 1.'��I'i'I �•s' ` i f IS - 1 `` i • r{ .'4: i. 1 ,�,i' , I`� 91 �i �' 4 4� }' fX P i i, 1!'h,1' J� � 11+y • Y 5, -Y.-1 li `1Ir 4 yi}i fl ✓I M7' SJ i lSV 't5 1� �• `y�'[�','f; 1 -��'r+ �'I' •,q,"��f�'i�- � � C H I T E C T S ;!. . ,�!':�,1; .,+�� '.@ ,''�,,.r�;s��l�+,', :. .. I • � .�'1+' ii�ti',1�.:.yY I, ,�S.n�lA�,k'�, tl', ,. .!S � ' � _ ..I. ICJ: . T'� t ,l { - : , L •.I.I � i� I ,4R 01 COVER SHEET 02 PROJECT NARRATIVE 03 PROJECT INFORMATION 04 ZONING INFO 05 ZONING INFO CONT. 06 VICINITY PLAN & NEARBY USES 07 VICINITY PLAN & PHOTOS 08 TOPOGRAPHIC SURVEY 09 SITE PLAN 10 PLAN - LEVEL 1 11 PLAN - LEVEL 2 12 PLAN - ROOF 13 BUILDING ELEVATIONS 14 BUILDING ELEVATIONS 15 SITE SECTION / MASS STUDY 16 PERSPECTIVE 1 17 PERSPECTIVE 2 18 PERSPECTIVE 3 19 PERSPECTIVE 4 L-1 LANDSCAPE PLAN C1.0 COVER SHEET C1.1 GENERAL NOTES C3.0 TESC PLAN C3.1 TESC DETAILS C4.0 ROAD, DRAINAGE, AND UTILITY PLAN C4.1 ROAD AND STORM DRAINAGE DETAILS lL--lklA DTF=9SCTcD HON SEC 3ro TWF 21 RGE 03 - S 1(o9FT OF N1/2 NWI/4 6E1/4 LESS TII4 PTN Ll" E OF UJ LN OF 100TII4 AVE W TGW S 1ro9FT OF E 135FT OF E1/2 NE1/4 NE1/4 6UJ1/4 LESS S 20FT FOR IRD 'VHCHNHTv.,-L.M..AP NOT TO SCALE rn 0 N O w Y 0 Q m w z O w w FZ 0 U N p V w o m o a w 0 0 -- Q N � r7 I m Y Q DRAWN: M CHECK: CFP JOB NO: 20016 Z 0 w Q Cj1 w C/) Lu } Q Q 3:: Z w C:) > r 0 0 Q �Z o 0 U (14 Lu P I R S C H E R ARCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: Attachment 4 Packet Pg. 30 5.1.a EXISTING SITE 4 CONTEXT: THE SUBJECT PROPERTY IS LOCATED AT 2312(o 100TH ,AVENUE WEST IN EDMONDS, WASHINGTON. THE PROPERTY CONSISTS OF ONE NEARLY RECTANGULAR PARCEL (NO. 21033600400500) WITH ,4 TOTAL AREA OF ,ABOUT 21,50(o SQUARE FEET. THE CENTRAL PORTION OF THE PROPERTY 15 DEVELOPED WITH A FORMER CONVENIENCE 5TORE/G,46 STATION BUILDING WITH ASPHALT AND CONCRETE PAVED AREAS SURROUNDING THE BUILDING. THE SITE HAS LOCAL VEGETATED AND GRAVELLED AREAS ALONG SOME OF THE PROPERTY MARGINS. THE SITE IS NEARLY LEVEL TO VERY SLIGHTLY SLOPING DOWNWARD FROM NORTH TO SOUTH WITH RELIEF OF ABOUT 4 FEET. THE WESTERN MARGIN SLOPES DOWNWARD TO THE WEST. THERE HAS BEEN UNDERGROUND STORAGE TANK (UST) REMOVAL NEAR THE BUILDING (EAST SIDE). ENVIRONMENTAL ASSESSMENT REPORTS HAVE BEEN PROVIDED ,AS PART OF THIS DESIGN REVIEW PACKET. THE SITE IS BORDERED TO THE NORTH BY A RESIDENTIAL PROPERTY, TO THE WEST BY 1016T ,AVENUE WEST, TO THE EAST BY 100TH AVENUE WEST, AND TO THE SOUTH BY 238TH STREET 5W. THE PROPOSED PROJECT DESCRIPTION - SITE THE PROPOSED PROJECT IS TO CONSIST OF A TWO (2) STORY OFFICE BUILDING WITH SAT -GRADE PARKING FOR 23 STALLS, THE OVERALL BUILDING OCCUPIED SQUARE FOOTAGE IS BROKEN DOWN AS FOLLOWS- -I. FIRST FLOOR = 5,353 GSF (FOOTPRINT) 2. SECOND FLOOR = 5,(013 GSF TOTAL = 10,9(0(0 GSF AS NOTED EARLIER, THE S 1 TE AREA 15 21150ro SF, THE COVERAGE RATIO OF BUILDING TO SITE AREA 15 C 10,9(oro / 21150ro) 51 ro. THE RATIO OF PERVIOUS AREA TO IMPERVIOUS AREA 0&1211 SF OF BUILDING FOOTPRINT PLUS HARD SURFACES TO 5,235 SF OF LANDSCAPED SURFACES) IS Iro% IMPERVIOUS SURFACE AREA AND 24% LANDSCAPE AREA, AS NOTED 45OVE, THE SITE IS NEARLY LEVEL AND WE ARE PROPOSING TO LOCATE THE NEW BUILDING IN A 5IMILA1;R LOCATION TO THE E X 1 ST ING STRUCTURE THAT IS TO BE DEMOLISHED. WE ARE PROPOSING E XTEN51 VE ENHANCEMENT TO THE PROPOSED SITE LAND SC,AP ING WHICH WILL EXCEED THAT OF 1" IOST NEIGH50RING PROPERTIES. THIS WILL INCLUDE PEDESTRIAN SCALE LANDSCAPING ALONG 100TH AVE W (SEE ATTACHED LANDSCAPE PLAN), AND PROPER SCREENING OF REFUSE AT THE REAR. THE PROPOSED PROJECT DESCRIPTION - BUILDING THE DESIGN OF THE BUILDING EXTERIOR SEEKS TO COMPLIMENT NEARBY STRUCTURES AND AT THE SAME TIME IS CONSISTENT WITH THE SITE DEVELOPMENT STANDARDS FOR THE NE IGH50R-IOOD BUSINESS ZONE WITHIN THE ECDC. THE PROPOSED TWO STORY BUILDING STAYS BELOW THE MAXIMUM I1" IUl" 1 25' HEIGHT LIMIT. 1IT. THE BUILDING PROPOSES MATERIALS OF BRICK VENEER CLADDING, HORIZONTAL METAL SIDING, EXTENSIVE STOREFRONT GLAZING ,AND ACCENTS OF METAL PANEL SIDING AS NOTED IN THE COLOR RENDERINGS. PEDESTRIAN VIEWS INTO THE GROUND FLOOR COMMERCIAL SPACE ARE CONSIDERED IMPORTANT THEREFORE A LARGE PORTION OF IT IS COMPRISED OF STOREFRONT, THE MAIN ENTRANCE ALONG THE FRONTAGE ARE WEATHER PROTECTED BY A 4' DEEP OVERHANG, WINDOW FRAMES ARE PROPOSED TO BE ANODIZED ALUMINUM AND ALL WINDOW ,AND DOOR FRAMES WILL BE TRIMMED WITH METAL TRIM PIECES. LEGAL DESCRIPTION: LOT 10 OF K. EL ISE, ACCORDING TO THE PLAT THEREOF RECORDED JUNE 19, 2002 UNDER RECORDING NO. 20020ro1950021 IN SNOHOMISH COUNTY, WASHINGTON. SUBJECT TO EASEMENTS, RESTRICTIONS ,AND RESERVATIONS OF RECORD. (/F 0 N O LLI Y U Q d w z Ow w FZ a_0 �N U o Cn Wo oQ m wo � 0 N Q � r7 I Q DRAWN: M CHECK: CFP JOB NO: 20016 O/ w Q Q w ^Z � Ld w— O �N r Cl�Z o OL P I R S C H E R ARCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: F4OX Attachment 4 1 Packet Pg. 31 5.1.a SITE ,4DDRES5: ZONING: COMPREHENSIVE PLAN DE61GNAT I ON: APN: LOT AREA., CURRENT USE: PROPOSED USE: 2312(o 1O0TH AVE W EDMONDS, WA 98020 DN (NE IGH50RHOOD 5USINE5S) NE I C H50RHOOD COMMERCIAL .i �of�of .io 21,50(o SF OR 0.413 ACRES VACANT COMMERCIAL SLDG 2 STOR�r OFFICE 5UILDING WITH AT GRADE PARKING HEIGHT ALLOWED: MAX BUILDING HEIGHT IS LIMITED TO 25' (PER ECDC 1&.45.020 T,45LE A) HE IGHT PROPOSED: 24' _(o II FROM 351.5' AVG GRADE PLANE (SEE SHEETS 13 4 14 FOR PROPOSED DLDG HEIGHT&) 6ET5AGK5: STREET: 20' MIN (PER ECDC 1ro.45.020 TA5LE A) SIDE: 0' (15' MIN IF ADJACENT TO R ZONED PROPERT*') REAR: 0' (15' MIN IF ADJACENT TO R ZONED PROPERT'�) REQ'D PARKING: PARKING: OFFICE WITHOUT CUSTOMERS 1/500 SF MAXIMUM FLOOR AREA. FLOOR AREA PROPOSED: PERVIOUS/IMPERVIOUS AREA: INTERIOR LANDSCAPING: 10,9roro / HALF OF SLDG = 5,483 / 500 = Cl) STALLS REQ'D OFFICE WITH CUSTOMERS 1 /400 SF 10,9&(o / HALF OF 5LDG = 5,483 / 400 = (14) STALLS REQ'D Cl) + (14) = 21 STALLS REQ'D (23) SURFACE PARKING PROVIDED 3 SQ FT PER SQ FOOT OF LOT AREA = 641518 SF 1ST FLOOR 2ND FLOOR 5,353 G&F 5,rO13 G6F 10,9roro G5F PERVIOUS ,AREA: 5,235 SF 5,235 SF / SITE ,AREA = 24io IMPERVIOUS AREA.- 161211 SF 1ro,211 SF / SITE AREA _ -16io 23 STALLS x 1l.5 SF = 402.5 SF REQ'D LEGAL DESCRIPTION: SEC 3ro TWf= 2-1 RGE 03 - S 1ro9FT OF N1/2 NWI/4 SE1/4 LESS TH PTN L�T' E OF W LN OF 1O0TH AVE W TGW S 1ro9FT OF E 135FT OF E1/2 NE1/4 NE1/4 6WI/4 LESS S 2OFT FOR RID 0 N O LLI Y U Q d w z Ow w FZ U N o (n W oQ m M wo 0 cV Q � rI I m Q DRAWN: M CHECK: CFP JOB NO: 20016 Z 0 0 LL Q m Z Q Q w ^z � Ld (Y— O r (1) Cl Z oo OL Lu P I R S C H E R ARCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: 544 SF PROVIDED Attachment 4 Packet Pg. 32 5.1.a ZCNING INFICF;��IATION Commercial WMU BP .. B FVMU BLEW CG Westgate Mixed Use ,Manned Business Neighborhood Business Firdale Village Mixed Use Community Business Community Business, BC -Edmonds Way General commercial Single Family R5-6 Single Family, 6,000 sq. eft. tots RS-8 Single Family, 8,000 sq. ft. tots RS-10 Single Family, 10,000 sq. ft. tots RS-12 Single Family, 12,000 sq. ft. lots RSW-1 2 waterfront Single Family,, 12,000 sq. ft. lots k:* RS-20 Single Family, 20,000 sq. ft. lots Y Y A A ,& RS-MP Single Famrfy, Master Plan 19 w tw cc V rn 0 N O H W Y U Q d w z O w FZ �0 �N U p V W � m Q wo O _ Q N � I Y Q DRAWN: M CHECK: CFP JOB NO: 20016 z O LU V / � w0 O r Q LU �Z 0 1� 6i LL. P I R S C H E R P23114 [ARCHITECTS + Pirscher Architects 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: O U) 3 0 0 0 0 0 0 N 0 N Z J a c a� a 3 0 a (D U) 0 0 0 N Co N Z J a c a Attachment 4 1 Packet Pg. 33 5.1.a L-_ Commercial rJAIIJO-M �.. B ... F MU . 04 BC-EW CG ILI r r jrlera A, IA%ra a -a rizarrzr r L.] - -I- 232N D ST S11i T - 1 216TH ST SW F 24C] I H 13 T 5 IN S 1 TE LOCATION Westgate Mixed Use Planned Business Neighborhood Business Firdate Village Mixed Use Community Business Community Business, BC -Edmonds Way Genera( Commercial A-ALi pBN 9 ;0_ FOFMer ooda Elementary Single Family RS-6 RS-10 \\\\\\� RS-12 RSW-1 2 RS-20 A YA r'& RS-MP �e • • &. %r 240TH ST -IN Single Family, 6,000 sq. ft. fobs Single Family, 8,000 sq. ft. lots H13LIi' L 11111 11 In 1119-1 Single Family, 10,000 sq* ft. lots Single Family, 12,000 sq. ft. lots Warerfront Single Family, 12,000 sq. ft. fors Single Family, 20,000 sq. ft. Pots Single Fomrdy, Master Plan rn 0 N O w Y U Q w zw Ow Z 0 U N p V W m Q W O O 1-- Q [V � I m Y Q DRAWN: M CHECK: CFP JOB NO: 20016 z 0 O Q (pLU Q Q ,tt V z Z z � � w 0 lu 0 00 PIRSCHER FRCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: 0 0 3 0 0 0 0 0 0 N 0 N Z J a Attachment 4 1 Packet Pg. 34 5.1.a VICIN17i FLAN i Ill 46 -7- .61 r lv�• NEA�5""' NON fRESI[DENTIAL USES PROJECT SITE 4DU100DUJA1' BARBER 4 SALON 4DGROUNDED ESPRESSO STAND MEINEKE CAR CARE CENTER 4DSCHOOL - EDMONDS HEIGHTS KI2 rn 0 N O W Y U Q d W Z O_ w of z U (N p C W m 0 Q W O O cV Q � I m Y Q DRAWN: M CHECK: CFP JOB NO: 20016 ' ') V / w Z \(\�\ O Q C Q w n 3 Q O 0 wU O o� > ul �0 P I R S C H E R ARCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: Attachment 4 Packet Pg. 35 5.1.a F�7 riY - "'F"�lveF V • �4h tlti WE LOOKING SOUTH ALONG WEST FRONTAGE (101st AVE W) SINGLE FAMILY HOME NORTH OF SITE SINGLE FAMIL)' HOME WEST OF SITE ACROSS 101st AVE W HAIR SALON SOUTH OF SITE 4 VIEW OF SOUTHWEST CORNER OF SITE VIEW OF SOUTHEAST CORNER OF SITE Y LOOKING NORTH ALONG EAST FRONTAGE ALONG 100th AVE W C L V,7 �, .. rail► `ir' - �r r v { w w-A A i w • . J 1, i _ .. �+ ' �� -mow i � ; ►-'�-�� tr`r Zi _ � 1i- •�► - Ar We " Y. fv .r rn 0 N O W Y U Q W z O W of F- 0- Z 0 U (N Wp W o0 o Q Ld � O N Q o i A DRAWN: M CHECK: CFP JOB NO: 20016 VJ VJ 1-� w z z Q 0- V Q Z Q O 0 wU N LL. O P I R S C H E R ARCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: 0 0 0 0 0 0 N 0 N Z J a � SINGLE FAMILI' HOME WEST OF SITE UNDEVELOPED LAND BAST OF SITE 4 I � I-1,41R SALON SOUTH OF SITE 4 VIEW ACROSS 101stAVE lU VIEW OF EXISTING CURB CUTALONG OF EXISTING CURB GUT OAF OF 100th AVE U1 238th ST SUJ Attachment 4 LOOKING WEST ALONG SOUTH FRONTAGE (238th ST 5W) Packet Pg. 36 5.1.a I a 20'-0" 18'-3" 70'-9" 32'-6" FIRST FLOOR (GROUND LEVEL SCALE: 1/8 11 = 1'-0" a T I cV N AREA CALCS 1ST FLOOR 2ND FLOOR 5,353 GSF 5,613 GSF 10,966 GSF rn 0 N O w Y U Q d Ld Zw Ow F z N� L U ,0 N p V W � m Q W O O -- Q [V � I m Y Q DRAWN: M CHECK: CFP JOB NO: 20016 IJ LL- �V1/J Z 0 I T� V' V l < Vf1/ LL o Z 0 O w0 O r Q Z cv 1U 0 o LL P I R S C H E R 023114 ARCHITECTS + pirscher Architects 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: 10 Attachment 4 Packet Pg. 37 5.1.a 00446700000400 I --------------------------- J I I 1 I F1 I 00446700000300 I I I 1 E y � h a } + h 1 i 1 x 00446700000200 i ,L I f" r' I I 1 I I I I I I k 1 " I 004467000015 � I � I " I � k r I � I ' SSMH RAM=355, I6 0044fi 70000 700 J +�' S" PvC(�rjmm34�,6r I i 1 IE 8PVC(S 346.5T i , + 1 I k F III I r , I I r I 1 I I 1 00446700001600 I a I " F r I I777 27 7773HSE � 1 I ASPHALT x%`x 123� 5 1 i ezzzf x} ENO FFNC'E 0, 4'(N) C JA'(E} OF CORIVE+R ,• ��- ,� .� x I� T4' FOUND 4 7f4' CONC- rdON. W2' --------- - ' N 88' I3'I�2' W I d , OO' C BT#i4SS f]ISJC & PUNCH AT ... -25 r I - I2-49, FOUND REBAtR W " 5'URFACf- 4fiSIT,EU STAM"EO 75VF 32442' ti r WALL c. BLG K FEE COR. 0 2 {N) AT CORNER }' OF PRaPERTY ONE 1 } x GPM s }' k FENCE tNT. 0.2'(S) + '� y OF PROPERTY LINE 4u I 1 I �� I I ' ----------- `" I C t C I I qd I � I L I i L I r I 2 , I I L I + 1 ! , L 00446700000100 I " Im I 4 f � t h 1 t � � t I � 1 17 7-.' i n `r ht L� J ---,"--w—, J.34 I �E42"OPP(S)= 348-T4 8 I I I I I 00615800000800 I I TES JV' h 1 h ! L I h Ll 1 L I I I I I I I 1 i r ! L I t F t h h t x AS'PH&T 4}}� —360— r CONC, r r r " r f 123726 # f 1 1 f r CONC. z� LOT AREA 2;,506 SF 7033600400500 z �} O 0 4 a CB R�AI=354-9D`) o BOLlAfS o D C 8' PVC(W)=352,90 ; tE 4' ItnC(N)=353, IO rr CD RIIU=353.22 r IE 8' PVC(Ef 351,47 r' Jd `� p{ C8, RIU=3M. 16 IE e,RCP(E)-355.24 k% ASPHALT r I a r i cONC. { -CONCRUE WA(X h " f SS W 881,3 U2" W(C)P7) I83,O V FOUND I IRON PIPE _ `^— WC?lf�fD TRE&aR �LLEGfBT E I 0,2'(S) OF CORNED F I CAP 0.2"(S) OF CORNER I-) TH6 SURVEY HAS BEEN PREPARED FZiR THE EXCLUS.1W USE OF PATRVES WHOSE NAIVES APPEAR HEREON ONLY, AND DOES NOT EUEND TO ANY WWMO MIRD .PMnES W HOUr EXPRESS RECERTTFO17CN SY NE tANO SURVEYOR, 2.) BOUNOAr7Y LINES SHOWN AND CORNERS SET REPRESENT DEED LOCARONS; OWNERSrHM LINES MAY VARY. NO aARANItE OF OWNET7WP IS EXPRESSED OR IUPL+EO, THIS SURVEY PERFOR)dED W77100T THE BENERT OF A TITLE REPORT AND DOES NOT PURPORT TO SHOW ALL E4MUENTS, RESTRCNONS, RESERVATIONS, AND OCCUPATION WHICH MAY ENCUUBER TITLE TO OR USE OF THIS PIROPE7RTY. 00615800000100 t f Jt f f FOUND D CASED SfV!'1Cr MOM W12 D,�,%%t mss & PUNCH- DOWN 0,6,, VSfu II-18-49, f f FOUND CASED CONC, MON. W 2" BRASS DISK & PUNCH. DO" '�.�'. VISITED f8-I9- } + SOMH MM-361. T 5 IE 12"' RCP(S)a354Z5 } IE 8RCPX -354.90 y IE 9 4 1 CP(W)-p354.9 rT QL• U� yam-/ I • 4 FOUND CASED L f m x ffi%�S'. W Or6SFEO I ] J. I" SsMFt tRtild=358-5 a IE 8" PVC =34 K54 + IE 8" PVC E =34 t.64 ! 11 1 jr C6 i r I I � I I I ni f h f i f 1 r � t 5 5 EQUIPMENT & PROCEDURES uEn4w OF SURvEy, S+1WEY PERFORMED BY FIELD TRAVERSE JNSTtRULjVJ'TATK*r LEICA T5I5 RD8OT� ftFCTRONtC rOfAL SrArTON PREMM MEETS OR EXCEEDS STAW STANDARDS WAG 332- T 30-090 WS OF 8MRIINfi, THE MONUMENTED CENTERLINE OF 237rH PL, S.W., AS THE f3Er4t7ING OF N 5755 39' W. SURVEY REFERENCES ENCES (R4 )PLOT OF RR MEADOWS NO. S -- V€ . I7, PG, 48 (R2)PLAT OF FIR MEADOWS- t+oL- 15, PG. 62 (Rs)PLAT Of I WVL-N - VOL- 14, PG. 8 LINE TABLE LINE LENGTH BEAR!N LI 20.96 N 0729'38" E CURVE TABLE CURVE LENGTH RADUS DELTA C1 2104J 520.00 2,r�1 O' C2 88,25 7.5-00 6725'1 7" C3 208.30 214&01 5'33 22" C4 59.89 2148.61 r'35'Sr" C5 T4k4f 2I48,OI 3'S7'3r' SDMH RIIIT= 352,95 A IE 72" CPP(N)=,34.5, 65 IE I2" CPP(W)=344.20 If 12- CPP(S)=,344,20 e SSMH R44=M122 IE 8' PVC(N)=342-67 IE 8" PVC(W)t342.67 If 8" tC(S 342,57 LEGAL DESCRIPTION PARCEL A: THE SOUTH 169 FEET OF THE EAST I35 FEET OF THE FAST HALF OF THE NORTIgFAST OUARTER OF THE NORT14LAST OVARTER OF THE SOOTHWEST QUARTER OF SE+'CTTON 36, TOWNSMP 27 NORTH. RANGE 3 EAST; l .M., W SNOWMEN COUNTY, WASMNG TON, EXCEPT TIME SOUTH 20 FEET,' ANT} EXCEPT THAF PORTON LYWG EASTERLY OF TIE WESTERLY LINE OF TOOTH AVENUE WEST. PARR 8 THAT PO RTKW OF TK S0077 r 169 FEET OF THE NORTH h ALF OF TIC NORTi KST OLARTER OF THE SOVFHEAST QUARTER OF SECTION 36, TOENSHP 27 NORTH, RANGE 3 EAST, WIU,, TN SNOHOWSH COUNTY, WASt,ttNGTON, LYTNG WESTERLY Or TOOTH AVENUE WEST' EXCEPT THEREFROM THAT PORTION TAKEN BY SNOHOMI514 COUNTY BY AGREED JUDGEMENT AND DECREE Or APPROMd+ WN F+LEO MARCH 74, 1972 UM)ER 5NOHOM6H COUW SUPERIOR COURT CAUSE NO, 107987, S't UATE W W COVMY OF SNOHOMISH, STATE OF WASHINGTON VERTICAL DATUM VD 88 FOUND CASED CONC. NON. W 2" BRASS OfStf & PUNCH AT THE IN'TERSECDON Of: 9M FL, W, AND 2,37TH FL. S.W ELE4! r 341,33' LEGEND SET 1 2" X 24' ROAR WICAP .STAMPED 'PCS 37536' 0 E'MPNG RE60 W CrAP, AS TOOTED )K SET NAIL AND WASHER STAMPED '"PCS 37536" ` SET TACK IN LEAD W1 WASHER STAAWPED "FCS 37536" } ExtSTItVG IWL AND WASHER AS NOTED FOUND CONCRM WOWAIENT AS NOTED RIGHT OF WAY CEWERONE O STDRIU ORNN NTANHOf E C CATcH a4sx I4 WATER VALVE WATER METER SAMTARY SEWER k4NHOLE o WLBCX -D- UPLITY 1bolfwR POLE CVY ANCHOR UGW POLE TRAMC SICK 4L JtJfYCWN BOX q GAS VALVE CEAAR TREE Pacific Coast Surveys Inc. .AND SURVEYING & MAPPING P. . B O X 13619 MILL (REED, WA 98082 PH. 42 .512.7 FAX 42-5'3-57- 577 www.PCSurveys.net SCALE, " = 20' 0 20 40 TOPOGRAPHIC SURVEY F RED SEA PROPE NE 114, SW ?, SEC. 6, T.27N.f DRAWN BY DATE 1DRAWINGFILE NAME S(Al F H ?7.7 .7 191789t0AdVV9 7, - ?0 rn 0 N O w Y U a W w z O Q� F-- a_ 'z^ V_ —^ N U) W C /�r�W � O N N Q 0 I Y Q DRAWN: M CHECK: CFP JOB NO: 20016 Z O Lu Q T� � V' ZO O O r Q w tr Z N oLL- O PIRSCHER ARCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: co 0 0 0 O O 0 N O N z a Attachment 4 Packet Pg. 38 5.1.a w L ;8 RIM=352.34 12" CPP(E)=348.14 E 12" CPP(S)=348.14 saA / n _ I / I / I / 5Uf LD INCH I4E IG�4T CALCULATIONS 545E HEIGHT ANAL"�515: FEE IN1 ORi RATIONAL HANDOUT 41 5ASED ON EX15TING GRADE5 TOTAL = 1/430 AVG GRADE = 351.5' (1/430 / 4) 1 IAX HEIGHT ALLOWED = 382.5' (351.5' + 2 5' ) \1/'1T= 5EE 51-IEETS 13 AND 14 1=01R FROFOSED 5UILD INCH HEIGHT 5A5ED ON CALCULATED AvG GRADE. 0 N O ~ W H Z Y W � a O W U Z W 0M Q O a O Z ~ W W Z O W 00 m N 0aaf LLJ 0 04 0 04 O 0 H N N Q � I � I 0 Y Q DRAWN: M CHECK: CFP JOB NO: 20016 VJ z O U U � z � N Q V Q V ! V QLLI O Q Z c� i 1U rn LL. of P I R S C H E R ARCHITECTS CDA + pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: c 0 :r rn 3 0 0 0 v 0 0 0 N O N Z J a Attachment 4 Packet Pg. 39 5.1.a I i� oc 20'— 0" 18'-3" 70'-9" SECOND FLOOR SCALE: 1/8 11 = 1'-0" 32'-6" m cV Lo I r \ 00 I AREA CALCS 1 ST FLOOR 2ND FLOOR 5,353 GSF 5,613 GSF 10,966 GSF rn 0 N O w Y U Q d Ld w z O w F z 0 U N p V W � m Q W O O -- Q [V � I m Y Q DRAWN: M CHECK: UP JOB NO: 20016 LL 0 0 —Ii LL- Z z p N 0 QLU m > .� z co Q Q � ,� Q � o ^z 0 0 w0 O r Q � Z cv 1U � o LL P I R S C H E R 023114 ARCHITECTS + pirscher Architects 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: Attachment 4 Packet Pg. 40 5.1.a EDGE OF 2NC FLOOR DECK EDGE OF 2ND FLOOR DECK FLOOR DECK ROOF PLAN- SCALE.- 1"= 20' SCALE: 1/8 pp = 1 ' - 0" 0 10' 20' 40' 60' TAIR HAFT #1 rn 0 N O H w Y U Q d w z O w w FZ �N U p V W � m cn Q w 0 0 1-- Q N � I m Y Q DRAWN: M CHECK: UP JOB NO: 20016 z O Q (f 1 � z C'() > Q Q � Q Z LL_ 0 0 �O z 0 O r Q 6z � (14 LU o o PIRSCHER FRCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: 12 Attachment 4 Packet Pg. 41 5.1.a TOP PLATE 7�--,-fir 01 w w I w I c� 2ND FLOOR in N m 12'-0" < cV m O 0 N Q O X p O I C'4 AVERAGE GRADE PLANE ELEV. 357.5' FINISHED FLOOR 0'-0" ELEV. 357.0' ELEVATION KEYNOTES SYMBOL �j RED METAL PANEL SIDING O VINYL WINDOWS, TYP (]D NAVY BLUE METAL PANEL SIDING O4 NOT USED O5 BALCONY WITH PREFAB ALUM RAILING © NOT USED O AVERAGE GRADE PLANE (357.5') ®25' HEIGHT PLANE FROM AVG GRADE OCOVERED ENTRYWAY TO COMMERICIAL LOBBY 10 COVERED ENTRYWAY TO MAIN LOBBY 11 ELEVATOR OVER -RUN 12 GROUND LEVEL LIGHTING 13 BRICK VENEER 14 TRANSOM WINDOWS 15 NOT USED 16 METAL TRIM, TYP AT WINDOWS AND CORNERS 17 ANODIZED STOREFRONT SYSTEM 18 PREFAB METAL CORNICE 19 NOT USED 20 NOT USED 21 SHED ROOFS BEYOND 22 HORIZONTAL METAL SIDING IVIMI7 U%J%dIN LIY 1IN I TV 1 Naml9 Nil I TO STAIR#2 EAST ELEVATION SCALE: 3/16" = 1'—O" I„ SUITE 102 EST ELEVATION SCALE: 3/16" = 1'—O" rn 0 N O ~z w Se U w � � O wm Z w 0 Q Ow0 F zI__ O w U w 00 z W m N o w of O N O N W _ O 04 ON 1 Q r1 I 0) 00 I Y Q DRAWN: M CHECK: CFP JOB NO: 20016 Cn z O Z Q o > LLJ Q (p Lu W C� % 3:: a Q O � 0 _j � O r Q Z 6z (14 Lu oLL. O PIRSCHER ARCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: 13 0 3 0 0 0 0 O 0 N O N z J a Attachment 4 Packet Pg. 42 5.1.a ELEVATION KEYNOTES SYMBOL �j RED METAL PANEL SIDING O VINYL WINDOWS, TYP (]D NAVY BLUE METAL PANEL SIDING O4 NOT USED O5 BALCONY WITH PREFAB ALUM RAILING © NOT USED O AVERAGE GRADE PLANE (357.5') ®25' HEIGHT PLANE FROM AVG GRADE OCOVERED ENTRYWAY TO COMMERICIAL LOBBY 10 COVERED ENTRYWAY TO MAIN LOBBY 11 ELEVATOR OVER -RUN 12 GROUND LEVEL LIGHTING 13 BRICK VENEER 14 TRANSOM WINDOWS 15 NOT USED 16 METAL TRIM, TYP AT WINDOWS AND CORNERS 17 ANODIZED STOREFRONT SYSTEM 18 PREFAB METAL CORNICE 19 NOT USED 20 NOT USED 21 SHED ROOFS BEYOND 22 HORIZONTAL METAL SIDING 0 0 0 CV TOP PLATE TIT-- rn 01 O � 0 W r•7E i w 2ND FLOOR io m 12'-0„ 04 Q 3 0 J J a x a O Ni AVERAGE GRADE PLANE ELEV. 357.5' FINISHED FLOOR 0'-0" ELEV. 357.0' TOP PLATE 22 —0 2ND FLOOR AVERAGE GRADE PLANE ELEV. 357.5' n►uC11 irn ri nnn 0'-0" ELEV. 357.0' SUITE 100 NORTH ELEVATION SCALE: 3/16" = 1'-O" SOUTH ELEVATION SCALE: 3/16" = 1'-O" rn 0 N O ~z w Se U w � � 0 wm Z w 0 Q O w O F- zI__ 0 w U o O w m cmn 0 Q W CL O N O N W - O N NN Q r1 �T 0) 00� Y Q DRAWN: M CHECK: CFP JOB NO: 20016 Cn z 0 z Q 0 > LLJ Q (p Lu W C� % Q z 3:: a Q O � 0 _j � 0 r Q Z 6z PIRSCHER M ARCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: 14 0 3 0 0 0 0 O 0 N O N z J a Attachment 4 Packet Pg. 43 5.1.a PPnoncan Qi nr, uCIrUT EXISTING SINGLE FAMILY RESIDENCE PROPERTY LINE SITE SECTION - MASSING STUDY SCALE: 1 /16" = 1'-0" KEYPLAN PROPERTY LINE SIDEWALK rn 0 N O H W Y U Q d Ld Z O W F z 0 U N p V W � m Q W O O 1-- Q [V � I m Y Q DRAWN: M CHECK: CFP JOB NO: 20016 z O Q � 7 L (p O L Cf) } � U � cri W Q ,� Q U) � ^Z OLLJ - Ld O r Q �Z PIRSCHER FRCHITECTS CDA + Pirscher Architects 23114 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: 15 Attachment 4 1 Packet Pg. 44 5.1.a z. -a "T Fr r_— tom wr R' a 40RIZONTAL METAL SIDING RED METAL PANEL SIDING NAVY BLUE PANEL SIDING GRAY BRIC-< VENEER SIDING i �I�■1�1 r r- "IA Ag IL ,•r - y , - • ' r '= rt TA 711 Ilk- y t- 1� � 4 • 40 ... s r i,r 7, _• �f frill• �_�� rxi _ .I Ire 1 L a -1 EEL— +' r-'+''��M1' '' 1'L I'•'rl ��„y i ,L + r1 ' L y ••I k� _ _ - � + •. 'f +''' i' li, '•G •`4!I•f �- ' ' F ' I �' + ' ' 'L I ' ' '• '''�' L�i ' 'F.y:'''7 {'•I � �� �:•_ ~r - - - -- r# _+•, }?! ,' ',' •r' + ' + 1 •I� I ,'•, F fI { I•r _ ' I , ; L y •Y y • , •' -` •3 i'.• 5 CL•5 r 5 i�, 5. .��� ., 1 yi,l • _ , •II{ ;. y +. �� •r I I ' 01. f .t J• '•74h•�. `_ w 1�.:� .� •'' I 1 , 5i y. _ r '{ , I. ; k ', ?1 l y '.� .. F .. •'� y 'I F� ,{�� 1 , Y '� + y jL1' 1. �7i.+ `+• .' r• I LZ •r •'+'l' ' '{ I,'1 Y ''rr r' .1 :'_ Ir, 'f 'r I '',' ��'•.''�4'k ll,�!,y� rI ,rLr _ �••1' S5 'i•'' +: '� �•1,• •,o, % i L - 7 .1. -- -' ' - - '•I - .' - M •,. 1 - II •� �' �7{ i + L1 ,L + 'y�rF �11i ,M L A R C H I T E C T r L L . _ •_ .y _I,1 Ly I SOUTH-EAST FACING; PEfRSPEGTIVE rn 0 N O W Y U Q d W z O_ w of F- 0- z 0 U (N p C W m 0 Q W O O cV Q � I m Y `Q L DRAWN: M CHECK: CFP JOB NO: 20016 V Z ff fu Z w Z O w Q 0-5 w Q v / O (Y_ Ld O ,\ J:i� Z O Lu PIRSCHER ARCHITECTS CDA + 23114 Pirscher Architects 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: I & �1 CO) 0 0 0 0 0 0 N 0 N z J a Attachment 4 1 Packet Pg. 45 r 4r F jw• . ri 0 r d 14 IM . Q; f F• � �_•J •r k +&1 6 '{+ , y � � •I F ' S ' S• Y 't • "� w � ~ � ■ 5' R YR Y may' ' L •� _ L �J4 i � �� �► rM ��''� i' • ' k ti.F i{ '4+ +�.{ �1 �5 �i ._ '� 1 '�� `�� ' F• tip' 1 ' i y z � * ', 1 a 43, i � J„i � y ~ � J ' ,- �• ya � ,. ' 11,.% A q i 7tiiy i;4L, r: i •+~I dp Y am, ' �� , - l -x F' - '' ,{ Y: I .+� •��, i. �1�1�� y4 +=.�'� -ti;{ � '- :�- �� 'Ar •� '�•_R" F 4 y *yam{}1�,�C,' 1 `L F `. L �� 5.1.a M1 k UJEST FACING PEiRSPECTIVE N,4V'' FLUE PANEL SIDING I I ., =) 17 „T. I t A I S,rr i- t h l r7 rn 0 N O F- ILL] Y U Q d W z O_ w of F- 0- z 0 U (N p C W m 0 Q W O 0O cV Q � I m Y Q DRAWN: M CHECK: CFP JOB NO: 20016 Z w LU Z LI J.� z 0 LLI Q LLI Q OL LLJ 0 I J:i�Z OL O N !u O PIRSCHER ARCHITECTS CDA + 23114 Pirscher Architects 100 AVE W EDMONDS, WASHINGTON, 98020 (206)368-9668 SHEET: Attachment 4 Packet Pg. 47 7:�. - �!tP SIN^ IF Ll .# ti ■ 3 % % • r j3 ■ a _ �� t dv T ` IL Ilk 46 • 46 IL � ' Y r _ _ ' - _ �. � aIFr 7 - qbb6 �-" �'�• ire • �� `� *�� � � �� Y # T •�� r a ' 1 t!1 10 Ir � WTV a _ I •r�- +t • , : - , � ' ■r+ f• ■ + I I+• � •mil 1. � r ; �y r5111 J n' `a 7 • - 'r• " Y.I ' 1• F Jifr+ '}j �u� { f- !1 - r+ �y+/`�r��� I_� �i�j ifr" L_{r �■� !J#. r { �� Pill 13 y ■ t�er +, 44 ,��_•'�;'�.:.,, 1 T.�. •■ . I 4i 1k k1Y.' +.I I `� . r , �:�+ y{I�+I: , ti�rr`'. :;'� ,��Y' �'�y+.�i AG ��y,� 77�� ��� rt 1 i Cam, i fFJ�{-,I{��'I �,�'ir'� +' + I r� �:'I�Ir''yy � ` alL � � .I �y11 � ;� � �::■ 1 �* r I '�+i #�'iF�+� •\■■M,■i I�{��I'F' kl Y,'�+,4. �•'r•'!�yu M1 .�_• ref; r4r• 1::�, a � •� � � '� :'! .� �, � • ��1' .5 �+ 4� rt'�J��I1+ �, �■Y i yf { ,�`i- �;� • �: } �4T � 1` Jf I :y+ -i. �Yry �. k Ir4�r,'•�• 51+ s. tt Y ■ jl�� M �# Y li '+I y• ` r f i + -;I k• I r' } 'I' �1+ N''+-J,} I.�-''ff,•,r r'r . +~:1. t 4 }ia'` ;�}1 �r r r Y 4 y „ 1� r It I IN. , •1,•�: fy•' Y'F } !+pyy F'j■r`y!".{`ylry+�1F r�� I�• 5- ;-; f +I. +� f. ; + 1 J 1+�'IL 1 1 ' J ■�Fi'1�1Y 1I i l� M .+: 1 I k• ,.4 tit !1',Y� 5 ,F I•�•�•~� �J ■ F� ti+4-'y�7} •�1 , r +{� �:ll:'� �'f'� +'�i + F 4� � I Ft` F 7 +,}]1� S�I�F'�y'.Itl� •�'IYYYL F �x�7Y_,.1"fr LLi I�• 4+4�L�r a-1F. t.I.1't+.��':.�,1J} Y �+ �� +}I ■ } 'J:IF kJ 1�,1■.1: J r Ihl h'41:I.i1}II +. f.y • L li/+� L�F 1 T'r �F •!j'•,, ,• �1 0 ■ J�a��7.r_ � F ! 7 t L k i Y �Sm_ CDA r' — q L —ad k # AW •4,c � r, NW 1/4 SE 1/4 SEC. 36, T. 27N., R. 03E, W.M. 5.1.a 00446700000300 -------------- 00446700000200 IF77 -------------- �:i o LjLI Q Cn 00446700000100 r- - IGRAVEL CB RIM=352.34 IE 12 CPP(E)=348.14 IE 12" CPP(S)=348.14 G& 12" C N 8 21.16' S - 0- I A - z FA WOODWAY STATION SSMH RIM=355.1 F I IE 8" PVC(N)=3 I IE 8' PVC(S)=3, ---------------------------------- I I I I - I SD I I 1 00446700002700 I I I 00446700001600 I I I 3 `O ASPHALT I HOUSE 123715 I I FOUND R WI�CAP 1 0 JZ I STAMPED SW 32442" AT CORNER / " 14 FOUND "x4" CONC. MON. W/2' v 25.0 ' N 8� 82 W 162, 0 ' 12 C 14" C BRASS bISK & PUNCH AT I I SURFACr. VISITED 11-12-19. / I I I a 6' WOOD ' 3 C FENCE (TYP) T �� c� 15' BSBL I I 5' ACCESS/SIDEWALK EASEMENT FIRST FLOOR LEVATOR ENTRANCE ° R45' ° ° I ° 1 I i ROOF LINE ° • 1a° ° // / R5'' % ° ° a ° °/ • °4 • I / • PROPOSED COMMERCIAL ° • / / ° o I I° _ BUILDING a /ate / • �' �/ IvQ FF=357.00 / c' 2ND FLOOR ABOVE ° ° e ° I / • a ° I O co 0 1I FIRE TRUCK a c / CDf 8.5' 1 TURNING PATH 12' z 12 I 3 STAIRS °� / / / I I° • / / I 11.5' I / V ° FIRE LANE - NO PARKINSi.. d - -� -' I 10' 12, �R25' / �16.5' 5 10.2' • ° ° a ° R / i / TYP �a a 7' / I • 1°2 d ° ° ° ° i I 13 / 20' � - _ R45' I 20' BBSBL - / / ISD S0. // R25'--,,, 8.5TYP / I / ° ° SDI � CB RIM=358.16 I 2 l IE 8" RCP(E)=355. PM IE NEW 8" (W)=355.24I 53. 2 IE 3 ° a ^ONCRETE WALK a 3'02 ' w A 48. 2 IE ° )=3q 1.47 / i o C RI `� G NI 8" F.-%••. --- - I SS 1 4' PVC(N)=353.10 / _ 147SS I .66' N 88' 1302" W(C)(R_ 1) 19,3.82' _ - - - _ - S SS 238 TH S T S.W. - l SSMH RIM=358.51 I W 1E 8" PVC - W - W W IE 8 PVC(E 341164 Ui- W Z3116\ / I I. I � j FOUND 1 " IRON PIPE 0 / 0.2'(S) OF CORNER n IE,2"RCPP(N)=345.65 @IE: S11 8RPVC V) 342.67 FOUND REBAR W/ILLEGIBLE IE 12- CPP(W=344.20 IE 8" PVC(W)=342.67 CAP 02 (S) OF CORNER ° ° 4/ IE 12" CPP(S)=344.20 IE 8" PVC(S)=342.57 EXISTING CONDITIONS Sf ac PARCELAREA 21,506 0.49 ❑N-SITE DISTURBED AREA 21,506 0.49 OFF -SITE DISTURBED AREA 2,512 0.06 ON -SITE IMPERVIOUS 19,996 0.46 ROOF 2,149 0.05 PAVING 13,318 0.31 GRAVEL 4,529 0.10 PERVIOUS (LS) 1,511 0.03 OFF -SITE ASPHALT/SW/DW 2,193 0.05 PERVIOUS (LS) 319 0.01 PROP. ON -SITE DEVELOPMENT Sf ac ❑ISTU RBED AREA 21,506 0.49 IMPERVIOUS 16,696 0.383 BLDG (ROOF) 6,603 0.152 PARKING LOT 9,633 0.221 W. SW/TRASH 460 0.011 PERVIOUS(LS) 4,811 0.110 PROP. OFF -SITE DEVELOPMENT Sf ac ❑ISTU REED AREA 2,512 0.06 IMPERVIOUS 736 0.017 DRIVEWAY/SW(BYPASS) 736 0.017 SW TRIB TO BIORETENT 407 0.009 PERVIOUS(LS) 1,776 0.041 >10,000 (MR#7 REQD PGIS >5,000 CO M I SITE INFORMATION: VERTICAL DATUM: NAVD 88 BASIS OF BEARING: THE MONUMENTED CENTERLINE SDMH RIM=361.15 OF 237TH PL. S.W., IE 12RCP(S)=354.65 IE 8" RCP(NE)=354.90 AS THE BEARING OF "I�r IE 8" RCP(W)=354.90Al N 59°55'39" W. 3022" W _W 9.00 ENCHMARK: FOUND CASED CONC. MON. 237 TH n PL S- W/2" BRASS DISK & PUNCH AT THE INTERSECTION OF 99TH PL. W. AND 237TH PL. S.W. ELEV. = 341.33' PARCEL(S): 27033600400500 ADDRESS: 23726 100th AVE. W. EDMONDS, WA 98020 PARCEL AREA: 21,506 SF (0.49AC) ZONE: BN LAND USE: NEIGHBORHOOD BUSINESS 0 ^`O SETBACKS: / MIN. REAR 0' MIN. SIDE 0' MIN. STREET 20' PERMITS REQUIRED: SIGN, GRADING, UTILITY, ROW, AND BUILDING PERMITS EX FIRE HYDRANT I n CB RIM=355.95 8' IE RCP(N)=349.55 238 TH S T. S.W. LEGAL DESCRIPTION: PARCEL A THE SOUTH 169 FEET OF THE EAST 135 FEET OF THE EAST HALF OF THE NORTHEAST QUARTER OF THE NORTHEAST QUARTER OF THE SOUTHWEST QUARTER OF SECTION 36, TOWNSHIP 27 NORTH, RANGE 3 EAST, W.M., IN SNOHOMISH COUNTY, WASHINGTON; EXCEPT THE SOUTH 20 FEET; AND EXCEPT THAT PORTION LYING EASTERLY OF THE WESTERLY LINE OF 100TH AVENUE WEST. PARCEL B: THAT PORTION OF THE SOUTH 169 FEET OF THE NORTH HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 36, TOENSHIP 27 NORTH, RANGE 3 EAST, W.M., IN SNOHOMISH COUNTY, WASHINGTON, LYING WESTERLY OF 100TH AVENUE WEST; EXCEPT THEREFROM THAT PORTION TAKEN BY SNOHOMISH COUNTY BY AGREED JUDGEMENT AND DECREE OF APPROPRIATION FILED MARCH 14, 1972 UNDER SNOHOMISH COUNTY SUPERIOR COURT CAUSE NO. 107987. SITUATE IN THE COUNTY OF SNOHOMISH, STATE OF WASHINGTON. DRAWING INDEX C1.0 COVER SHEET C1.1 GENERAL NOTES C2.0 TOPOGRAPHICAL SURVEY C3.0 TESC PLAN C3.1 TESC DETAILS C4.0 GRADING PLAN C4.1 ROAD DETAILS C5.0 DRAINAGE PLAN C5.1 DRAINAGE DETAILS C6.0 UTILITY PLAN C6.1 WATER AND SEWER DETAILS TOPOGRAPHY, BOUNDARY, AND UTILITIES STATEMENT: FURR ENGINEERING SERVICES PLLC. DOES NOT WARRANT THE TOPOGRAPHY, BOUNDARY, AND/OR EXISTING UTILITIES SHOWN ON THESE PLANS. IT IS THE CONTRACTORS' RESPONSIBILITY TO HAVE ALL EXISTING IMPROVEMENTS FIELD VERIFIED PRIOR TO CONSTRUCTION. ANY SUBSURFACE EXPLORATION OF EXISTING UNDERGROUND UTILITIES (POWER, WATER, SEWER, TELECOM, ETC.) SHALL BE PERFORMED BY THE CONTRACTOR. DISCREPANCIES BETWEEN WHAT IS SHOWN ON THE PLANS AND LOCATED BY THE CONTRACTOR SHALL BE BROUGHT TO THE ATTENTION OF FURR ENGINEERING SERVICES PLLC.. PRIOR TO CONSTRUCTION ACTIVITIES. �.. a � ,u 2371 1 A m � i 2�1 J St M Y ' ScnbeLr Lake High Scholl FiormLr Woodway w High School 7emporaF11y cbstd b u .9 Madroria K-8 School Hickman Park �; 9 � 258thS't SITE z a 2UM FI We f 24trch PI sv1 6 244hh I'I SWul � y. a 2aT st F' F-W � 3 3 FIRDALE VILLA -GE �a3rdpl5y! Ti,a TrIni's P'arbtry Brackett Apo 244* a SW T �F_ s Bc lame Carden i MW Rai TA st VICINITY MAP 1" = 1000' PROJECT TEAM: APPLICANT/ RED SEA PROPERTIES LLC LEGAL OWNER: 15423 36TH AVE SE BOTHELL, WA 98012 CIVIL FURR ENGINEERING SERVICES PLLC ENGINEER: DEAN FURR 4715 142ND PL SW UNIT#B EDMONDS, WA 98026 (206) 890-8291 FURRENGINEERING@GMAIL.COM GEOTECHNICAL COBALT GEOSCIENCES CONSULTANT P.O. BOX 82243 KENMORE, WA 98028 PHIL HABERMAN (206) 331-1097 COBALTGEO@GMAIL.COM SURVEYOR: PACIFIC COAST SURVEYS, INC. P.O. BOX 13619 MILL CREEK, WA 98082 425.512.7099 WWW.PCSURVEYS.NET ARCHITECT: CDA+PIRSCHER ARCHITECTS, INC. 23114 100 AVE W EDMONDS, WA CARL PIRSCHER 206-368-9668 EXT 107 UTILITIES: GAS: PUGET SOUND ENERGY (425) 882-4406 ELECTRICITY: PUGET SOUND ENERGY (425) 882-4406 STORM: CITY OF EDMONDS (425) 771-0235 SEWER: CITY OF EDMONDS (425) 771-0235 WATER: CITY OF EDMONDS (425) 771-0235 GARBAGE: REPUBLIC SERVICES (425) 778-0188 FIRE: SNOHOMISH COUNTY FIRE DIST. #1 (425)-551-1200 Know what's below. Call before you dig. A N 20 10 0 20 40 SCALE: 1 INCH = 20 FEET APPROVED FOR CONSTRUCTION CITY OF EDMONDS DATE., BY. CITY ENGINEERING DIVISION WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PLN 2020-0040 Key Plan Registration 12/28/2020 ruRR ENGINEERIN SERVICES 4715142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title COVER SHEET Revisions Scale: FES Project No: 20068 Date: OCTOBER 01, 2020 Designed: DAF Drawn: DAF Checked: DAF Sheet Number C 1 0 0 1 Packet Pg. 49 0 ca co 0 0 0 v 0 0 0 N 0 N z J P.m. Attachment 5 NW 1/4 SE 1/4 SEC. 36, T. 27N., R. 03E, W.M. WOODWAY STATION 5.1.a GENERAL NOTES 1. ALL MATERIALS AND WORK SHOWN ON THESE PLANS SHALL CONFORM TO THE CITY OF EDMONDS STANDARD PLANS AND DETAILS, THE FOLLOWING SPECIFICATIONS AND CODES, AND ALL OTHER APPLICABLE LOCAL MUNICIPAL, STATE, AND FEDERAL CODES, RULES AND REGULATIONS: - CURRENT INTERNATIONAL BUILDING CODE (IBC) - 2016 WSDOT/APWA STANDARD SPECIFICATIONS FOR ROAD, BRIDGE AND MUNICIPAL CONSTRUCTION - WASHINGTON STATE DEPARTMENT OF ECOLOGY STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN (CURRENT EDITION) 2. STANDARD PLAN AND TYPE NUMBERS INDICATED ON THESE DRAWINGS REFER TO CITY OF EDMONDS STANDARD DETAILS, UNLESS NOTED OTHERWISE 3. A COPY OF THESE APPROVED PLANS MUST BE ON THE JOBSITE WHENEVER CONSTRUCTION IS IN PROGRESS. 4. DEVIATIONS FROM THESE PLANS MUST BE APPROVED BY THE ENGINEER OF RECORD AND THE LOCAL GOVERNING AUTHORITY. 5. CONTRACTOR SHALL RECORD ALL APPROVED DEVIATIONS FROM THESE PLANS ON A SET OF "AS -BUILT" DRAWINGS AND SHALL SUMMARIZE ALL AS -BUILT CONDITIONS ON ONE SET OF REPRODUCIBLE DRAWINGS FOR SUBMITTAL TO THE OWNER PRIOR PROJECT COMPLETION AND ACCEPTANCE. A SET OF AS -BUILT DRAWINGS SHALL BE SUBMITTED TO THE CITY OF EDMONDS PRIOR TO FINAL APPROVAL OF THE BUILDING OCCUPANCY/FINAL PROJECT APPROVAL. 6. ELEVATIONS SHOWN ARE IN FEET. SEE SURVEY FOR BENCHMARK INFORMATION. 7. THE LOCATIONS OF EXISTING UTILITIES AND SITE FEATURES SHOWN HEREON HAVE BEEN FURNISHED BY OTHERS BY FIELD SURVEY OR OBTAINED FROM AVAILABLE RECORDS AND SHOULD THEREFORE BE CONSIDERED APPROXIMATE ONLY AND NOT NECESSARILY COMPLETE. IT IS THE SOLE RESPONSIBILITY OF THE CONTRACTOR TO INDEPENDENTLY VERIFY THE ACCURACY OF ALL UTILITY LOCATIONS SHOWN AND TO FURTHER DISCOVER AND PROTECT ANY OTHER UTILITIES NOT SHOWN HEREON WHICH MAY BE AFFECTED BY THE IMPLEMENTATION OF THIS PLAN. CONTRACTOR SHALL VERIFY LOCATION, DEPTH, SIZE, TYPE AND CONDITION OF EXISTING UTILITY LINES AT CONNECTION OR CROSSING POINTS BEFORE TRENCHING FOR NEW UTILITIES. ENGINEER ASSUMES NO RESPONSIBILITY FOR THE COMPLETENESS OR ACCURACY OF THE EXISTING UTILITIES AND SITE FEATURES PRESENTED ON THESE DRAWINGS. ENGINEER SHALL BE NOTIFIED IMMEDIATELY OF CONFLICTS THAT ARISE. 8. CONTRACTOR SHALL LOCATE AND PROTECT ALL UTILITIES DURING CONSTRUCTION AND SHALL CONTACT THE UNDERGROUND UTILITIES LOCATION SERVICE (1-800-424-5555) AT LEAST 48 HOURS PRIOR TO CONSTRUCTION. 9. CONTRACTOR SHALL VERIFY ALL CONDITIONS AND DIMENSIONS AT THE PROJECT SITE BEFORE STARTING WORK AND SHALL NOTIFY OWNER'S REPRESENTATIVE OF ANY DISCREPANCIES. 10. PIPE LENGTHS WHERE SHOWN ARE APPROXIMATE AND MAY CHANGE DUE TO FIELD CONDITIONS. 11. CONTRACTOR SHALL OBTAIN A COPY OF THE GEOTECHNICAL REPORT (WHERE APPLICABLE) AND SHALL THOROUGHLY FAMILIARIZE HIMSELF WITH THE CONTENTS THEREOF. ALL SITE WORK SHALL BE PERFORMED IN STRICT COMPLIANCE WITH THE RECOMMENDATIONS OF THIS REPORT. 12. STRUCTURAL FILL MATERIAL AND PLACEMENT SHALL CONFORM TO THE RECOMMENDATIONS OF THE PROJECT GEOTECHNICAL REPORT. 13. SUBGRADE SOILS IN ALL AREAS WHERE RAIN GARDENS, INFILTRATION OR PERVIOUS PAVEMENT IS TO BE PLACED SHALL BE DELINEATED AND PROTECTED AT ALL TIMES FROM COMPACTIVE ACTIVITIES (i.e. HEAVY EQUIPMENT, STOCKPILING). 14. MANHOLES, CATCH BASINS, UTILITIES AND PAVEMENT SHALL BEAR ON MEDIUM DENSE TO VERY DENSE NATIVE SOIL OR COMPACTED STRUCTURAL FILL. IF SOIL IS DISTURBED, SOFT, LOOSE, WET OR IF ORGANIC MATERIAL IS PRESENT AT SUBGRADE ELEVATION, REMOVE AND REPLACE WITH COMPACTED STRUCTURAL FILL PER GEOTECHNICAL REPORT. 15. SEE SURVEY AND ARCHITECTURAL DRAWINGS FOR DIMENSIONS AND LOCATIONS OF BUILDINGS, LANDSCAPED AREAS AND OTHER PROPOSED OR EXISTING SITE FEATURES. 16. SEE ARCHITECTURAL DRAWINGS FOR PERIMETER FOUNDATION DRAINS. FOUNDATION DRAINS SHALL BE INDEPENDENT OF OTHER SITE DRAIN LINES AND SHALL BE TIGHTLINED TO THE STORM DRAIN SYSTEM WHERE INDICATED ON THE PLANS. 17. ALL REQUIRED STORMWATER FACILITIES MUST BE CONSTRUCTED AND IN OPERATION PRIOR TO INSTALLATION OF ANY PAVEMENT UNLESS OTHERWISE APPROVED BY THE ENGINEER. 18. ALL ROOF DRAINS, PERIMETER FOUNDATION DRAINS, CATCH BASINS AND OTHER EXTERNAL DRAINS SHALL BE CONNECTED TO THE STORM DRAINAGE SYSTEM, UNLESS NOTED OTHERWISE. 19. ALL FOOTING DRAINS SERVING BUILDINGS, WALLS, ROCKERIES, ETC. SHALL CONNECT TO THE DRAINAGE SYSTEM DOWNSTREAM OF THE SITE STORMWATER DETENTION SYSTEM. 20. CONTRACTOR SHALL OBTAIN AND PAY FOR ALL PERMITS REQUIRED FOR INSTALLATION OF ALL SITE IMPROVEMENTS INDICATED ON THESE DRAWINGS. 21. A SEPARATE IRRIGATION PERMIT MUST BE OBTAINED FROM THE CITY PUBLIC WORKS DEPARTMENT. PRIOR TO FINAL CONSTRUCTION ACCEPTANCE, PROVIDE TO THE CITY WATER QUALITY TECHNICIAN, A COPY OF THE BACKFLOW TEST REPORT. TEST REPORTS CAN BE FAXED TO 425-744-6057 OR EMAILED TO JEFF.KOBLYK@EDMONDSWA.GOV. BACKFLOW TESTING SHALL BE COMPLETED BY THE OWNER ANNUALLY THEREAFTER. 22. AS A MINIMUM REQUIREMENT, ALL DISTURBED AREAS ON AND OFF SITE SHALL BE RETURNED TO THE EQUIVALENT OF THEIR PRECONSTRUCTION CONDITION IN ACCORDANCE WITH APPROPRIATE REQUIREMENTS AND STANDARDS. 23. ALL DISTURBED SOIL AREAS SHALL BE COMPOST AMENDED AND SEEDED OR STABILIZED BY OTHER ACCEPTABLE METHODS FOR THE PREVENTION OF ON -SITE EROSION AFTER THE COMPLETION OF CONSTRUCTION. SEE EROSION CONTROL PLANS FOR SPECIFIC GRADING AND EROSION CONTROL REQUIREMENTS. 24. THE CONTRACTOR SHALL KEEP OFF -SITE STREETS CLEAN AT ALL TIMES BY SWEEPING. WASHING OF THESE STREETS WILL NOT BE ALLOWED WITHOUT PRIOR APPROVAL. 25. THIS PROJECT IS NOT A BALANCED EARTHWORK PROJECT. BOTH EXPORT AND IMPORT OF SOIL AND ROCK MATERIALS ARE REQUIRED. 26. SLOPE OF FINISHED GRADE SHALL BE CONSTANT BETWEEN FINISHED CONTOURS OR SPOT ELEVATIONS SHOWN. 27. FINISHED GRADE SHALL SLOPE AWAY FROM BUILDING WALLS AT MINIMUM 5% SLOPE FOR A MINIMUM DISTANCE OF 10 FEET. 28. CONTRACTOR SHALL BE RESPONSIBLE FOR AND SHALL INSTALL AND MAINTAIN SHORING AND BRACING AS NECESSARY TO PROTECT WORKERS, EXISTING BUILDINGS, STREETS, WALKWAYS, UTILITIES AND OTHER EXISTING AND PROPOSED IMPROVEMENTS AND EXCAVATIONS AGAINST LOSS OF GROUND OR CAVING EMBANKMENTS. CONTRACTOR SHALL ALSO BE RESPONSIBLE FOR REMOVAL OF SHORING AND BRACING, AS REQUIRED. 29. CONTRACTOR SHALL OBTAIN APPROVAL FROM THE CITY AND FOLLOW CITY PROCEDURES FOR ALL WATER SERVICE INTERRUPTIONS, HYDRANT SHUTOFFS, STREET CLOSURES OR OTHER ACCESS RESTRICTIONS. CONTRACTOR SHALL NOT RELOCATE OR ELIMINATE ANY HYDRANTS WITHOUT FIRST OBTAINING WRITTEN APPROVAL FROM THE FIRE MARSHAL. 30. COORDINATE AND ARRANGE FOR ALL UTILITY CONNECTIONS, UTILITY RELOCATIONS AND/OR SERVICE INTERRUPTIONS WITH THE AFFECTED OWNERS AND APPROPRIATE UTILITY COMPANIES. CONNECTIONS TO EXISTING UTILITIES SHALL BE MADE ONLY WITH ADVANCE WRITTEN APPROVAL OF THE AUTHORITIES GOVERNING SAID UTILITIES. 31. ALL UTILITIES SHALL BE PLACED UNDERGROUND. 32. EXISTING UTILITY LINES IN SERVICE WHICH ARE DAMAGED DUE TO CONSTRUCTION WORK SHALL BE REPAIRED AT CONTRACTOR'S EXPENSE AND INSPECTED AND ACCEPTED BY CITY OF EDMONDS AND OWNER'S REPRESENTATIVE PRIOR TO BACKFILLING. 33. NEW UTILITY LOCATIONS ARE GENERALLY SHOWN BY DIMENSION, WHERE NO DIMENSIONS ARE INDICATED, LOCATIONS MAY BE SCALED FROM DRAWINGS. FIELD ADJUSTMENTS SHALL BE APPROVED BY OWNER'S REPRESENTATIVE AND CITY. 34. FIELD STAKE ALL UTILITY STUBS AT THE PROPERTY LINE. 35. TRENCH BACKFILL OF UTILITIES LOCATED WITHIN THE CITY RIGHT-OF-WAY SHALL BE COMPACTED TO 95%. COMPACTION TEST REPORTS SHALL BE PROVIDED TO THE CITY PRIOR TO PAVING. 36. WHERE NEW PIPE CLEARS AN EXISTING OR NEW UTILITY BY 6" OR LESS, PLACE POLYETHYLENE PLASTIC FOAM AS A CUSHION BETWEEN THE UTILITIES. 37. SEE MECHANICAL DRAWINGS (WHERE APPLICABLE) FOR CONTINUATION OF SITE UTILITIES WITHIN THE BUILDING. 38. SEE ELECTRICAL DRAWINGS (WHERE APPLICABLE) FOR EXTERIOR ELECTRICAL WORK. 39. SEE LANDSCAPE DRAWINGS (WHERE APPLICABLE) FOR SITE IRRIGATION SYSTEM. 40. PIPE MATERIAL AND SIGNAGE SUBMITTALS SHALL BE PROVIDED TO CITY ENGINEERING DIVISION FOR APPROVAL PRIOR TO INSTALLATION. WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PLN 2020-0040 Key Plan Registration 12/28/2020 FUM ►N6INEERIN6 4NERVICES 4715142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title GENERAL NOTES Revisions Scale: FES Project No: 20068 Date: OCTOBER 01, 2020 Designed: DAF Drawn: DAF Checked: DAF Attachment 5 APPROVED FOR CONSMCTlON CITY OF EDMONDS DATE.• By. CITY ENGINEERING DIVISION Sheet Number C1.1 Packet Pg. 50 5.1.a 00446700000400 00446700000300 00446700000200 00446700000100 j o c� I I� Ij I� ------� 1 I Q Al Co A 1 o I r^ J23726 ;4 n / I�l ONC C. z 1/ ° I o V h ° / I I ' \�O ' V ' 1® LOT AREA 21,506 SF Q Q ' 27033600400500 `s<v, W I o j � I ' CB RIM=358.16 v I IE 9'\\RCP(E)=355.24 v I GRAVEL I 0 0 0 0 0 0 CB RIM=354.90 , o i I - SD IE 8" PVC(W)=352.90 BOLLARDS 0 ASPHALT --J I SDI IE 4" PVC(N)=353.10 I i SD CB RIM=352.34 CB RIM=353.22 / i CONC. l ' IE 12" CPP(E)=348.14 I ,' IE 12" CPP(W)=348.62 i I - i\ IE 12" CPP(S)=348.14 / IE 8" PVC(E)=351.47 -0- GPM GPM GPM G -GPM N 88' 13'02" W ° ° ' 122.45'-- i N B I b - CONCRETE WALK �\ ,- I ----SD--�-2 .16- ' - SS25.0'----- ❑ -----=--------- 147.66' SS I i 30' 1I. N 0 TES I I I ''III Y� I I I �I �I I S I SSMH RIM=355.16 IE 8" PVC(N)=346.61 IE 8" PVC(S)=346.51 I / I 25. y Lo ASPHALT END FENCE 0.4'(N) & / 3.4'(E) OF CORNER FOUND REBAR W/CAP STAMPED 'SVP 32442" AT CORNER I \ I \ I I \ I I I I I I I I I I I I I I I I I I I I I \ I 00446700001500 00446700001600 ��\ V HOUSE 123715 1/1L1 1/1.11� 12" 14" N 88'13'02" W 162.00' C C T 00446700002700 / I• / FOUND 4"x4" CONC. MON. W/2" / BRASS DISK & PUNCH AT SURFACE. VISITED 11-12-19. CONC. BLOCK 11 I WA I FENCE COR. 0.2'(N) X o xv ' o I I I \ \ \ OF PROPERTY LINE FENCE INT 0.2'(S) OF PROPERTY LINE �? i CONC. jii ASPHALT \ S ( )()- - - - - - - - - - - - I I N 88' 13'02" W C R 1 193.82' �� _ S S. V V . SSMH RIM=,358.51 IE 8" PVC(W)=341.54 IE 8" PVC(E)=341.64 ---------------- FOUND 1 " IRON PIPE------- 0.2'(S) OF CORNER FOUND REBAR W/ILLEGIBLE CAP 0.2'(S) OF CORNER °' ' Lw o Q 30' i / / a - z i V) 0 i 00615800000100 30, / I I I 1.) THIS SURVEY HAS BEEN PREPARED FOR THE EXCLUSIVE USE OF PARTIES WHOSE NAMES APPEAR HEREON ONLY, AND DOES NOT EXTEND TO ANY UNNAMED THIRD PARTIES WITHOUT EXPRESS RECERTIFICATION BY THE LAND SURVEYOR. 2.) BOUNDARY LINES SHOWN AND CORNERS SET REPRESENT DEED LOCATIONS; OWNERSHIP LINES MAY VARY. NO GUARANTEE OF OWNERSHIP IS EXPRESSED OR IMPLIED. THIS SURVEY PERFORMED WITHOUT THE BENEFIT OF A TITLE REPORT AND DOES NOT PURPORT TO SHOW ALL EASEMENTS, RESTRICTIONS, RESERVATIONS, i AND OCCUPATION WHICH MAY ENCUMBER TITLE TO OR USE OF THIS PROPERTY. I ❑ CB RIM=355.95 IE 8" RCP(N) SS I I � I FOUND CASED CONC. MON. W/2" BRASS DISK & PUNCH. DOWN i 0.6'. VISITED 11-18-19. I J \`� FOUND CASED CONC. MON. W/2" \ BRASS DISK & PUNCH. DOWN 0.6'. VISITED 11-18-19. \ SDMH RIM=361.15 \ \ IE 12" RCP(S)=354.65 \ IE 8" RCP(NE)=354.90 IE 8" RCP(W)=354.90 / \ - - - -N 82'30 22" W 79. 00' Ty PL j0 FOUND CASED CONC. MON. W/2" BRASS DISK & PUNCH. DOWN 0.6'. VISITED 11-18-19. \ I I Iw w I I I I I I I EQUIPMENT &PROCEDURES LEGAL DESCRIPTION METHOD OF SURVEY SURVEY PERFORMED BY FIELD TRAVERSE INSTRUMENTATION: LEICA TS 15 ROBOTIC ELECTRONIC TOTAL STATION PRECISION: MEETS OR EXCEEDS STATE STANDARDS WAC 332-130-090 BASIS OF BEARING: THE MONUMENTED CENTERLINE OF 237TH PL. S.W., AS THE BEARING OF N 59'5539" W. SURVEY REFERENCES (R1)PLAT OF FIR MEADOWS NO. 5 - VOL. 17, PG. 48 (R2)PLAT OF FIR MEADOWS - VOL. 15, PG. 62 (R3)PLAT OF WOODHAVEN - VOL. 14, PG. 8 LINE TABLE LINE LENGTH BEARING L 1 20.96 N 07'29'38" E CURVE TABLE CURVE LENGTH RADIUS DELTA C 1 210.43 520.00 23' 11 '09 " C2 88.25 75.00 67'25' 17" C3 208.30 2148.01 5'33'22" C4 59.89 2148.01 1'35'51 " C5 148.41 1 2148.01 3*57'31 " SDMH RIM=352.95 A IE 12" CPP(N)=345.65 IE 12" CPP(W)=344.20 IE 12" CPP(S)=344.20 SSMH RIM=353.22 B IE 8" PVC(N)=342.67 IE 8" PVC(W)=342.67 IE 8" PVC(S)=342.57 �1� W R\ WAS•yt'�,�% co o 37536 \DNALS LAI`� PARCEL A: THE SOUTH 169 FEET OF THE EAST 135 FEET OF THE EAST HALF OF THE NORTHEAST QUARTER OF THE NORTHEAST QUARTER OF THE SOUTHWEST QUARTER OF SECTION 36, TOWNSHIP 27 NORTH, RANGE 3 EAST, W.M., IN SNOHOMISH COUNTY, WASHINGTON, EXCEPT THE SOUTH 20 FEET,• AND EXCEPT THAT PORTION LYING EASTERLY OF THE WESTERLY LINE OF 100TH AVENUE WEST. PARCEL B: THAT PORTION OF THE SOUTH 169 FEET OF THE NORTH HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 36, TOENSHIP 27 NORTH, RANGE 3 EAST, W.M., IN SNOHOMISH COUNTY, WASHINGTON, LYING WESTERLY OF 100TH AVENUE WEST,• EXCEPT THEREFROM THAT PORTION TAKEN BY SNOHOMISH COUNTY BY AGREED JUDGEMENT AND DECREE OF APPROPRIATION FILED MARCH 14, 1972 UNDER SNOHOMISH COUNTY SUPERIOR COURT CAUSE NO. 107987. SITUATE IN THE COUNTY OF SNOHOMISH, STATE OF WASHINGTON. VER TI CAL DATUM � NA VD 88 FOUND CASED CONC. MON. W/2" BRASS DISK & PUNCH AT THE INTERSECTION OF 99TH PL. W. AND 237TH PL. S. W. ELEV = 341.33' LEGEND • SET 1/2" X 24" REBAR W/CAP STAMPED 'PCS 37536" O EXISTING REBAR W/CAP, AS NOTED X SET NAIL AND WASHER STAMPED "PCS 37536" + SET TACK IN LEAD W/ WASHER STAMPED 'PCS 37536" xi EXISTING NAIL AND WASHER AS NOTED OFOUND CONCRETE MONUMENT AS NOTED RIGHT OF WAY CENTERLINE Q❑ STORM DRAIN MANHOLE ❑ CATCH BASIN N WATER VALVE ® WATER METER Q SANITARY SEWER MANHOLE o MAILBOX -0- UTILITY/POWER POLE GUY ANCHOR LIGHT POLE Z TRAFFIC SIGNAL JUNCTION BOX �j GAS VALVE CEDAR TREE SCALE: 1 " = 20' D 20 40 Attachment 5 1 Packet Pg. 51 NW 1/4 SE 1/4 SEC. 36, T. 27N., R. 03E, W.M. WOODWAY STATION 5.1.a 00446700000300 1 -------------- ®1 1 00446700000200 1 V'" -------------- �ti W Q can IO 00446700000100 CB RIM=352.34 IE 12: CPP(E)= IE 12 CPP(S)= S I SSMH RIM=355.16 I 1 IE 8' PVC(N)=346.61 I IE 8' PVC(S)=346.51----------------- I I � I 1 I I I 1 00446700002700 I 1 00446700001600 I I I I I 3 ASPHALT HOUSE I K 123715 %1 I tivu rtivLt u.4 w��CA 3.4'(E) OF COR ER "SVP 32442"1 I i i r:rxnin OB ORANGE BARRIER FENCE X SILT FENCE LIMITS OF CLEARING AND GRADING L\ ASPHALT/CONCRETE TO BE REMOVED 4� L —1 — �._ —L o.) CONSTRUCTION ACCESS pl r0 to Q0v� a 9101,22 d INLET PROTECTION STOCKPILE AREA — — — — — — — — SAWCUT LINE REMOVE CURB t t t fREMOVE GRAVEL + + CONSTRUCTION SEQUENCE NOTES SDMH RIM=361.15 IE 12' RCP (S)=354.65 1. SCHEDULE A PRE -CONSTRUCTION MEETING WITH CITY ENGINEERING DIVISION AT IE 8" RCP(NE)=354.90 IE R" Qf'pIW)=354.90 425-771-0220, EXT. 1326. TWO DAY (48 HR) NOTICE IS REQUIRED. N 82'30' 2. REVIEW TEMPORARY EROSION AND SEDIMENT CONTROL NOTES. w 79 00' � 237TH P�2» � 3. CALL FOR UTILITY LOCATES. 4. INSTALL TESC MEASURES AND MAINTAIN DUST CONTROL WHILE PREVENTING DISTURBANCE OF ANY AREAS OF VEGETATION OUTSIDE THE CONSTRUCTION ZONE. 5. HAVE EROSION CONTROL MEASURES INSPECTED BY CITY OF EDMONDS CITY ENGINEERING INSPECTOR. ALL TEMPORARY SEDIMENTATION AND EROSION CONTROL MEASURES MUST BE IN PLACE AND INSPECTED PRIOR TO ANY CONSTRUCTION OR SITE CLEARING. EROSION AND SEDIMENTATION CONTROL PRACTICES AND/OR DEVICES SHALL BE MAINTAINED UNTIL PERMANENT VEGETATION IS ESTABLISHED. Va 6. DEMOLISH EXISTING STRUCTURES. 7. ROUGH GRADE SITE AS REQUIRED TO INSTALL DRAINAGE FEATURES. 8. CLEAR, GRUB & ROUGH GRADE SITE. REVEGETATE DISTURBED AREAS NOT SUBJECT TO ADDITIONAL SURFACE DISTURBANCE IMMEDIATELY AFTER ROUGH GRADING. (OTHER EXPOSED AREAS SHALL BE STABILIZED PER EROSION CONTROL NOTES BELOW). 9. INSTALL UTILITIES AND OTHER SITE IMPROVEMENTS, INCLUDING FRONTAGE IMPROVEMENTS. 10. STABILIZE AND COMPOST AMEND ALL EXPOSED SOILS PRIOR TO REVEGETATION OF ENTIRE SITE. 11. ESTABLISH LANDSCAPING AND PERMANENT VEGETATION. ALL TEMPORARY EROSION CONTROL MEASURES SHALL BE REMOVED UPON FINAL SITE STABILIZATION AND APPROVAL BY CITY INSPECTOR. CONSTRUCTION NOTES OSTABILIZED CONSTRUCTION ENTRANCE PER DETAIL ON SHEET C3.1 OFILTER FABRIC (SILT) FENCE PER DETAIL ON SHEET C3.1 OSAWCUT FULL DEPTH OINSTALL ORANGE BARRIER FENCE AROUND INFILTRATION AREA. AREA MUST NOT BE SUBJECT TO CONSTRUCTION EQUIPMENT COMPACTION. OSTORM INLET PROTECTION PER DETAIL ON SHEET C2.1 OPLASTIC COVERED STOCKPILE PER DETAIL ON SHEET C2.1 OREMOVE DRIVEWAY ENTRANCE OREMOVE CONCRETE SIDEWALK OREMOVE CURB, GUTTER, AND SIDEWALK 1 Q REMOVE EXISTING STRUCTURES 11 REMOVE EXISTING WALLS AND FENCES 12 REMOVE ON -SITE PAVING 1 REMOVE LIGHT 14 REMOVE EXIST UTILITIES, BY OTHERS 15 REMOVE EXISTING SD 1 SEDIMENT TRAP - SEE DETAIL SHEET C3.1 17 INTERCEPTOR SWALE - SEE DETAIL SHEET C3.1 EARTHWORK QUANTITIES (SITE) CUT = 744 CY FILL = 84 CY NET = 660 CY CUT CONTRACTOR TO VERIFY TOPOGRAPHY, BOUNDARY, AND UTILITIES STATEMENT: FURR ENGINEERING SERVICES PLLC. DOES NOT WARRANT THE TOPOGRAPHY, BOUNDARY, AND/OR EXISTING UTILITIES SHOWN ON THESE PLANS. IT IS THE CONTRACTORS' RESPONSIBILITY TO HAVE ALL EXISTING IMPROVEMENTS FIELD VERIFIED PRIOR TO CONSTRUCTION. ANY SUBSURFACE EXPLORATION OF EXISTING UNDERGROUND UTILITIES (POWER, WATER, SEWER, TELECOM, ETC.) SHALL BE PERFORMED BY THE CONTRACTOR. DISCREPANCIES BETWEEN WHAT IS SHOWN ON THE PLANS AND LOCATED BY THE CONTRACTOR SHALL BE BROUGHT TO THE ATTENTION OF FURR ENGINEERING SERVICES PLLC.. PRIOR TO CONSTRUCTION ACTIVITIES. Know what's below. Call before you dig. A N 20 10 0 20 40 SCALE: 1 INCH = 20 FEET APPROOMD FOR CONSTRUCTION CITY OF EDMONDS DATE., BY. CITY ENGINEERING DIVISION WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 P LN Key Plan Registration 2020— 0040 10/29/2020 ruRR ENDINEERIN SERVICES 4715 142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title TESC PLAN Revisions Scale: FES Project No: Date: Designed: Drawn: Checked: Sheet Number DAF DAF DAF 20068 OCTOBER 01, 2020 C300 I Packet Pg. 52 c 2 ca co 0 0 0 0 O a N O N Z J a Attachment 5 NW 1/4 SE 1/4 SEC. 36, T. 27N., R. 03E, W.M. WOODWAY STATION 5.1.a 2" x 2" WOOD/STEEL FILTER FABRIC SECURED TO 2" x 2" 14 GA WIRE FABRIC EQUAL 2'-0" 12" NATIVE BACKFILL MATERIAL J� 8„ LJ 2'-0" FILTER FABRIC MATERIAL IN CONTINOUS ROLLS USE STAPLES OR WIRE RINGS TO ATTACH FABRIC TO WIRE 2" x 2" WOOD/STEEL POSTS WIRE MESH FENCE TO SUPPORT FILTER FABRIC 2'-6" '-BURY BOTTOM OF FILTER MATERIAL 8"6TQ ,4 NOTES: 1. CONTRACTOR/DEVELOPER SHALL MAINTAIN AND ENSURE PROPER EROSION CONTROL THROUGHOUT PROJECT. 2. SILT FENCE TO BE PLACED DOWNSLOPE OF CONSTRUCTION ACTIVITY. `st. 18y., CITY INSPECTION REQUIRED ON ALL EROSION CONTROL METHODS BEFORE OTHER WORK CAN BEGIN REVISION DATE CITY OF EDMONDS FILTER FABRIC FENCE JANUARY 2018 FILTRATION SYSTEMS PUBLIC WORKS STANDARD DEPARTMENT DETAIL APPROVED BY: R. ENGLISH E R— 9 0 0 3.5' — 5' FLAT BOTTOM 11' MIN 3:1 1_ 4 MINLIT 3:1 1' MIN OVERFLOW 1' MIN DISCHARGE TO STABILIZED 7Lr CONVEYANCE, OUTLET OR LEVEL SPREADER RIP RAP 3/4'-1 1/2 WASHED GRAVEL 2"-4" ROCK NOTE: TRAP MAY BE FORMED BY BERM GEOTEXTILE OR BY PARTIAL EXCAVATION CROSS SECTION MAINTENANCE STANDARDS 1. SEDIMENT SHALL BE REMOVED FROM THE TRAP WHEN IT REACHES 1 FOOT IN DEPTH 2. ANY DAMAGE TO THE TRAP EMBANKMENTS OR SLOPES SHALL BE REPAIRED SEDIMENT TRAP DETAIL NOT TO SCALE I �E FULL WIDTH TRESS/EGRESS DETAIL NOTES: 10 THE MINIMUM LENGTH SHALL BE EXTENDED AS NECESSARY TO ENSURE MATERIAL IS NOT TRACKED OFF SITE AND/OR INTO THE PUBLIC RIGHT-OF-WAY. 20 ATB DRIVEWAY RAMP AND/OR SITE ACCESS ROAD 15' WIDE MIN. SEE TABLE BELOW FOR REQUIRED LENGTH. NOTES: 1. SURFACE WATER - ALL SURFACE WATER FLOWING OR DIVERTED TOWARD CONSTRUCTION ENTRANCES SHALL BE PIPED ACROSS THE ENTRANCE. IF PIPING IS IMPRACTICAL, A MOUNTABLE BERM WITH 5:1 SLOPES WILL BE PERMITTED. 2. MAINTENANCE - THE ENTRANCE SHALL BE MAINTAINED IN A CONDITION WHICH WILL PREVENT TRACKING OR FLOWING OF SEDIMENT OFF SITE AND/OR ONTO PUBLIC RIGHT-OF-WAY. THIS MAY REQUIRE PERIODIC TOP DRESSING WITH ADDITIONAL QUARRY SPALLS AS CONDITIONS DEMAND AND REPAIR AND/OR CLEANOUT OF ANY MEASURES USED TO TRAP SEDIMENT. ALL SEDIMENT SPILLED, DROPPED, WASHED OR TRACKED OFF SITE AND/OR ONTO PUBLIC RIGHT-OF-WAY MUST BE REMOVED IMMEDIATELY. 3. WHEELS SHALL BE CLEANED TO REMOVE SEDIMENT PRIOR TO LEAVING THE SITE. WHEN WASHING IS USED, IT SHALL BE DONE ON AN AREA STABILIZED WITH QUARRY SPALLS AND WHICH DRAINS INTO AN APPROVED SEDIMENT TRAPPING DEVICE. 4. INSPECTION AND NEEDED MAINTENANCE SHALL BE PROVIDED AFTER EACH RAIN. PROJECT SIZE MIN LENGTH OF (FEET) QUARRY SPALLS* < 1/4 ACRE 30 < 1 ACRE 50 < 3 ACRE 100 > 3 ACRE 100 • PROVIDE ATB OR ASPHALT TRANSITION WHERE FRONTAGE ROAD IS AN ARTERIAL. LENGTH TO BE DETERMINED BY CITY INSPECTOR. CITY INSPECTION REQUIRED ON ALL EROSION CONTROL METHODS BEFORE OTHER WORK CAN BEGIN REVISION DATE CITY OF EDMONDS STABILIZED CONSTRUCTION JANUARY 2018 ENTRANCE PUBLIC WORKS STANDARD 4 DEPARTMENT DETAIL Fs t 189 � APPROVED BY: R. ENGLISH E R — 9 01 INTERCEPTOR SWALE NOT TO SCALE 2;1 O O O 0 O O O O O O O O O O O O C O O O e / I O A 9 FILTER ISOCK WITH OVER FLOW HOLES (TYP) a .a `st. Is9— C ^ 8 O A a a a a CITY OF EDMONDS PUBLIC WORKS DEPARTMENT GRATE FILTER SOCK WITH OVER FLOW HOLES (TYP) CATCH BASIN NOTES: CATCH BASIN 1. CONTRACTOR/DEVELOPER SHALL MAINTAIN THIS APPLICATION AT ALL TIMES DURING CONSTRUCTION PERIOD. 2. ANY SEDIMENT IN CATCH BASIN INSERT SHALL BE REMOVED WHEN INSERT IS ONE-THIRD FULL. 3. CITY INSPECTION REQUIRED ON ALL EROSION CONTROL METHODS BEFORE OTHER WORK CAN BEGIN. REVISION DATE TEMPORARY JANUARY 2018 SEDIMENT TRAP FOR CATCH BASINS STANDARD DETAIL APPROVED BY: R. ENGLISH E R— 9 0 2 Ei WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PL-N 2020-0040 Key Plan Registration rw UM 10/29/2020 SERVICES 4715142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title TESC DETAILS Revisions Scale: FES Project No: 20068 Date: OCTOBER 01, 2020 Designed: DAF Drawn: DAF Checked: DAF c 0 ca co 0 0 0 v 0 0 0 N 0 N z J P.m. Attachment 5 APPROVED FOUR COAWWC7701V CITY OF EDMONDS DATE. BY. CITY ENGINEERING DIVISION Sheet Number C30 1 1 Packet Pg. 53 NW 1/4 SE 1/4 SEC. 36, T. 27N, R. 03E, W.M. CONSTRUCTION NOTES 5.1.a RESERVED PARKING 8A1E 01�®�Ng1R RESERVED PARKING �AIE OI�BL®IMgIR VAN AO.E ADA PARKING STALL SIGN NTS 12" 1 RESERVED 12"x18" SIGN WITH INTERNATIONAL PARKING SYMBOL OF ACCESS AND "STATE 18" El DISABLED PARKING PERMIT vERreEo REQUIRED" TEXT 5'-0" 6„ MIN ADA PARKING SIGN DETAIL 2" SCH. 40 GALVANIZED PIPE CONCRETE FOUNDATION NTS EACH PARKING SPACE RESERVED FOR PERSONS WITH PHYSICAL DISABILITIES SHALL BE IDENTIFIED BY A REFLECTORIZED SIGN PERMANENTLY POSTED IMMEDIATELY ADJACENT TO AND VISIBLE FROM EACH STALL OR SPACED CONSISTING OF A PROFILE VIEW OF A WHEELCHAIR WITH OCCUPANT IN WHITE ON DARK BLUE BACKGROUND. THE SIGN SHALL NOT BE SMALLER THAN 70 SQUARE INCHES IN AREA AND SHALL BE CENTERED ON AND JUST BEYON THE FRONT EDGE OF THE PARKING STALL. SIGNS MAY ALSO BE HUNG ON THE WALL AT THE INTERIOR END OF THE PARKING SPACE. SIGN MOUNTING HEIGHT SHALL BE 60 INCHES ABOVE THE PARKING SPACE FINISHED GRADE ., I A%i Mn All WHITE DE ADA PARKING DETAIL NOT TO SCALE WOODWAY STATION I -------------------- - i I I I I I 00446700000300 ------------- ED 00446700000200 - - - - - - - - - - - - - Q O 00446700000100 IGIMVEL CB 04=352.34 IE 12" CPP(E)= IE 12" CPP(S)= OPORTLAND CEMENT CONCRETE (RIGID) PAVEMENT Min. PCC Depth Aggregate Base* Compacted Subgrade* ** 6.0 in. 6.0 in. 12.0 in. * 95% compaction based on ASTM Test Method D1557 ** A proof roll may be performed in lieu of in place density tests The asphaltic concrete depth in the flexible pavement tables should be a surface course type asphalt, such as Washington Department of Transportation (WSDOT) 1/z inch HMA. The rigid pavement design is based on a Portland Cement Concrete (PCC) mix that has a 28 day compressive strength of 4,000 pounds per square inch (psi). The design is also based on a concrete flexural strength or modulus of rupture of 550 psi. PORTLAND CEMENT CONCRETE 8 1" 3" GUTTER 2.0% 6 2.0% 6" 2" HMA ° 2" COMPACTED SUBGRADE PROOF ROLLED TO ACHIEVE 95% DENSITY 4" COMPACTED PER ASTM D-1557. DEPTH CSBC CONCRETE SLAB - GARBAGE CONTAINERS 3" ?�� M #4 REBAR @ 12" CENTERS LONGITUDINAL #4 REBAR@12" CENTERS NOT TO SCALE 3" HMA CLASS 1/2" CSBC --12" COMPACTED SUBGRADE PROOF ROLLED TO ACHIEVE 95% DENSITY PER ASTM D-1557 STANDARD ASPHALT PAVING SECTION NOTES: 1. REBAR TO BE ASTM A615, GRADE 60. 2. ALL LAP SPLICES TO BE 12" MIN.. 3. CONCRETE 3.1. PORTLAND CEMENT C-150, TYPE 2 PER ACI 318 3.2. AGGREGATE ASTM C-33 3.3. STRENGTH: 3,000PSI, 28-DAY 4. SURFACE SHALL BE SMOOTH 5. 2" MINIMUM COVER. NTS x4" CONC. MON. W/2" U SK & PUNCH AT I 6 I VISITED 11-12-19. � EG 360.44 I A `° I 50 e 5' ACCESS/SIDEWALK EASEMENT 0 o I , I fr /'I EG 359.44 I I 359.57 a ° I " 1 - 1G / I IF359.27 ° a 2 ° / h EG 359.101�1: I LW, c ,/ I Q ° 359.68 Q, I /1 O 3 %/ I O J .a / I1.50% 11.5' G n V 5' 7 10.2' �I ° . a I O ° � I a/ BOTTOM EL=357.00 I �SO I / I GCB RIM=358.1 F 6 IE NEW 8" (W)=355.24I � I I I SSMH 7RIM=358.51 I W IE 8: PV VI W IE 8 PVC(E) 3,1164 a I / L11 I CIP WALL - EX. GRADE 0.5' 4' MAX. 12" SDMH RIM=361.15 IE 12' RCP(S)=354.65 IE 8" RCP(NE)=354.90 IE 8" RCP(W)=354.90 N' 237_8230P2 _79_oo, rH L. S w- 8" "471 ASPHALT 2% B CIP RETAINING WALL DETAIL C4.0 NTS OSAWCUT/PAVEMENT RESTORATION - SEE DETAIL C4.1 ODRIVEWAY ENTRANCE - SEE DETAIL SHEET C4.1 OSIDEWALK - SEE DETAIL SHEET C4.1 4O CURB AND GUTTER - SEE DETAIL SHEET C4.1 OEXTRUDED CURB - SEE DETAIL SHEET C4.1 OMATCH EXISTING OSEE CONCRETE SLAB DETAIL - THIS SHEET OINSTALL ADA PARKING SIGN OCONCRETE PAVING OVER DRYWELL - SEE NOTE BELOW MODIFIED DRIVEWAY ENTRANCE - OMIT LEFT SIDE WING - ONLY 1 Q REPLACE RIGHT WING AND PANEL - REFER TO DETAIL TR-541 SHEET C4.1 PROPOSED LEGEND ASPHALT PAVEMENT a� a CONCRETE PAVEMENT PROPERTY BOUNDARY RD 6" ROOF DRAIN 8" STORM DRAIN - - - - - - SAWCUT LINE KEYSTONE WALL - - - - - RIDGE LINE KEYSTONE WALL NOTES 1. MINIMUM WALL EMBEDMENT IS 6". 2. SUBSURFACE SOIL TO BE COMPACTED TO 95% STANDARD PROCTOR. 3. ALL BACKFILL MATERIAL TO BE COMPACTED TO 95% STANDARD PROCTOR OR 92% MODIFIED PROCTOR. 4. APPLY KEYSTONE KAPSEAL CAP AND WALL ADHESIVE OR EQUIVALENT BETWEEN BLOCKS. 5. CONSULT KEYSTONE RETAINING WALL SYSTEMS, A CONTECH COMPANY, FOR ADDITIONAL INFORMATION AND INSTALLATION INSTRUCTIONS. 6. GEOGRID IS TO BE PLACED ON LEVEL BACKFILL AND EXTENDED OVER THE FIBERGLASS PINS. PLACE NEXT UNIT PULL GRID TAUGHT AND BACKFILL. INSIDE AND OUTSIDE CORNERS AND JOINTS SHALL OVERLAP. BMP T5.13 SOIL AMENDMENT AMEND EXISTING SITE TOPSOIL OR SUBSOIL EITHER AT DEFAULT AO "PRE -APPROVED" RATES, OR AT CUSTOM CALCULATED RATES BASED ON TESTS OF THE SOIL AND AMENDMENT. 0� 2.25' ± I KEYSTONE WALL APPLY ADHESIVE BETWEEN BLOCKS 31 (TYP) --� I ,<\/ TOPOGRAPHY, BOUNDARY, AND UTILITIES STATEMENT: FURR ENGINEERING SERVICES PLLC. DOES NOT WARRANT THE TOPOGRAPHY, BOUNDARY, AND/OR EXISTING UTILITIES SHOWN ON THESE PLANS. IT IS THE CONTRACTORS' RESPONSIBILITY TO HAVE ALL EXISTING IMPROVEMENTS FIELD VERIFIED PRIOR TO CONSTRUCTION. ANY SUBSURFACE EXPLORATION OF EXISTING UNDERGROUND UTILITIES (POWER, WATER, SEWER, TELECOM, ETC.) SHALL BE PERFORMED BY THE CONTRACTOR. DISCREPANCIES BETWEEN WHAT IS SHOWN ON THE PLANS AND LOCATED BY THE CONTRACTOR SHALL BE BROUGHT TO THE ATTENTION OF FURR ENGINEERING SERVICES PLLC.. PRIOR TO CONSTRUCTION ACTIVITIES. Az' 3' R PA R ID UNDER PARKING EXTRUDED CURB A KEYSTONE WALL DETAIL C4.0 NTS Know what's below. Call before you dig. 20 10 0 20 40 SCALE: 1 INCH = 20 FEET APPROVED FOR CONSTRUCnON CITY OF EDMONDS DATE.• BY. CITY ENGINEERING DIVISION WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PLN 2020-0040 Key Plan Registration 12/28/2U20 FURRCNOINEERINi ZURVIIM 4715 142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title GRADING PLAN Revisions Scale: FES Project No: 20068 Date: OCTOBER 01, 2020 Designed: DAF Drawn: DAF Checked: DAF Sheet Number C400 I Packet Pg. 54 C 2 ca co 0 0 0 v 0 0 0 N 0 N Z J Pm. Attachment 5 NW 1/4 SE 1/4 SEC. 36, T. 27N., R. 03E, W.M. WOODWAY STATION 5.1.a / pRp VEWq r T Pq�S�T/O w�Or ERA Sq�4PR�C 0 90 EC N HOP DR�V� PROVED BRn'gTe / q r qT aP r can, ° A R eR� CINE Q EXPANSION EXPANSION P} JOINT _ JOINT SEE DRIVEWAY 24' CURB 3 ,M,qk %� J �` TRANSITIONAL Mqk I" /4Z 4f DETAIL BELOW {00 Gq U'� MMfRO�� DRIVEWAY APPROACH CONCRETE CURB AND GUTTER, SEE / 0 COE STD DTL TR-520 6' TYP 1 EXISTING PAVEMENT FULL DEPTH MAX 15' 1/2 EXPANSION 2' MIN JOINT SAWCUT 8.,3 O4 7 2 MAX 6" CURB MAX SLOPE r . ,..�.: 3 2 SECTION A -A DRIVEWAY CURB TRANSITIONAL DETAIL FOR CURB AND GUTTER OR VERTICAL CURBS NOTES: O PCURB RIOR N G R ER SHALL BE POURED SEPARATELY FROM THE SIDEWALK. CITY INSPECTION REQUIRED ON FORM WORK O DRIVEWAY APRON INCLUDING WING RAMPS SHALL BE A MINIMUM OF 6" THICK AND SHALL BE PLACED ON 2" OF 5/8" CSTC COMPACTED TO 95% MAXIMUM DENSITY. O3 SUBGRADE SHALL BE COMPACTED TO 95% MAXIMUM DENSITY, O 2' ASPHALT SAWCUT MAY BE REQUIRED WITH CURB/GUTTER INSTALLATION. REFER TO COE STD DTL TR-520. O5 CONCRETE SHALL BE CLASS 3000. O CURB TRANSITION SHOULD MAINTAIN A SLOPE NO GREATER THAN 8.3%. IF THE SLOPE REQUIREMENT CANNOT BE ACHIEVED, MAXIMUM CURB THE TRANSITION LENGTH SHALL BE 15-FEET. O7 MAINTAIN 1/2" LIP AT GUTTER. O8 IF DRIVEWAY WIDTH EXCEEDS 15', INSTALL A FULL DEPTH EXPANSION JOINT AT CENTER OF DRIVEWAY. O9 INSTALL MINIMUM 5-FT TRANSITION PANEL BETWEEN DRIVEWAYS AND WHEN CONNECTING TO EXISTING SIDEWALK. 10 FINISH SHALL BE LIGHT BROOM. REVISION DATE CITY OF EDMONDS DRIVEWAY APPROACH JANUARY 2018 TYPE I PUBLIC WORKS STANDARD DEPARTMENT DETAIL APPROVED BY: R. ENGLISH T R - 5 41 III PLAN VIEW (NOT TO SCALE) 5' MIN FULL DEPTH 1/2" EXPANSION CURB/GUTTER JOINT MATERIAL SEE COE STD DTL TR-520 2% MAX a a 1/2" R 4 4. 4 d 1 /2" R 4 a a a a a a a a 2" MIN 5/8" MINUS CSTC ON NATIVE BEARING SOIL SECTION VIEW SEE NOTE 9 NOTES: (NOT TO SCALE) 1. CITY INSPECTION REQUIRED ON FORM WORK PRIOR TO POUR. 2. CONCRETE SHALL BE CLASS 3000. 3, FINISH SHALL BE LIGHT BROOM. 4. SIDEWALK THICKNESS SHALL BE 4". 5. SIDEWALK THICKNESS AT DRIVEWAYS SHALL BE 6" THICK. 6. CURB AND GUTTER SHALL BE POURED SEPARATELY FROM SIDEWALK. 7. LIDS FOR JUNCTION BOXES AND UTILITY VAULTS SHALL BE NON-SKID AS SPECIFIED BY ENGINEER. 8. SEE COE STD DTL TR-550 FOR POSSIBLE ROOT BARRIER INSTALLATION. 9. SUBGRADE SHALL BE COMPACTED TO 95% MAXIMUM DENSITY. 10. ALL EDGES WITH EXPANSION JOINTS SHALL HAVE J" RADIUS CITY OF EDMONDS PUBLIC WORKS DEPARTMENT CONCRETE SIDEWALK APPROVED BY: R. ENGLISH REVISION DATE JUNE 2019 STANDARD DETAIL TR-531 R-1 /2" 5-1 /2" � I� R=1 " 1" BATTER R=1 " N 0.05 FT/FT 74 co 4 a 2' MIN SAWCUT SEE NOTE 10 " / J 4 -5 8"18" STANDARD 6"-5/8" MINUS CSTC I+ SEE NOTE 11 _ I MINUS CSTC STANDARD TYPE "A" CURBfGUTTER (NOT TO SCALE) NOTES: HMA 4" OR MATCH EXISTING, WHICHEVER IS GREATER SEE NOTE 12 1. CITY INSPECTION REQUIRED ON FORM WORK PRIOR TO POUR. 2. FORMS SHALL BE TRUE TO LINE AND GRADE AND SECURELY STAKED. 3. EXPANSION JOINTS SHALL BE PLACED ADJACENT TO ANY STRUCTURE. 4. EXPANSION JOINTS SHALL BE EVERY 10 FEET. 5. EXPANSION JOINTS SHALL HAVE 1/2" TO 5/8" WIDE PREMOLDED JOINT FILLER. 6. CONCRETE SHALL BE CLASS 3000. 7. FINISH SHALL BE LIGHT BROOM. 8. CURB SHALL BE SPRAYED WITH CLEAR CURING COMPOUND OR SHALL BE COVERED AND KEPT MOIST FOR 72 HOURS. 9. REMOVAL/REPLACEMENT OF CONCRETE CURB SHALL BE FROM EXPANSION TO EXPANSION JOINT, UNLESS OTHERWISE DIRECTED BY CITY ENGINEER. 10, A 2-FT MINIMUM ASPHALT SAWCUT MAY BE REQUIRED AS DETERMINED BY CITY ENGINEER. 11. CURB/GUTTER SHALL BE 18" OR AS DIRECTED BY CITY ENGINEER. 12. ALL VERTICAL EDGES SHALL BE TACKED. `St. 18`_�" REVISION DATE CITY OF EDMONDS CONCRETE CURB [JANUARY 2018 AND GUTTER PUBLIC WORKS STANDARD DEPARTMENT DETAIL APPROVED BY: R. ENGLISH TR-520 0 z Y a. 0 z 1 w z g 5 w LL c� Z y M D U J ¢ 6- 0 o_ O N 12" MIN W/ fl A 2 STROKE m z PAINTED m STRIPING O z O D Z 20' MIN OO -4" PERIMETER STRIPING (TO BE 6" OFFSET FROM CURB OR EDGE OF PAVEMENT 12� _ NO PARKING z. ANY TIME x FIRE T LANE * THE USE OF SIGNS REQUIRES FIRE MARSHAL APPROVAL NOTES: 10 FIRE LANE MUST MEET ALL MINIMUM CITY OF EDMONDS DRIVEWAY/ACCESS STANDARDS AND SOUTH SNOHOMISH COUNTY REGIONAL FIRE AUTHORITY'S (SSCRFA) FIRE LANE STANDARD. O FIRE LANE SHALL MAINTAIN AN UNOBSTRUCTED MINIMUM WIDTH OF 20' UNLESS APPROVED BY THE FIRE MARSHAL. O FIRE LANE TO BE ASPHALT OR APPROVED EQUIVALENT. O4 FIRE LANE SHALL MAINTAIN AN UNOBSTRUCTED MINIMUM VERTICAL CLEARANCE OF 13.5'. O FIRE LANE SHALL NOT HAVE A GRADE EXCEEDING 12% UNLESS APPROVED BY SSCRFA. O PAINTED STRIPING SHALL BE YELLOW IN COLOR. O REFER ALSO TO CITY OF EDMONDS AND SSCRFA FIRE LANE STANDARD FOR CIRCULATION AND TURN-AROUNDS. REVISION DATE CITY OF EDMONDS FIRE LANE SPECIFICATIONS JANUARY 2018 (MULTI -FAMILY AND PUBLIC WORKS COMMERCIAL) STANDARD DEPARTMENT DETAIL s 1Sg� APPROVED BY: R. ENGLISH TR-567 i 1/2" MINI CONSTRUCT OUT OF HMA PAVEMENT CONCRETE CURB SHALL BE NO LESS THAN 3" IN HEIGHT 1 2-1/2"� " R=1-1/2" R=1„ 1 ''J PLACE SCORE MARKS EVERY 10' SLOPE 1:1 Z as t a a. 4 a. DRIVEWAY WING OR CURB RAMP SLOPE EXTEND PAVEMENT 1.3' FROM THE FACE OF CURB IF NECESSARY TO SUPPORT EXTRUDED CURB m U 0 w U NOTES: L PLACE 6" COMPACTED 5/8" CSTC BELOW HMA EXTENSION 1. NOT TO BE USED IN RIGHT-OF-WAY EXCEPT TO REPAIR EXISTING EXTRUDED CURB, AS APPROVED BY CITY ENGINEER. 2. BONDING AGENT IS THE ONLY ATTACHMENT METHOD TO BE USED BETWEEN HMA AND EXTRUDED CURB. 3. CONCRETE SHALL BE AIR -ENTRAINED CLASS 3000 PER WSDOT STANDARD SPECIFICATIONS. 4. NATIVE AND GRAVEL SUBGRADE SHALL BE COMPACTED TO A MINIMUM OF 95% MAX DENSITY. REVISION DATE CITY OF EDMONDS CONCRETE DECEMBER 2018 EXTRUDED CURB `St. 181�- PUBLIC WORKS STANDARD DEPARTMENT DETAIL APPROVED BY: R. ENGLISH T R- 5 2 2 FINAL JOINT SHALL BE A NEAT STRAIGHT HMA CLASS 1/2" LINE. ALL EXPOSED VERTICAL EDGES SHALL PG 58H-22 BE TACKED NEATLY PER WSDOT STANDARD (SEE NOTES 4 & 5) 1' SPECIFICATIONS 5-04.3(5)A APPROVED TACK OR APPROVED EQUAL AND SEALED PER 1' WSDOT STD 5-04.3(5)C. SLOPE EXCAVATION TO AVOID UNDERMINING EXISTING PAVEMENT. NOTES: 1. SEE CITY OF EDMONDS MODIFICATIONS TO DIVISION 9 OF THE CURRENT WSDOT STANDARD SPECIFICATIONS FOR BACKFILLING REQUIREMENTS. 2, SUBMIT PROCTOR AND DENSITY TESTS FROM CERTIFIED TESTING COMPANIES DOCUMENTING THAT THE BACKFILL MEETS A MINIMUM OF 95% DENSITY PER ASTM D 1557. 3. CSBC DEPTH SHALL BE A MINIMUM 6" OR MATCH EXISTING WHICHEVER IS GREATER. WHEN MATCHING EXISTING CSBC DEPTH GREATER THEN 6", THEN CSBC SHALL BE INSTALLED IN MULTIPLE EQUAL THICKNESS LIFTS NOT EXCEEDING 6". 4. ROADWAY HMA DEPTH SHALL BE A MINIMUM OF 4" THICK. UNLESS APPROVED BY THE ENGINEER, ANY DEPTH GREATER THAN 4" SHALL MATCH EXISTING. 5. ALLEY HMA DEPTH SHALL BE A MINIMUM OF 2" THICK. UNLESS APPROVED BY THE ENGINEER, ANY DEPTH GREATER THAN 2" SHALL MATCH EXISTING. 6. UNLESS APPROVED BY THE ENGINEER, THE HMA SHALL BE INSTALLED IN MULTIPLE EQUAL THICKNESS LIFTS NOT EXCEEDING 2". 7. FINAL PAVEMENT JOINTS SHALL BE NEATLY AND UNIFORMILY SEALED WITH WSDOT STANDARD SPECIFICATIONS 5-04.3(5)C APPROVED JOINT SEALANT OR APPROVED EQUAL. `St. JB9' CITY OF EDMONDS PUBLIC WORKS DEPARTMENT REVISION DATE TYPICAL HMA AND [FEBRUARY 2020 UTILITY PATCH STANDARD D ETAI L APPROVED BY: R. ENGLISH G U - 41 0 APPROVED FOR CC /SMC7701V CITY OF EDA401VDS DATE.• BY. CITY ENGINEERING DIVISION WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PLN 2020-0040 Key Plan Registration FLIRR 12/28/2020 / \&MCES 4715142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title ROAD DETAILS Revisions Scale: FES Project No: 20068 Date: OCTOBER 01, 2020 Designed: DAF Drawn: DAF Checked: DAF Sheet Number C40 1 Packet Pg. 55 c a co 3 0 0 0 v 0 0 0 N 0 N z J P.m. Attachment 5 NW 1/4 SE 1/4 SEC. 36, T. 27N, R. 03E, W.M. WOODWAY STATION 5.1.a - - S I SSMH RIM=355.16 TI IE 8" PVC(N)=346.61 I I IE 8 PVC(S)=346.51 _--------------- - - - - - - - - - - - - - - I 00446" 0044670 00446700 _K I W CONSTRUCTION NOTES SDMH RIM=361.15 O 20' x 20' DRYWELL - SEE DETAIL SHEET C5.1 11E 12" RCP(S)=354.65 E E8" RCP(NE)=354.90E 8" RCP(W)=354.90 O BIORETENTION - SEE DETAIL SHEET C5.1 30 Z2„ W 237Ty —79_oo, P I L. S. W O GRASS -LINED SWALE @ 3:1 OINSTALL FLOATABLE MATERIAL SEPARATOR - SEE DETAIL SHEET C5.1 ONOT USED a°I O CONCRETE PAVING OVER DRYWELL 7O SEE DETAIL SS-200, SHEET C5.1 PROPOSED LEGEND ASPHALT PAVEMENT CONCRETE PAVEMENT d PROPERTY BOUNDARY RD 6" ROOF DRAIN 8" STORM DRAIN - — — — — - SAWCUT LINE KEYSTONE WALL DRYWELLSIZING MED SAND IMP (SF) READ (SF) 90 C F/ 1000S F 16,696 1,503 L W D VOL 20 20 4 1600 TOPOGRAPHY, BOUNDARY, AND UTILITIES STATEMENT: FURR ENGINEERING SERVICES PLLC. DOES NOT WARRANT THE TOPOGRAPHY, BOUNDARY, AND/OR EXISTING UTILITIES SHOWN ON THESE PLANS. IT IS THE CONTRACTORS' RESPONSIBILITY TO HAVE ALL EXISTING IMPROVEMENTS FIELD VERIFIED PRIOR TO CONSTRUCTION. ANY SUBSURFACE EXPLORATION OF EXISTING UNDERGROUND UTILITIES (POWER, WATER, SEWER, TELECOM, ETC.) SHALL BE PERFORMED BY THE CONTRACTOR. DISCREPANCIES BETWEEN WHAT IS SHOWN ON THE PLANS AND LOCATED BY THE CONTRACTOR SHALL BE BROUGHT TO THE ATTENTION OF FURR ENGINEERING SERVICES PLLC.. PRIOR TO CONSTRUCTION ACTIVITIES. 1,503 Know what's below. Call before you dig. A IN 20 10 0 20 40 SCALE: 1 INCH = 20 FEET APPROVED FOR CONS7RUC7101V CITY OF EDMONDS DATE.• BY. CITY ENGINEERING DIVISION WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PLN 2020-0040 Key Plan Registration FURR 12/28/2U20 \&Rvlm. as 4715 142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title DRAINAGE PLAN Revisions Scale: FES Project No: Date: Designed: DAF Drawn: DAF Checked: DAF Sheet Number 20068 OCTOBER 01, 2020 C500 1 Packet Pg. 56 c 2 ca co 3 0 0 0 v 0 0 0 N 0 N Z J P.m. Attachment 5 NW 1/4 SE 1/4 SEC. 36, T. 27N., R. 03E, W.M. WOODWAY STATION 5.1.a OBSERVATION PIPE MARKING TYPE 1 OR 1-L CATCH GUTTER CENTER OF DRYWELL BASIN W/ SOLID LID PER DRYWELL (PER PLAN) CITY STANDARD DETAIL SD-303 OR SD-304 ROOF PERFORATED PVC UNDERDRAIN PIPE � _ (PER PLAN) 4" (MIN) PVC DRAIN CLEANOUT \ PIPE (TYP) _ w z� 5' J z (MIN) w \ / W � �` / 0 a L(MIN) PROPERTY LINE/EASEMENT PLAN RooF SEE FLOATABLE MATERIAL SEPARATOR NTS DETAIL ON THIS SHEET ROOF WBOX 8" PVC DRAIN PIPE PER WSDOT DOWNSPOUT SPEC. 9-05.1(5), 1% (MIN) SLOPE TEST PLUG IN PLASTIC MARKED "DRAIN" CLEANOUT SEE CONCRETE 12" BUILDING PAVING DETAIL THIS SHEET • > ..• • F 1-7• 12" 4" (MIN) PVC DRAIN PIPE PER WSDOT TOP=353:83 MIN SPEC. 9-05.1(5), POSITIVE SLOPE HWS=353.15 GENERAL NOTES: �QI JOO 8" PERFORATED 1. REFER TO THE 2017 CITY OF EDMONDS O PVC UNDERDRAIN REMOVABLE STORMWATER ADDENDUM FOR SETBACK O PIPE PER WSDOT (CHECKLIST 13) AND INFEASIBILITY PUSH -ON PVC REQUIREMENTS. SPEC. 9-05.1(6) TEE 2. MINIMUM COVER DEPTHS ASSUME NO y GEOTEXTILE, SEE NOTE 1 VEHICULAR LOADING. DESIGNER TO SPECIFY BOTTOM=349.13 COVER DEPTHS IF VEHICULAR TRAFFIC ANTICIPATED. WASHED DRAIN ROCK, SE 3. PROVIDE 10 FEET (MIN) SPACING BETWEEN NOTE 2 - DRY WELLS. NOTES: UNCOMPACTED NATIVE MATERIAL, SCARIFY 3" (MIN) 1. PLACE GEOTEXTILE FABRIC ALONG WALLS AND TOP OF WASHED ROCK. 1' (MIN) ABOVE SEASONAL HIGH GEOTEXTILE SHALL CONFORM TO WSDOT SPEC. 9-33.2(1), GEOTEXTILE FOR GROUNDWATER TABLE OR SEPARATION, NON -WOVEN TYPE, HYDRAULICALLY RESTRICTIVE LAYER 2. WASHED DRAIN ROCK SHALL CONFORM TO WSDOT SPEC. 9-03.12 5 , ( ) GRAVEL BACKFILL FOR DRYWELLS. PROFILE NTS 3. OBSERVATION WELL SHALL CONFORM TO WSDOT SPEC. 9-05.2(6), PERFORATED PVC UNDERDRAIN PIPE. CURB AND GUTTER TRANSITION ZONE, SEE NOTE 6 TRANSITION ZONE J SOIL (TYP), SEE NOTE 7 MULCH PER STD DETAIL SD-641 OVERFLOW STRUCTURE WHERE SHOWN ON PLANS PER STD DETAIL SD-615 OR SD-616 BIORETENTION VEGETATION PER BOTTOM WIDTH STD DETAIL SD-641 VARIES, 12" (MIN) &" {MIN} FREEBOARD SIDEWALK 12" (MIN) 2"-12" 1 P0NDING DEPTH,, JJ w _�58.00 HWS = 357.50 BT_ . = 357.00 3 (MIN) F,x �3 (MIN): ••r- ,'a. . M b-: '.t,^-`{-` ` /'•;'i P/, `'=�_ ._ ''F Pa:.�=, _.-; :_:, �•r'�'a '=��, Ism+_ - - ,�\�\� ANGLE OF REPOSE J\ SOIL(MIN) DEPTH EDIAp SEE NOTES 2NTIb� JII \j \ \U APPROXIMATE FLOW LINE \i� AT CURB CUT LOCATIONS, SCARIFIED AND UNCOMPACTED SEE STD DETAIL TR-602 SUBGRADE, SEE NOTE 1 1' (MIN) ABOVE SEASONAL HIGH GROUNDWATER TABLE OR HYDRAULICALLY RESTRICTIVE LAYER, SEE NOTE 5 SECTION B NTS SD-61 1 _ T -601 NOTES: 1. SCARIFY SUBGRADE 3" (MIN) BEFORE BIORETENTION SOIL MEDIA (BSM) INSTALLATION. 2. BSM SHALL CONFORM TO 2017 CITY OF EDMONDS STORMWATER ADDENDUM (CHECKLIST 10) SPECIFICATIONS. 3. BSM PLACEMENT, GRADING, AND CONSOLIDATION SHALL NOT OCCUR WHEN THE BSM IS EXCESSIVELY WET, OR HAS BEEN SUBJECTED TO MORE THAN 1/2 INCH OF PRECIPITATION WITHIN 48 HOURS PRIOR TO PLACEMENT. EXCESSIVELY WET IS DEFINED AS BEING AT OR ABOVE 22 PERCENT SOIL MOISTURE BY A GENERAL TOOLS & INSTRUMENTS DSMM500 PRECISION DIGITAL SOIL MOISTURE METER WITH PROBE (OR EQUIVALENT). THERE SHOULD BE NO VISIBLE FREE WATER IN THE MATERIAL. 4. PLACE BSM LOOSELY WITH A CONVEYOR BELT OR WITH AN EXCAVATOR OR LOADER FROM A HEIGHT OF 6 FEET OR LESS (I.E., DO NOT DUMP MATERIAL DIRECTLY FROM TRUCK INTO CELL). COMPACT BSM USING NON -MECHANICAL COMPACTION METHODS (E.G., BOOT PACKING, HAND TAMPING, OR WATER CONSOLIDATION) TO 83 PERCENT (+/- 2%) OF THE MAXIMUM DRY DENSITY PER MODIFIED PROCTOR TEST (ASTM D1557). 5. MINIMUM DEPTH TO GROUNDWATER OR HYDRAULICALLY RESTRICTIVE LAYER VARIES BY CONTRIBUTING AREA. SEE 2017 CITY OF EDMONDS STORMWATER ADDENDUM (CHECKLIST 10). 6. TRANSITION ZONE SHALL BE 2' (MIN) FOR LOCAL AND COLLECTOR STREETS AND 4' (MIN) FOR ARTERIALS. PROVIDE 2.5' (MIN) TRANSITION ZONE WHERE ADJACENT TO PARALLEL PARKING. 7. TRANSITION ZONE SOIL SHALL BE UNDISTURBED NATIVE OR APPROVED SOIL COMPACTED TO 95% MAXIMUM DRY DENSITY PER MODIFIED PROCTOR TEST (ASTM D1557). 1" VENT HOLE WHEN NOT CONNECTED TO COMBINED SEWER 6" OR 8" PVC FACTORY TEE 24" 6" OR 8" PVC PLUG N r-I p 14" 1° MAX FLOW FLOW 0 _ ADAPTOR OR PIPE JOINT z Q 6" OR 8" PVC PIPE SAND COLLAR OR COR-N-SEAL TYPICAL v 6" OR 8" PVC PIPE AS REQUIRED 00 32" FLOATABLE MATERIAL SEPARATOR NOT TO SCALE REVISION DATE CITY OF EDMONDS BIORETENTION SECTION DECEMBER 2017 PUBLIC WORKS STANDARD DEPARTMENT DETAIL APPROVED BY: R. ENGLISH S D - 61 2 SEE APPLICABLE STANDARD DETAILS FRAME AND GRATE ) hr r S4 .�O b (WSDOT STD SPEC 9-05.12(2) �0 4 CORRUGATED POLYETHYLENE S+ STORM SEWER PIPE �2", 4", 6", OR 12" NOTES: RISER SECTION 1. CATCH BASINS SHALL BE CONSTRUCTED IN ACCORDANCE WITH WSDOT STANDARD SPECIFICATION 9-05.50(3). 2. AS AN ACCEPTABLE ALTERNATIVE TO REBAR, WELDED WIRE FABRIC HAVING A MIN. AREA OF 0.12 SQUARE INCHES PER FOOT MAY BE USED. WELDED WIRE FABRIC SHALL COMPLY 22y TO ASTM A497 (AASHTO M 221). WIRE FABRIC SHALL NOT " BE PLACED IN KNOCKOUTS. 3. APPLY NON -SHRINK GROUT TO INSIDE AND OUTSIDE OF ALL JOINTS, RINGS, RISERS AND FRAMES. �\ 4. ROUND KNOCKOUTS MAY BE ON ALL 4 SIDES, WITH MAX DIAMETER OF 20". KNOCKOUTS MAY BE EITHER ROUND OR s "D" SHAPE. N 5. THE MAX DEPTH FROM THE FINISHED GRADE TO THE PIPE INVERT IS 5'-0". 6. THE TAPER ON THE SIDES OF THE PRECAST BASE SECTION AND RISER SECTION SHALL NOT EXCEED 1 /2"/FT. 7. CATCH BASIN FRAME AND GRATE SHALL BE IN ACCORDANCE WITH STANDARD SPECIFICATIONS. MATING SURFACES SHALL ° BE FINISHED TO ASSURE NON -ROCKING FIT WITH ANY COVER POSITION. (MEASUREMENT AT THE TOP OF THE BASE) 8. VERTICAL EDGE OF RISER SHALL NOT BE MORE THAN 2" PRECAST BASE SECTION FROM VERTICAL EDGE OF CATCH BASIN WALL. CITY OF EDMONDS PUBLIC WORKS DEPARTMENT CATCH BASIN TYPE I APPROVED BY: R. ENGLISH REVISION DATE JANUARY 2018 STANDARD D ETAI L SD-303 z RESIDENCE IL w o CLEANOUT a WITH 45' BEND AND 2' CAP CLEANOUT (MAX) (TYP) NOT TO EXCEED 100' BETWEEN CLEANOUTS CLEANOUT (WYE WITH CAP AND CLEANOUT COVER) AND z CONCRETE LEVELING COLLAR w w IL 12" LOCKING COVER 0 12" FINISHED GRADE a_ 3 SEE NOTE 3 w 0 END OF PIPER GRIPPER PLUG \ \ (CHERNE 27061 OR APPROVED EQUAL) "f a_ U WATER TIGHT CAP RISER LEVELING COLLAR 45' SEE NOTE 4 45' 12" PVC SLEEVE L3• 4" OR 6" SIDE SEWER 6" RISER 6" WYE AND 6" CITY STUB GENERAL CLEANOUT DETAIL 45' BEND 4" OR 6" 12" LOCKING COVER SIDE SEWER CLEANOUT DETAIL 3 F SEE NOTE 3 AT PROPERTY LINE/CITY €ASEMENT � w LEVELING COLLAR NOTES: z o LU SEE NOTE 4 a a� v ASPHALT SURFACE 1. SEWER PIPE SHALL BE SDR-35 AND JOINTS SHALL BE GASKETED. 12"f 2. PIPE SLOPE TO BE 2% MIN AND UP TO 50% MAX. 3. SEWER CLEANOUT COVER TO BE EAST JORDAN IRON WORKS 1 FOOT LONG 12" PVC PRODUCT #00366102 STAR PIPE COSP48L OR APPROVED SLEEVE EQUAL. 6" RISER END OF PIPE GRIPPER 4. LEVELING COLLAR SHALL BE CONSTRUCTED AS FOLLOWS: PLUG (CHERNE 270261 OR APPROVED EQUAL) IN ROADWAYS PER COE STD DWG GU-424 TYPICAL CLEANOUT • IN SIDEWALK/LANDSCAPED AREAS, EITHER 24%24%6" UNDER ASPHALT OR CONCRETE DEEP CONCRETE COLLAR OR 24" DIAMETER x 6" DEEP CONCRETE COLLAR REVISION DATE SEWER CLEANOUT DETAILS CITY OF EDMONDS JANUARY 2018 PUBLIC WORKS STANDARD DEPARTMENT DETAIL APPROVED BY: R. ENGLISH SS-200 APPROVED FOR CCW7)9UC7I01V CITY OF EDA401VDS DATE.• BY. CITY ENGINEERING DIVISION WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PLN 2020-0040 Key Plan Registration FL 12/28/2020 / \&MCES 4715142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title ROAD AND DRAINAGE DETAILS Revisions Scale: FES Project No: Date: Designed: Drawn: Checked: Sheet Number 20068 OCTOBER 01, 2020 DAF DAF 50 1 Packet Pg. 57 c 0 ca co 0 0 0 0 v 0 0 0 N 0 N z J P.m. Attachment 5 NW 1/4 SE 1/4 SEC. 36, T. 27N, R. 03E, W.M. WOODWAY STATION 5.1.a i 00 004 SSMH RIM=355.16 1 1 IE 8" PVC(N)=346.61 1 IE 8' PVC(S)=346.51 _ — --——————————————————————— — — — — —— I c.� I I IDEWALK ENT ' 4 /I I r �I I I LW I� I Z► lo� I I I I I W SDMH RIM=361.15 IE 12" RCP(S)=354.65 IE 8" RCP(NE)=354.90 IE 8" RCP(W)=354.90 _-30 22 " w 2377_':__ �79f, S. YY. WATER INSTALLATION NOTES INSTALL 2" WATER METER PER CITY OF EDMONDS DETAIL WA-131, SHEET C5.1 INSTALL DCDV PER THE CITY OF EDMONDS DETAIL WA-141, SHEET C5.1 WITH 2 4" POST INDICATOR VALVE (PIV) AND FIRE DEPARTMENT CONNECTION (FDC) PER CITY OF EDMONDS DETAIL WA-184, SHEET C5.1 INSTALL FIRE HYDRANT ASSEMBLY PER CITY OF EDMONDS DETAIL WA-100, 13-1 SHEET C5.1 SEWER INSTALLATION NOTES 6" SS @ 2% MIN PER CITY OF EDMONDS DETAIL SS-202, SHEET C5.1 v IE=344.85 6" SSCO PER CITY OF EDMONDS DETAIL SS-200, SHEET C5.1 PROPOSED LEGEND ASPHALT PAVEMENT a a ° °< CONCRETE PAVEMENT ° PROPERTY BOUNDARY 0 ^`O 8" STORM DRAIN SAWCUT LINE ■■■■■■■■■■■■ • -0- PIV VALVE is FIRE HYDRANT 4- FIRE DEPT CONNECTION Q SEWER CLEANOUT FIRE SPRINKLER SYSTEMS NOTES SPRINKLER SYSTEMS SHALL MEET CITY OF EDMONDS STANDARDS AND THE FOLLOWING REQUIREMENTS: 1. PROPOSED FIRE LINE TO BE SIZED BY A FIRE PROTECTION ENGINEER. 2. BACKFLOW PROTECTION IS REQUIRED ON FIRE SPRINKLER LINES. 3. A SEPARATE DETAILED PLAN OF THE UNDERGROUND FIRE SPRINKLER SUPPLY LINE SHALL BE APPROVED BY THE FIRE MARSHAL AND INSTALLED BY A WASHINGTON STATE CERTIFIED LEVEL "U" CONTRACTOR IN ACCORDANCE WITH WAC 212-80-010. 4. A POST INDICATOR VALVE SHALL BE INSTALLED ON THE FIRE SPRINKLER SUPPLY LINE TO ISOLATE THE SYSTEM FROM THE CITY'S WATER SYSTEM WHEN REQUIRED FOR REPAIR. 5. BLOCKING, PIPING, AND RODDING DETAILS SHALL BE PROVIDED WITHIN THE SUBMITTAL. 6. APPROVAL OF THE CIVIL PLANS DOES NOT APPROVE THE INSTALLATION OF THE SPRINKLER SYSTEM SUPPLY PIPING. CROSS CONNECTION CONTROL NOTES CROSS CONNECTION CONTROL SHALL MEET THE FOLLOWING REQUIREMENTS: 1. ALL BACKFLOW PREVENTION ASSEMBLIES SHALL BE INSTALLED IN A MANNER THAT WILL ALLOW PROPER OPERATION, AND IN -LINE TESTING AND MAINTENANCE. I 2. A BACKFLOW ASSEMBLY PERMIT IS REQUIRED FOR ALL ASSEMBLIES INSTALLED WITHIN THE CITY OF EDMONDS, AND/OR THE CITY'S WATER DISTRIBUTION SYSTEM. 3. BACKFLOW ASSEMBLIES MUST BE ON THE CURRENT WASHINGTON STATE DEPARTMENT OF HEALTH - BACKFLOW ASSEMBLIES APPROVED FOR INSTALLATION LIST. 4. BACKFLOW ASSEMBLIES MUST BE TESTED BY A STATE CERTIFIED BACKFLOW ASSEMBLY TESTER, AND INSPECTED AND APPROVED BY A CITY OF EDMONDS CROSS CONNECTION CONTROL SPECIALIST. 5. UPON RECEIVING APPROPRIATE FEE PAYMENTS AND VERIFYING THAT REDUCED PRESSURE BACKFLOW ASSEMBLY (RPBA) HAS BEEN INSTALLED (NOT BY CITY), THE CITY WILL INSTALL THE DOMESTIC METER INSIDE THE DOMESTIC METER VAULT. THE PASSING TEST REPORT FOR THE RPBA MUST BE RECEIVED BY THE CITY WITHIN 24 HOURS OF THE INSTALLATION OF THE DOMESTIC METER. 6. DOUBLE CHECK VALVE ASSEMBLY (DCVA, NOT BY CITY) TO BE INSTALLED ONTO THE FIRE SERVICE LINE. THE PASSING TEST REPORT FOR THE DCVA MUST BE RECEIVED BY THE CITY WITHIN 24 HOURS OF THE CONNECTION OF THE BUILDING FIRE SERVICE LINE TO THE CITY MAIN. TOPOGRAPHY, BOUNDARY, AND UTILITIES STATEMENT: FURR ENGINEERING SERVICES PLLC. DOES NOT WARRANT THE TOPOGRAPHY, BOUNDARY, AND/OR EXISTING UTILITIES SHOWN ON THESE PLANS. IT IS THE CONTRACTORS' RESPONSIBILITY TO HAVE ALL EXISTING IMPROVEMENTS FIELD VERIFIED PRIOR TO CONSTRUCTION. ANY SUBSURFACE EXPLORATION OF EXISTING UNDERGROUND UTILITIES (POWER, WATER, SEWER, TELECOM, ETC.) SHALL BE PERFORMED BY THE CONTRACTOR. DISCREPANCIES BETWEEN WHAT IS SHOWN ON THE PLANS AND LOCATED BY THE CONTRACTOR SHALL BE BROUGHT TO THE ATTENTION OF FURR ENGINEERING SERVICES PLLC.. PRIOR TO CONSTRUCTION ACTIVITIES. Know what's below. Call before you dig. A IN 20 10 0 20 40 SCALE: 1 INCH = 20 FEET APPROVED FOR CONSTRUCnON CITY OF EDMONDS DATE.• BY. CITY ENGINEERING DIVISION WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PLN 2020-0040 Key Plan Registration FURR 12/28/2U20 \&Rvlm. as 4715 142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title UTILITY PLAN Revisions Scale: FES Project No: 20068 Date: OCTOBER 01, 2020 Designed: DAF Drawn: DAF Checked: DAF Sheet Number C600 I Packet Pg. 58 c 0 �a co 3 0 0 3.1 v 0 0 0 N 0 N Z J P.m. Attachment 5 NW 1/4 SE 1/4 SEC. 36, T. 27N., R. 03E, W.M. WOODWAY STATION 5.1.a z (IF STUB FOR FUTURE DEVELOPMENT) z SEWER STUB SHALL BE LOCATED 10' INSIDE PROPERTY LINE & STAKED. PLACE 2"x4" < TIMBER AT END OF SIDE SEWER STUB AND CUT TO LENGTH TO ENSURE 3 FEET EXTENDS ABOVE GRADE. PAINT TOP 18 INCHES WHITE. IN 3 INCH HIGH LETTERS, RESIDENCE a w STENCIL THE NUMBER OF EVEN FEET FROM GROUND ELEVATION TO THE SEWER STUB INVERT. 8 GAUGE WIRE TO BE DOUBLE WRAPPED AROUND PIPE AND 2 x 4 STAKE AT CLEANOUT a N OR ABOVE FINISHED GRADE. WITH 45' z SETBACK BEND AND z LINE 2' CAP CLEANOUT (MAX) EXIST PROPERTY (NP) IL LOCKING CLEANOUT COVER WATER MAIN x PER COE STD DTL SS-200 C I NOT TO EXCEED 1 DO' BETWEEN C LEANOUTS /// DCDA & VAULT CLEANOUT (WYE WITH CAP \/\/\/\/\/\/\/\l\/\ SEE COE STD TLS WA-142A & WA-142B AND CLEANOUT COVER) AND z i,, -1 I CONCRETE LEVELING COLLAR UJ w w a'Er, z w w o z SEE COE STD DTL WA- 0 12" LOCKING COVER Z� a a. SEE NOTE 3 - w a w o / 2" DOMESTIC SERVICE I 3 12"t FINISHED GRADE w o END OF PIPER GRIPPER PLUG 0 22.5' OR 45' BEND U, �_ (COPPER) YyM (CHERNE 27061 OR APPROVED EQUAL ) 'h af ¢ �' 6" TEST TEE } I , l _ I BLDG IL v o 6" LATERAL SEWER a SLOPE - 2% MIN TO 50% MAX 6" WYE/6" ROMAC SADDLE ` l FDC WATER TIGHT CAP ���/: /\f�� /\\�/�\\! SEE NOTES 1 AND 2 4" (MIN) FIRE LINE (DIP) <. 9., PIV \ LEVELING COLLAR 45• RISER L 10' SEEWER MAIN RESILIENT GATE VALVES (TYP) $ SEE NOTE 4 SEE COE STD DTLS WA-180 45. 12" PVC SLEEVE LOCATION AND WA-181 a 6" RISER CURB 4" OR 6" SIDE SEWER 22.5' OR 45' BEND SIDEWALK I �� 6' WYE AND GENERAL CLEANOUT DETAIL 45' BEND TEST TEE I f6" 6" TEE 4 OR 6 " 12" LOCKING COVER SIDE SEWER CLEANOUT DETAIL SEE NOTE 3 AT PROPERTY LINEZCITY EASEMENT POSSIBLE SEWER MAIN o W LEVELING COLLAR w M NOTES: LOCATION NOTES (BLDGS WITH SETBACKS)- a W SEE NOTE 4 NOTES: a a v ASPHALT SURFACE 1. SEWER PIPE SHALL BE SDR-35 AND JOINTS SHALL BE 1. THE DCDA AND VAULT SHALL BE LOCATED ON PRIVATE PROPERTY AND ADJACENT TO GASKETED. 1. WHEN TAPPING INTO EXISTING MAIN A ROMAC STYLE CB SADDLE SHALL BE USED. PLACEMENT OF TEE SHALL DEPEND ON THE RIGHT-OF-WAY LINE. - MIN AND UP TO 50% MAX. 12"f 2. PIPE SLOPE TO BE 2� DEPTH OF SEWER MAIN. AS A MINIMUM, THE TEE SHALL BE PLACED AT A 45 DEGREE ANGLE FROM PIPE SPRINGLINE. 2, THE PIV AND FDC SHALL BE LOCATED ON PRIVATE PROPERTY AND SHALL BE NEAR 3. SEWER CLEANOUT COVER TO BE EAST JORDAN IRON WORKS 2. IF NEW MAIN IS BEING INSTALLED OR MAIN IS BEING REPLACED, SERVICE CONNECTION TO THE MAIN SHALL BE DONE THE DCDA. 1 FOOT LONG 12" PVC PRODUCT #00366102 STAR PIPE COSP48L OR APPROVED WITH A WYE. WYE SHALL BE AT A 45 DEGREE ANGLE FROM PIPE SPRINGLINE. 3. THE PIV AND FDC SHALL HAVE A 3' MINIMUM CLEARANCE BETWEEN AND AROUND SLEEVE EQUAL. 3. IF CONNECTING EXISTING PRIVATE SIDE SEWER TO NEW CITY LATERAL, A CONCRETE/PVC STRONGBACK FERNCO RC SERIES THEM. 6" RISER END OF PIPE GRIPPER 4. LEVELING COLLAR SHALL BE CONSTRUCTED AS FOLLOWS: OR ROMAC COUPLING SHALL BE USED AND SECURED PER MFR'S INSTRUCTIONS. 4, THE FDC SHALL HAVE A 22' BEND WITH 4" STORZ ADAPTER ON THE END. PLUG (CHERNE 270261 OR APPROVED EQUAL) IN ROADWAYS PER COE STD DWG GU-424 4. BORING OF SERVICES WITHIN RIGHT OF WAY IS NOT ALLOWED. TYPICAL CLEANOUT • IN SIDEWALK/LANDSCAPED AREAS, EITHER 24"x24"x6" 5. SEWER PIPE SHALL BE SDR-35 AND JOINTS SHALL BE GASKETED. DEEP CONCRETE COLLAR OR 24" DIAMETER x 6" DEEP UNDER ASPHALT OR CONCRETE CONCRETE COLLAR 6. IF STUB FOR FUTURE DEVELOPMENT, USE RUBBER JOINT BISCUIT PLUG OR OTHER APPROVED WATERTIGHT PLUG. REVISION DATE REVISION DATE �� REVISION DATE JANUARY 2018 MAY 2018 FIRE LINE AND 2 DOMESTIC JANUARY 2018 CITY OF EDMONDS SEWER CLEANOUT DETAILS CITY OF EDMONDS NEW LATERAL SEWER CITY OF EDMONDS SERVICE CONNECTIONS (PLAN VIEW) r PUBLIC WORKS STANDARD PUBLIC WORKS STANDARD PUBLIC WORKS ALL ZONES EXCEPT ZERO -SETBACK STANDARD DEPARTMENT DETAIL DEPARTMENT DETAIL DEPARTMENT BUSINESS/COMMERCIAL DETAIL s 18 s s- 2 0 o Fs t 1 g 9 S S- 2 0 2 s 1 g WA- 184 APPROVED BY: R. ENGLISH APPROVED BY: R. ENGLISH APPROVED BY: R. ENGLISH MOUNT HYDRANT PLUMB PROPERTY CEMENT PROVIDE 3' MINIMUM GROUND/ROADWAY/FINISH GRADE LINE VAULT BOX CLEARANCE AROUND HYDRANT GROUND/ROADWAY I -_-_-_-_-_-_-_-_-_-_-_ --DRILL HOLE FOR _6" 7W fi6" MIN } 4" STORZ ADAPTER LOCATOR WIRE. II °' II DOUBLE SIDED BLUE ROAD WIRE PROVIDE INVALVE IBOXF I I I I o �O O o 1 /2" EXPANSION RAISED PAVEMENT l O O I JOINT MATERIAL 18" MIN-24" MAX MARKERS i I I e' ABOVE 1 4" MIN-6" MAX I GRADE FINISHED ALIGN VALVE BOX EARS 11 o z 71) P II II NOTES: PARALLEL WITH THE 3 II II a THICK CONCRETE FINISH GRADE WATER LINE IT SERVES I 4" N �° 1. THE DCDA SHALL BE A WASHINGTON STATE PAD APPROVED - MODEL SHALL BE WATTS " HYDRANT '. FL x MJ 6" R.W. CAST IRON ADJUSTABLE L R L 007DCDA OR APPROVED EQUAL. 6 MIN GATE GATE VALVE VALVE BOX 1 CY 1-1/2" WASHED TEE WITH C <- 2. VAULT MUST BE UTILITY VAULT MODEL OR ROCK, 1' MIN ABOVE I RESTRAINED JOINTS FLANGED FLANGED 0 M B E APPROVED EQUAL. - < FOR 2 INCH DCDA: UTILITY VAULT #644-LA MEGA -LUG OR DRAIN HOLES AND CO NECTION CONNECTION EQUAL FROM d as :. FOR 3 INCH DCDA: UTILITY VAULT #675-LA FOR HYDRANT AROUND HYDRANT HYDRANT TO VALVE LINE. VALVE BOTTOM OF DITCH L H H PLAN VIEW 3. LIDS FOR VAULT SHALL BE LW HATCH - SENSOR SR2 W/TRPL COVER TOP AND SIDES (nP) D Q WATERTIGHT WITH GUTTER AND SIDE DRAIN. REMOTE READ, TRPL WITH MIRAFI 160N OR THRUST BLOCK * N SHALL BE INSTALLED H-20 DOUBLE LEAF TRAFFIC SIZE SHALL BE 3' WIDE x 6' LONG. APPROVED EQUAL. j` - - � 22' MAX ON HATCH CLOSE TO BEARING LID FOR ALL AREAS 4. APPROVED DOUBLE CHECK DETECTOR /j * SERVICE TAP TO MAIN SHALL BE ANGLED AND NOT EXCEED 22 DEGREES HINGE EXCEPT IN HIGH TRAFFIC AREAS ASSEMBLY TO LAY HORIZONTAL WITH THE I USE H-30 DOUBLE LEAF GROUND. d . 10 MIL PLASTIC A I TRAFFIC RATED LID IN HIGH I I 5. TEST COCKS TO EITHER FACE OUTWARDS OR \ MATERIAL LIST: TRAFFIC AREAS (IE: DRIVEWAY] I UPWARDS FROM ASSEMBLY. I UNDISTURBED EARTH /. /\\/�� / BETWEEN BLOCK EXISTING ENTRANCES) 6. ALL TEST COCKS MUST BE PROVIDED WITH & TEE OA 2" (IP TAP) DOUBLE STRAP SADDLE EQUAL TO G WHEN REPLACING EXISTING SERVICES: GROUND PVC PLUGS. 12"x12"x4" CONC. BILK. 12"x12"x4" I 2" MIN CONC BILK CLEARANCE ROMAC STYLE 202'S EQUAL TO FORD VBB87-12HB-1177 i7 7. THOROUGHLY FLUSH LINES PRIOR TO / - INSTALLATION OF ASSEMBLY. " HYDRANT CONNECTION PIPE TO a BETWEEN WHEN PLACING NEW SERVICES (HIGH BYPASS); O 2" BRASS IP BALL CORP EQUAL TO FORD VBH87-12HB-1177 6" MIN SIDE DRAIN 8. DO NOT INSTALL IN AN AREA SUBJECT TO BE DUCTILE IRON CLASS 52. ' . BLOCKING DRAIN TO GRAVEL SUMP FLOODING. ANY INTERMEDIATE JOINTS TO BE . • ANDMUST `- O 2 - 2" BRASS STREET ELLS FOR SWING JOINT O METER BOX ARMORCAST A6001640PCX1$, WITH :4. OR TO CATCH BASIN 9. BE FROM FREEZING RESTRAINED •_ " :a. BOLTS ARMORCAST LID A6001947TRCI-H7 OR APPROVED CO D11TIONSROTECTED 4° - • I ^ "a ; : OD REHAU MUNICIPEX PIPE (2") WITH STAINLESS STEEL INSERT EQUAL STRAIGHT WALL POLYMER BOX (NO � 10. IF SOIL CONDITIONS OR PRESENCE OF GROUND WATER DO NOT ALLOW DRAINAGE TO SUMP, THRUST MOUSEHOLES) WITH 20K COVER WITH HINGED CI - in in DRAIN SHALL BE DIRECTED TO ONSITE '� .e < BLOCK O 2" MIPT X CTS GRIP FITTING READER N ° DRAINAGE SYSTEM. NOTES: O TRACER WIRE: #12 AWG, SOLID COPPER CLAD STEEL, HDPE O 2„ BRASS PIPE (L.T.F) 0 00 COATED. CONNECTION AT THE METER SETTER SHALL BE o O � ® O O 1. HYDRANTS AND ALL MATERIALS TO BE IN ACCORDANCE WITH CITY OF EDMONDS APPROVED MATERIAL MODIFICATIONS MADE WITH AN ALL STAINLESS STEEL HOSE CLAMP. O SCHEDULE 40 2" PVC CAP OR PLUG REMOVED LISTINGS. CONNECTION AT MAIN LINE WIRE SHALL BE MADE WITH A WHEN CONNECTION MADE TO CUSTOMER 2. CONSTRUCT 3' X 3' X 3.5" THICK CONCRETE PAD AROUND HYDRANT PIPE. HYDRANTS SET IN CONCRETE REQUIRES AN SPLIT -BOLT CONNECTOR, STRIP COATING PRIOR TO CONNECTION. WRAP WIRE AROUND PIPE. ON 4"x4"x8" CONCRETE BLOCK SUPPORTS " GRINNEL CONNECT TO EXISTING 6" TYP a . 12 MIN SADDLE SERVICE LINE EXPANSION STRIP AROUND HYDRANT BARREL. IN ADDITION, THE INSTALLATION OF THE HYDRANT ON PRIVATE PROPERTY © BACK SIDE OF METER BOX SHALL BE SET AT THE OO 2" RESILIENT WEDGE GATE VALVE FIP) WITH °= PROVIDE BENDS & SHALL EQUAL OR EXCEED STANDARDS SET FORTH FOR THE INSTALLATION OF PUBLIC FIRE HYDRANTS IN THE CITY OF (FIP x CONNECTIONS AS REQUIRED EDMONDS. PROPERTY LINE UNLESS APPROVED BY THE CITY ENGINEER. 2" AWWA OPERATING NUT METER BOXES SHALL NOT BE SET IN DRIVEWAY AREAS � � � 3_ ALL HYDRANTS SHALL HAVE A 6" MECHANICAL JOINT (MJ) BASE. TRAFFIC MODEL PROVIDED WITH (2) 2-1/2" HOSE UNLESS LOCATION AND TRAFFIC RATED BOX IS APPROVED © 2 PIECE VALVE BOX - TOP SECTION TO BE RICH FLOOR DRAIN NOZZLES AND (1) 4-1/2" NATIONAL STANDARD THREAD (NST) PUMPER NOZZLE WITH 4" STORZ QUICK COUPLING BY CITY ENGINEER. 940 STYLE 18" WITH REGULAR BASE SECTION 5/8" MINUS C.S.T.C. ��/\/� �, 2" PVC ADAPTER, LENGTH TO FIT OH 2" BRASS ELL GRAVEL (12" MIN) COMPACTED TO 95% WASHED ROCK DRAIN SUMP (SIZED PER DESIGN) 4_ PUMPER PORT SHALL FACE THE STREET OR ROADWAY FOR FIRE ENGINE ACCESS. ® WATER SERVICE TO BUILDING INSTALLED AND SIDE VIEW MAX DENSITY (SEE NOTE 10) 1 METER SPACER TO BE SUPPLIED AND INSTALLED BY CONNECTED AT METER SETTER BY 0 5. THREE FOOT MINIMUM LEVEL CLEARANCE SHALL BE MAINTAINED AROUND HYDRANT WHEN PLACING LANDSCAPING. THE CONTRACTOR. SPACER MUST HAVE A MINIMUM OF OWNER/CONTRACTOR VIA COMPRESSION FITTING * SIZE OF PIPE USED DICTATES MINIMUM DEPTH OF BOX INCLUDING REQUIRED CLEARANCES. 8 - 1 /4" HOLES DRILLED IN SPACER BODY. 6. FIRE HYDRANTS SHALL BE PAINTED SAFETY YELLOW BRAND: KELLY MOORE (1700-63 SUNBURST YELLOW) OR APPROVED NOTE: PROPERTY OWNER RESPONSIBLE FOR PURCHASING 2' MIPT X I.P.COMPRESSION FITTING O ** HEIGHT TO TOP OF STEM BASED ON THE SIZE OF PIPE USED. EQUAL. 1-1/2" OR 2" METER THROUGH THE CITY DEVELOPMENT SERVICES DEPARTMENT. THE CITY WILL SUPPLY METER MUST BE TESTED AFTER INSTALLATION AND YEARLY THEREAFTER BY A 7. RAISED PAVEMENT MARKER TO BE PLACED 4" FROM PAVEMENT C/L OR PAINTED LINE ON HYDRANT SIDE OF ROAD. AFTER PURCHASE FOR CONTRACTOR INSTALL. IF 1-1/2" WASHINGTON STATE CERTIFIED DCDA ASSEMBLY TESTER. THE TEST METER IS USED CONTRACTOR WILL SUPPLY REDUCERS TO REPORT MUST BE SENT TO THE CITY OF EDMONDS WATER DIVISION. 8. FIRE HYDRANT LOCATION SHALL BE SHOWN ON THE PLANS AT A LOCATION APPROVED BY THE CITY ENGINEER. CONNECT METER. REVISION DATE 77 77 REVISION DATE �� 2�� - 3 DOUBLE CHECK REVISION DATE CITY OF EDMONDS FIRE HYDRANT ASSEMBLY JANUARY 2018 CITY OF EDMONDS WATER SERVICE NOVEMBER 2018 CITY OF EDMONDS DETECTOR ASSEMBLY JANUARY 2018 PUBLIC WORKS STANDARD PUBLIC WORKS INSTALLATION STANDARD PUBLIC WORKS (DCDA) (NEW) STANDARD DEPARTMENT DETAIL DEPARTMENT DETAIL DEPARTMENT DETAIL s 1 g 9 WA- 100 4 s t 1 g 9 WA- 131 WA- 141 APPROVED BY: R. ENGLISH APPROVED BY: R. ENGLISH APPROVED BY: R. ENGLISH APPROVED FOR CON67RUC770IV CITY OF EDA40NDS DATE: BY. CITY ENGINEERING DIVISION WOODWAY STATION 23726 100TH AVE. W. EDMONDS, WA 98020 PLN 2020-0040 Key Plan Registration rules 12/28/2020 SERVICES 4715142nd PI. SW #B, Edmonds, WA 98026 ph 206.890.8291 Sheet Title WATER AND SEWER DETAILS Revisions Scale: FES Project No: Date: Designed: DAF Drawn: DAF Checked: DAF Sheet Number 20068 OCTOBER 01, 2020 C6.1 c 0 ca co 0 0 0 v 0 0 0 N 0 N z J P.m. Attachment 5 Packet Pg. 59 5.1.a 2'' ladgepoI inc tr stakes 8 Ion driver into undisturb d grou Stain brown Water basin with 2 Plontinei pit twice s ze o Undisturbed suit TREE PLANTING DETAIL No Scale une diseased and oken branches Ater basin with mulch �m acted topsoil iter thoroughly, rti l ize as req d �nting hole min. ice size of root ball SHRUB PLANTING DETAIL No Scale NOTES Prune diseased and broken branches 'Chainlock'' or equal tree tie material (I" width); nail or staple tree tie to hold vertically, loop each tie around half tree loosely to provide I'' slack for trunk growth 0lazed planting pit ace 1/2 topsoil, 1/2 native soil, water thoroughly, fertilize Planting be 2'' mulch 1/2 spacing distance I. installation includes removal of stakes one year after installation. 2. Adjust tree ties during establishment to allow for growth. GROUND COVER SPACING DETAIL No Scale- Triangular Spacing I. Subgrades, including berms, to within I 1/I0th foot provided by General Contractor unless otherwise noted. 2. Subgrade shall be scarified or rototilled if conditions require. 5. 4'' depth 5-Nay topsoil or equal in all planting areas. 4. 2'' depth fine grade bark mulch in all planting beds. 5. All plant material shall be healthy, full and conform to USA standard nursery stock, latest edition. G. Plant material or size or kind not available may be substituted only with approval of landscape Architect or Owner. i. All mass plantings shall have triangular spacing. 8. All tree pits shall be inspected to insure proper drainage. 01. Positive drainage shall be maintained. Mound planting areas minimum 6''. 10. landscape Contractor shall maintain site until final inspection and acceptance by Owner. >�NT LIST l E30TAN10A1 / OOMMON * QUANTITY 51ZE Tilio omericana 'Redmond'/ 8 2'' cal 5�E3 Redmond American linden Pinus flexilis ''Vondewolf's Pyramid/ 12 10' min. 5$5 Vandewolf's Pyramid Pine Licpidombar Styr. 'Glydesform' / 5 2'' cal 5$ E3 Emerald Sentinel Swoetgum Mahonia Ac,uilfolium / 5 gallon full bushy Oregon Crape Viburnum tinus .Spring 5ouo[uet' / 5 gallon full bushy Spring 5ouquet Viburnum Rhododendron unique/ 27" min full bushy Unique Rhododendron Hobe buxifolia / 5 gallon full bushy 0 5ox leaf Hobe Nondino domestics 'Moon E3sy'/ 2 gallon full bushy J Moon Bay Heavenly 5amboo Hakonechloa macra / I gallon full bushy Hokone Orass Juncus bolticus / I gallon full bushy O 5altic Rush Carex stipata / I gallon full bushy 5eaked Sedge Arctostsphylos uva-ursi / 4'' pots full kinnickinnik 24" o.c. Sodded lawn Confirm all plant quantities NEW 6' NI, WOOD FE TYF AL01 WEST L07 WATER LINE M L-/\I1=1� I II°l1� :2�5e�TH CONCRETE WAL< AIL L AI E) 5CAF FLAN 5c,4LE. 1"-2o'' 0 0 0 0 E N N o N 0 LL� Z F K LU ~ U M M zo = 0 0 a ZZ z o� � N 0. �Ni7 Q a wL_ NaW N � YF g W CO CO WU 00 AW-� O z� W � o WQ CO W U W z Q O •N Sheet LANDSCAPE PLAN 0 co 3 0 0 0 0 0 0 N 0 N c aD E Q 3 `0 a 0 v 0 O 0 N O N Z J a c a� E a Attachment 6 L�i Packet Pg. 60 5.1.a O O ish grade/ Top of mulch p-Up sprysprinkler plastic MICR nozzle -Inch male NPTx .4CiO Inch -b Elbow Nipple or Funny Pipe G Schedule 40 Tee or Ell -Inch male NPT x ACiO Inch -b Elbow rvG Lateral Pipe POP-UP SPRAY SPRINKLER No Scale Junction box I" pvc schedu to power supl Controller per irrigation schedule pvc schedule 40 nduit and fittings --wires to remote controle valves WALL MOUNT CONTROLLER No Scale Paving Finished grade II1=1I1=_=1I1=1I1=1 II1=1I1=_ -III-III-III ° � I1=1I1=1I1=1 Select ba c kf i I I,- -1 11=1 I 111=111=1 11= Select backfill, =III=1 III -III -III remove rocks, - 1=III==111 -III -III ° 1=1 1=1 I- remove rocks, =1 _ III=III=III debris and 1=III 1=III=III=1N debris and 1=III ° 11=III=III= sharp objects III -II III-III=III--LU sharp objects 1=III 1=III=III=1 J � 1=1T1=1T1 11=1T1: -1T-11 111=1T=1T- -I 1=1T1=1T1 ° 111=1T1: - 111-IT-1T- -I I I -I I I -I III- 11=1T1=1T1=� PVG Glass 200 III- - PVG Glass 200 III=III=III- sleeving twice lli il-11 Lateral size of pipe Lateral or -- o - PVG schedule 40 o - Mainline Mainline Volve Wires SLEEVING DETAIL TRENCHING DETAIL No Scale No Scale 5 Pressure Reducing Valve, g 5 if required Cate Valve Ouick Ceoupler ValvMaster Valve, if required for winter blowout PVC Mainline Double Check Valve Stub out from Domestic Meter, or separate irrigation meter POINT OF CONNECTION Eio,]' No Scale IRRIGATION SCHEDULE �YMRnI F)P�( RIPTInNI RAnlll(� (1PM PSI F 3Q H a O �7 r-) RAINBIRD 1800 MPR 15' SERIES POP-UP, 4'' LAWN, G'' G,C" 15' 1"85H 30 Oo Oo W RAINBIRD 1800 MPR 12' SERIES POP-UP, 4'' LAWN, ro" C,"C" 12' 1301-4 30 m O 0 RAINBIRD 1800 MPR 10' SERIES POP-UP, 4'' LAWN, G " G,C" 10' 0.79H 30 zj I RAINBIRD 1800 MPR 8' SERIES POP-UP, 4'' LAWN G " G C" 8' 0.52H 30 O 0 RAINBIRD 1,500 MPR 5' SERIES POP-UP, 4'' LAWN 6'' G.0 5' 02H 30 ❑ RAINBIRD 1&00 MPR SIDE STRIP POP-UP, 4'' LAWN (o'' G.0 9'X18' 113 30 ❑ R,4INBIRD 1&00 MPR SIDE STRIP POP-UP, 4'' LAWN, 6'' G,C, 4'X30' 1.21 30 ® RAINBIRD 1&00 MPR END STRIP POP-UP, 4'' LAWN, ro'' G,C;. 41X15' 0.ro1 30 lu ,& r-=t tltr-,it�:, r-rL,4z:1 1 ic.. v,4Lvt,�:, © RAINBIRD ESP MODULAR SERIES 10 STATION CONTROLLER - CONFIRM LOCATION ® POINT OF CONNECTION: 3/4'' IRRIGATION METER - CONFIRM LOCATION 3/4'' FEBCO 850 DOUBLE CHECK VALVE I" QUICK COUPLER VALVE I STATION 2-1 CzPM 1-1/2'' MAINLINE, PVC SCHEDULE 40 LATERAL LINE, PVC CLASS 200 SLEEVING, PVC SCHEDULE 40. MINIMUM 2X LINE SIZE. 0 CONFIRM EXACT LOCATION OF P.O.C., CONTROLLER, AND WATER PRESSURE AT P.O"C. o ALL VALVES IN 'AMETEK' OR 'CARBON' BOXES SET AT FINISHED GRADE. o ALL WORK PER PLANS, LOCAL CODES AND MANUFACTURER'S SPECS. o PRESSURE TEST BEFORE 5,4CKFILLING. o PLAN IS DIAGRAMMATIC, ADJUST LINE AND HEAD LOCATIONS AS NECEBBARI' TO ASSURE PROPER COVERAGE AND CONFORM WITH ACGEPTED CONSTRUCTION PRACTICE&" GONGRETE NAL< IGAT I CN FLAN L 5C,4LE: 1" _ _20'' O E N N O O N O O� U M zp = o0� a z z W O� � N 0. HNo Q zo NQW N 3� Yi= c� g w a �. W � CID U CID � o 0 I � U � o Q w 0 W � Q co U n z Q o N Sheet IRRIOATION PLAN 0 3 0 0 0 0 0 0 N 0 N c a� E Q 3 `0 a 0 0 0 0 N 0 N z J a a 0 v Q Packet Pg. 61 Attachment 6 MEMORANDUM To: Carl Pirscher, CDA + Pirscher Architects From: Matthew Palmer, PE .1fV Project: Woodway Station Update, GTC #20-169 City of Edmonds Trip Generation and Mitigation Date: November 18, 2020 This memorandum summarizes the updated trip generation and mitigation analysis for the proposed development which will consist of 11,168 Square Feet (SF) of commercial building space. The site is located at 23726 100th Avenue W in the City of Edmonds. There is an existing 1,600 SF building that will be removed with the development. The existing building had been a gas station with convenience store (4 vehicle fueling positions); however, the last known use was as a general office use. The site currently has three access points: one to 100th Avenue W and two to 238th Street SW. The access to 100th Avenue W and the west access to 238th Street SW will be used for future access. Trip Generation Trip generation calculations for the proposed development are based on national research data for land uses contained in the Institute of Transportation Engineers' (ITE) Trip Generation, 10`h Edition (2017). The trip generation calculations for the development are based on the average trip generation rates for ITE Land Use Code 710, general office. Both the existing and future trip generation will use the same general office trip generation. The trip generation is summarized in Table 1. Table 1: Trip Generation Summary Land Use Size Average Daily Trips AM Peak -Hour Trips PM Peak -Hour Trips In Out Total In Out Total General Office 11,168 SF 109 11 2 13 2 11 13 General Office (Removed) 1 -1,600 SF -16 -2 0 -2 0 -2 -2 TOTAL 93 9 2 11 2 9 11 The development will generate approximately 93 average daily trips with 11 AM peak -hour trips and 11 PM peak -hour trips. The trip generation rate for the PM peak -hour was confirmed to be 1.15 trips per 1,000 SF and the trip generation sheet from ITE is included in the attachments. 2813 Rockefeller Avenue • Suite B • Everett, WA 98201 Tel: 425-339-8266 • Fax: 425-258-2922 • E-mail: info@gibsontraffic.com Attachment 7 Packet Pg. 62 5.1.a Woodway Station Update Trip Generation & Mitigation Memo Mitigation Fees The applicable traffic mitigation fees are from City of Edmonds Code Section 3.36.125. The 2019 Impact Fee Rate for the new building is $10.89 per SF of office space. The traffic mitigation fee calculation for the Woodway Station is summarized in Table 2. Table 2: Traffic Mitigation Fee Calculation Land Use SF Cost per Unit Total Office Space 11,168 SF $10.89 $121,619.52 Office Space -1,600 SF $10.89 -$17,424.00 Total 9,568 SF $10.89 $104,195.52 Access Analysis The site currently has three access points: one to 100th Avenue W and two to 238th Street SW. The access to 100th Avenue W and the west access to 238th Street SW will be used for future access. Each of the new accesses have approximately 100 feet of corner clearance from the intersection of 100th Avenue W at 238th Street SW. The speed limit on 100th Avenue W is 30 mph and the speed limit on 238th Street SW is 25 mph. Using Standard Detail TR-590 for a commercial driveway, the required sight distance for the access to 100th Avenue W is 300 feet and the required sight distance for the access to 238th Street SW is 250 feet. For the access to 1001 Avenue W from 10 feet back of the edge of the traveled way there is over 350 feet of sight distance to the south and with vegetation clearing on the northeast corner of the property there should be a minimum of 350 feet of sight distance to the north. For the access to 238th Street SW from 10 feet back there is over 250 feet of sight distance to the west and to the east there is approximately 140 feet from the exiting lane of the access to 100th Avenue W. Collision data in the site vicinity was collected from WSDOT for the years January 1, 2015 through December 31, 2019. There were 9 total collisions over the 5 years (3 enter at angle, 4 opposite direction, 1 rear end, and 1 fixed object). There were no collisions associated with bikes or pedestrians and none of the collisions resulted in a fatality. There is no collision history at the existing accesses. Left turns from the site on to 238th Street SW would not cause any new significant impacts and the removal of the access closest to the intersection of 100th Avenue W at 238th Street SW would improve the safety of the adjacent signalized intersection. The 95th percentile queue for the eastbound left -turn is anticipated to be 89 feet which will not interact with exiting vehicles. Attachments (A-1 to A-15) Gibson Traffic Consultants, Inc. November 2020 info@gibsontraffic.com 2 GTC #20-169 Attachment 7 Packet Pg. 63 5.1.a _ 0 t 00 e \ w F z z _ / 9 \ 2 \�K CD a> zw 3 c c c E � LU ¢ 0 CD CD CD wog m « a = c c c � \w o } \ G 2 w + Cl) LU ® -_ ° CD CD w2�K �� 0 z g w o b K LLI % i£ J J $L�cc o � 2 0§ k\ c c CD CD 04 2 « $ 0-- 0---1 ) a�cc W IL 7<"00--+.. \ / \ c \ / E CLJ) m \ u / k )k/{/cc q 7/ kk�-\ 00 -L) 0- = _ $ ¢ « e § LO 0 )\ �t 2 o o Lo® 0 J3 \ % ) k ° ° 6 CL { { 2 &m e z 2 (CL - ]0 ® ® / w / ° 00 a 2 � }} c � o 6 $ {0 � « § \ \ � » - AaCh en!E\k Packet Pg. 6 c o rn 't5 U >o 3 U o F- 3 U Q L L O � 2 O Y 2 N Y a. a� a m W Y Y N N N N G 5.1.a Packet Pg. 65 c o rn 't5 U >o 3 U o F- 3 U a Al G 5.1.a Packet Pg. 66 5.1.a Woodway Station GTC #20-169 AM Peak -Hour % New ADT New AM Peak Hour Trips In I Out 11 Total 100% 931 101 211 11 1 % 0.93 0.10 0.02 0.11 2% 1.86 0.19 0.03 0.22 3% 2.80 0.29 0.05 0.33 4% 3.73 0.38 0.06 0.44 5% 4.66 0.48 0.08 0.55 6% 5.591 0.57 0.09 0.67 7% 6.52 0.67 0.11 0.78 8% 7.46 0.76 0.12 0.89 9% 8.39 0.86 0.14 1.00 10% 9.32 0.95 0.16 1.11 11 % 10.25 1.05 0.17 1.22 12% 11.18 1.14 0.19 1.33 13% 12.12 1.24 0.20 1.44 14% 13.05 1.34 0.22 1.55 15% 13.98 1.43 0.23 1.66 16% 14.91 1.53 0.25 1.77 17% 15.84 1.62 0.26 1.89 18% 16.78 1.72 0.28 2.00 19% 17.71 1.81 0.29 2.11 20% 18.64 1.91 0.31 2.22 21 % 19.57 2.00 0.33 2.33 22% 20.50 2.10 0.34 2.44 23% 21.44 2.19 0.36 2.55 24% 22.37 2.29 0.37 2.66 25% 23.30 2.39 0.39 2.77 26% 24.23 2.48 0.40 2.88 27% 25.161 2.58 0.42 2.99 28% 26.101 2.67 0.43 3.11 29% 27.03 2.77 0.45 3.22 30% 27.96 2.86 0.47 3.33 31 % 28.89 2.96 0.48 3.44 32% 29.82 3.05 0.50 3.55 33% 30.76 3.15 0.51 3.66 34% 31.691 3.24 0.53 3.77 35% 32.62 3.34 0.54 3.88 36% 33.55 3.43 0.56 3.99 37% 34.48 3.53 0.57 4.10 38% 35.42 3.63 0.59 4.21 39% 36.35 3.72 0.60 4.33 40% 37.281 3.82 0.62 4.44 41 % 38.21 3.91 0.64 4.55 42% 39.14 4.01 0.65 4.66 43% 40.08 4.10 0.67 4.77 44% 41.01 4.20 0.68 4.88 45% 41.94 4.29 0.70 4.99 46% 42.871 4.39 0.71 5.10 47% 43.80 4.48 0.73 5.21 48% 44.74 4.58 0.74 5.32 49% 45.67 4.67 0.76 5.43 50% 46.60 4.77 0.78 5.55 % New ADT New AM Peak Hour Trips In 1Out Total 100% 931 101 211 11 51 % 47.53 4.87 0.79 5.66 52% 48.46 4.96 0.81 5.77 53% 49.40 5.06 0.82 5.88 54% 50.33 5.15 0.84 5.99 55% 51.26 5.25 0.85 6.10 56%1 52.19 5.341 0.87 6.21 57% 53.12 5.44 0.88 6.32 58% 54.06 5.53 0.90 6.43 59% 54.99 5.63 0.91 6.54 60% 55.92 5.72 0.93 6.65 61 % 56.85 5.82 0.95 6.76 62%1 57.78 5.911 0.96 6.88 63% 58.72 6.011 0.98 6.99 64% 59.65 6.11 0.99 7.10 65% 60.58 6.20 1.01 7.21 66% 61.51 6.30 1.02 7.32 67% 62.44 6.39 1.04 7.43 68%1 63.38 6.49 1.05 7.54 69% 64.31 6.581 1.07 7.65 70% 65.24 6.68 1.09 7.76 71 % 66.17 6.77 1.10 7.87 72% 67.10 6.87 1.12 7.98 73% 68.04 6.96 1.13 8.10 74%1 68.97 7.06 1.15 8.21 75% 69.90 7.161 1.16 8.32 76% 70.83 7.251 1.18 8.43 77% 71.76 7.35 1.19 8.54 78% 72.70 7.44 1.21 8.65 79% 73.63 7.54 1.22 8.76 80%1 74.56 7.63 1.24 8.87 81 % 75.49 7.73 1.26 8.98 82% 76.42 7.82 1.27 9.09 83% 77.36 7.92 1.29 9.20 84% 78.29 8.01 1.30 9.32 85% 79.22 8.11 1.32 9.43 86% 80.15 8.20 1.331 9.54 87% 81.08 8.30 1.35 9.65 88% 82.02 8.40 1.36 9.76 89% 82.95 8.49 1.38 9.87 90% 83.88 8.59 1.40 9.98 91 % 84.81 8.68 1.41 10.09 92% 85.74 8.78 1.431 10.20 93% 86.68 8.87 1.44 10.31 94% 87.61 8.97 1.46 10.42 95% 88.54 9.06 1.47 10.54 96% 89.47 9.16 1.49 10.65 97% 90.40 9.251 1.50 10.76 98% 91.34 9.35 1.52 10.87 99% 92.27 9.44 1.53 10.98 100% 93.20 9.54 1.55 11.09 CO N c N E t U R r Q t �3 1= O Q d W R r N O 0 0 O N O N Z J d c O t c� cC Q Attachment 7 1Packet Pg. 67 5.1.a Woodway Station GTC #20-169 PM Peak -Hour % New ADT New PM Peak Hour Trips In I Out 11 Total 100% 931 21 911 11 1 % 0.93 0.02 0.09 0.11 2% 1.86 0.04 0.18 0.22 3% 2.80 0.05 0.28 0.33 4% 3.73 0.07 0.37 0.44 5% 4.66 0.09 0.46 0.55 6% 5.591 0.11 0.55 0.66 7% 6.52 0.12 0.65 0.77 8% 7.46 0.14 0.74 0.88 9% 8.39 0.16 0.83 0.99 10% 9.32 0.18 0.92 1.10 11% 10.25 0.19 1.02 1.21 12% 11.18 0.21 1.11 1.32 13% 12.12 0.23 1.20 1.43 14% 13.05 0.25 1.29 1.54 15% 13.98 0.26 1.39 1.65 16% 14.91 0.28 1.48 1.76 17% 15.84 0.30 1.57 1.87 18% 16.78 0.32 1.66 1.98 19% 17.71 0.33 1.76 2.09 20% 18.64 0.35 1.85 2.20 21 % 19.57 0.37 1.94 2.31 22% 20.50 0.39 2.03 2.42 23% 21.44 0.40 2.13 2.53 24% 22.37 0.42 2.22 2.64 25% 23.30 0.44 2.31 2.75 26% 24.23 0.46 2.40 2.86 27% 25.16 0.48 2.49 2.97 28% 26.10 0.49 2.59 3.08 29% 27.03 0.51 2.68 3.19 30% 27.96 0.53 2.77 3.30 31 % 28.89 0.55 2.86 3.41 32% 29.82 0.56 2.96 3.52 33% 30.76 0.58 3.05 3.63 34% 31.69 0.60 3.14 3.74 35% 32.62 0.62 3.23 3.85 36% 33.55 0.63 3.33 3.96 37% 34.481 0.65 3.42 4.07 38% 35.42 0.67 3.51 4.18 39% 36.35 0.69 3.60 4.29 40% 37.28 0.70 3.70 4.40 41 % 38.21 0.72 3.79 4.51 42% 39.14 0.74 3.88 4.62 43% 40.081 0.76 3.97 4.73 44% 41.01 0.77 4.07 4.84 45% 41.94 0.79 4.16 4.95 46% 42.87 0.81 4.25 5.06 47% 43.80 0.83 4.34A5.50 48% 44.74 0.84 4.44 49% 45.67 0.86 4.53 50% 46.60 0.88 4.62 % New ADT New PM Peak Hour Trips In 1Out Total 100% 931 21 911 11 51 % 47.53 0.90 4.71 5.61 52% 48.46 0.92 4.80 5.72 53% 49.40 0.93 4.90 5.83 54% 50.33 0.95 4.99 5.94 55% 51.26 0.97 5.08 6.05 56%1 52.19 0.991 5.17 6.16 57% 53.12 1.00 5.27 6.27 58% 54.06 1.02 5.36 6.38 59% 54.99 1.04 5.45 6.49 60% 55.92 1.06 5.54 6.60 61 % 56.85 1.07 5.64 6.71 62%1 57.78 1.091 5.73 6.82 63% 58.72 1.111 5.82 6.93 64% 59.65 1.13 5.91 7.04 65% 60.58 1.14 6.01 7.15 66% 61.51 1.16 6.10 7.26 67% 62.44 1.18 6.19 7.37 68%1 63.38 1.20 6.28 7.48 69% 64.31 1.211 6.38 7.59 70% 65.24 1.231 6.47 7.70 71 % 66.17 1.25 6.56 7.81 72% 67.10 1.27 6.65 7.92 73% 68.04 1.28 6.75 8.03 74%1 68.97 1.30 6.84 8.14 75% 69.90 1.32 6.93 8.25 76% 70.83 1.341 7.02 8.36 77% 71.76 1.36 7.11 8.47 78% 72.70 1.37 7.21 8.58 79% 73.63 1.39 7.30 8.69 80%1 74.56 1.41 7.39 8.80 81 % 75.49 1.43 7.481 8.91 82% 76.42 1.44 7.581 9.02 83% 77.36 1.46 7.67 9.13 84% 78.29 1.48 7.76 9.24 85% 79.22 1.50 7.85 9.35 86% 80.15 1.51 7.95 9.46 87% 81.08 1.53 8.04 9.57 88% 82.02 1.55 8.13 9.68 89% 82.95 1.57 8.22 9.79 90% 83.88 1.58 8.32 9.90 91 % 84.81 1.60 8.41 10.01 92% 85.74 1.62 8.50 10.12 93% 86.68 1.64 8.59 10.23 94% 87.61 1.65 8.69 10.34 95% 88.54 1.67 8.78 10.45 96% 89.47 1.69 8.87 10.56 97% 90.40 1.71 8.96 10.67 98% 91.34 1.72 9.06 10.78 99% 92.27 1.74 9.15 10.89 100% 93.20 1.76 9.24 11.00 N c N E t U R r Q t �3 O Q d R r N O 0 0 O N O N Z J d C N E t c� cC Q Attachment 7 1Packet Pg. 68 5.1.a General Office Building (710) Vehicle Trip Ends vs: 1000 Sq. Ft. GFA On a: Weekday, Peak Hour of Adjacent Street Traffic, One Hour Between 4 and 6 p.m. Setting/Location: General Urban/Suburban Number of Studies: 32 Avg. 1000 Sq. Ft. GFA: 114 Directional Distribution: 16% entering, 84% exiting Vehicle Trip Generation per 1000 Sq. Ft. GFA Average Rate Range of Rates Standard Deviation 1.15 0.47 - 3.23 0.42 Data Plot and Equation 400 X X X 300 X w X X Q X X 200 X X XXX 100 X ?C X X XX X X X X 00 100 200 300 X = 1000 Sq. Ft. GFA X Study Site Fitted Curve Fitted Curve Equation: Ln(T) = 0.95 Ln(X) + 0.36 400 X 500 Average Rate R2= 0.88 Trip Gen Manual, 10th Ed + Supplement • Institute of Transportation Engineers 600 c 0 c� 0 3 0 0 0 0 0 0 N 0 N Z J d Attachment 7 1Packet Pg. 69 5.1.a 0 ivy, 1 n ' rr o ,z a 3 00 ' y� C N ply O R11 O CoI O �I �I U.,I a Z7 CL Cj I�/ ¢y�1 W P P2 P P. Y Q tm I v N m 1❑ 07 ❑3 0 0 U n a] 1D 1) o o M o 0 w0 Attachment 7 Packet Pg. 70 \!!!!!\!!! 5.1.a \( Attachment 7 Packet Pg. 71 5.1.a : ; �||!|]). Attachment 7 Packet Pg. 7 5.1.a 5 3 i q r E G rrrzrr r=r E E_ E E_ E E E E n O n achment 7 Packet P . 73 C fC 3 O O 0 O 0 N O N Z J IL N C N t t) r Q r 3 O 0. N� I.L VI 0 O 0 N O N Z J a c a) E n: s Q 5.1.a Existing Conditions.syn 1: 100th Avenue W & 238th Street SW Woodway Station (20-169) t Lane Group EBL EBR NBL NBT SBT SBR Lane Configurations r tt t Traffic Volume (vph) 101 63 82 441 362 110 Future Volume (vph) 101 63 82 441 362 110 Ideal Flow (vphpl) 1900 1900 1900 1900 1900 1900 Storage Length (ft) 0 140 60 0 Storage Lanes 1 1 1 0 Taper Length (ft) 25 25 Lane Util. Factor 1.00 1.00 1.00 0.95 0.95 0.95 Ped Bike Factor 0.99 0.99 Frt 0.850 0.965 Flt Protected 0.950 0.950 Satd. Flow (prot) 1787 1599 1787 3574 3419 0 Flt Permitted 0.950 0.431 Satd. Flow (perm) 1787 1599 805 3574 3419 0 Right Turn on Red Yes Yes Satd. Flow (RTOR) 66 55 Link Speed (mph) 30 30 30 Link Distance (ft) 592 379 589 Travel Time (s) 13.5 8.6 13.4 Confl. Peds. (#/hr) 7 7 Peak Hour Factor 0.96 0.96 0.96 0.96 0.96 0.96 Heavy Vehicles (%) 1% 1% 1% 1% 1% 1% Adj. Flow (vph) 105 66 85 459 377 115 Shared Lane Traffic (%) Lane Group Flow (vph) 105 66 85 459 492 0 Turn Type Prot Perm pm+pt NA NA Protected Phases 4 5 2 6 Permitted Phases 4 2 Detector Phase 4 4 5 2 6 Switch Phase Minimum Initial (s) 5.0 5.0 5.0 5.0 5.0 Minimum Split (s) 22.5 22.5 9.5 22.5 22.5 Total Split (s) 31.0 31.0 17.0 59.0 42.0 Total Split (%) 34.4% 34.4% 18.9% 65.6% 46.7% Maximum Green (s) 26.5 26.5 12.5 54.5 37.5 Yellow Time (s) 3.5 3.5 3.5 3.5 3.5 All -Red Time (s) 1.0 1.0 1.0 1.0 1.0 Lost Time Adjust (s) 0.0 0.0 0.0 0.0 0.0 Total Lost Time (s) 4.5 4.5 4.5 4.5 4.5 Lead/Lag Lead Lag Lead -Lag Optimize? Yes Yes Vehicle Extension (s) 3.0 3.0 3.0 3.0 3.0 Recall Mode None None None Max Max Walk Time (s) 7.0 7.0 7.0 7.0 Flash Dont Walk (s) 11.0 11.0 11.0 11.0 Pedestrian Calls (#/hr) 0 0 0 0 Act Effct Green (s) 9.6 9.6 57.5 58.4 49.5 Actuated g/C Ratio 0.13 0.13 0.78 0.79 0.67 v/c Ratio 0.45 0.25 0.12 0.16 0.21 GTC (MJP) Synchro 10 Report Page 1 Attachment 7 1Packet Pg. 74 5.1.a Existing Conditions.syn 1: 100th Avenue W & 238th Street SW Woodway Station (20-169) t t Lane Group EBL EBR NBL NBT SBT SBR Control Delay 35.7 10.5 3.3 2.9 6.4 Queue Delay 0.0 0.0 0.0 0.0 0.0 Total Delay 35.7 10.5 3.3 2.9 6.4 LOS D B A A A Approach Delay 26.0 3.0 6.4 Approach LOS C A A Queue Length 50th (ft) 45 0 8 24 43 Queue Length 95th (ft) 89 32 21 45 77 Internal Link Dist (ft) 512 299 509 Turn Bay Length (ft) 140 60 Base Capacity (vph) 640 615 791 2821 2304 Starvation Cap Reductn 0 0 0 0 0 Spillback Cap Reductn 0 0 0 0 0 Storage Cap Reductn 0 0 0 0 0 Reduced v/c Ratio 0.16 0.11 0.11 0.16 0.21 Intersection Summary Area Type: Other Cycle Length: 90 Actuated Cycle Length: 74 Natural Cycle: 55 Control Type: Actuated -Uncoordinated Maximum v/c Ratio: 0.45 Intersection Signal Delay: 7.6 Intersection LOS: A Intersection Capacity Utilization 36.4% ICU Level of Service A Analysis Period (min)15 Splits and Phases: 1: 100th Avenue W & 238th Street SW 102 04 05 7 06 GTC (MJP) Synchro 10 Report Page 2 Attachment 7 1Packet Pg. 75 5.1.a 100th Avenue W @ 238th Street SW (North Intersection) Woodway, WA I hT 1 \ � 7 I > Tue 7/21/2020 4:00 PM - 6:00 PM Q t • o O 238th Street SW (N Intersection) jol WB Total N N 3 C N VI II � II m U y U U6031 V N L 1a U N > d 2 T n @ w 2 Approach PHF HV NB Approach 0.97 1.3% SB Approach 0.87 1.5% EB Approach 0.95 1.2% Intersection PHF = Peak Hour Factor HV = Heavy Vehicles u- Peds Crossing North Leg = 0 Bicycles = 4 Heavy Vehicles = 7 SB Total = 472 tight Thru U-Turn M 1 Intersection Peak Hour 4:30 PM - 5:30 PM Volume 1159 PHF 0.96 HV 1.4% 4Totalof U-Turn Left NB Total = 523 Heavy Vehicles = 7 Bicycles = 3 Peds Crossing South Leg = 0 TURNING MOVEMENTS DIAGRAM PEAK HOUR SUMMARY TTRA FFIC DATA GATHERING Attachment 7 Packet Pg. 76 5.1.a z z z 7 > > U 0 u L� J Z r _ W F Z N !0 L ~ O O O O O O O O O C O � r' N Z J N O M N N N N O O O c W W ? 3 ; F � O O O O O O O O o � N LL N = O O O O O O N d u d 6i o o N o 0 N N a t K 0 0 0 0 0 0 0 0 2 t H o 0 0 0 0 0 0 0 0 J O a Z O O O O O O O O O H H o 0 0 0 0 0 0 0 0 IQ f � LL = O O O O O O O O O § d u d 00 o 0 0 0 0 0 0 0 0 y a o 0 0 0 0 0 0 0 t K O O O O o o O O {p V f � O N N IN IN N Ol Z O d J N 2 C C O � a LL = o V M M o o d u d m M o 0 o M N M b d a 0 O O O O O O O O N N N M M V W L iIl W W OND W O OJ r {O+l J O O O O O O O O O n 0 3 x K O > Z Q c H 7 O O O O O O O O o � � r x O N M N 10 u 6i d y a O O O O O O O O a Z ° > Z O W Q W p ¢ M O M V O >> > r z w Q J J Y a a a J N Q > J h 0 n M N W F r Or O O O O O N V add NM O M Id V � Z L C O L r 0 0 0 0 0 0 0 0 0 0 0 w �y O O O O O N V r O W 2 J O = N C W ? F 0 0 0 0 0 0 0 0 0 0 0 0 0 � h h N d u GI O O O O O O<< M V M M N d a a 0 0 0 0 0 V Id O N W h OJ I� L K 0 0 0 0 0 0 0 0 0 0 0 0 0 t H o 0 0 0 0 0 0 0 0 0 0 0 0 Z O d J 0 0 0 0 0 0 0 0 0 0 0 0 0 wo H o 0 0 0 0 0 0 0 0 0 0 0 0 � O x o 0 0 0 0 0 0 0 0 0 0 0 0 d u d GO o 0 0 0 0 0 0 0 0 0 0 0 0 y a o 0 0 0 0 0 0 0 0 o o o 0 L K 0 0 0 0 0 0 0 0 0 0 0 0 0 � FO O O O O O NN N «((((VVVVVV Z C J O O O O O N M (00 O) NM r r O d 2 C r d Q O d C f J O O O O O O O O O O O O O 0 a LL 0 0 0 0 o v r o H r v N d u ro d . I O O O O O O O O O o � r pp O � d J 0 0 0 0 0 0 0 0 0 0 0 0 0 = r c K C z > Z Q J H 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 u m d y a 0 0 0 0 0 0 0 0 0 0 0 0 0 a w M M M M V V V V N N N N !o a� d d LL LL LL O N N (O�f N Q O N di 2 di M ri 1f Q ri Op v ml a a V O a vi Attachment 7 Packet Pg. 77 a3Nmo and ME 01086 Vf1YS4NOWd3 M aA'V 001 9ZL£Z ° Nnl I H I C i vMnnnM b m 8 \ Q_LLo s �s ' v I o m->z a iN eti i s — Q I •- � U �WW 3 Ili 'M 3AV 1SIOI O u t_� J � ® .M 3nVo —T-------------T------- -- ---T— a I e I i Ir---- II 8 i a i 8 I w I 0 O � m 0 � = a Z 0 S a mm a w i N Zz Uq Attachment 7 a- is 5.1.a COBALT 0 E 0 S C I E N C E S Geotechnical Investigation Proposed Commercial Development 23726 1001h Avenue West Edmonds, Washington July 31, 2020 Attachment 8 Packet Pg. 79 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON Table of Contents i.o INTRODUCTION............................................................................................................. 1 2.0 PROJECT DESCRIPTION.............................................................................................. 1 3.0 SITE DESCRIPTION....................................................................................................... 1 4.o FIELD INVESTIGATION............................................................................................... 2 4.1.1 Site Investigation Program................................................................................... 2 5.0 SOIL AND GROUNDWATER CONDITIONS.............................................................. 2 5.1.1 Area Geology........................................................................................................ 2 5.1.2 Groundwater........................................................................................................ 2 6.o GEOLOGIC HAZARDS ................................................................................................... 3 6.1 Erosion Hazard.................................................................................................... 3 6.2 Seismic Hazard.................................................................................................... 3 7.o DISCUSSION................................................................................................................... 4 7.1.1 General.................................................................................................................4 8.o RECOMMENDATIONS.................................................................................................. 4 8.1.1 Site Preparation................................................................................................... 4 8.1.2 Temporary Excavations........................................................................................ 4 8.1.3 Erosion and Sediment Control.............................................................................. 5 8.1.4 Foundation Design............................................................................................... 6 8.1.5 Stormwater Management..................................................................................... 7 8.1.6 Slab-on-Grade...................................................................................................... 7 8.1.E Groundwater Influence on Construction.............................................................. 8 8.1.8 Utilities................................................................................................................ 8 8.1.9 Pavements............................................................................................................ 9 9.o CONSTRUCTION FIELD REVIEWS...........................................................................10 io.o CLOSURE...................................................................................................................10 LIST OF APPENDICES Appendix A — Statement of General Conditions Appendix B — Figures Appendix C — Exploration Logs c O c� 3 O O 0 0 0 0 N O N Z J d i Attachment 8 Packet Pg. 80 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 i.o Introduction COBALT GEOSCIENCES In accordance with your authorization, Cobalt Geosciences, LLC (Cobalt) has completed a geotechnical investigation for the proposed commercial development located at 23126 tooth Avenue West in Edmonds, Washington (Figure 1). The purpose of the geotechnical investigation was to identify subsurface conditions and to provide geotechnical recommendations for foundation design, stormwater management, earthwork, soil compaction, and suitability of the on -site soils for use as fill. The scope of work for the geotechnical evaluation consisted of a site investigation followed by engineering analyses to prepare this report. Recommendations presented herein pertain to various geotechnical aspects of the proposed development, including foundation support of the new building and new pavement. 2.0 Project Description The project includes construction of a new two-story commercial building in the central portion of the property. Additional development will include paved areas, utilities, and stormwater infrastructure. The preliminary site layout is shown in Figure 2. Anticipated building loads are expected to be light to moderate and site grading will include cuts and fills on the order of 3 feet or less. Stormwater management will include infiltration devices, if feasible. We should be provided with the final plans when they become available. 3.0 Site Description The site is located at 23726 — iooth Avenue West in Edmonds, Washington (Figure 1). The property consists of one nearly rectangular parcel (No. 270336oO400500) with a total area of about 21,5o6 square feet. The central portion of the property is developed with a former convenience store/gas station building with asphalt and concrete paved areas surrounding the building. The site has local vegetated and gravelled areas along some of the property margins. The site is nearly level to very slightly sloping downward from north to south with relief of about 4 feet. The western margin slopes downward to the west. There is evidence of underground storage tank (UST) removal near the building (east side). We have reviewed environmental assessment reports that discuss UST removal and removal of ancillary equipment and petroleum impacted soils. From our review, the USTs were backfilled with pea gravel and possibly an upper zone of structural fill. The site is bordered to the north by a residential property, to the west by lolst Avenue West, to the east by tooth Avenue West, and to the south by 238th Street SW. PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 Packet Pg. 81 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 4. o Field Investigation 4.1.1 Site Investigation Program L 2 COBALT GEOSCIENCES The geotechnical field investigation program was completed on July 15, 202o and included advancing two auger borings within the property for subsurface analysis. Test pits were proposed; however, there was inadequate area to dig test pits due to the presence of asphalt surfacing in most areas. The soils encountered were logged in the field and are described in accordance with the Unified Soil Classification System (USCS). A Cobalt Geosciences field representative conducted the explorations, collected disturbed soil samples, classified the encountered soils, kept a detailed log of the explorations, and observed and recorded pertinent site features. The results of the sampling are presented on the exploration logs enclosed in Appendix C. 5.0 Soil and Groundwater Conditions 5.m Area Geology The site lies within the Puget Lowland. The lowland is part of a regional north -south trending trough that extends from southwestern British Columbia to near Eugene, Oregon. North of Olympia, Washington, this lowland is glacially carved, with a depositional and erosional history including at least four separate glacial advances/retreats. The Puget Lowland is bounded to the west by the Olympic Mountains and to the east by the Cascade Range. The lowland is filled with glacial and non -glacial sediments consisting of interbedded gravel, sand, silt, till, and peat lenses. The Geologic Map of Washington — Northwest Quadrant, indicates that the site is underlain by Vashon Advance Outwash. Vashon Advance Outwash includes fine to medium grained sand with local silt and gravel. These deposits are typically dense below a variably -thick weathered zone. These soils are typically highly permeable. Explorations The explorations encountered approximately 6 inches of crushed rock or topsoil underlain by approximately 4 to 5 feet of loose to medium dense, silty -fine to medium grained sand trace to some gravel (Weathered Advance Outwash). These deposits were underlain by fine to medium grained sand trace to some gravel and silt (Advance Outwash), which continued to the termination depths of the borings. 5.1.2 Groundwater Groundwater was not encountered in any of the explorations. There is a very slight chance that perched groundwater may be encountered during late winter and early spring months. Any groundwater would be within finer grained areas in the upper soil strata. �: PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 Packet Pg. 82 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 L 2 COBALT GEOSCIENCES Water table elevations often fluctuate over time. The groundwater level will depend on a variety of factors that may include seasonal precipitation, irrigation, land use, climatic conditions and soil permeability. Water levels at the time of the field investigation may be different from those encountered during the construction phase of the project. 6.o Geologic Hazards 6.1 Erosion Hazard The Natural Resources Conservation Services (NRCS) maps for Snohomish County indicate that the site is underlain by Alderwood-Urban land complex (2 to 8 percent slopes). These soils would have a slight to severe erosion potential in a disturbed state, depending on the slope magnitude. It is our opinion that soil erosion potential at this project site can be reduced through landscaping and surface water runoff control. Typically erosion of exposed soils will be most noticeable during periods of rainfall and may be controlled by the use of normal temporary erosion control measures, such as silt fences, hay bales, mulching, control ditches and diversion trenches. The typical wet weather season, with regard to site grading, is from October 315t to April 1st. Erosion control measures should be in place before the onset of wet weather. 6.2 Seismic Hazard The overall subsurface profile corresponds to a Site Class D as defined by Table 1613.5.2 of the 2015 International Building Code (2015 IBC). A Site Class D applies to an overall profile consisting of dense to very dense soils within the upper too feet. We referenced the U.S. Geological Survey (USGS) Earthquake Hazards Program Website to obtain values for Ss, S,, FQ, and F,,. The USGS website includes the most updated published data on seismic conditions. The site specific seismic design parameters and adjusted maximum spectral response acceleration parameters are as follows: PGA (Peak Ground Acceleration, in percent of g) Ss 128.00% of g S, 44.90% of g FA 1.2 Fv Null Additional seismic considerations include liquefaction potential and amplification of ground motions by soft/loose soil deposits. The liquefaction potential is highest for loose sand with a high groundwater table. The relatively dense soil deposits that underlie the site have a low liquefaction potential. PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 3 Packet Pg. 83 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 7.o DISCUSSION 7-m General L 2 COBALT GEOSCIENCES The site is underlain by weathered to unweathered advance outwash with local areas of former UST backfill (mostly pea gravel). The proposed commercial building may be supported on a shallow foundation system bearing on medium dense or firmer native soils and/or structural fill placed on suitable native soils. Local overexcavation of fill and/or loose soils may be necessary below proposed foundation elements. If poor soils are encountered to greater depths in the UST backfill area, pin piles could be locally required. Infiltration of stormwater runoff is feasible below approximately 4 feet in slightly weathered outwash. We recommend utilizing several drywells or deeper trenches to infiltrate stormwater runoff. We should be provided with final stormwater plans to verify suitability of the system locations and sizes. 8. o Recommendations 8.m Site Preparation Trees, shrubs and other vegetation should be removed prior to stripping of surficial organic -rich soil and fill. Based on observations from the site investigation program, it is anticipated that the stripping depth will be 6 to 18 inches, where vegetation and/or fill is present. Deeper excavations will be necessary below foundations, utilities, and in any areas underlain by undocumented fill materials. The native soils consist of silty -sand with gravel and poorly graded sand with gravel. These soils may be used as structural fill provided they achieve compaction requirements and are within 3 percent of the optimum moisture. Some of these soils may only be suitable for use as fill during the summer months, as they will be above the optimum moisture levels in their current state. These soils are variably moisture sensitive and may degrade during periods of wet weather and under equipment traffic. Imported structural fill should consist of a sand and gravel mixture with a maximum grain size of 3 inches and less than 5 percent fines (material passing the U.S. Standard No. 200 Sieve). Structural fill should be placed in maximum lift thicknesses of 12 inches and should be compacted to a minimum of 95 percent of the modified proctor maximum dry density, as determined by the ASTM D 1557 test method. 8.1.2 Temporary Excavations Based on our understanding of the project, we anticipate that the grading could include local cuts on the order of approximately 6 feet or less for foundation and utility placement. Excavations should be sloped no steeper than 1.5H:1V in loose soils and 1H:1V in medium dense native soils. If an excavation is subject to heavy vibration or surcharge loads, we recommend that the excavations be sloped no steeper than 2H:1V, where room permits. Temporary cuts should be in accordance with the Washington Administrative Code (WAC) Part N, Excavation, Trenching, and Shoring. Temporary slopes should be visually inspected daily by a qualified person during construction activities and the inspections should be documented in daily reports. The 4 PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 Packet Pg. 84 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 L 2 COBALT GEOSCIENCES contractor is responsible for maintaining the stability of the temporary cut slopes and reducing slope erosion during construction. Temporary cut slopes should be covered with visqueen to help reduce erosion during wet weather, and the slopes should be closely monitored until the permanent retaining systems or slope configurations are complete. Materials should not be stored or equipment operated within io feet of the top of any temporary cut slope. Soil conditions may not be completely known from the geotechnical investigation. In the case of temporary cuts, the existing soil conditions may not be completely revealed until the excavation work exposes the soil. Typically, as excavation work progresses the maximum inclination of temporary slopes will need to be re-evaluated by the geotechnical engineer so that supplemental recommendations can be made. Soil and groundwater conditions can be highly variable. Scheduling for soil work will need to be adjustable, to deal with unanticipated conditions, so that the project can proceed and required deadlines can be met. If any variations or undesirable conditions are encountered during construction, we should be notified so that supplemental recommendations can be made. If room constraints or groundwater conditions do not permit temporary slopes to be cut to the maximum angles allowed by the WAC, temporary shoring systems may be required. The contractor should be responsible for developing temporary shoring systems, if needed. We recommend that Cobalt Geosciences and the project structural engineer review temporary shoring designs prior to installation, to verify the suitability of the proposed systems. 8.1.3 Erosion and Sediment Control Erosion and sediment control (ESC) is used to reduce the transportation of eroded sediment to wetlands, streams, lakes, drainage systems, and adjacent properties. Erosion and sediment control measures should be implemented and these measures should be in general accordance with local regulations. At a minimum, the following basic recommendations should be incorporated into the design of the erosion and sediment control features for the site: • Schedule the soil, foundation, utility, and other work requiring excavation or the disturbance of the site soils, to take place during the dry season (generally May through September). However, provided precautions are taken using Best Management Practices (BMP's), grading activities can be completed during the wet season (generally October through April). • All site work should be completed and stabilized as quickly as possible. • Additional perimeter erosion and sediment control features may be required to reduce the possibility of sediment entering the surface water. This may include additional silt fences, silt fences with a higher Apparent Opening Size (AOS), construction of a berm, or other filtration systems. • Any runoff generated by dewatering discharge should be treated through construction of a sediment trap if there is sufficient space. If space is limited other filtration methods will need to be incorporated. PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 5 Packet Pg. 85 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 8.1.4 Foundation Design L 2 COBALT GEOSCIENCES The proposed commercial building may be supported on a shallow spread footing foundation system bearing on undisturbed medium dense or firmer native soils or on properly compacted structural fill placed on the suitable native soils. If structural fill is used to support foundations, then the zone of structural fill should extend beyond the faces of the footing a lateral distance at least equal to the thickness of the structural fill. For shallow foundation support, we recommend widths of at least 18 and 24 inches, respectively, for continuous wall and isolated column footings supporting the proposed structure. Provided that the footings are supported as recommended above, a net allowable bearing pressure of 2,000 pounds per square foot (psf) may be used for design. The geotechnical engineer must be on site to verify foundation subgrade conditions. It may be necessary to locally remove UST backfill if the materials do not consist of either properly compacted structural fill or other deleterious materials. Please note that the depth of USTs is typically more than io feet (up to 20 feet in places). It may be necessary to install several steel pipe piles to support footings in former UST areas if poor soils are present. We will provide location -specific recommendations if non-native soils are present. A 1/3 increase in the above value may be used for short duration loads, such as those imposed by wind and seismic events. Structural fill placed on bearing, native subgrade should be compacted to at least 95 percent of the maximum dry density based on ASTM Test Method D1557. Footing excavations should be inspected to verify that the foundations will bear on suitable material. Exterior footings should have a minimum depth of 18 inches below pad subgrade (soil grade) or adjacent exterior grade, whichever is lower. Interior footings should have a minimum depth of 12 inches below pad subgrade (soil grade) or adjacent exterior grade, whichever is lower. If constructed as recommended, the total foundation settlement is not expected to exceed 1 inch. Differential settlement, along a 25-foot exterior wall footing, or between adjoining column footings, should be less than 1/2 inch. This translates to an angular distortion of 0.002. Most settlement is expected to occur during construction, as the loads are applied. However, additional post -construction settlement may occur if the foundation soils are flooded or saturated. All footing excavations should be observed by a qualified geotechnical consultant. Resistance to lateral footing displacement can be determined using an allowable friction factor of 0.40 acting between the base of foundations and the supporting subgrades. Lateral resistance for footings can also be developed using an allowable equivalent fluid passive pressure of 225 pounds per cubic foot (pcf) acting against the appropriate vertical footing faces (neglect the upper 12 inches below grade in exterior areas). The allowable friction factor and allowable equivalent fluid passive pressure values include a factor of safety of 1.5. The frictional and passive resistance of the soil may be combined without reduction in determining the total lateral resistance. Care should be taken to prevent wetting or drying of the bearing materials during construction. Any extremely wet or dry materials, or any loose or disturbed materials at the bottom of the footing excavations, should be removed prior to placing concrete. The potential for wetting or drying of the 6 PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 Packet Pg. 86 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 L 2 COBALT GEOSCIENCES bearing materials can be reduced by pouring concrete as soon as possible after completing the footing excavation and evaluating the bearing surface by the geotechnical engineer or his representative. 8.1.5 Stormwater Management The site is underlain by Vashon Advance Outwash that is locally suitable for infiltration of stormwater runoff. We performed a small-scale pilot infiltration test in a larger excavation near B-2 at a depth of 4 feet below grade. Following a typical 6-hour saturation period, testing, and application of correction factors for variability (0.33 used), influent control (o.9), and testing analysis type (0.5), the observed infiltration rate was 1.2 inches per hour. We analyzed the cation exchange capacity (CEC) and organic content from a soil sample at a depth of 4 feet below grade. The CEC was 5.2 meq and the organic content was 2.1 percent by weight. Following infiltration testing, we explored the area with a deeper excavation to determine if there was a restrictive layer or mounded groundwater from the testing. Neither were encountered and the soils appear to continue as outwash to greater depths below site (likely at least 20 feet). Infiltration systems should have a depth of 4 to 7 feet below existing grades and located at least io feet from any property lines or buildings and at least 15 feet from other systems. Any fine grained soils or interbeds of fine grained soils must be removed prior to rock placement. Any system should have adequate overflow to City infrastructure. We should be provided with final plans for review to determine if the intent of our recommendations has been incorporated or if additional modifications are needed. Verification testing of infiltration systems should be performed during construction. 8.1.6 Slab -on -Grade We recommend that the upper 18 inches of the existing fill and/or native soils within slab areas be re - compacted to at least 95 percent of the modified proctor (ASTM D1557 Test Method). Often, a vapor barrier is considered below concrete slab areas. However, the usage of a vapor barrier could result in curling of the concrete slab at joints. Floor covers sensitive to moisture typically requires the usage of a vapor barrier. A materials or structural engineer should be consulted regarding the detailing of the vapor barrier below concrete slabs. Exterior slabs typically do not utilize vapor barriers. The American Concrete Institutes ACI 36oR-o6 Design of Slabs on Grade and ACI 302AR-04 Guide for Concrete Floor and Slab Construction are recommended references for vapor barrier selection and floor slab detailing. A minimum 4 inch thick capillary break should be placed over the prepared subgrade. This may consist of pea gravel or 5/8 inch clean angular rock. Slabs on grade may be designed using a coefficient of subgrade reaction of 18o pounds per cubic inch (pci) assuming the slab -on -grade base course is underlain by structural fill placed and compacted as outlined in Section 8.1. A 4 inch thick capillary break material should be placed over the prepared subgrade. This could include pea gravel or 5/8 inch clean angular rock. PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 Packet Pg. 87 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 L 2 COBALT GEOSCIENCES A perimeter drainage system is recommended unless interior slab areas are elevated a minimum of 12 inches above adjacent exterior grades. If installed, a perimeter drainage system should consist of a 4 inch diameter perforated drain pipe surrounded by a minimum 6 inches of drain rock wrapped in a non -woven geosynthetic filter fabric to reduce migration of soil particles into the drainage system. The perimeter drainage system should discharge by gravity flow to a suitable stormwater system. Exterior grades surrounding buildings should be sloped at a minimum of one percent to facilitate surface water flow away from the building and preferably with a relatively impermeable surface cover immediately adjacent to the building. 8.1.7 Groundwater Influence on Construction Groundwater was not encountered in any of the explorations. There is a very slight chance that light groundwater could be encountered above finer grained soils at variable depths. If groundwater is encountered, we anticipate that sump excavations and small diameter pumps systems will adequately de -water short-term excavations, if required. Any system should be designed by the contractor. We can provide additional recommendations upon request. 8.1.8 Utilities Utility trenches should be excavated according to accepted engineering practices following OSHA (Occupational Safety and Health Administration) standards, by a contractor experienced in such work. The contractor is responsible for the safety of open trenches. Traffic and vibration adjacent to trench walls should be reduced; cyclic wetting and drying of excavation side slopes should be avoided. Depending upon the location and depth of some utility trenches, groundwater flow into open excavations could be experienced, especially during or shortly following periods of precipitation. In general, silty and sandy soils were encountered at shallow depths in the explorations at this site. These soils have low cohesion and density and will have a tendency to cave or slough in excavations. Shoring or sloping back trench sidewalls is required within these soils in excavations greater than 4 feet deep. All utility trench backfill should consist of imported structural fill or suitable on site soils. Utility trench backfill placed in or adjacent to buildings and exterior slabs should be compacted to at least 95 percent of the maximum dry density based on ASTM Test Method D1557. The upper 5 feet of utility trench backfill placed in pavement areas should be compacted to at least 95 percent of the maximum dry density based on ASTM Test Method D1557. Below 5 feet, utility trench backfill in pavement areas should be compacted to at least 90 percent of the maximum dry density based on ASTM Test Method D1557. Pipe bedding should be in accordance with the pipe manufacturer's recommendations. The contractor is responsible for removing all water -sensitive soils from the trenches regardless of the backfill location and compaction requirements. Depending on the depth and location of the proposed utilities, we anticipate the need to re -compact existing fill soils below the utility structures and pipes. The contractor should use appropriate equipment and methods to avoid damage to the utilities and/or structures during fill placement and compaction procedures. PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 :, Packet Pg. 88 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 8.1.9 Pavement Recommendations L 2 COBALT GEOSCIENCES The near surface subgrade soils generally consist of silty sand with gravel and poorly graded sand trace silt and gravel. These soils are rated as good for pavement subgrade material (depending on silt content and moisture conditions). We estimate that the subgrade will have a California Bearing Ratio (CBR) value of io and a modulus of subgrade reaction value of k = 200 pci, provided the subgrade is prepared in general accordance with our recommendations. We recommend that at a minimum, 12 inches of the existing subgrade material be moisture conditioned (as necessary) and re -compacted to prepare for the construction of pavement sections. Deeper levels of recompaction or overexcavation and replacement may be necessary in areas where fill and/or very poor (soft/loose) soils are present. The subgrade should be compacted to at least 95 percent of the maximum dry density as determined by ASTM Test Method D1557. In place density tests should be performed to verify proper moisture content and adequate compaction. The recommended flexible and rigid pavement sections are based on design CBR and modulus of subgrade reaction (k) values that are achieved, only following proper subgrade preparation. It should be noted that subgrade soils that have relatively high silt contents will likely be highly sensitive to moisture conditions. The subgrade strength and performance characteristics of a silty subgrade material may be dramatically reduced if this material becomes wet. Based on our knowledge of the proposed project, we expect the traffic to range from light duty (passenger automobiles) to heavy duty (delivery trucks). The following tables show the recommended pavement sections for light duty and heavy duty use. ASPHALTIC CONCRETE (FLEXIBLE) PAVEMENT LIGHT DUTY Asphaltic Concrete Aggregate Base* Compacted Subgrade* ** 2.5 in. 6.o in. 12.0 in. HEAVY DUTY Asphaltic Concrete Aggregate Base* Compacted Subgrade* ** 3.5 in. 6.o in. 12.0 in. PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 60 Packet Pg. 89 5.1.a COBALT GEOTECHNICAL INVESTIGATION GEOSCIENCES EDMONDS, WASHINGTON July 31, 2020 PORTLAND CEMENT CONCRETE (RIGID) PAVEMENT Min. PCC Depth Aggregate Base* Compacted Subgrade* ** 6.o in. 6.o in. I 12.0 in. * 95% compaction based on ASTM Test Method D1557 **A proof roll may be performed in lieu of in place density tests The asphaltic concrete depth in the flexible pavement tables should be a surface course type asphalt, such as Washington Department of Transportation (WSDOT) 1/2 inch HMA. The rigid pavement design is based on a Portland Cement Concrete (PCC) mix that has a 28 day compressive strength of 4,000 pounds per square inch (psi). The design is also based on a concrete flexural strength or modulus of rupture of 550 psi. 9. o Construction Field Reviews Cobalt Geosciences should be retained to provide part time field review during construction in order to verify that the soil conditions encountered are consistent with our design assumptions and that the intent of our recommendations is being met. This will require field and engineering review to: ■ Monitor and test structural fill placement and soil compaction ■ Observe bearing capacity at foundation locations ■ Observe slab -on -grade preparation ■ Evaluate infiltration and other stormwater systems ■ Monitor subgrade preparation of roadways ■ Observe excavation stability Geotechnical design services should also be anticipated during the subsequent final design phase to support the structural design and address specific issues arising during this phase. Field and engineering review services will also be required during the construction phase in order to provide a Final Letter for the project. mo Closure This report was prepared for the exclusive use of Richard Bennett and his appointed consultants. Any use of this report or the material contained herein by third parties, or for other than the intended purpose, should first be approved in writing by Cobalt Geosciences, LLC. The recommendations contained in this report are based on assumed continuity of soils with those of our test holes, and assumed structural loads. Cobalt Geosciences should be provided with final architectural and civil drawings when they become available in order that we may review our design recommendations and advise of any revisions, if necessary. 10 PO Box 82243 Kenmore, WA 98028 cobaltgeoRgmail.com 2o6-331-1097 Attachment 8 Packet Pg. 90 5.1.a GEOTECHNICAL INVESTIGATION EDMONDS, WASHINGTON July 31, 2020 E��lCOBALT GEOSCIENCES Use of this report is subject to the Statement of General Conditions provided in Appendix A. It is the responsibility of Richard Bennett who is identified as "the Client" within the Statement of General Conditions, and its agents to review the conditions and to notify Cobalt Geosciences should any of these not be satisfied. Respectfully submitted, Cobalt Geosciences, LLC Original signed by: � �iAONy wAsyl� � • 4 16h y Z J 54896 ` V ia� �7 16NAL July 31, 2020 Phil Haberman, PE, LG, LEG Principal PH/sc PO Box 82243 Kenmore, WA 98028 cob altgeo Cd) email. com 2o6-331-1097 A. Flab. rm,- 9 ! Attachment 8 11 c 0 c� 0 3 0 0 0 0 0 a N O N Z J d Packet Pg. 91 5.1.a APPENDIX A Statement of General Conditions c� CO U) E M a 3 0 a am w 0 r 0 v 0 0 0 N 0 N Z J d C N E t V cC Q Attachment 8 1Packet Pg. 92 5.1.a Statement of General Conditions USE OF THIS REPORT: This report has been prepared for the sole benefit of the Client or its agent and may not be used by any third parry without the express written consent of Cobalt Geosciences and the Client. Any use which a third party makes of this report is the responsibility of such third parry. BASIS OF THE REPORT: The information, opinions, and/or recommendations made in this report are in accordance with Cobalt Geosciences present understanding of the site specific project as described by the Client. The applicability of these is restricted to the site conditions encountered at the time of the investigation or study. If the proposed site specific project differs or is modified from what is described in this report or if the site conditions are altered, this report is no longer valid unless Cobalt Geosciences is requested by the Client to review and revise the report to reflect the differing or modified project specifics and/or the altered site conditions. STANDARD OF CARE: Preparation of this report, and all associated work, was carried out in accordance with the normally accepted standard of care in the state of execution for the specific professional service provided to the Client. No other warranty is made. INTERPRETATION OF SITE CONDITIONS: Soil, rock, or other material descriptions, and statements regarding their condition, made in this report are based on site conditions encountered by Cobalt Geosciences at the time of the work and at the specific testing and/or sampling locations. Classifications and statements of condition have been made in accordance with normally accepted practices which are judgmental in nature; no specific description should be considered exact, but rather reflective of the anticipated material behavior. Extrapolation of in situ conditions can only be made to some limited extent beyond the sampling or test points. The extent depends on variability of the soil, rock and groundwater conditions as influenced by geological processes, construction activity, and site use. VARYING OR UNEXPECTED CONDITIONS: Should any site or subsurface conditions be encountered that are different from those described in this report or encountered at the test locations, Cobalt Geosciences must be notified immediately to assess if the varying or unexpected conditions are substantial and if reassessments of the report conclusions or recommendations are required. Cobalt Geosciences will not be responsible to any parry for damages incurred as a result of failing to notify Cobalt Geosciences that differing site or sub -surface conditions are present upon becoming aware of such conditions. PLANNING, DESIGN, OR CONSTRUCTION: Development or design plans and specifications should be reviewed by Cobalt Geosciences, sufficiently ahead of initiating the next project stage (property acquisition, tender, construction, etc), to confirm that this report completely addresses the elaborated project specifics and that the contents of this report have been properly interpreted. Specialty quality assurance services (field observations and testing) during construction are a necessary part of the evaluation of sub -subsurface conditions and site preparation works. Site work relating to the recommendations included in this report should only be carried out in the presence of a qualified geotechnical engineer; Cobalt Geosciences cannot be responsible for site work carried out without being present. Attachment 8 Packet Pg. 93 5.1.a PO Box 82243 Kenmore, WA 98028 cob altgeo Cd) email. com 206-331-1097 APPENDIX B Figures: Vicinity Map, Site Plan Attachment 8 10.2 U) E a 3 0 a am w 0 r 0 v 0 0 0 N 0 N Z J d C N E t V cC Q Packet Pg. 94 3.000' W 122a22.uL.- --a. W WGS84 122°19,C 0 0 0 o+ �t 0 0 co z 0 0 0 n WAS IINGTON ti I . } r r 799th [ W _ r Y Edmonds - :" i,' Z I. 3 3 ' t5:�. `f :• _ r to 1 'I' .�^2U2dd 5t•SW1 � S� 2nd PI 5N1 A• � 1� � -' • D2nt� .`r1PY a20 rY d� t SW - i Project _ -� a.: FF • „ Location Y � I, a � . d � 206t1i �t cW .•, # a. 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JLF r' � } . c- o N 85rh 5 .a a R .• 991,e INE 185th t�'r• a t r,� � � I .. •�� iyd �a �'¢ � SOtn � l �Oa _ ;'+ •• m ¢ � � �� h7apereated Ivitr` r 20 ojNatio al -eogra_hlar�_ /d It Atlas, Ref 122°2 .000' W 122°22MO' W 122n21.000' W 122a20.000' W WG584 122'19.000' W N o s r TIN MN lr NAT10NAL MILES o ,d�10 zme 3mf) 9� suoa GEOGRAPHIC KI1 As FFU 1 $01 d METr[is U(N) OA OS/19 Cobalt Geosciences, LLC Proposed Commercial Development VICINITY P.O. Box 82243 23'726 - tooth Avenue West MAP Kenmore, WA 98028 COBALT(2o6) 331-1097 Edmonds, Washington FIGURE i www.cobaltgeo.com Attachment 8 cob Packet Pg. 95 Q4 I Y 7771 tow � I GOMMERG I AL 5,454 G5r 15T r-Lf2. 5,154 65F 2ND Ft-R. orti I ...-1.1 . ..A. J 1S N 88'}3'02" W(C)(R7) 193.82' B-1 Approximate Boring Location i I I I I I I I j I uN0 4 x4 CO W VSK R PLWCH AT B-2 Sv 5 � r 9 ' Y H r 1 d 9 I ITS C 5.1.a C O _ � O O 0 o 0 N O N Z J a N A Not to Scale Proposed Commercial Development SITE PLAN P.O. Box 82243 23726 - tooth Avenue West Kenmore, WA 98028 (2o6) 331-1097 Edmonds, Washington ton F' IGURE 1 www.cobaltgeo.com Attachment 8 cob Packet Pg. 96 5.1.a APPENDIX C Exploration Logs c� CO U) E M a 3 0 a am w 0 r 0 v 0 0 0 N 0 N Z J d C N E t V cC Q Attachment 8 Packet Pg. 97 5.1.a Unified Soil Classification System (USCS) MAJOR DIVISIONS SYMBOL TYPICAL DESCRIPTION Clean Gravels GW Well -graded gravels, gravels, gravel -sand mixtures, little or no fines Gravels (more than 50% (less than 5% fines) GP Poorly graded gravels, gravel -sand mixtures, little or no fines COARSE GRAINED SOILS of coarse fraction retained on No. 4 sieve) Gravels with Fines (more than 12% fines) GM Silty gravels, gravel -sand -silt mixtures GC Clayey gravels, gravel -sand -clay mixtures (more than 50% retained on Clean Sands ;°e sw Well -graded sands, gravelly sands, little or no fines No. 200 sieve) Sands (50% or more of coarse fraction (less than 5% fines) SP Poorly graded sand, gravelly sands, little or no fines passes the No. 4 sieve) Sands with Fines sM Silty sands, sand -silt mixtures (more than 12% fines) sc Clayey sands, sand -clay mixtures ML Inorganic silts of low to medium plasticity, sandy silts, gravelly silts, FINE GRAINED SOILS (50% or more Silts and Clays (liquid limit less than 50) Inorganic or clayey silts with slight plasticity cL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays silty clays, lean clays Organic oL Organic silts and organic silty clays of low plasticity passes the MH Inorganic silts, micaceous or diatomaceous fine sands or silty soils, No. 200 sieve) Silts and Clays (liquid limit 50 or more) Inorganic elastic silt CH Inorganic clays of medium to high plasticity, sandy fat clay, or gravelly fat clay Organic OH Organic clays of medium to high plasticity, organic silts HIGHLY ORGANIC SOILS primarily organic matter, dark in color, and organic odor PT Peat, humus, swamp soils with high organic content (ASTM D4427) 1 Classification of Soil Constituents 1 MAJOR constituents compose more than 50 percent, by weight, of the soil. Major constituents are capitalized (i.e., SAND). Minor constituents compose 12 to 50 percent of the soil and precede the major constituents (i.e., silty SAND). Minor constituents preceded by "slightly" compose 5 to 12 percent of the soil (i.e., slightly silty SAND). Trace constituents compose o to 5 percent of the soil (i.e., slightly silty SAND, trace gravel). Relative Density (Coarse Grained Soils) Consistency (Fine Grained Soils) N, SPT, Relative N, SPT, Relative Blows/FT Density Blows/FT Consistency 0-4 Very loose Under 2 Very soft 4 -10 Loose 2-4 Soft 10 - 30 Medium dense 4-8 Medium stiff 30 - 50 Dense 8 -15 Stiff Over 50 Very dense 15 - 30 Very stiff Over 3o Hard Cobalt Geosciences, LLC P.O. Box 82243 Kenmore, WA 98028 (2o6) 331-1097 www.cobalt eg o.com cobaltgeo(d-) gmail.com Grain Size Definitions Description Sieve Number and/or Size Fines <#200 (o.o8 mm) Sand -Fine #200 to #40 (o.o8 to 0.4 mm) -Medium #40 to #10 (0.4 to 2 mm) -Coarse #10 to #4 (2 to 5 mm) Gravel -Fine #4 to 3/4 inch (5 to 19 mm) -Coarse 3/4 to 3 inches (19 to 76 mm) Cobbles 3 to 12 inches (75 to 305 mm) Boulders >12 inches (305 mm) Moisture Content Definitions Dry Absence of moisture, dusty, dry to the touch Moist Damp but no visible water Wet Visible free water, from below water table Soil Classification Chart Attachment 8 Figure C1 Packet Pg. 98 1 I 5.1.a I Log of Auger Boring AB-1 Date: July 15, 2020 Contractor: Method: Hand Auger m o o N N L U N o ° U Depth: 7' Initial Groundwater: None Elevation: N/A Sample Type: Grab Logged By: PH Checked By: SC Final Groundwater: N/A Moisture Content (%) Plastic 1 Liquid Limit Limit 0 Material Description o DCP N-Value C 0 10 20 30 40 Gravel --- ---- -- -- --------------------------------------------- SM/ Loose to medium dense, silty -fine to medium grained sand with gravel SP yellowish brown to grayish brown. (Weathered Outwash) — 2 _ —3 —4 —5 -- 6 ---- -- ---- ------------------------------------------- -- SP Medium dense to dense, fine to medium grained sand with gravel, grayish brown, moist. (Advance Outwash) End of Auger Boring 7' —8 —9 — 10 —12 Cobalt Geosciences, LLC P.O. Box 82243 Proposed Commercial Building Kenmore, WA98028 23726 tooth Avenue West (2o6) 331-1097 _ www.cobaltgeo.com Edmonds Washington cobaltgeo(&gmail.com Attachment $ M ■: 0 Auger Boring Log Packet Pg. 99 I 5.1.a I Log of Auger Boring AB-2 Date: July 15, 2020 Contractor: Method: Hand Auger m o o N N L U N o ° U Depth: 9' Initial Groundwater: None Elevation: N/A Sample Type: Grab Logged By: PH Checked By: SC Final Groundwater: N/A Moisture Content (%) Plastic 1 Liquid Limit Limit 0 Material Description o DCP N-Value C 0 10 20 30 40 Vegetation/Topsoil ---- ---- -- -- --------------------------------------------- "� SM/ Loose to medium dense, silty -fine to medium grained sand with gravel, — 1 SP yellowish brown to grayish brown. (Weathered Outwash) —2 —3 — 4 -- 5 — — — — — — — -- — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — �' SP Medium dense to dense, fine to medium grained sand with gravel, grayish brown, moist. (Advance Outwash) — 6' — 7 —8 End of Auger Boring 9' — 10 —12 Cobalt Geosciences, LLC P.O. Box 82243 Proposed Commercial Building Kenmore, WA98028 23726 tooth Avenue West (2o6) 331-1097 _ www.cobaltgeo.com Edmonds Washington cobaltgeopgmail.com Attachment $ E ■ 0: Auger Boring Log Packet Pg. 100 5.1.a Construction Stormwater General Permit Stormwater Pollution Prevention Plan (SWPPP) for Woodway Station Permit # Prepared for: The Washington State Department of Ecology Northwest Region Permittee / Owner Developer Operator / Contractor Red Sea Properties, LLC SAME SAME 15423 36th Ave SE Bothell, WA 98012 Edmonds, WA Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number TBD TBD TBD SWPPP Prepared By Name Organization Contact Phone Number Dean A. Furr, P.E., CESCL Furr Engineering, PLLC 206.890.8291 SWPPP Preparation Date July 28, 2020 Project Construction Dates Activity / Phase Start Date End Date Commercial 5/1 /2021 12/1 /2021 Attachment 9 Packet Pg. 101 5.1.a Table of Contents 1 Project Information.............................................................................................................. 4 1.1 Existing Conditions...................................................................................................... 4 1.2 Proposed Construction Activities.................................................................................. 4 2 Construction Stormwater Best Management Practices(BMPs)........................................... 6 2.1 The 13 Elements.......................................................................................................... 6 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits ........................................ 6 E 2.1.2 Element 2: Establish Construction Access............................................................ 7 y 2.1.3 Element 3: Control Flow Rates............................................................................. 8 2.1.4 Element 4: Install Sediment Controls.................................................................... 8 0 0 CD 2.1.5 Element 5: Stabilize Soils..................................................................................... 9 0 2.1.6 Element 6: Protect Slopes....................................................................................10 v c 2.1.7 Element 7: Protect Drain Inlets............................................................................11 c N 2.1.8 Element 8: Stabilize Channels and Outlets..........................................................12 J 2.1.9 Element 9: Control Pollutants...............................................................................13 a -- 2.1.10 Element 10: Control Dewatering..........................................................................16 2.1.11 Element 11: Maintain BMPs.................................................................................17 E 2.1.12 Element 12: Manage the Project..........................................................................18 r 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs.................................20 Q 3 Pollution Prevention Team.................................................................................................21 4 Monitoring and Sampling Requirements............................................................................22 0 4.1 Site Inspection............................................................................................................22 m 4.2 Stormwater Quality Sampling......................................................................................22 4.2.1 Turbidity Sampling...............................................................................................22 4.2.2 pH Sampling........................................................................................................24 0 c 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies .........................25 N 5.1 303(d) Listed Waterbodies..........................................................................................25 a 5.2 TMDL Waterbodies.....................................................................................................25 6 Reporting and Record Keeping..........................................................................................26 E 6.1 Record Keeping..........................................................................................................26 6.1.1 Site Log Book......................................................................................................26 a 6.1.2 Records Retention...............................................................................................26 6.1.3 Updating the SWPPP...........................................................................................26 6.2 Reporting....................................................................................................................27 6.2.1 Discharge Monitoring Reports..............................................................................27 6.2.2 Notification of Noncompliance..............................................................................27 Page 1 1 Attachment 9 Packet Pg. 102 5.1.a List of Tables Table 1 — Summary of Site Pollutant Constituents................................................................ 4 Table2 — Pollutants................................................................................................................13 Table 3 — pH -Modifying Sources............................................................................................14 Table4 — Dewatering BMPs....................................................................................................16 Table5 — Management............................................................................................................18 Table 6 — BMP Implementation Schedule..............................................................................19 Table7 — Team Information....................................................................................................21 Table 8 — Turbidity Sampling Method....................................................................................22 Table 9 — pH Sampling Method..............................................................................................24 List of Appendices Appendix/Glossary A. Site Map B. BMP Detail C. Correspondance D. Site Inspection Form E. Construction Stormwater General Permit (CSWGP) F. 303 (d) List Waterbodies/TMDL Waterbodies Information G. Contamiated Site Information H. Engineering Calculations Page 12 Attachment 9 Packet Pg. 103 5.1.a List of Acronyms and Abbreviations Acronym / Abbreviation Explanation 303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies BFO Bellingham Field Office of the Department of Ecology BMP(s) Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead COz Carbon Dioxide CRO Central Regional Office of the Department of Ecology CSWGP Construction Stormwater General Permit CWA Clean Water Act DMR Discharge Monitoring Report DO Dissolved Oxygen Ecology Washington State Department of Ecology EPA United States Environmental Protection Agency ERO Eastern Regional Office of the Department of Ecology ERTS Environmental Report Tracking System ESC Erosion and Sediment Control GUILD General Use Level Designation NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Units NWRO Northwest Regional Office of the Department of Ecology pH Power of Hydrogen RCW Revised Code of Washington SPCC Spill Prevention, Control, and Countermeasure sU Standard Units SWMMEW Stormwater Management Manual for Eastern Washington SWMMWW Stormwater Management Manual for Western Washington SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control SWRO Southwest Regional Office of the Department of Ecology TMDL Total Maximum Daily Load VFO Vancouver Field Office of the Department of Ecology WAC Washington Administrative Code WSDOT Washington Department of Transportation WWHM Western Washington Hydrology Model c 0 c� U) 3 0 0 0 0 0 0 N 0 N Z J d Page 13 Attachment 9 Packet Pg. 104 5.1.a Project Information Project/Site Name: Woodway Station Street/Location: 23726 100th Ave W City: Edmonds State: WA Subdivision: - Receiving waterbody: Puget Sound Zip code: 98020 1.1 Existing Conditions Total acreage (including support activities such as off -site equipment staging yards, material storage areas, borrow areas). The proposed commercial project will be constructed on a 0.49ac parcel. The site slopes slightly to the southwest. Total acreage: 0.49ac Disturbed acreage: 0.49ac Existing structures: Gas Station building and fueling island Landscape 0.06ac Topography: Drainage patterns: Flow to the southwest, almost completely impervious coverave. Existing Vegetation: Small strip along the north property line Critical Areas (wetlands, streams, high erosion risk, steep or difficult to stabilize slopes): NA List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: N/A Table 1 includes a list of suspected and/or known contaminants associated with the construction activity. List all known or suspected contaminants associated with this site in Table 1. Include contaminants previously remediated. & A A There are no known contaminents within the soil at this location. Table 1 — Summary of Site Pollutant Constituents Constituent (Pollutant) Location Depth Concentration None known to exist on site 1.2 Proposed Construction Activities The proposal is to construct a townhouse residences accessed by individual driveways off of the alley. Page 14 Attachment 9 Packet Pg. 105 5.1.a Construction Activities: Remove building, foundation and paving to include driveway cuts and sidewalk. Construct new driveway cuts and rough grade for drive lane and parking lot. Install unde4rground utilities (water, sewer and stormwater). Excavate for drywell and pave. Landscape to stabilize site. Construct building. Surface runoff from the project will be collected and conveyed to the drywell to the south for full infiltration. Final stabilization consists of driveways, townhouse construction and landscaping. Page 5 Attachment 9 Packet Pg. 106 5.1.a 2 Construction Stormwater Best Management Practices (BMPs) The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e., hand-written notes and deletions). Update the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design. 2.1 The 13 Elements 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits The site will be delineated by silt fence and high visibility fencing along the north and south property lines and at the edge of proposed clearing along the east. A protective barrier shall be placed around the protected trees prior to land preparation or construction activities, and shall remain in place until all construction activity is terminated. No equipment, chemicals, soil deposits or construction materials shall be placed within the protective barriers. No construction will be allowed within the tree retention zone as shown on the TESC Plan. Any landscaping activities subsequent to the removal of the barriers shall be accomplished with light machinery or hand labor. List and describe BMPs: BMP C101: Preserving Natural Vegetation BMP C102: Buffer Zone BMP C103: High Visibility Plastic or Metal Fence BMP C233: Silt Fence Installation Schedules: once prior to construction Inspection and Maintenance plan: Weekly and daily during storm events Responsible Staff: TBD Page 16 Attachment 9 Packet Pg. 107 5.1.a 2.1.2 Element 2: Establish Construction Access The paved alley will be used as the "construction" entrance. Street washing is not permitted, even after shoveling or sweeping. During construction, if material is being deposited on off -site streets, consider implementing the following: 1. Regenerative -type vacuum sweepers and repeated or continuous sweeping. 2. Wheel wash (or an improved wheel wash if one already exists). 3. Special site procedures and provisions (such as transferring haul -outs to trucks that travel only on paved and maintained surfaces in the site). 4. Suspension of work until dry weather. List and describe BMPs: The paved alley will be used as the "construction" entrance. However, BMP C105: Stabilized Construction Entrance / Exit may be constructed on -site, but it is not anticipated that is needed Inspection and Maintenance plan: Weekly It will be the responsibility to clean all roadway surfaces using regenerative vacuum sweepers Installation Schedules: once prior to the removal of the existing gravel driveway. Responsible Staff: TBD Page 17 Attachment 9 Packet Pg. 108 5.1.a 2.1.3 Element 3: Control Flow Rates Will you construct stormwater retention and/or detention facilities? ❑ Yes ❑ No Will you use permanent infiltration ponds or other low impact development (example: rain gardens, bio-retention, porous pavement) to control flow during construction? ® Yes ❑ No List and describe BMPs: It is anticipated that Flow Control BMP's will NOT be necessary, however, either of the following BMPs could be installed BMP C241: Sediment Trap BMP C200: Interceptor Swale BMP Installation Schedules: Once at the beginning of the project. Inspection and Maintenance plan: Weekly and after every storm event. Sediment shall be removed when it reaches 1ft above the bottom. Responsible Staff: TBD 2.1.4 Element 4: Install Sediment Controls Silt fence will be installed along the determined clearing limits. List and describe BMPs: BMP C233: Silt Fence Installation Schedules: once prior to construction activities Inspection and Maintenance plan: Weekly and daily during storm events Responsible Staff: TBD If the standards are not being met, additional BMPs (including site -specific designs) shall be implemented. If additional BMPs are not implemented or are not successful, work may be suspended until the City approves a new SWPPP (see Vol. II: 2.3). Page 18 Attachment 9 Packet Pg. 109 5.1.a 2.1.5 Element 5: Stabilize Soils All unworked exposed soil will be covered by mulching, plastic covering or permanently vegetated. It is the intent to have all hardscape constructed early in the project. West of the Cascade Mountains Crest Season Dates Number of Days Soils Can be Left Exposed During the Dry Season May 1 — September 30 7 days During the Wet Season October 1 —April 30 2 days Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Anticipated project dates: Start date: 5/1/2021 End date: 12/1/2021 Will you construct during the wet season? ❑ Yes ❑ No It is anticipated that any construction during the wet season will be confined to interior finishing of the buildings only. All proposed hardscaps will be constructed prior to the wet season and all landscaping will be planted and mulched. List and describe BMPs: BMP C121: Mulching BMP C125: Topsoiling/Composting - as a requirement to provide on -site stormwater management to implement BMP T5.13: Post Construction Soil Quality and Depth - Installed per plan BMP C123: Plastic Covering to be used on stockpiles and cut slopes BMP C150: Materials on Hand - in the event that additional TESC materials are necessary during emergency situations. Installation Schedules: As soon as soils get exposed Inspection and Maintenance plan: Weekly and daily during storm events Responsible Staff: TBD Page 19 Attachment 9 Packet Pg. 110 5.1.a 2.1.6 Element 6: Protect Slopes There will be a temporary cut for the drywell on the order of 8ft and BMP C123: Plastic covering could be used to protect the cut. The exposed soil must be covered with mulch. Clearing/grading work shall comply with the Stormwater Manual, geotechnical recommendations, SEPA (State Environmental Policy Act) conditions, and other applicable regulations and standards. These project -specific requirements are in addition to and take priority over general standards. Will steep slopes be present at the site during construction? ❑ Yes ❑ No List and describe BMPs: BMP C120: Temporary and Permanent Seeding BMP C121: Mulching BMP C123: Plastic Covering to be used on stockpiles and cut slopes Installation Schedules: when the cuts are made Inspection and Maintenance plan: Daily Responsible Staff: TBD Page 1 10 Attachment 9 Packet Pg. 111 5.1.a 2.1.7 Element 7: Protect Drain Inlets All off -site catchbasins adjacent to the project will be fitted with inlet protection. If on -site catchbasins and yard basins are constructed prior to site stabilization, they shall be fitted with inlet protection as well. The Contractor shall remove inlet protection at the end of the project without releasing captured sediment into the storm system. List and describe BMPs: BMP C220 Inlet Protection Installation Schedules: Once prior to construction activities Inspection and Maintenance plan: Weekly and during storm events. Sediment buildup must be removed when the device is filled by one third (1/3). Responsible Staff: TBD Page 1 11 Attachment 9 Packet Pg. 112 5.1.a 2.1.8 Element 8: Stabilize Channels and Outlets Temporary conveyance channels shall be stabilized for the 10-year, 24-hour frequency storm, and assuming full build out of tributary area(s). List and describe BMPs: NA Installation Schedules: Inspection and Maintenance plan: Responsible Staff: Page 112 Attachment 9 Packet Pg. 113 5.1.a 2.1.9 Element 9: Control Pollutants The following pollutants are anticipated to be present on -site: Table 2 — Pollutants Pollutant (List pollutants and source, if applicable) concrete from foundation and asphalt driveway construction All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well -organized, and free of debris. Dust will be controlled and is in compliance with the Puget Sound Clean Air Agency and Work in Critical Areas conforms to requirements of the City's Critical Areas Ordinance (CAO). If required, BMPs to be implemented to control specific sources of pollutants are discussed below. List and describe BMPs: BMP C151: Concrete Handling BMP C152: Saw cutting and Surfacing Pollution Prevention BMP C153: Material Delivery, Storage and containment Installation Schedules: Prior to construction and during foundation and driveway construction Inspection and Maintenance plan: Weekly and during storm events Responsible Staff: TBD Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on -site? ❑ Yes ® No List and describe BMPs: Installation Schedules: Inspection and Maintenance plan: Responsible Staff: Will wheel wash or tire bath system BMPs be used during construction? ❑ Yes ® No If yes, provide disposal methods for wastewater generated by BMPs. Page 113 Attachment 9 Packet Pg. 114 5.1.a If discharging to the sanitary sewer, include the approval letter from your local sewer district under Correspondence in Appendix C. List and describe BMPs: Installation Schedules: Inspection and Maintenance plan: Responsible Staff: Will pH -modifying sources be present on -site? ❑ Yes ❑ No If yes, check the source(s). Table 3 — pH -Modifying Sources ❑ None ❑ Bulk cement ❑ Cement kiln dust ❑ Fly ash ❑ Other cementitious materials ® New concrete washing or curing waters ❑ Waste streams generated from concrete grinding and sawing ❑ Exposed aggregate processes ❑ Dewatering concrete vaults ❑ Concrete pumping and mixer washout waters ❑ Recycled concrete ❑ Recycled concrete stockpiles ❑ Other (i.e., calcium lignosulfate) [please describe: ] Construction concrete washout is planned to be done onsite using an eco-pan type system. On a weekly basis the eco pans will be disposed of offsite at an approved facility. List and describe BMPs: BMP C151: Concrete Handling BMP C152: Saw cutting and Surfacing Pollution Prevention BMP C153: Material Delivery, Storage and containment Installation Schedules: Throughout the project Inspection and Maintenance plan: Inspection and Maintenance plan: Inspect weekly and dispose of eco pans weekly or more frequently. Dispose to an approved facility Responsible Staff: TBD Adjust pH of stormwater if outside the range of 6.5 to 8.5 su. Page 1 14 Attachment 9 Packet Pg. 115 5.1.a Obtain written approval from Ecology and the City of Sammamish before using chemical treatment with the exception of CO2 or dry ice to modify pH. Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete must not be dumped on -site, except in designated concrete washout areas with appropriate BMPs installed. Will uncontaminated water from water -only based shaft drilling for construction of building, road, and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits discharge to surface waters? ❑ Yes ❑ No If yes, provide BMPs to contain the wastewater during infiltration. Prior to infiltration, water from water- only based shaft drilling that comes into contact with curing concrete must be neutralized until pH is in the range of 6.5 to 8.5 (su). List and describe BMPs: Installation Schedules: Inspection and Maintenance plan: Responsible Staff: Page 15 Attachment 9 Packet Pg. 116 5.1.a 2.1.10 Element 10: Control Dewatering Dewatering is not anticipated for this project. Check treatment of disposal option for dewatering water, if applicable: Table 4 — Dewatering BMPs ❑ Infiltration ❑ Transport off -site in a vehicle (vacuum truck for legal disposal) ❑ Ecology -approved on -site chemical treatment or other suitable treatment technologies ❑ Sanitary or combined sewer discharge with local sewer district approval (last resort) ❑ Use of sedimentation bag with discharge to ditch or swale (small volumes of localized dewaterin List and describe BMPs: Installation Schedules: Inspection and Maintenance plan: Responsible Staff: Page 1 16 Attachment 9 Packet Pg. 117 5.1.a 2.1.11 Element 11: Maintain BMPs All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume 11 of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on -site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. Page 117 Attachment 9 Packet Pg. 118 5.1.a 2.1.12 Element 12: Manage the Project The project will be managed based on the following principles: • Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. • Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map. Sampling station(s) are located in accordance with applicable requirements of the CSWGP. • Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Check all the management BMPs that apply at your site: Table 5 — Management ® Design the project to fit the existing topography, soils, and drainage patterns ❑ Emphasize erosion control rather than sediment control ❑ Minimize the extent and duration of the area exposed ® Keep runoff velocities low ® Retain sediment on -site ® Thoroughly monitor site and maintain all ESC measures ® Schedule major earthwork during the dry season ❑ Other (please describe) Page 1 18 Attachment 9 Packet Pg. 119 5.1.a Table 6 — BMP Implementation Schedule Phase of Construction Project Stormwater BMPs Date Wet/Dry Season Pre construction Establish Clearing Limits, Silt 5/1/2021 Dry Fence, Construction Entrance, High Visibility Fence Excavate Dust Control to include sprinkling 5/15/2021 Dry water on soil and vacuum or wet sweep fine dirt and skid control materials from paved roads soon after rain events or when needed. Site Grading utility Maintain installed BMPS and 6/1/2021 Dry trenching Dust Control Parking Lot construction BMP C151: Concrete Handling, 7/15/2020 Dry BMP C152: Saw cutting and Surfacing Pollution Prevention, BMP C153: Material Delivery, Storage and containment Building Foundation BMP C151: Concrete Handling, 8/15/2021 Dry BMP C152: Saw cutting and Surfacing Pollution Prevention, BMP C153: Material Delivery, Storage and containment Building Construction 10/1/2021 Wet Landscaping BMP C120: Temporary and 9/1/2021 Dry Permanent Seeding BMP C125: Topsoiling/Composting - as a requirement to provide on -site stormwater management to implement BMP T5.13: Post Construction Soil Quality and Depth - Installed per plan BMP C150: Materials on Hand - in the event that additional TESC materials are necessary during emergency situations. Completed Project Site stabilized during building 11/1/2021 WET construction U) U) c as E U a 3 0 a as 0 0 v 0 0 0 N 0 N Z J d c as E 0 a Page 119 Attachment 9 Packet Pg. 120 5.1.a 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs The site will utilized infiltration as an LID. It is important the soils within the infiltration area not be compacted. Use of High Visibility/Silt fence be installed around the drywell. Page 120 Attachment 9 Packet Pg. 121 5.1.a 3 Pollution Prevention Team Table 7 — Team Information Title Names Phone Number Certified Erosion and Sediment Control Lead (CESCL) TBD TBD Resident Engineer Dean A. Furr, P.E., CESCL 206.890.8291 Emergency Ecology Contact Report A Spill 425.649.7000 Emergency Permittee/ Owner Contact TBD TBD Non -Emergency Owner Contact TBD TBD Monitoring Personnel TBD TBD Ecology Regional Office Northwest Regional Office 425.649.7000 Page 121 Attachment 9 Packet Pg. 122 5.1.a 4 Monitoring and Sampling Requirements Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on -site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Stormwater sampling data Create your own Site Inspection Form or use the Construction Stormwater Site Inspection Form found on Ecology's website. http://www.ecV.wa.gov/programs/wq/stormwater/construction/index. htm I File a blank form under Appendix D. The site log book must be maintained on -site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. 4.1 Site Inspection Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with the applicable requirements of the CSWGP. 4.2 Stormwater Quality Sampling 4.2.1 Turbidity Sampling Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Check the analysis method you will use: Table 8 — Turbidity Sampling Method ® Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size) ® Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. Page 122 Attachment 9 Packet Pg. 123 5.1.a If the discharge's turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: 1. Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Region's Environmental Report Tracking System (ERTS) within 24 hours. • Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, Yakima): (509) 575-2490 or http://www.ecy.wa.gov/programs/spills/forms/nerts online/CRO nerts online.html • Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400 or http://www.ecy.wa.gov/programs/spills/forms/nerts online/ERO nerts online.html • Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 or http://www.ecV.wa.gov/programs/spills/forms/nerts online/NWRO nerts online.html • Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 or httD://www.ecv.wa.aov/Droarams/spills/forms/nerts online/SWRO nerts online.html 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: • Turbidity is 25 NTU (or lower). • Transparency is 33 cm (or greater). • Compliance with the water quality limit for turbidity is achieved. 0 1 - 5 NTU over background turbidity, if background is less than 50 NTU 0 1 % - 10% over background turbidity, if background is 50 NTU or greater • The discharge stops or is eliminated. Page 123 Attachment 9 Packet Pg. 124 5.1.a 4.2.2 pH Sampling pH monitoring is required for "Significant concrete work" (i.e., greater than 1000 cubic yards poured concrete over the life of the project). The use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement -treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (CO2) sparging (liquid or dry ice). 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Method for sampling pH: Check the analysis method you will use: Table 9 — pH Sampling Method ® pH meter ® pH test kit ❑ Wide range pH indicator paper Page 124 Attachment 9 Packet Pg. 125 5.1.a 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies 5.1 303(d) Listed Waterbodies Circle the applicable answer, if necessary: Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH? ❑ Yes ❑ No List the impairment(s): If yes, discharges must comply with applicable effluent limitations in S&C and S&D of the CSWGP. 5.2 TMDL Waterbodies Waste Load Allocation for CWSGP discharges: Describe the method(s) for TMDL compliance: List and describe BMPs: Discharges to TMDL receiving waterbodies will meet in -stream water quality criteria at the point of discharge. The Construction Stormwater General Permit Proposed New Discharge to an Impaired Water Body form is included in Appendix F. Page 125 Attachment 9 Packet Pg. 126 5.1.a 6 Reporting and Record Keeping 6.1 Record Keeping This section does not need to be filled out. It is a list of reminders for the permittee. 6.1.1 Site Log Book A site log book will be maintained for all on -site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Sample logs 6.1.2 Records Retention Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.0 of the CSWGP. Permit documentation to be retained on -site: • CSWGP • Permit Coverage Letter • SWPPP • Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. 6.1.3 Updating the SWPPP The SWPPP will be modified if: • Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. • There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. Page 126 Attachment 9 Packet Pg. 127 5.1.a 6.2 Reporting 6.2.1 Discharge Monitoring Reports Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period the DMR will be submitted as required, reporting "No Discharge". The DMR due date is fifteen (15) days following the end of each calendar month. DMRs will be reported online through Ecology's WQWebDMR System. To sign up for WQWebDMR go to: http://www.ecV.wa.gov/programs/wq/permits/paris/webdmr.html 6.2.2 Notification of Noncompliance If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Specific information to be included in the noncompliance report is found in Special Condition S5.F.3 of the CSWGP. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. • Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Include the following information: 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results Page 127 Attachment 9 Packet Pg. 128 5.1.a 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. Page 128 Attachment 9 Packet Pg. 129 5.1.a Appendix/Glossary A. Site Map a Page 129 Attachment 9 Packet Pg. 130 00446700000200 11 C 0 1 00446700001600 X23.1 L — J T__ X=-I6z,�;, J 4 TBR 1 6\I 0 \ IIIAENT\TRAP \ \ 250 SF REQ'D 284 SF SHOW DEEP SIDD SLOPTS Al IT NW 1/4 SE 1/4 SEC. 36, T. 27N,, R. 03E, W.M. WOODWAY STATION I so I I I I00446700002700 I I I I I r I I I CUNO Ay"x4" CONC MON_ 1/2" o BRASS'b15K & PUNCH Ai 11-12-19. I 7 , a -- 2 �13 � w I- �B R I AS Li 14 11 /I(I I /I TB 7 I I 17 ! �3 x 12 � ; �■� Wl ;MQ 3 U1 IE 3�147 2 -1 = ✓� CB RIM 35490 _ ' IE 8" PVC(W)=35290 _ IF 4" PVC(N)-353. 10 _ zSDD _ � g g � 888813'02" W(C)(R1) 19382' \ - - - 2387H ST. S W �� n� �c — w i//i FOUND 02'(S) I' IRON PIPE U 50MH RIM=352.95 U SSMN RIM=353.22 OF CORNER IE 12" CPP N -345 fi5 IE 8" PVC N -342fiJ () () FOUND REBAR W/ILLEGIBLE l d IE 12" CPP(W))=344.20 IE 8" PVC(W))=342.6] TIE 12 CPP(S),344.20 IE 8" PVC(S)=34257 CAP 0.2'(S) OF CORNER a� /°� LEGEND OB ORANGE BARRIER FENCE X SILT FENCE LIMITS OF CLEARING AND GRADING ASPHALTICONCRETE TO BE REMOVED CONSTRUCTION ACCESS 8 �I I ',CB RIM=358.16 ( l IF 8" RCP(E)-35524I /1\ _ 5 I INLET PROTECTION STOCKPILE AREA e�a�d - - - - - - - - SAWICUTUNE REMOVE CURB REMOVE GRAVEL SDMH RIM=361. 15 CONSTRUCTION SEQUENCE NOTES WOODWAY STATION , IE 12"RCP(S)=354.65 1. SCHEDULEA PRE -CONSTRUCTION MEETING WITH CITY ENGINEERING DIVISION AT 23726 1 OOTH AVE. W. IEs"RCP(NE)=35a.90 IF 8" RCP(W)=35490 425-771-0220,EXT. 1326.TW0 DAY (48 HR)NOTICE IS REQUIRED. EDM ONDS, WA 98020 - M 82'.To22° 2. REVIEW TEMPORARY EROSION AND SEDIMENT CONTROL NOTES. W 237N p� S2� �� 3. CALL FOR UTILITY LOCATES. 4. INSTALL TESC MEASURES AND MAINTAIN DUST CONTROL WHILE PREVENTING DISTURBANCE OF ANY AREAS OF VEGETATION OUTSIDE THE CONSTRUCTION ZONE. 5. HAVE EROSION CONTROL MEASURES INSPECTED BY CITY OF EDMONDS CITY ENGINEERING INSPECTOR. ALL TEMPORARY SEDIMENTATION AND EROSION CONTROL MEASURES MUST BE IN PLACE AND INSPECTED PRIOR TO ANY CONSTRUCTION OR SITE CLEARING. EROSION AND = SEDIMENTATION CONTROL PRACTICES AND/OR DEVICES SHALL BE MAINTAINED UNTIL PERMANENT VEGETATION IS ESTABLISHED. C 6. DEMOLISH EXISTING STRUCTURES. ++ 7. ROUGH GRADE SITE AS REQUIRED TO INSTALL DRAINAGE FEATURES. ++ / B. CLEAR, GRUB &ROUGH GRADE SITE. REVEGETATE DISTURBED AREAS NOT SUBJECT TO Key Plan ADDITIONAL SURFACE DISTURBANCE IMMEDIATELY AFTER ROUGH GRADING. (OTHER o EXPOSED AREAS SHALL BE STABILIZED PER EROSION CONTROL NOTES BELOW). 3 INSTALL UTILITIES AND OTHER SITE IMPROVEMENTS, INCLUDING FRONTAGE 0 IMPROVEMENTS. 10. STABILIZE AND COMPOST AMEND ALL EXPOSED SOILS PRIOR TO REVEGETATION OF ENTIRE O / SITE. 11. ESTABLISH LANDSCAPING AND PERMANENT VEGETATION. ALL TEMPORARY EROSION CONTROL MEASURES SHALL BE REMOVED UPON FINAL SITE STABILIZATION AND APPROVAL O BY CITY INSPECTOR. O O r O Registration O A F p4 sy� z J CONSTRUCTION NOTES 4 FPe � a O STABILIZED CONSTRUCTION ENTRANCE PER DETAIL ON SHEET C3.1 Y k 1sN—ti4�'O" fr i SIGNAL Bl� (D OFILTER FABRIC PER DETAIL ON SHEET C3.1 0/2020 E� (SILT)FENCE U OSAWCUT FULL DEPTH O INSTALL ORANGE BARRIER FENCE AROUND INFILTRATION AREA FIT Q AREA MUST NOT BE SUBJECT TO CONSTRUCTION EQUIPMENT COMPACTION. CNGINEERING � O STORM INLET PROTECTION PER DETAIL ON SHEET CIA3 SERVICES O PLASTIC COVERED STOCKPILE PER DETAIL ON SHEET C2.1 4715142nd PI. SW #B, Edmonds, _ L 98026 !Z REMOVE DRIVEWAY ENTRANCE O ph 206.89 ph 6.890.8291 1X % Ss- w— Attachment 9 O$ REMOVE CONCRETE SIDEWALK Sheet Title O REMOVE CURB, GUTTER, AND SIDEWALK TESC PLAN to //r^ V/ 1O REMOVE EXISTING STRUCTURES O 11 REMOVE EXISTING WALLS AND FENCES O 12 REMOVE ..SITE PAVING O N CD 13 REMOVE LIGHT N 14 REMOVE EXIST UTILITIES, BY OTHERS Revisions J 15 REMOVE EXISTING SD - a r C 16 SEDIMENT TRAP - SEE DETAIL SHEET C3.1 1T INTERCEPTOR SCALE- SEE DETAIL SHEET C3.1 - EARTHWORK QUANTITIES (SITE) CUT=94D CY FILL=85CY NET=855CYCUF CONTRACTORTOVERIFY TOPOGRAPHY, BOUNDARY, AND UTILITIES STATEMENT: FURR ENGINEERING SERVICES PLLC. DOES NOT WARRANT THE TOPOGRAPHY, BOUNDARY, ANDIOR EXISTING UTILITIES SHOWN ON THESE PLANS. IT 15 THE CONTRACTORS' RESPONSIBILITY TO HAVE ALL EXISTING IMPROVEMENTS FIELD VERIFIED PRIOR TO CONSTRUCTION, ANY SUBSURFACE EXPLORATION OF EXISTING UNDERGROUND UTILITIES (POWER, WATER, SEWER, TELECOM, ETC.) SHALL BE PERFORMED BY THE CONTRACTOR. DISCREPANCIES BETWEEN WHAT IS SHOWN ON THE PLANS AND LOCATED BV THE CONTRACTOR SHALL BE BROUGHT TO THE ATTENTION OF PURR ENGINEERING SERVICES PLLC. PRIOR TO CONSTRUCTION ACTIVITIES, R a v N Smle: Fry Project No: 20068 Dote: OCTOBER 01, 2020 20 10 0 20 40 Designed: DAF Drown: DAF SCALE: 1 INCH = 20 FEET Checked: DAF AII FOR COAUTRWTI V C/TYOFEDMOAM Sheet Number DATE.' Know whaft below. Call before you dig. ar. cnr eNciWt�RiMc answW � � e Packet Pg. 131 5.1.a B. BMP Detail a Page 130 Attachment 9 Packet Pg. 132 5.1.a Table II-4.1.1 Source Control BMPs by SWPPP Element Ele- Element ment Ele- _ l Ele- #8 Ele- ment Element serve Element ment ment Stab- Ele- ment #12 #13 Pro- Veget- #2 Estab- #6 ment BMP or Ele #5 ilize #11 Man- tect Low ation/ lish Con- PrO _ 9 Con ment Name Stab- Chan- Main- age Impact Mark struction tect rol Pol ilize nels tain the Devel- Clear- Access Slope lutants Soils and BMPs Pro- opment ing Lim- s Out- ject its lets BMP C101: ✓ Preserving Natural Vegetation tp.266) BMP C102: ✓ ✓ Buffer Zones tp.2681 BMP C103: High Vis- ibility ✓ ✓ Fence tp.269) BMP C105: ✓ Stabilized Con- struction Entrance / Exit (p.270) BMP C106: ✓ Wheel Wash (p 274) BMP C107: Con- struction ✓ Road/Park- ing Area Stab- 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 262 Packet Pg. 133 5.1.a Table II-4.1.1 Source Control BMPs by SWPPP Element (continued) Ele- Element ment Ele- _ l Ele- #8 Ele- ment Element serve Element ment ment Stab- Ele- ment #12 #13 Pro- Veget- #2 Estab- #6 ment BMP or Ele #5 ilize #11 Man- tect Low ation/ lish Con- PrO _ 9 Con ment Name Stab- Chan- Main- age Impact Mark struction tect rol Pol ilize nels tain the Devel- Clear- Access Slope lutants Soils and BMPs Pro- opment ing Lim- s Out- ject its lets ilization .277 BMP C120: ✓ ✓ Temporary and Per- manent Seeding (p 278) BMP C121: ✓ ✓ Mulching (p 284) BMP C122: ✓ ✓ ✓ Nets and Blankets (p 288) BMP C123: ✓ ✓ Plastic Covering tp.294) BMP C124: ✓ ✓ Sodding (p 296) BMP C125: ✓ Topsoiling / Com- posting (p 297) BMP C126: ✓ Poly- acrylamide 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 263 Packet Pg. 134 5.1.a Table II-4.1.1 Source Control BMPs by SWPPP Element (continued) Ele- Element ment Ele- _ l Ele- #8 Ele- ment Element serve Element ment ment Stab- Ele- ment #12 #13 Pro- Veget- #2 Estab- #6 ment BMP or Ele #5 ilize #11 Man- tect Low ation/ lish Con- PrO _ 9 Con ment Name Stab- Chan- Main- age Impact Mark struction tect rol Pol ilize nels tain the Devel- Clear- Access Slope lutants Soils and BMPs Pro- opment ing Lim- s Out- ject its lets PAM for Soil Ero- sion Pro- tection tp.300) BMP C130: Surface Rough- ✓ ✓ ening (p 304) BMP C131: ✓ ✓ Gradient Terraces tp.307) BMP C140: ✓ Dust Con- trol (p.310) BMP C150: ✓ ✓ Materials on Hand tp.31 BMP C151: ✓ Concrete Handling tp.3131 BMP C152: ✓ Sawcuttin and Sur- facing Pol- lution 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 264 Packet Pg. 135 5.1.a Table II-4.1.1 Source Control BMPs by SWPPP Element (continued) Ele- Element ment Ele- _ l Ele- #8 Ele- ment Element serve Element ment ment Stab- Ele- ment #12 #13 Pro- Veget- #2 Estab- #6 ment BMP or Ele #5 ilize #11 Man- tect Low ation/ lish Con- PrO _ 9 Con ment Name Stab- Chan- Main- age Impact Mark struction tect rol Pol ilize nels tain the Devel- Clear- Access Slope lutants Soils and BMPs Pro- opment ing Lim- s Out- ject its lets Prevention (p 314) BMP C153: Material Delivery, ✓ Storage and Con- tainment tp.315 BMP C154: ✓ Concrete Washout Area tp.317) BMP C160: Certified Erosion and Sed- ✓ ✓ iment Con- trol Lead (p 325) BMP C162: ✓ Schedul- ing (p.326) 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 265 Packet Pg. 136 5.1.a BMP C101: Preserving Natural Vegetation Purpose The purpose of preserving natural vegetation is to reduce erosion wherever practicable. Limiting site disturbance is the single most effective method for reducing erosion. For example, conifers can hold up to about 50 percent of all rain that falls during a storm. Up to 20-30 percent of this rain may never reach the ground but is taken up by the tree or evaporates. Another benefit is that the rain held in the tree can be released slowly to the ground after the storm. Conditions of Use Natural vegetation should be preserved on steep slopes, near perennial and intermittent watercourses or swales, and on building sites in wooded areas. . As required by local governments. Phase construction to preserve natural vegetation on the project site for as long as possible during the construction period. Design and Installation Specifications Natural vegetation can be preserved in natural clumps or as individual trees, shrubs and vines. The preservation of individual plants is more difficult because heavy equipment is gen- erally used to remove unwanted vegetation. The points to remember when attempting to save individual plants are: Is the plant worth saving? Consider the location, species, size, age, vigor, and the work involved. Local governments may also have ordinances to save natural veget- ation and trees. Fence or clearly mark areas around trees that are to be saved. It is preferable to keep ground disturbance away from the trees at least as far out as the dripline. Plants need protection from three kinds of injuries: Construction Equipment- This injury can be above or below the ground level. Damage results from scarring, cutting of roots, and compaction of the soil. Placing a fenced buffer zone around plants to be saved prior to construction can prevent construction equipment injuries. Grade Changes - Changing the natural ground level will alter grades, which affects the plant's ability to obtain the necessary air, water, and minerals. Minor fills usu- ally do not cause problems although sensitivity between species does vary and should be checked. Trees can typically tolerate fill of 6 inches or less. For shrubs 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 266 Packet Pg. 137 5.1.a and other plants, the fill should be less. When there are major changes in grade, it may become necessary to supply air to the roots of plants. This can be done by placing a layer of gravel and a tile system over the roots before the fill is made. A tile system protects a tree from a raised grade. The tile system should be laid out on the original grade leading from a dry well around the tree trunk. The system should then be covered with small stones to allow air to circulate over the root area. Lowering the natural ground level can seriously damage trees and shrubs. The highest percentage of the plant roots are in the upper 12 inches of the soil and cuts of only 2-3 inches can cause serious injury. To protect the roots it may be neces- sary to terrace the immediate area around the plants to be saved. If roots are exposed, construction of retaining walls may be needed to keep the soil in place. Plants can also be preserved by leaving them on an undisturbed, gently sloping mound. To increase the chances for survival, it is best to limit grade changes and other soil disturbances to areas outside the dripline of the plant. . Excavations - Protect trees and other plants when excavating for drainfields, power, water, and sewer lines. Where possible, the trenches should be routed around trees and large shrubs. When this is not possible, it is best to tunnel under them. This can be done with hand tools or with power augers. If it is not possible to route the trench around plants to be saved, then the following should be observed: • Cut as few roots as possible. When you have to cut, cut clean. Paint cut root ends with a wood dressing like asphalt base paint if roots will be exposed for more than 24-hours. • Backfill the trench as soon as possible. • Tunnel beneath root systems as close to the center of the main trunk to pre- serve most of the important feeder roots. Some problems that can be encountered with a few specific trees are: . Maple, Dogwood, Red alder, Western hemlock, Western red cedar, and Douglas fir do not readily adjust to changes in environment and special care should be taken to protect these trees. . The windthrow hazard of Pacific silver fir and madrona is high, while that of Western hemlock is moderate. The danger of windthrow increases where dense stands have been thinned. Other species (unless they are on shallow, wet soils less than 20 inches deep) have a low windthrow hazard. • Cottonwoods, maples, and willows have water -seeking roots. These can cause trouble in sewer lines and infiltration fields. On the other hand, they thrive in high moisture conditions that other trees would not. . Thinning operations in pure or mixed stands of Grand fir, Pacific silver fir, Noble fir, 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 267 Packet Pg. 138 5.1.a Sitka spruce, Western red cedar, Western hemlock, Pacific dogwood, and Red alder can cause serious disease problems. Disease can become established through damaged limbs, trunks, roots, and freshly cut stumps. Diseased and weakened trees are also susceptible to insect attack. Maintenance Standards Inspect flagged and/or fenced areas regularly to make sure flagging or fencing has not been removed or damaged. If the flagging or fencing has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. . If tree roots have been exposed or injured, "prune" cleanly with an appropriate prun- ing saw or loppers directly above the damaged roots and recover with native soils. Treatment of sap flowing trees (fir, hemlock, pine, soft maples) is not advised as sap forms a natural healing barrier. BMP C102: Buffer Zones Purpose Creation of an undisturbed area or strip of natural vegetation or an established suitable planting that will provide a living filter to reduce soil erosion and runoff velocities. Conditions of Use Natural buffer zones are used along streams, wetlands and other bodies of water that need protection from erosion and sedimentation. Vegetative buffer zones can be used to protect natural swales and can be incorporated into the natural landscaping of an area. Critical -areas buffer zones should not be used as sediment treatment areas. These areas shall remain completely undisturbed. The local permitting authority may expand the buffer widths temporarily to allow the use of the expanded area for removal of sed- iment. Design and Installation Specifications . Preserving natural vegetation or plantings in clumps, blocks, or strips is generally the easiest and most successful method. . Leave all unstable steep slopes in natural vegetation. . Mark clearing limits and keep all equipment and construction debris out of the nat- ural areas and buffer zones. Steel construction fencing is the most effective method in protecting sensitive areas and buffers. Alternatively, wire -backed silt fence on steel posts is marginally effective. Flagging alone is typically not effective. . Keep all excavations outside the dripline of trees and shrubs. . Do not push debris or extra soil into the buffer zone area because it will cause 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 268 Packet Pg. 139 5.1.a damage from burying and smothering. . Vegetative buffer zones for streams, lakes or other waterways shall be established by the local permitting authority or other state or federal permits or approvals. Maintenance Standards Inspect the area frequently to make sure flagging remains in place and the area remains undisturbed. Replace all damaged flagging immediately. BMP C103: High Visibility Fence Purpose Fencing is intended to: 1. Restrict clearing to approved limits. 2. Prevent disturbance of sensitive areas, their buffers, and other areas required to be left undisturbed. 3. Limit construction traffic to designated construction entrances, exits, or internal roads. 4. Protect areas where marking with survey tape may not provide adequate pro- tection. Conditions of Use To establish clearing limits plastic, fabric, or metal fence may be used: . At the boundary of sensitive areas, their buffers, and other areas required to be left uncleared. . As necessary to control vehicle access to and on the site. Design and Installation Specifications High visibility plastic fence shall be composed of a high -density polyethylene material and shall be at least four feet in height. Posts for the fencing shall be steel or wood and placed every 6 feet on center (maximum) or as needed to ensure rigidity. The fencing shall be fastened to the post every six inches with a polyethylene tie. On long continuous lengths of fencing, a tension wire or rope shall be used as a top stringer to prevent sag- ging between posts. The fence color shall be high visibility orange. The fence tensile strength shall be 360 lbs./ft. using the ASTM D4595 testing method. If appropriate install fabric silt fence in accordance with BMP C233: Silt Fence (p.367) to act as high visibility fence. Silt fence shall be at least 3 feet high and must be highly vis- ible to meet the requirements of this BMP. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 269 1Packet Pg. 140 5.1.a Metal fences shall be designed and installed according to the manufacturer's spe- cifications. Metal fences shall be at least 3 feet high and must be highly visible. Fences shall not be wired or stapled to trees. Maintenance Standards If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. BMP C105: Stabilized Construction Entrance / Exit Purpose Stabilized Construction entrances are established to reduce the amount of sediment transported onto paved roads by vehicles or equipment. This is done by constructing a stabilized pad of quarry spalls at entrances and exits for construction sites. Conditions of Use Construction entrances shall be stabilized wherever traffic will be entering or leaving a construction site if paved roads or other paved areas are within 1,000 feet of the site. For residential construction provide stabilized construction entrances for each residence, rather than only at the main subdivision entrance. Stabilized surfaces shall be of suf- ficient length/width to provide vehicle access/parking, based on lot size/configuration. On large commercial, highway, and road projects, the designer should include enough extra materials in the contract to allow for additional stabilized entrances not shown in the initial Construction SWPPP. It is difficult to determine exactly where access to these projects will take place; additional materials will enable the contractor to install them where needed. Design and Installation Specifications See Figure II-4.1.1 Stabilized Construction Entrance (p.273) for details. Note: the 100' minimum length of the entrance shall be reduced to the maximum practicable size when the size or configuration of the site does not allow the full length (100'). Construct stabilized construction entrances with a 12-inch thick pad of 4-inch to 8-inch quarry spalls, a 4-inch course of asphalt treated base (ATB), or use existing pavement. Do not use crushed concrete, cement, or calcium chloride for construction entrance sta- bilization because these products raise pH levels in stormwater and concrete discharge to surface waters of the State is prohibited. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 270 Packet Pg. 141 5.1.a A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM D4751) 200 psi min. Grab Tensile Elongation (ASTM D4632) 30% max. Mullen Burst Strength (ASTM D3786-80a)400 psi min. AOS (ASTM D4751) 20-45 (U.S. standard sieve size) . Consider early installation of the first lift of asphalt in areas that will paved; this can be used as a stabilized entrance. Also consider the installation of excess concrete as a stabilized entrance. During large concrete pours, excess concrete is often available for this purpose. . Fencing (see BMP C103: High Visibility Fence (p.269)) shall be installed as neces- sary to restrict traffic to the construction entrance. . Whenever possible, the entrance shall be constructed on a firm, compacted sub - grade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. . Construction entrances should avoid crossing existing sidewalks and back of walk drains if at all possible. If a construction entrance must cross a sidewalk or back of walk drain, the full length of the sidewalk and back of walk drain must be covered and protected from sediment leaving the site. Maintenance Standards Quarry spalls shall be added if the pad is no longer in accordance with the spe- cifications. If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include replacement/cleaning of the existing quarry spalls, street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. Any sediment that is tracked onto pavement shall be removed by shoveling or street sweeping. The sediment collected by sweeping shall be removed or sta- bilized on site. The pavement shall not be cleaned by washing down the street, except when high efficiency sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, the construction of a small sump to con- tain the wash water shall be considered. The sediment would then be washed into the sump where it can be controlled. Perform street sweeping by hand or with a high efficiency sweeper. Do not use a non -high efficiency mechanical sweeper because this creates dust and throws soils into storm systems or conveyance ditches. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 271 Packet Pg. 142 5.1.a . Any quarry spalls that are loosened from the pad, which end up on the roadway shall be removed immediately. . If vehicles are entering or exiting the site at points other than the construction entrance(s), fencing (see BMP C103) shall be installed to control traffic. Upon project completion and site stabilization, all construction accesses intended as permanent access for maintenance shall be permanently stabilized. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 272 Packet Pg. 143 5.1.a Figure II-4.1.1 Stabilized Construction Entrance cu roadsi Notes: 1. Driveway shall meet the requirements of the permitting agency. 2. It is recommended that the entrance be crowned so that runoff drains off the pad. DEPARTMENT OF ECOLOGY State of Washington NOT TO SCALE 1. 5' min. 12" minimum thickness Provide full width of ingress/egress area Figure II-4.1.1 Stabilized Construction Entrance Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 273 Packet Pg. 144 5.1.a Approved as Equivalent Ecology has approved products as able to meet the requirements of BMP C105: Stab- ilized Construction Entrance / Exit. The products did not pass through the Technology Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to con- sideration for local use. The products are available for review on Ecology's website at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html BMP C106: Wheel Wash Purpose Wheel washes reduce the amount of sediment transported onto paved roads by motor vehicles. Conditions of Use When a stabilized construction entrance (see BMP C105: Stabilized Construction Entrance / Exit (p.270)) is not preventing sediment from being tracked onto pavement. . Wheel washing is generally an effective BMP when installed with careful attention to topography. For example, a wheel wash can be detrimental if installed at the top of a slope abutting a right-of-way where the water from the dripping truck can run unimpeded into the street. . Pressure washing combined with an adequately sized and surfaced pad with dir- ect drainage to a large 10-foot x 10-foot sump can be very effective. . Discharge wheel wash or tire bath wastewater to a separate on -site treatment sys- tem that prevents discharge to surface water, such as closed -loop recirculation or upland land application, or to the sanitary sewer with local sewer district approval. . Wheel wash or tire bath wastewater should not include wastewater from concrete washout areas. Design and Installation Specifications Suggested details are shown in Figure II-4.1.2 Wheel Wash (p.276). The Local Per- mitting Authority may allow other designs. A minimum of 6 inches of asphalt treated base (ATB) over crushed base material or 8 inches over a good subgrade is recommended to pave the wheel wash. Use a low clearance truck to test the wheel wash before paving. Either a belly dump or lowboy will work well to test clearance. Keep the water level from 12 to 14 inches deep to avoid damage to truck hubs and filling the truck tongues with water. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 274 Packet Pg. 145 5.1.a Midpoint spray nozzles are only needed in extremely muddy conditions. Wheel wash systems should be designed with a small grade change, 6- to 12-inches for a 10-foot-wide pond, to allow sediment to flow to the low side of pond to help prevent re - suspension of sediment. A drainpipe with a 2- to 3-foot riser should be installed on the low side of the pond to allow for easy cleaning and refilling. Polymers may be used to promote coagulation and flocculation in a closed -loop system. Polyacrylamide (PAM) added to the wheel wash water at a rate of 0.25 - 0.5 pounds per 1,000 gallons of water increases effectiveness and reduces cleanup time. If PAM is already being used for dust or erosion control and is being applied by a water truck, the same truck can be used to change the wash water. Maintenance Standards The wheel wash should start out the day with fresh water. The wash water should be changed a minimum of once per day. On large earthwork jobs where more than 10-20 trucks per hour are expected, the wash water will need to be changed more often. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 275 Packet Pg. 146 5.1.a Figure II-4.1.2 Wheel Wash 3" trash pump with 6" sewer pipe with A floats on suction hose butterfly valves 2" schedule 40 8' x 8' sump with 5' of catch 1 %z " schedule 40 for sprayers 2% slope 5:1 slope 5:1 slope midpoint spray nozzles, if needed — — 2% slope 1:1 slope 15' ATB apron to protect 6" ATB construction entrance A ground from splashing water Ball valves Asphalt curb on the low road side to direct water back to pond Plan View 6" sleeve under road 15' 15,20' r 15' 50'� I r 6" sleeve Elevation View Locate invert of top pipe 1' above bottom of wheel wash 8' x 8' sump 18' Water level 3' ';zL= 5 r-7 12 —�{ 'I —F Drain pipe I 1:1 slope Section A -A Notes: 1. Build 8' x 8' sump to accomodate cleaning by trackhoe. NOT TO SCALE Figure II-4.1.2 Wheel Wash DEPARTMENT OF Revised June2015 ECOLOGYPlease see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. N C N E t U R a 3 O Q d w R r N 0 O O O N 0 N Z J d C a 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 276 1Packet Pg. 147 5.1.a BMP C107: Construction Road/Parking Area Stabilization Purpose Stabilizing subdivision roads, parking areas, and other on -site vehicle transportation routes immediately after grading reduces erosion caused by construction traffic or runoff. Conditions of Use Roads or parking areas shall be stabilized wherever they are constructed, whether per- manent or temporary, for use by construction traffic. . High Visibility Fencing (see BMP C103: High Visibility Fence (p.269)) shall be installed, if necessary, to limit the access of vehicles to only those roads and park- ing areas that are stabilized. Design and Installation Specifications • On areas that will receive asphalt as part of the project, install the first lift as soon as possible. . A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB) may also be used, or the road/parking area may be paved. It may also be possible to use cement or calcium chloride for soil stabilization. If cement or cement kiln dust is used for roadbase stabilization, pH monitoring and BMPs (BMP C252: High pH Neutralization Using CO2 (p.409) and BMP C253: pH Control for High pH Water (p.412)) are necessary to evaluate and minimize the effects on stormwater. If the area will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel may also be used, but this is likely to require more maintenance. Whenever possible, construction roads and parking areas shall be placed on a firm, compacted subgrade. . Temporary road gradients shall not exceed 15 percent. Roadways shall be care- fully graded to drain. Drainage ditches shall be provided on each side of the road- way in the case of a crowned section, or on one side in the case of a super - elevated section. Drainage ditches shall be directed to a sediment control BMP. • Rather than relying on ditches, it may also be possible to grade the road so that run- off sheet -flows into a heavily vegetated area with a well -developed topsoil. Land- scaped areas are not adequate. If this area has at least 50 feet of vegetation that water can flow through, then it is generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap. The 50 feet shall not include wetlands or their buffers. If runoff is allowed to sheetflow through adjacent vegetated areas, it is vital to design the roadways and parking areas so that no concentrated runoff is created. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 277 Packet Pg. 148 5.1.a . Storm drain inlets shall be protected to prevent sediment -laden water entering the storm drain system (see BMP C220: Storm Drain Inlet Protection (p.357)). Maintenance Standards Inspect stabilized areas regularly, especially after large storm events. Crushed rock, gravel base, etc., shall be added as required to maintain a stable driving surface and to stabilize any areas that have eroded. Following construction, these areas shall be restored to pre -construction condition or bet- ter to prevent future erosion. Perform street cleaning at the end of each day or more often if necessary. BMP C120: Temporary and Permanent Seeding Purpose Seeding reduces erosion by stabilizing exposed soils. A well -established vegetative cover is one of the most effective methods of reducing erosion. Conditions of Use Use seeding throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. The optimum seeding windows for western Washington are April 1 through June 30 and September 1 through October 1. Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is established. Between October 1 and March 30 seeding requires a cover of mulch with straw or an erosion control blanket until 75 percent grass cover is established. Review all disturbed areas in late August to early September and complete all seeding by the end of September. Otherwise, vegetation will not establish itself enough to provide more than average protection. . Mulch is required at all times for seeding because it protects seeds from heat, mois- ture loss, and transport due to runoff. Mulch can be applied on top of the seed or simultaneously by hydroseeding. See BMP C121: Mulching (p.284) for spe- cifications. . Seed and mulch, all disturbed areas not otherwise vegetated at final site sta- bilization. Final stabilization means the completion of all soil disturbing activities at the site and the establishment of a permanent vegetative cover, or equivalent per- 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 278 Packet Pg. 149 5.1.a manent stabilization measures (such as pavement, riprap, gabions, or geotextiles) which will prevent erosion. Design and Installation Specifications Seed retention/detention ponds as required. Install channels intended forvegetation before starting major earthwork and hydroseed with a Bonded Fiber Matrix. Forvegetated channels thatwill have high flows, install erosion control blankets over hydroseed. Before allowing water to flow in vegetated channels, establish 75 percent vegetation cover. If vegetated channels cannot be estab- lished by seed before water flow; install sod in the channel bottom —over hydromulch and erosion control blankets. Confirm the installation of all required surface water control measures to prevent seed from washing away. . Hydroseed applications shall include a minimum of 1,500 pounds per acre of mulch with 3 percent tackifier. See BMP C121: Mulching (p 284) for specifications . Areas that will have seeding only and not landscaping may need compost or meal - based mulch included in the hydroseed in order to establish vegetation. Re -install native topsoil on the disturbed soil surface before application. . When installing seed via hydroseeding operations, only about 1/3 of the seed actu- ally ends up in contact with the soil surface. This reduces the ability to establish a good stand of grass quickly. To overcome this, consider increasing seed quantities by up to 50 percent. Enhance vegetation establishment by dividing the hydromulch operation into two phases: 1. Phase 1- Install all seed and fertilizer with 25-30 percent mulch and tackifier onto soil in the first lift. 2. Phase 2- Install the rest of the mulch and tackifier over the first lift. Or, enhance vegetation by: 1. Installing the mulch, seed, fertilizer, and tackifier in one lift. 2. Spread or blow straw over the top of the hydromulch at a rate of 800-1000 pounds per acre. 3. Hold straw in place with a standard tackifier. Both of these approaches will increase cost moderately but will greatly improve and enhance vegetative establishment. The increased cost may be offset by the reduced need for: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 279 Packet Pg. 150 5.1.a . Irrigation. Reapplication of mulch. . Repair of failed slope surfaces. This technique works with standard hydromulch (1,500 pounds per acre minimum) and BFM/MBFMs (3,000 pounds per acre minimum). . Seed may be installed by hand if: . Temporary and covered by straw, mulch, or topsoil. . Permanent in small areas (usually less than 1 acre) and covered with mulch, topsoil, or erosion blankets. . The seed mixes listed in the tables below include recommended mixes for both temporary and permanent seeding. . Apply these mixes, with the exception of the wetland mix, at a rate of 120 pounds per acre. This rate can be reduced if soil amendments or slow - release fertilizers are used. . Consult the local suppliers or the local conservation district for their recom- mendations because the appropriate mix depends on a variety of factors, including location, exposure, soil type, slope, and expected foot traffic. Altern- ative seed mixes approved by the local authority may be used. Other mixes may be appropriate, depending on the soil type and hydrology of the area. . Table II-4.1.2 Temporary Erosion Control Seed Mix (p.280) lists the standard mix for areas requiring a temporary vegetative cover. Table II-4.1.2 Temporary Erosion Control Seed Mix % Weight % Purity % Germination Chewings or annual bluegrass 40 98 90 Festuca rubra var. commutate or Poa anna Perennial rye 50 98 90 Lolium perenne Redtop or colonial bentgrass 5 92 85 Agrostis alba or Agrostis tenuis White dutch clover 5 98 90 Trifolium repens . Table II-4.1.3 Landscaping Seed Mix (p.281) lists a recommended mix for land- scaping seed. 2014 Stormwater Management Manual for Western Washington VolumeA t "Pipt Page 280 Packet Pg. 151 5.1.a Table II-4.1.3 Landscaping Seed Mix % Weight % Purity % Germination Perennial rye blend 70 98 90 Lolium perenne Chewings and red fescue blend 30 98 90 Festuca rubra var. commutate or Festuca rubra . Table II-4.1.4 Low -Growing Turf Seed Mix (p.281) lists a turf seed mix for dry situ- ations where there is no need for watering. This mix requires very little main- tenance. Table II-4.1.4 Low -Growing Turf Seed Mix % Weight % Purity % Germination Dwarf tall fescue (several varieties) 45 98 90 Festuca arundinacea var. Dwarf perennial rye (Barclay) 30 98 90 Lolium perenne var. barclay Red fescue 20 98 90 Festuca rubra Colonial bentgrass 5 98 90 Agrostis tenuis . Table II-4.1.5 Bioswale Seed Mix* (p.281) lists a mix for bioswales and other inter- mittently wet areas. Table II-4.1.5 Bioswale Seed Mix* % Weight % Purity % Germination Tall or meadow fescue Festuca arundinacea or Festuca ela- 75-80 98 90 tior Seaside/Creeping bentgrass 10-15 92 85 Agrostis palustris Redtop bentgrass 5-10 90 80 Agrostis alba or Agrostis gigantea * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix . Table II-4.1.6 Wet Area Seed Mix* (p.282) lists a low -growing, relatively non-invas- ive seed mix appropriate for very wet areas that are not regulated wetlands. Apply 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 281 Packet Pg. 152 5.1.a this mixture at a rate of 60 pounds per acre. Consult Hydraulic Permit Authority (HPA) for seed mixes if applicable. Table II-4.1.6 Wet Area Seed Mix* % Weight % Purity % Germination Tall or meadow fescue Festuca arundinacea or Festuca ela- 60-70 98 90 tior Seaside/Creeping bentgrass 10-15 98 85 Agrostis palustris Meadow foxtail 10-15 90 80 Alepocurus pratensis Alsike clover 1-6 98 90 Trifolium hybridum Redtop bentgrass 1-6 92 85 Agrostis alba * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix Table II-4.1.7 Meadow Seed Mix (p.282) lists a recommended meadow seed mix for infrequently maintained areas or non -maintained areas where colonization by native plants is desirable. Likely applications include rural road and utility right-of- way. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. Consider the appro- priateness of clover, a fairly invasive species, in the mix. Amending the soil can reduce the need for clover. Table II-4.1.7 Meadow Seed Mix % Weight % Purity % Germination Redtop or Oregon bentgrass 20 92 85 Agrostis alba or Agrostis oregonensis Red fescue 70 98 90 Festuca rubra White dutch clover 10 98 90 Trifolium repens • Roughening and Rototilling: The seedbed should be firm and rough. Roughen all soil no matter what the slope. Track walk slopes before seeding if engineering purposes require 2014 Stormwater Management Manual for Western Washington VolumeA t "Pipt gage 282 Packet Pg. 153 5.1.a compaction. Backblading or smoothing of slopes greater than 4H:1 V is not allowed if they are to be seeded. Restoration -based landscape practices require deeper incorporation than that provided by a simple single -pass rototilling treatment. Wherever prac- tical, initially rip the subgrade to improve long-term permeability, infiltration, and water inflow qualities. At a minimum, permanent areas shall use soil amendments to achieve organic matter and permeability performance defined in engineered soil/landscape systems. For systems that are deeper than 8 inches complete the rototilling process in multiple lifts, or prepare the engineered soil system per specifications and place to achieve the specified depth. • Fertilizers: • Conducting soil tests to determine the exact type and quantity of fertilizer is recommended. This will prevent the over -application of fertilizer. . Organic matter is the most appropriate form of fertilizer because it provides nutrients (including nitrogen, phosphorus, and potassium) in the least water- soluble form. . In general, use 10-4-6 N-P-K (nitrogen -phosphorus -potassium) fertilizer at a rate of 90 pounds per acre. Always use slow -release fertilizers because they are more efficient and have fewer environmental impacts. Do not add fer- tilizer to the hydromulch machine, or agitate, more than 20 minutes before use. Too much agitation destroys the slow -release coating. . There are numerous products available that take the place of chemical fer- tilizers. These include several with seaweed extracts that are beneficial to soil microbes and organisms. If 100 percent cottonseed meal is used as the mulch in hydroseed, chemical fertilizer may not be necessary. Cottonseed meal provides a good source of long-term, slow -release, available nitrogen. . Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix: On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber Matrix (MBFM) products. Apply BFM/MBFM products at a minimum rate of 3,000 pounds per acre of mulch with approximately 10 percent tackifier. Achieve a minimum of 95 percent soil coverage during application. Numer- ous products are available commercially. Installed products per man- ufacturer's instructions. Most products require 24-36 hours to cure before rainfall and cannot be installed on wet or saturated soils. Generally, products come in 40-50 pound bags and include all necessary ingredients except for seed and fertilizer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 283 Packet Pg. 154 5.1.a . BFMs and MBFMs provide good alternatives to blankets in most areas requir- ing vegetation establishment. Advantages over blankets include: . BFM and MBFMs do not require surface preparation. • Helicopters can assist in installing BFM and MBFMs in remote areas. • On slopes steeper than 2.5H:1V, blanket installers may require ropes and harnesses for safety. . Installing BFM and MBFMs can save at least $1,000 per acre com- pared to blankets. Maintenance Standards Reseed any seeded areas that fail to establish at least 80 percent cover (100 percent cover for areas that receive sheet or concentrated flows). If reseeding is ineffective, use an alternate method such as sodding, mulching, or nets/blankets. If winter weather pre- vents adequate grass growth, this time limit may be relaxed at the discretion of the local authority when sensitive areas would otherwise be protected. . Reseed and protect by mulch any areas that experience erosion after achieving adequate cover. Reseed and protect by mulch any eroded area. • Supply seeded areas with adequate moisture, but do not water to the extent that it causes runoff. Approved as Equivalent Ecology has approved products as able to meet the requirements of BMP C120: Tem- porary and Permanent Seeding. The products did not pass through the Technology Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to con- sideration for local use. The products are available for review on Ecology's website at htta://www.ecv.wa.aov/aroarams/wa/stormwater/newtech/eauivalent.html. BMP C121: Mulching Purpose Mulching soils provides immediate temporary protection from erosion. Mulch also enhances plant establishment by conserving moisture, holding fertilizer, seed, and top- soil in place, and moderating soil temperatures. There is an enormous variety of mulches that can be used. This section discusses only the most common types of mulch. Conditions of Use As a temporary cover measure, mulch should be used: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 284 Packet Pg. 155 5.1.a . For less than 30 days on disturbed areas that require cover. . At all times for seeded areas, especially during the wet season and during the hot summer months. • During the wet season on slopes steeper than 3H:1 V with more than 10 feet of ver- tical relief. Mulch may be applied at any time of the year and must be refreshed periodically. . For seeded areas mulch may be made up of 100 percent: cottonseed meal; fibers made of wood, recycled cellulose, hemp, kenaf; compost; or blends of these. Tack- ifier shall be plant -based, such as guar or alpha plantago, or chemical -based such as polyacrylamide or polymers. Any mulch or tackifier product used shall be installed per manufacturer's instructions. Generally, mulches come in 40-50 pound bags. Seed and fertilizer are added at time of application. Design and Installation Specifications For mulch materials, application rates, and specifications, see Table II-4.1.8 Mulch Standards and Guidelines (p.286). Always use a 2-inch minimum mulch thickness; increase the thickness until the ground is 95% covered (i.e. not visible under the mulch layer). Note: Thickness may be increased for disturbed areas in or near sensitive areas or other areas highly susceptible to erosion. Where the option of "Compost" is selected, it should be a coarse compost that meets the following size gradations when tested in accordance with the U.S. Composting Council "Test Methods for the Examination of Compost and Composting" (TMECC) Test Method 02.02-B. Coarse Compost Minimum Percent passing 3" sieve openings 100% Minimum Percent passing 1" sieve openings 90% Minimum Percent passing 1/4" sieve openings 70% Minimum Percent passing'/4" sieve openings 40% Mulch used within the ordinary high-water mark of surface waters should be selected to minimize potential flotation of organic matter. Composted organic materials have higher specific gravities (densities) than straw, wood, or chipped material. Consult Hydraulic Permit Authority (HPA) for mulch mixes if applicable. Maintenance Standards . The thickness of the cover must be maintained. . Any areas that experience erosion shall be remulched and/or protected with a net 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 285 Packet Pg. 156 5.1.a or blanket. If the erosion problem is drainage related, then the problem shall be fixed and the eroded area remulched. Table II-4.1.8 Mulch Standards and Guidelines Mulch Quality Application Remarks Material Standards Rates Cost-effective protection when applied with adequate thickness. Hand -application generally requires greater thickness than blown straw. The thickness of straw may be reduced by half when used in conjunction with seeding. In windy areas Air-dried; 2„ 3„ thick; straw must be held in place by crimping, using a free from 5 bales per tackifier, or covering with netting. Blown straw Straw undesirable 1,000 sf or always has to be held in place with a tackifier as seed and 2-3 tons per even light winds will blow it away. Straw, how - coarse ever, has several deficiencies that should be con - material. acre acre sidered when selecting mulch materials. It often introduces and/or encourages the propagation of weed species and it has no significant long-term benefits It should also not be used within the ordinary high-water elevation of surface waters (due to flotation). Approx. 25- Shall be applied with hydromulcher. Shall not be No growth 30 Ibs per 1,000 sf or used without seed and tackifier unless the applic- Hydromulch inhibiting 1,500 - ation rate is at least doubled. Fibers longer than factors. 2,000 Ibs about 3/4 - 1 inch clog hydromulch equipment. Fibers should be kept to less than 3/4 inch. per acre No visible water or More effective control can be obtained by increas- dust during ing thickness to 3". Excellent mulch for protecting handling. 2" thick final grades until landscaping because it can be Must be pro min.; directly seeded or tilled into soil as an amend- duced per approx. 100 ment. Compost used for mulch has a coarser size Compost WAC 173- tons per gradation than compost used for BMP C125: Top- 350, Solid acre soiling / Composting (p.297) or BMP T5.13: Post - Waste (approx. Construction Soil Quality and Depth .911 . It is more stable and practical to use in wet areas and Handling 800 Ibs per Standards, yard) during rainy weather conditions. Do not use near but may wetlands or near phosphorous impaired water have up to bodies. 35% 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 286 Packet Pg. 157 5.1.a Table II-4.1.8 Mulch Standards and Guidelines (continued) Mulch Quality Application Remarks Material Standards Rates biosolids. Average size shall This is a cost-effective way to dispose of debris be several from clearing and grubbing, and it eliminates the inches. problems associated with burning. Generally, it Chipped Gradations should not be used on slopes above approx. 10% Site Veget- from fines 2" thick because of its tendency to be transported by run- ation to 6 inches min.; off. It is not recommended within 200 feet of sur- in length for face waters. If seeding is expected shortly after texture, vari mulch, the decomposition of the chipped veget- ation, and ation may tie up nutrients important to grass estab interlocking lishment. properties. No visible water or dust during handling. This material is often called "hog or hogged fuel". Must be pur 2" thick The use of mulch ultimately improves the organic Wood- chased min.; matter in the soil. Special caution is advised based from a sup- approx. 100 regarding the source and composition of wood - Mulch or plier with a tons per based mulches. Its preparation typically does not Wood SoliWasdte acre provide any weed seed control, so evidence of Straw (approx. residual vegetation in its composition or known Handling lbs. per inclusion of weed plants or seeds should be mon- Permit or cubic yard) itored and prevented (or minimized). one exempt from solid waste reg- ulations. A blend of Cost-effective protection when applied with loose, long, adequate thickness. A minimum of 95-percent of thin wood the wood strand shall have lengths between 2 Wood pieces and 10-inches, with a width and thickness Strand derived 2" thick min. between 1/16 and 3/8-inches. The mulch shall not Mulch from native contain resin, tannin, or other compounds in conifer or quantities that would be detrimental to plant life. deciduous Sawdust or wood shavings shall not be used as trees with mulch. (WSDOT specification (9-14.4(4)) 2014 Stormwater Management Manual for Western Washington VolumeA t "Pipt Page 287 Packet Pg. 158 5.1.a Table II-4.1.8 Mulch Standards and Guidelines (continued) Mulch Quality Application Remarks Material Standards Rates high length - to -width ratio. BMP C122: Nets and Blankets Purpose Erosion control nets and blankets are intended to prevent erosion and hold seed and mulch in place on steep slopes and in channels so that vegetation can become well established. In addition, some nets and blankets can be used to permanently reinforce turf to protect drainage ways during high flows. Nets (commonly called matting) are strands of material woven into an open, but high -tensile strength net (for example, coconut fiber matting). Blankets are strands of material that are not tightly woven, but instead form a layer of interlocking fibers, typically held together by a biodegradable or photodegradable netting (for example, excelsior or straw blankets). They generally have lower tensile strength than nets, but cover the ground more completely. Coir (coconut fiber) fabric comes as both nets and blankets. Conditions of Use Erosion control nets and blankets should be used: . To aid permanent vegetated stabilization of slopes 2H:1 V or greater and with more than 10 feet of vertical relief. For drainage ditches and swales (highly recommended). The application of appro- priate netting or blanket to drainage ditches and swales can protect bare soil from channelized runoff while vegetation is established. Nets and blankets also can cap- ture a great deal of sediment due to their open, porous structure. Nets and blankets can be used to permanently stabilize channels and may provide a cost-effective, environmentally preferable alternative to riprap. 100 percent synthetic blankets manufactured for use in ditches may be easily reused as temporary ditch liners. Disadvantages of blankets include: . Surface preparation required. On slopes steeper than 2.5H:1V, blanket installers may need to be roped and har- nessed for safety. . They cost at least $4,000-6,000 per acre installed. Advantages of blankets include: 2014 Stormwater Management Manual for Western Washington VolumeA t "Pipt gage 288 Packet Pg. 159 5.1.a . Installation without mobilizing special equipment. . Installation by anyone with minimal training . Installation in stages or phases as the project progresses. . Installers can hand place seed and fertilizer as they progress down the slope. . Installation in any weather. . There are numerous types of blankets that can be designed with various para- meters in mind. Those parameters include: fiber blend, mesh strength, longevity, biodegradability, cost, and availability. Design and Installation Specifications See Figure II-4.1.3 Channel Installation .292 and Figure II-4.1.4 Slope Install- ation .293 for typical orientation and installation of blankets used in channels and as slope protection. Note: these are typical only; all blankets must be installed per manufacturer's installation instructions. Installation is critical to the effectiveness of these products. If good ground contact is not achieved, runoff can concentrate under the product, resulting in significant erosion. . Installation of Blankets on Slopes: 1. Complete final grade and track walk up and down the slope. 2. Install hydromulch with seed and fertilizer. 3. Dig a small trench, approximately 12 inches wide by 6 inches deep along the top of the slope. 4. Install the leading edge of the blanket into the small trench and staple approx- imately every 18 inches. NOTE: Staples are metal, "U"-shaped, and a min- imum of 6 inches long. Longer staples are used in sandy soils. Biodegradable stakes are also available. 5. Roll the blanket slowly down the slope as installer walks backwards. NOTE: The blanket rests against the installer's legs. Staples are installed as the blanket is unrolled. It is critical that the proper staple pattern is used for the blanket being installed. The blanket is not to be allowed to roll down the slope on its own as this stretches the blanket making it impossible to main- tain soil contact. In addition, no one is allowed to walk on the blanket after it is in place. 6. If the blanket is not long enough to cover the entire slope length, the trailing edge of the upper blanket should overlap the leading edge of the lower 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 289 Packet Pg. 160 5.1.a blanket and be stapled. On steeper slopes, this overlap should be installed in a small trench, stapled, and covered with soil. With the variety of products available, it is impossible to coverall the details of appropriate use and installation. Therefore, it is critical that the design engineer consult the manufacturer's information and that a site visit takes place in order to ensure that the product specified is appropriate. Information is also available at the following web sites: 1. WSDOT (Section 3.2.4): http://www.wsdot.wa.gov/NR/rdonlyres/3B41 E087-FA86-4717-932D- D7A8556CCD57/0/ErosionTrainingManual.pdf 2. Texas Transportation Institute: http://www.txdot.gov/business/doing_business/product_evaluation/erosion_ control.htm Use jute matting in conjunction with mulch (BMP C121: Mulching (p.284)). Excel- sior, woven straw blankets and coir (coconut fiber) blankets may be installed without mulch. There are many other types of erosion control nets and blankets on the market that may be appropriate in certain circumstances. . In general, most nets (e.g., jute matting) require mulch in order to prevent erosion because they have a fairly open structure. Blankets typically do not require mulch because they usually provide complete protection of the surface. . Extremely steep, unstable, wet, or rocky slopes are often appropriate candidates for use of synthetic blankets, as are riverbanks, beaches and other high-energy environments. If synthetic blankets are used, the soil should be hydromulched first. . 100-percent biodegradable blankets are available for use in sensitive areas. These organic blankets are usually held together with a paper or fiber mesh and stitching which may last up to a year. . Most netting used with blankets is photodegradable, meaning they break down under sunlight (not UV stabilized). However, this process can take months or years even under bright sun. Once vegetation is established, sunlight does not reach the mesh. It is not uncommon to find non -degraded netting still in place several years after installation. This can be a problem if maintenance requires the use of mowers or ditch cleaning equipment. In addition, birds and small animals can become trapped in the netting. Maintenance Standards . Maintain good contact with the ground. Erosion must not occur beneath the net or blanket. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 290 Packet Pg. 161 5.1.a . Repair and staple any areas of the net or blanket that are damaged or not inclose contact with the ground. . Fix and protect eroded areas if erosion occurs due to poorly controlled drainage. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 291 Packet Pg. 162 5.1.a Figure II-4.1.3 Channel Installation NnT Tn SCAI F LONGITUDINAL ANCHOR TRENCH TERMINAL SLOPE AND CHANNEL ANCHOR TRENCH � P STAKE AT 3'-5' P INTERVALS. 1 CHECK SLOT AT 25' INTERVALS INITIAL CHANNEL ANCHOR TRENCH INTERMITTENT CHECK SLOT Source: Clackamas County 2009 Notes: Erosion Prevention Planning and 1. Check slots to be constructed per manufacturers specifications. Design Manual 2. Staking or stapling layout per manufacturers specifications. DEPARTMENT OF ECOLOGY Figure II-4.1.3 Channel Installation Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. C O cC tv 3 0 0 0 0 0 O N O N Z J d 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 292 1Packet Pg. 163 5.1.a Figure II-4.1.4 Slope Installation Notes: 1. Slope surface shall be smooth before placement for proper soil contact. 2. Stapling pattern as per manufacturer's recommendations. 3. Do not stretch blankets/mattings tight - allow the rolls to mold to any irregularities. 4. For slopes less than 3H:1 V, rolls may be placed in horizontal strips. 5. If there is a berm at the top of the slope, anchor upslope of the berm. 6. Lime, fertilize, and seed before installation. Planting of shrubs, trees, etc. should occur after installation. DEPARTMENT OF ECOLOGY State of Washington area, turn the end under 4" and staple at 12" intervals Figure II-4.1.4 Slope Installation NOT TO SCALE Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 293 1Packet Pg. 164 5.1.a BMP C123: Plastic Covering Purpose Plastic covering provides immediate, short-term erosion protection to slopes and dis- turbed areas. Conditions of Use Plastic covering may be used on disturbed areas that require cover measures for less than 30 days, except as stated below. . Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable for long-term (greater than six months) applications. . Due to rapid runoff caused by plastic covering, do not use this method upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes. . Plastic sheeting may result in increased runoff volumes and velocities, requiring additional on -site measures to counteract the increases. Creating a trough with wattles or other material can convey clean water away from these areas. . To prevent undercutting, trench and backfill rolled plastic covering products. . While plastic is inexpensive to purchase, the added cost of installation, main- tenance, removal, and disposal make this an expensive material, up to $1.50-2.00 per square yard. . Whenever plastic is used to protect slopes install water collection measures at the base of the slope. These measures include plastic -covered berms, channels, and pipes used to covey clean rainwater away from bare soil and disturbed areas. Do not mix clean runoff from a plastic covered slope with dirty runoff from a project. • Other uses for plastic include: 1. Temporary ditch liner. 2. Pond liner in temporary sediment pond. 3. Liner for bermed temporary fuel storage area if plastic is not reactive to the type of fuel being stored. 4. Emergency slope protection during heavy rains. 5. Temporary drainpipe ("elephant trunk") used to direct water. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 294 Packet Pg. 165 5.1.a Design and Installation Specifications . Plastic slope cover must be installed as follows: 1. Run plastic up and down slope, not across slope. 2. Plastic may be installed perpendicular to a slope if the slope length is less than 10 feet. 3. Minimum of 8-inch overlap at seams. 4. On long or wide slopes, or slopes subject to wind, tape all seams. 5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top of the slope and backfill with soil to keep water from flowing underneath. 6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and tie them together with twine to hold them in place. 7. Inspect plastic for rips, tears, and open seams regularly and repair imme- diately. This prevents high velocity runoff from contacting bare soil which causes extreme erosion. 8. Sandbags may be lowered into place tied to ropes. However, all sandbags must be staked in place. . Plastic sheeting shall have a minimum thickness of 0.06 millimeters. . If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable pro- tection shall be installed at the toe of the slope in order to reduce the velocity of run- off. Maintenance Standards . Torn sheets must be replaced and open seams repaired. • Completely remove and replace the plastic if it begins to deteriorate due to ultra- violet radiation. • Completely remove plastic when no longer needed. . Dispose of old tires used to weight down plastic sheeting appropriately. Approved as Equivalent Ecology has approved products as able to meet the requirements of BMP C123: Plastic Covering. The products did not pass through the Technology Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.htmi 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 295 Packet Pg. 166 5.1.a BMP C124: Sodding Purpose The purpose of sodding is to establish permanent turf for immediate erosion protection and to stabilize drainage ways where concentrated overland flow will occur. Conditions of Use Sodding may be used in the following areas: . Disturbed areas that require short-term or long-term cover. . Disturbed areas that require immediate vegetative cover. . All waterways that require vegetative lining. Waterways may also be seeded rather than sodded, and protected with a net or blanket. Design and Installation Specifications Sod shall be free of weeds, of uniform thickness (approximately 1-inch thick), and shall have a dense root mat for mechanical strength. The following steps are recommended for sod installation: • Shape and smooth the surface to final grade in accordance with the approved grad- ing plan. The swale needs to be overexcavated 4 to 6 inches below design elev- ation to allow room for placing soil amendment and sod. . Amend 4 inches (minimum) of compost into the top 8 inches of the soil if the organic content of the soil is less than ten percent or the permeability is less than 0.6 inches per hour. See hftp://www.ecy.wa.gov/programs/swfa/organics/soil.html for further information. . Fertilize according to the supplier's recommendations. . Work lime and fertilizer 1 to 2 inches into the soil, and smooth the surface. . Lay strips of sod beginning at the lowest area to be sodded and perpendicular to the direction of water flow. Wedge strips securely into place. Square the ends of each strip to provide for a close, tight fit. Staggerjoints at least 12 inches. Staple on slopes steeper than 3H:1V. Staple the upstream edge of each sod strip. . Roll the sodded area and irrigate. . When sodding is carried out in alternating strips or other patterns, seed the areas between the sod immediately after sodding. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 296 Packet Pg. 167 5.1.a Maintenance Standards If the grass is unhealthy, the cause shall be determined and appropriate action taken to reestablish a healthy groundcover. If it is impossible to establish a healthy groundcover due to frequent saturation, instability, or some other cause, the sod shall be removed, the area seeded with an appropriate mix, and protected with a net or blanket. BMP C125: Topsoiling / Composting Purpose Topsoiling and composting provide a suitable growth medium for final site stabilization with vegetation. While not a permanent cover practice in itself, topsoiling and com- posting are an integral component of providing permanent cover in those areas where there is an unsuitable soil surface for plant growth. Use this BMP in conjunction with other BMPs such as seeding, mulching, or sodding. Note that this BMP is functionally the same as BMP T5.13: Post -Construction Soil Quality and Depth (p.911) which is required for all disturbed areas that will be developed as lawn or landscaped areas at the completed project site. Native soils and disturbed soils that have been organically amended not only retain much more stormwater, but they also serve as effective biofilters for urban pollutants and, by supporting more vigorous plant growth, reduce the water, fertilizer and pesticides needed to support installed landscapes. Topsoil does not include any subsoils but only the material from the top several inches including organic debris. Conditions of Use . Permanent landscaped areas shall contain healthy topsoil that reduces the need for fertilizers, improves overall topsoil quality, provides for better vegetal health and vitality, improves hydrologic characteristics, and reduces the need for irrigation. . Leave native soils and the duff layer undisturbed to the maximum extent prac- ticable. Stripping of existing, properly functioning soil system and vegetation for the purpose of topsoiling during construction is not acceptable. Preserve existing soil systems in undisturbed and uncompacted conditions if functioning properly. . Areas that already have good topsoil, such as undisturbed areas, do not require soil amendments. . Restore, to the maximum extent practical, native soils disturbed during clearing and grading to a condition equal to or better than the original site condition's mois- ture -holding capacity. Use on -site native topsoil, incorporate amendments into on - site soil, or import blended topsoil to meet this requirement. . Topsoiling is a required procedure when establishing vegetation on shallow soils, and soils of critically low pH (high acid) levels. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 297 1Packet Pg. 168 5.1.a Beware of where the topsoil comes from, and what vegetation was on site before disturbance, invasive plant seeds may be included and could cause problems for establishing native plants, landscaped areas, or grasses. . Topsoil from the site will contain mycorrhizal bacteria that are necessary for healthy root growth and nutrient transfer. These native mycorrhiza are acclimated to the site and will provide optimum conditions for establishing grasses. Use com- mercially available mycorrhiza products when using off -site topsoil. Design and Installation Specifications Meet the following requirements for disturbed areas that will be developed as lawn or landscaped areas at the completed project site: . Maximize the depth of the topsoil wherever possible to provide the maximum pos- sible infiltration capacity and beneficial growth medium. Topsoil shall have: • A minimum depth of 8-inches. Scarify subsoils below the topsoil layer at least 4-inches with some incorporation of the upper material to avoid stratified lay- ers, where feasible. Ripping or re -structuring the subgrade may also provide additional benefits regarding the overall infiltration and interflow dynamics of the soil system. • A minimum organic content of 10% dry weight in planting beds, and 5% organic matter content in turf areas. Incorporate organic amendments to a minimum 8-inch depth except where tree roots or other natural features limit the depth of incorporation. • A pH between 6.0 and 8.0 or matching the pH of the undisturbed soil. • If blended topsoil is imported, then fines should be limited to 25 percent passing through a 200 sieve. • Mulch planting beds with 2 inches of organic material Accomplish the required organic content, depth, and pH by returning native topsoil to the site, importing topsoil of sufficient organic content, and/or incorporating organic amendments. When using the option of incorporating amendments to meet the organic content requirement, use compost that meets the compost specification for Bioretention (See BMP T7.30: Bioretention Cells, Swales, and Planter Boxes (p 959)), with the exception that the compost may have up to 35% biosolids or manure. Sections three through seven of the document entitled, Guidelines and Resources for Implementing Soil Quality and Depth BMP T5.13 in WDOE Stormwater Man- agement Manual for Western Washington, provides useful guidance for imple- menting whichever option is chosen. It includes guidance for pre -approved default strategies and guidance for custom strategies. Check with your local jurisdiction 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 298 Packet Pg. 169 5.1.a concerning its acceptance of this guidance. It is available through the organization, Soils for Salmon. As of this printing the document may be found at: http://www.soils- forsalmon.org/pdf/Soil BMP Manual.pdf. . The final composition and construction of the soil system will result in a natural selection or favoring of certain plant species over time. For example, incorporation of topsoil may favor grasses, while layering with mildly acidic, high -carbon amend- ments may favor more woody vegetation. . Allow sufficient time in scheduling for topsoil spreading prior to seeding, sodding, or planting. . Take care when applying top soil to subsoils with contrasting textures. Sandy top- soil over clayey subsoil is a particularly poor combination, as water creeps along the junction between the soil layers and causes the topsoil to slough. If topsoil and subsoil are not properly bonded, water will not infiltrate the soil profile evenly and it will be difficult to establish vegetation. The best method to prevent a lack of bond- ing is to actually work the topsoil into the layer below for a depth of at least 6 inches. . Field exploration of the site shall be made to determine if there is surface soil of suf- ficient quantity and quality to justify stripping. Topsoil shall be friable and loamy (loam, sandy loam, silt loam, sandy clay loam, and clay loam). Avoid areas of nat- ural ground water recharge. • Stripping shall be confined to the immediate construction area. A 4-inch to 6-inch stripping depth is common, but depth may vary depending on the particular soil. All surface runoff control structures shall be in place prior to stripping. . Do not place topsoil while in a frozen or muddy condition, when the subgrade is excessively wet, or when conditions exist that may otherwise be detrimental to proper grading or proposed sodding or seeding. . In any areas requiring grading remove and stockpile the duff layer and topsoil on site in a designated, controlled area, not adjacent to public resources and critical areas. Stockpiled topsoil is to be reapplied to other portions of the site where feas- ible. . Locate the topsoil stockpile so that it meets specifications and does not interfere with work on the site. It may be possible to locate more than one pile in proximity to areas where topsoil will be used. Stockpiling of topsoil shall occur in the following manner: • Side slopes of the stockpile shall not exceed 2H:1V. . Between October 1 and April 30: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 299 Packet Pg. 170 5.1.a . An interceptor dike with gravel outlet and silt fence shall surround all topsoil. . Within 2 days complete erosion control seeding, or covering stockpiles with clear plastic, or other mulching materials. . Between May 1 and September 30: . An interceptor dike with gravel outlet and silt fence shall surround all topsoil if the stockpile will remain in place for a longer period of time than active construction grading. . Within 7 days complete erosion control seeding, or covering stockpiles with clear plastic, or other mulching materials. . When native topsoil is to be stockpiled and reused the following should apply to ensure that the mycorrhizal bacterial, earthworms, and other beneficial organisms will not be destroyed: 1. Re -install topsoil within 4 to 6 weeks. 2. Do not allow the saturation of topsoil with water. 3. Do not use plastic covering. Maintenance Standards . Inspect stockpiles regularly, especially after large storm events. Stabilize any areas that have eroded. . Establish soil quality and depth toward the end of construction and once estab- lished, protect from compaction, such as from large machinery use, and from erosion. • Plant and mulch soil after installation. . Leave plant debris or its equivalent on the soil surface to replenish organic matter. . Reduce and adjust, where possible, the use of irrigation, fertilizers, herbicides and pesticides, rather than continuing to implement formerly established practices. BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection Purpose Polyacrylamide (PAM) is used on construction sites to prevent soil erosion. Applying PAM to bare soil in advance of a rain event significantly reduces erosion and controls sediment in two ways. First, PAM increases the soil's available pore volume, 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 300 Packet Pg. 171 5.1.a thus increasing infiltration through flocculation and reducing the quantity of stormwater runoff. Second, it increases flocculation of suspended particles and aids in their depos- ition, thus reducing stormwater runoff turbidity and improving water quality. Conditions of Use PAM shall not be directly applied to water or allowed to enter a water body. In areas that drain to a sediment pond, PAM can be applied to bare soil under the fol- lowing conditions: . During rough grading operations. . In Staging areas. . Balanced cut and fill earthwork. . Haul roads prior to placement of crushed rock surfacing. . Compacted soil roadbase. . Stockpiles. . After final grade and before paving or final seeding and planting. . Pit sites. . Sites having a winter shut down. In the case of winter shut down, or where soil will remain unworked for several months, PAM should be used together with mulch. Design and Installation Specifications PAM may be applied with water in dissolved form. The preferred application method is the dissolved form. PAM is to be applied at a maximum rate of 2/3 pound PAM per 1,000 gallons water (80 mg/L) per 1 acre of bare soil. Table II-4.1.9 PAM and Water Application Rates (p.301) can be used to determine the PAM and water application rate for a disturbed soil area. Higher concentrations of PAM do not provide any additional effectiveness. Table II-4.1.9 PAM and Water Application Rates Disturbed Area (ac) PAM (Ibs) Water (gal) 0.50 0.33 500 1.00 0.66 1,000 1.50 1.00 1,500 2.00 1.32 2,000 2.50 1.65 2,500 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 301 Packet Pg. 172 5.1.a Table II-4.1.9 PAM and Water Application Rates (continued) Disturbed Area (ac) PAM (Ibs) Water (gal) 3.00 2.00 3,000 3.50 2.33 3,500 4.00 2.65 4,000 4.50 3.00 4,500 5.00 3.33 5,000 The Preferred Method: . Pre -measure the area where PAM is to be applied and calculate the amount of product and water necessary to provide coverage at the specified application rate (2/3 pound PAM/1000 gallons/acre). • PAM has infinite solubility in water, but dissolves very slowly. Dissolve pre -meas- ured dry granular PAM with a known quantity of clean water in a bucket several hours or overnight. Mechanical mixing will help dissolve the PAM. Always add PAM to water - not water to PAM. • Pre -fill the water truck about 1/8 full with water. The water does not have to be pot- able, but it must have relatively low turbidity — in the range of 20 NTU or less. . Add PAM /Water mixture to the truck • Completely fill the water truck to specified volume. . Spray PAM/Water mixture onto dry soil until the soil surface is uniformly and com- pletely wetted. An Alternate Method: PAM may also be applied as a powder at the rate of 5 Ibs. per acre. This must be applied on a day that is dry. For areas less than 5-10 acres, a hand-held "organ grinder" fertilizer spreader set to the smallest setting will work. Tractor -mounted spreaders will work for lar- ger areas. The following shall be used for application of powdered PAM: • Powered PAM shall be used in conjunction with other BMPs and not in place of other BMPs. • Do not use PAM on a slope that flows directly into a stream or wetland. The storm - water runoff shall pass through a sediment control BMP prior to discharging to sur- face waters. . Do not add PAM to water discharging from site. . When the total drainage area is greater than or equal to 5 acres, PAM treated 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 302 Packet Pg. 173 5.1.a areas shall drain to a sediment pond. . Areas less than 5 acres shall drain to sediment control BMPs, such as a minimum of 3 check dams per acre. The total number of check dams used shall be max- imized to achieve the greatest amount of settlement of sediment prior to dis- charging from the site. Each check dam shall be spaced evenly in the drainage channel through which stormwater flows are discharged off -site. • On all sites, the use of silt fence shall be maximized to limit the discharges of sed- iment from the site. . All areas not being actively worked shall be covered and protected from rainfall. PAM shall not be the only cover BMP used. . PAM can be applied to wet soil, but dry soil is preferred due to less sediment loss. . PAM will work when applied to saturated soil but is not as effective as applications to dry or damp soil. . Keep the granular PAM supply out of the sun. Granular PAM loses its effectiveness in three months after exposure to sunlight and air. . Proper application and re -application plans are necessary to ensure total effect- iveness of PAM usage. . PAM, combined with water, is very slippery and can be a safety hazard. Care must be taken to prevent spills of PAM powder onto paved surfaces. During an applic- ation of PAM, prevent over -spray from reaching pavement as pavement will become slippery. If PAM powder gets on skin or clothing, wipe it off with a rough towel rather than washing with water -this only makes cleanup messier and take longer. • Some PAMs are more toxic and carcinogenic than others. Only the most envir- onmentally safe PAM products should be used. The specific PAM copolymer formulation must be anionic. Cationic PAM shall not be used in any application because of known aquatic toxicity problems. Only the highest drinking water grade PAM, certified for compliance with ANSI NSF Standard 60 for drinking water treatment, will be used for soil applications. Recent media attention and high interest in PAM has resulted in some entrepreneurial exploitation of the term "polymer." All PAM are polymers, but not all polymers are PAM, and not all PAM products comply with ANSI/NSF Standard 60. PAM use shall be reviewed and approved by the local permitting authority. . PAM designated for these uses should be "water soluble" or "linear" or "non -cross - linked". Cross -linked or water absorbent PAM, polymerized in highly acidic (pH<2) conditions, are used to maintain soil moisture content. . The PAM anionic charge density may vary from 2-30 percent; a value of 18 percent 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 303 Packet Pg. 174 5.1.a is typical. Studies conducted by the United States Department of Agriculture (USDA)/ARS demonstrated that soil stabilization was optimized by using very high molecular weight (12-15 mg/mole), highly anionic (>20% hydrolysis) PAM. . PAM tackifiers are available and being used in place of guar and alpha plantago. Typically, PAM tackifiers should be used at a rate of no more than 0.5-1 lb. per 1000 gallons of water in a hydromulch machine. Some tackifier product instruc- tions say to use at a rate of 3 —5 lbs. per acre, which can be too much. In addition, pump problems can occur at higher rates due to increased viscosity. Maintenance Standards . PAM maybe reapplied on actively worked areas after a 48-hour period. Reapplication is not required unless PAM treated soil is disturbed or unless tur- bidity levels show the need for an additional application. If PAM treated soil is left undisturbed a reapplication may be necessary after two months. More PAM applic- ations may be required for steep slopes, silty and clayey soils (USDA Clas- sification Type "C" and "D" soils), long grades, and high precipitation areas. When PAM is applied first to bare soil and then covered with straw, a reapplication may not be necessary for several months. . Loss of sediment and PAM may be a basis for penalties per RCW 90.48.080. BMP C130: Surface Roughening Purpose Surface roughening aids in the establishment of vegetative cover, reduces runoff velo- city, increases infiltration, and provides for sediment trapping through the provision of a rough soil surface. Horizontal depressions are created by operating a tiller or other suit- able equipment on the contour or by leaving slopes in a roughened condition by not fine grading them. Use this BMP in conjunction with other BMPs such as seeding, mulching, or sodding. Conditions for Use . All slopes steeperthan 3H:1V and greaterthan 5 vertical feet require surface rough- ening to a depth of 2 to 4 inches prior to seeding.. . Areas that will not be stabilized immediately may be roughened to reduce runoff velocity until seeding takes place. • Slopes with a stable rock face do not require roughening. . Slopes where mowing is planned should not be excessively roughened. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 304 Packet Pg. 175 5.1.a Design and Installation Specifications There are different methods for achieving a roughened soil surface on a slope, and the selection of an appropriate method depends upon the type of slope. Roughening meth- ods include stair -step grading, grooving, contour furrows, and tracking. See Figure II- 4.1.5 Surface Roughening by Tracking and Contour Furrows (p.306) for tracking and con- tour furrows. Factors to be considered in choosing a method are slope steepness, mow- ing requirements, and whether the slope is formed by cutting or filling. • Disturbed areas that will not require mowing may be stair -step graded, grooved, or left rough after filling. • Stair -step grading is particularly appropriate in soils containing large amounts of soft rock. Each "step" catches material that sloughs from above, and provides a level site where vegetation can become established. Stairs should be wide enough to work with standard earth moving equipment. Stair steps must be on con- tour or gullies will form on the slope. . Areas that will be mowed (these areas should have slopes less steep than 3H:1 V) may have small furrows left by disking, harrowing, raking, or seed -planting machinery operated on the contour. • Graded areas with slopes steeper than 3H:1V but less than 2H:1V should be roughened before seeding. This can be accomplished in a variety of ways, includ- ing "track walking," or driving a crawler tractor up and down the slope, leaving a pattern of cleat imprints parallel to slope contours. . Tracking is done by operating equipment up and down the slope to leave hori- zontal depressions in the soil. Maintenance Standards . Areas that are graded in this manner should be seeded as quickly as possible Regular inspections should be made of the area. If rills appear, they should be re- graded and re -seeded immediately. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 305 Packet Pg. 176 5.1.a Figure II-4.1.5 Surface Roughening by Tracking and Contour Furrows Tracki the slc catch ; Gr mL DEPARTMENT OF ECOLOGY State of Washington Tracking O SCALE Figure II-4.1.5 Surface Roughening by Tracking and Contour Furrows Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 306 Packet Pg. 177 5.1.a BMP C131: Gradient Terraces Purpose Gradient terraces reduce erosion damage by intercepting surface runoff and conducting it to a stable outlet at a non -erosive velocity. Conditions of Use . Gradient terraces normally are limited to denuded land having a water erosion problem. They should not be constructed on deep sands or on soils that are too stony, steep, or shallow to permit practical and economical installation and main- tenance. Gradient terraces may be used only where suitable outlets are or will be made available. See Figure II-4.1.6 Gradient Terraces (p.309) for gradient terraces. Design and Installation Specifications . The maximum vertical spacing of gradient terraces should be determined by the fol- lowing method: V1=(0.8)s+y Where: VI = vertical interval in feet s = land rise per 100 feet, expressed in feet y = a soil and cover variable with values from 1.0 to 4.0 Values of "y" are influenced by soil erodibility and cover practices. The lower val- ues are applicable to erosive soils where little to no residue is left on the surface. The higher value is applicable only to erosion -resistant soils where a large amount of residue (1'/2 tons of straw/acre equivalent) is on the surface. . The minimum constructed cross-section should meet the design dimensions. . The top of the constructed ridge should not be lower at any point than the design elevation plus the specified overfill for settlement. The opening at the outlet end of the terrace should have a cross section equal to that specified for the terrace chan- nel. • Channel grades may be either uniform or variable with a maximum grade of 0.6 feet per 100 feet length (0.6%). For short distances, terrace grades may be increased to improve alignment. The channel velocity should not exceed that which is nonerosive for the soil type. . All gradient terraces should have adequate outlets. Such an outlet may be a grassed waterway, vegetated area, or tile outlet. In all cases the outlet must convey 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 307 Packet Pg. 178 5.1.a runoff from the terrace or terrace system to a point where the outflow will not cause damage. Vegetative cover should be used in the outlet channel. The design elevation of the water surface of the terrace should not be lower than the design elevation of the water surface in the outlet at theirjunction, when both are operating at design flow. Vertical spacing determined by the above methods may be increased as much as 0.5 feet or 10 percent, whichever is greater, to provide better alignment or location, to avoid obstacles, to adjust for equipment size, or to reach a satisfactory outlet. The drainage area above the terrace should not exceed the area that would be drained by a terrace with normal spacing. The terrace should have enough capacity to handle the peak runoff expected from a 2-year, 24-hour design storm without overtopping. The terrace cross-section should be proportioned to fit the land slope. The ridge height should include a reasonable settlement factor. The ridge should have a min- imum top width of 3 feet at the design height. The minimum cross -sectional area of the terrace channel should be 8 square feet for land slopes of 5 percent or less, 7 square feet for slopes from 5 to 8 percent, and 6 square feet for slopes steeper than 8 percent. The terrace can be constructed wide enough to be maintained using a small vehicle. Maintenance Standards . Maintenance should be performed as needed. Terraces should be inspected reg- ularly; at least once a year, and after large storm events. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 308 Packet Pg. 179 5.1.a DEPARTMENT OF ECOLOGY State of Washington Figure II-4.1.6 Gradient Terraces Figure II-4.1.6 Gradient Terraces NOT TO SCALE Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 309 Packet Pg. 180 5.1.a BMP C140: Dust Control Purpose Dust control prevents wind transport of dust from disturbed soil surfaces onto roadways, drainage ways, and surface waters. Conditions of Use In areas (including roadways) subject to surface and air movement of dust where on -site and off -site impacts to roadways, drainage ways, or surface waters are likely. Design and Installation Specifications . Vegetate or mulch areas that will not receive vehicle traffic. In areas where plant- ing, mulching, or paving is impractical, apply gravel or landscaping rock. . Limit dust generation by clearing only those areas where immediate activity will take place, leaving the remaining area(s) in the original condition. Maintain the ori- ginal ground cover as long as practical. . Construct natural or artificial windbreaks or windscreens. These maybe designed as enclosures for small dust sources. Sprinkle the site with water until surface is wet. Repeat as needed. To prevent carryout of mud onto street, refer to BMP C105: Stabilized Construction Entrance / Exit (p.270). . Irrigation water can be used for dust control. Irrigation systems should be installed as a first step on sites where dust control is a concern. . Spray exposed soil areas with a dust palliative, following the manufacturer's instructions and cautions regarding handling and application. Used oil is pro- hibited from use as a dust suppressant. Local governments may approve other dust palliatives such as calcium chloride or PAM. PAM (BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection (p.300)) added to water at a rate of 0.5 lbs. per 1,000 gallons of water per acre and applied from a water truck is more effective than water alone. This is due to increased infilt- ration of water into the soil and reduced evaporation. In addition, small particles are bonded together and are not as easily transported by win PAM may actually reduce the quantity of water needed for dust control. PAM could be a cost-effective dust control method. Techniques that can be used for unpaved roads and lots include: d soil . Adding Use of 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt gage 310 Packet Pg. 181 5.1.a . Lower speed limits. High vehicle speed increases the amount of dust stirred up from unpaved roads and lots. . Upgrade the road surface strength by improving particle size, shape, and mineral types that make up the surface and base materials. . Add surface gravel to reduce the source of dust emission. Limit the amount of fine particles (those smaller than .075 mm) to 10 to 20 percent. • Use geotextile fabrics to increase the strength of new roads or roads undergoing reconstruction. . Encourage the use of alternate, paved routes, if available. . Restrict use of paved roadways by tracked vehicles and heavy trucks to prevent damage to road surface and base. . Apply chemical dust suppressants using the admix method, blending the product with the top few inches of surface material. Suppressants may also be applied as surface treatments. . Pave unpaved permanent roads and other trafficked areas. • Use vacuum street sweepers. . Remove mud and other dirt promptly so it does not dry and then turn into dust. . Limit dust -causing work on windy days. • Contact your local Air Pollution Control Authority for guidance and training on other dust control measures. Compliance with the local Air Pollution Control Authority constitutes compliance with this BMP. Maintenance Standards Respray area as necessary to keep dust to a minimum. BMP C150: Materials on Hand Purpose Keep quantities of erosion prevention and sediment control materials on the project site at all times to be used for regular maintenance and emergency situations such as unex- pected heavy summer rains. Having these materials on -site reduces the time needed to implement BMPs when inspections indicate that existing BMPs are not meeting the Con- struction SWPPP requirements. In addition, contractors can save money by buying some materials in bulk and storing them at their office or yard. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 311 Packet Pg. 182 5.1.a Conditions of Use Construction projects of any size or type can benefit from having materials on hand. A small commercial development project could have a roll of plastic and some gravel available for immediate protection of bare soil and temporary berm construction. A large earthwork project, such as highway construction, might have several tons of straw, several rolls of plastic, flexible pipe, sandbags, geotextile fab- ric and steel "T" posts. . Materials are stockpiled and readily available before any site clearing, grubbing, or earthwork begins. A large contractor or developer could keep a stockpile of mater- ials that are available for use on several projects. If storage space at the project site is at a premium, the contractor could maintain the materials at their office or yard. The office or yard must be less than an hour from the project site. Design and Installation Specifications Depending on project type, size, complexity, and length, materials and quantities will vary. A good minimum list of items that will cover numerous situations includes: Material Clear Plastic, 6 mil Drainpipe, 6 or 8 inch diameter Sandbags, filled Straw Bales for mulching, Quarry Spalls Washed Gravel Geotextile Fabric Catch Basin Inserts Steel "T" Posts Silt fence material Straw Wattles Maintenance Standards . All materials with the exception of the quarry spalls, steel "T" posts, and gravel should be kept covered and out of both sun and rain. . Re -stock materials used as needed. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 312 Packet Pg. 183 5.1.a BMP C151: Concrete Handling Purpose Concrete work can generate process water and slurry that contain fine particles and high pH, both of which can violate water quality standards in the receiving water. Concrete spillage or concrete discharge to surface waters of the State is prohibited. Use this BMP to minimize and eliminate concrete, concrete process water, and concrete slurry from entering waters of the state. Conditions of Use Any time concrete is used, utilize these management practices. Concrete construction projects include, but are not limited to, the following: . Curbs • Sidewalks . Roads . Bridges . Foundations . Floors • Runways Design and Installation Specifications . Assure that washout of concrete trucks, chutes, pumps, and internals is performed at an approved off -site location or in designated concrete washout areas. Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams. Refer to BMP C154: Concrete Washout Area (p.317) for inform- ation on concrete washout areas. . Return unused concrete remaining in the truck and pump to the originating batch plant for recycling. Do not dump excess concrete on site, except in designated con- crete washout areas. . Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels into formed areas only. . Wash equipment difficult to move, such as concrete pavers in areas that do not dir- ectly drain to natural or constructed stormwater conveyances. . Do not allow washdown from areas, such as concrete aggregate driveways, to drain directly to natural or constructed stormwater conveyances. • Contain washwater and leftover product in a lined container when no formed areas 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 313 Packet Pg. 184 5.1.a are available. Dispose of contained concrete in a manner that does not violate ground water or surface water quality standards. . Always use forms or solid barriers for concrete pours, such as pilings, within 15- feet of surface waters. . Refer to BMP C252: High pH Neutralization Using CO2 (p.409) and BMP C253: pH Control for High pH Water (p.412) for pH adjustment requirements. . Refer to the Construction Stormwater General Permit for pH monitoring require- ments if the project involves one of the following activities: • Significant concrete work (greater than 1,000 cubic yards poured concrete or recycled concrete used over the life of a project). . The use of engineered soils amended with (but not limited to) Portland cement -treated base, cement kiln dust orfly ash. . Discharging stormwater to segments of water bodies on the 303(d) list (Cat- egory 5) for high pH. Maintenance Standards Check containers for holes in the liner daily during concrete pours and repair the same day. BMP C152: Sawcutting and Surfacing Pollution Prevention Purpose Sawcutting and surfacing operations generate slurry and process water that contains fine particles and high pH (concrete cutting), both of which can violate the water quality standards in the receiving water. Concrete spillage or concrete discharge to surface waters of the State is prohibited. Use this BMP to minimize and eliminate process water and slurry created through sawcutting or surfacing from entering waters of the State. Conditions of Use Utilize these management practices anytime sawcutting or surfacing operations take place. Sawcutting and surfacing operations include, but are not limited to, the following: • Sawing . Coring . Grinding . Roughening 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 314 Packet Pg. 185 5.1.a . Hydro -demolition . Bridge and road surfacing Design and Installation Specifications . Vacuum slurry and cuttings during cutting and surfacing operations. • Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight. • Slurry and cuttings shall not drain to any natural or constructed drainage con- veyance including stormwater systems. This may require temporarily blocking catch basins. . Dispose of collected slurry and cuttings in a manner that does not violate ground water or surface water quality standards. . Do not allow process water generated during hydro -demolition, surface rough- ening or similar operations to drain to any natural or constructed drainage con- veyance including stormwater systems. Dispose process water in a manner that does not violate ground water or surface water quality standards. . Handle and dispose cleaning waste material and demolition debris in a manner that does not cause contamination of water. Dispose of sweeping material from a pick-up sweeper at an appropriate disposal site. Maintenance Standards Continually monitor operations to determine whether slurry, cuttings, or process water could enter waters of the state. If inspections show that a violation of water quality stand- ards could occur, stop operations and immediately implement preventive measures such as berms, barriers, secondary containment, and vacuum trucks. BMP C153: Material Delivery, Storage and Containment Purpose Prevent, reduce, or eliminate the discharge of pollutants to the stormwater system or watercourses from material delivery and storage. Minimize the storage of hazardous materials on -site, store materials in a designated area, and install secondary con- tainment. Conditions of Use These procedures are suitable for use at all construction sites with delivery and storage of the following materials: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 315 Packet Pg. 186 5.1.a . Petroleum products such as fuel, oil and grease • Soil stabilizers and binders (e.g., Polyacrylamide) . Fertilizers, pesticides and herbicides . Detergents . Asphalt and concrete compounds . Hazardous chemicals such as acids, lime, adhesives, paints, solvents, and curing compounds . Any other material that may be detrimental if released to the environment Design and Installation Specifications The following steps should be taken to minimize risk: . Temporary storage area should be located away from vehicular traffic, near the con- struction entrance(s), and away from waterways or storm drains. . Material Safety Data Sheets (MSDS) should be supplied for all materials stored. Chemicals should be kept in their original labeled containers. . Hazardous material storage on -site should be minimized. . Hazardous materials should be handled as infrequently as possible. • During the wet weather season (Oct 1 — April 30), consider storing materials in a covered area. . Materials should be stored in secondary containments, such as earthen dike, horse trough, or even a children's wading pool for non -reactive materials such as deter- gents, oil, grease, and paints. Small amounts of material may be secondarily con- tained in "bus boy" trays or concrete mixing trays. . Do not store chemicals, drums, or bagged materials directly on the ground. Place these items on a pallet and, when possible, and within secondary containment. . If drums must be kept uncovered, store them at a slight angle to reduce ponding of rainwater on the lids to reduce corrosion. Domed plastic covers are inexpensive and snap to the top of drums, preventing water from collecting. Material Storage Areas and Secondary Containment Practices: . Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or 302 shall be stored in approved containers and drums and shall not be overfilled. Containers and drums shall be stored in temporary secondary containment facil- ities. . Temporary secondary containment facilities shall provide for a spill containment 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 316 Packet Pg. 187 5.1.a volume able to contain 10% of the total enclosed container volume of all con- tainers, or 110% of the capacity of the largest container within its boundary, whichever is greater. • Secondary containment facilities shall be impervious to the materials stored therein for a minimum contact time of 72 hours. . Secondary containment facilities shall be maintained free of accumulated rain- water and spills. In the event of spills or leaks, accumulated rainwater and spills shall be collected and placed into drums. These liquids shall be handled as haz- ardous waste unless testing determines them to be non -hazardous. . Sufficient separation should be provided between stored containers to allow for spill cleanup and emergency response access. . During the wet weather season (Oct 1 — April 30), each secondary containment facility shall be covered during non -working days, prior to and during rain events. . Keep material storage areas clean, organized and equipped with an ample supply of appropriate spill clean-up material (spill kit). . The spill kit should include, at a minimum: 1-Water Resistant Nylon Bag o 3-Oil Absorbent Socks 3"x 4' 2-Oil Absorbent Socks 3"x 10' o 12-Oil Absorbent Pads 17"x19" O 1-Pair Splash Resistant Goggles 3-Pair Nitrile Gloves 10-Disposable Bags with Ties o Instructions BMP C154: Concrete Washout Area Purpose Prevent or reduce the discharge of pollutants to stormwater from concrete waste by con- ducting washout off -site, or performing on -site washout in a designated area to prevent pollutants from entering surface waters or ground water. Conditions of Use Concrete washout area best management practices are implemented on construction projects where: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 317 Packet Pg. 188 5.1.a . Concrete is used as a construction material . It is not possible to dispose of all concrete wastewater and washout off -site (ready mix plant, etc.). . Concrete trucks, pumpers, or other concrete coated equipment are washed on -site. . Note: If less than 10 concrete trucks or pumpers need to be washed out on -site, the washwater may be disposed of in a formed area awaiting concrete or an upland disposal site where it will not contaminate surface or ground water. The upland dis- posal site shall be at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands. Design and Installation Specifications Implementation The following steps will help reduce stormwater pollution from concrete wastes: . Perform washout of concrete trucks at an approved off -site location or in des- ignated concrete washout areas only. . Do not washout concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams. . Do not allow excess concrete to be dumped on -site, except in designated concrete washout areas. . Concrete washout areas may be prefabricated concrete washout containers, or self -installed structures (above -grade or below -grade). . Prefabricated containers are most resistant to damage and protect against spills and leaks. Companies may offer delivery service and provide regular maintenance and disposal of solid and liquid waste. . If self -installed concrete washout areas are used, below -grade structures are pre- ferred over above -grade structures because they are less prone to spills and leaks. . Self -installed above -grade structures should only be used if excavation is not prac- tical. Education . Discuss the concrete management techniques described in this BMP with the ready -mix concrete supplier before any deliveries are made. . Educate employees and subcontractors on the concrete waste management tech- niques described in this BMP. . Arrange for contractor's superintendent or Certified Erosion and Sediment Control 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 318 Packet Pg. 189 5.1.a Lead (CESCL) to oversee and enforce concrete waste management procedures. A sign should be installed adjacent to each temporary concrete washout facility to inform concrete equipment operators to utilize the proper facilities. Contracts Incorporate requirements for concrete waste management into concrete supplier and sub- contractor agreements. Location and Placement . Locate washout area at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands. . Allow convenient access for concrete trucks, preferably near the area where the concrete is being poured. . If trucks need to leave a paved area to access washout, prevent track -out with a pad of rock or quarry spalls (see BMP C105: Stabilized Construction Entrance / Exit (p.270)). These areas should be far enough away from other construction traffic to reduce the likelihood of accidental damage and spills. . The number of facilities you install should depend on the expected demand for stor- age capacity. . On large sites with extensive concrete work, washouts should be placed in mul- tiple locations for ease of use by concrete truck drivers. On -site Temporary Concrete Washout Facility, Transit Truck Washout Procedures: . Temporary concrete washout facilities shall be located a minimum of 50 ft from sensitive areas including storm drain inlets, open drainage facilities, and water- courses. See Figure II-4.1.7a Concrete Washout Area (p.322), Figure II-4.1.7b Con- crete Washout Area (p.323), and Figure II-4.1.8 Prefabricated Concrete Washout Containerw/Ramp (p.324). • Concrete washout facilities shall be constructed and maintained in sufficient quant- ity and size to contain all liquid and concrete waste generated by washout oper- ations. . Washout of concrete trucks shall be performed in designated areas only. . Concrete washout from concrete pumper bins can be washed into concrete pumper trucks and discharged into designated washout area or properly disposed of off -site. • Once concrete wastes are washed into the designated area and allowed to 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 319 Packet Pg. 190 5.1.a harden, the concrete should be broken up, removed, and disposed of per applic- able solid waste regulations. Dispose of hardened concrete on a regular basis. . Temporary Above -Grade Concrete Washout Facility . Temporary concrete washout facility (type above grade) should be con- structed as shown on the details below, with a recommended minimum length and minimum width of 10 ft, but with sufficient quantity and volume to contain all liquid and concrete waste generated by washout operations. . Plastic lining material should be a minimum of 10 mil polyethylene sheeting and should be free of holes, tears, or other defects that compromise the imper- meability of the material. . Temgorary Below -Grade Concrete Washout Facilitv . Temporary concrete washout facilities (type below grade) should be con- structed as shown on the details below, with a recommended minimum length and minimum width of 10 ft. The quantity and volume should be suf- ficient to contain all liquid and concrete waste generated by washout oper- ations. . Lath and flagging should be commercial type. • Plastic lining material shall be a minimum of 10 mil polyethylene sheeting and should be free of holes, tears, or other defects that compromise the imper- meability of the material. . Liner seams shall be installed in accordance with manufacturers' recom- mendations. • Soil base shall be prepared free of rocks or other debris that may cause tears or holes in the plastic lining material. Maintenance Standards Inspection and Maintenance . Inspect and verify that concrete washout BMPs are in place prior to the com- mencement of concrete work. . During periods of concrete work, inspect daily to verify continued performance. • Check overall condition and performance. . Check remaining capacity (% full). . If using self -installed washout facilities, verify plastic liners are intact and side - walls are not damaged. . If using prefabricated containers, check for leaks. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 320 Packet Pg. 191 5.1.a . Washout facilities shall be maintained to provide adequate holding capacity with a minimum freeboard of 12 inches. . Washout facilities must be cleaned, or new facilities must be constructed and readv for use once the washout is 75% full. . If the washout is nearinq capacity, vacuum and dispose of the waste material in an approved manner. . Do not discharge liquid or slurry to waterways, storm drains or directly onto ground. Do not use sanitary sewer without local approval. . Place a secure, non -collapsing, non -water collecting cover over the concrete washout facility prior to predicted wet weather to prevent accumulation and overflow of precipitation. . Remove and dispose of hardened concrete and return the structure to a func- tional condition. Concrete may be reused on -site or hauled away for disposal or recycling. When you remove materials from the self -installed concrete washout, build a new structure; or, if the previous structure is still intact, inspect for signs of weakening or damage, and make any necessary repairs. Re -line the structure with new plastic after each cleaning. Removal of Temporary Concrete Washout Facilities When temporary concrete washout facilities are no longer required for the work, the hardened concrete, slurries and liquids shall be removed and properly dis- posed of. Materials used to construct temporary concrete washout facilities shall be removed from the site of the work and disposed of or recycled. . Holes, depressions or other ground disturbance caused by the removal of the tem- porary concrete washout facilities shall be backfilled, repaired, and stabilized to prevent erosion. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 321 Packet Pg. 192 5.1.a 0 Varies 0 Figure II-4.1.7a Concrete Washout Area 3m Minimum O v / � O O o Plan Lath and flagging 0 on 3 sides Sandbag Berm 10 mil plastic lining A 0 A J 0 1m T � /, 0 Section A -A - 10 mil plastic lining — Type "Below Grade" 0 Stake (typ.) iil plastic lining Sandbag Berm 1. Actual layout determined in the field. 2. A concrete washout sign shall be installed within 10 m of the temporary concrete washout facility. Wood frame securely fastened around entire perimeter with two stakes 10 mil Z— plastic lining Section B-B 2x12 rough Plan wood frame Tvpe "Above Grade" with Wood Planks NOT TO SCALE Figure II-4.1.7a Concrete Washout Area DEPARTMENT OF Revised June2015 ECOLOGYPlease see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume Att@A"RJPt Page 322 Packet Pg. 193 5.1.a Straw bale Staples (2 per bale) Wood or metal stakes (2 per bale) Figure II-4.1.7b Concrete Washout Area 10 mil plastic lining Native material (optional) Gar+inn R_R 3m Minimum Stake (typ) B� Varies 11 Binding wire d Plj610mm 1200 mm x Wood post paint (89 mm x 89 mm Lag screws x 2.4 m) (12.5 mm) CONCRETE! Black letters WASHOUT 150 mm height 91 915 mm —F Concrete Washout Sign Detail (or equivalent) B 50 mm 200 mm (1�� 3.05 mm dia. J-- steel wire Staple Detail Straw bale J 10 mil plastic lining Notes: (typ) 1. Actual layout Plan determined in the field. 2. The concrete washout sign shall be installed within 10 m of the temporary concrete washout facility. Type "Above Grade" with Straw Bales NOT TO SCALE Figure II-4.1.7b Concrete Washout Area DEPARTMENT OF Revised June2015 ECOLOGYPlease see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. C O cC R O O 0 0 0 O N 0 N Z J d 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 323 1Packet Pg. 194 5.1.a Figure II-4.1.8 Prefabricated Concrete Washout Container w/Ramp r1� DEPARTMENT OF ECOLOGY State of Washington NOT TO SCALE Figure II-4.1.8 Prefabricated Concrete Washout Container w/Ramp Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 324 Packet Pg. 195 5.1.a BMP C160: Certified Erosion and Sediment Control Lead Purpose The project proponent designates at least one person as the responsible representative in charge of erosion and sediment control (ESC), and water quality protection. The des- ignated person shall be the Certified Erosion and Sediment Control Lead (CESCL) who is responsible for ensuring compliance with all local, state, and federal erosion and sed- iment control and water quality requirements. Conditions of Use A CESCL shall be made available on projects one acre or larger that discharge storm - water to surface waters of the state. Sites less than one acre may have a person without CESCL certification conduct inspections; sampling is not required on sites that disturb less than an acre. . The CESCL shall: . Have a current certificate proving attendance in an erosion and sediment con- trol training course that meets the minimum ESC training and certification requirements established by Ecology (see details below). Ecology will maintain a list of ESC training and certification providers at: http://www.ecy.wa.gov/programs/wq/stormwater/cescl.html OR . Be a Certified Professional in Erosion and Sediment Control (CPESC); for additional information go to: http://www.envirocertintl.org/cpesc/ Specifications . Certification shall remain valid for three years. . The CESCL shall have authority to act on behalf of the contractor or developer and shall be available, or on -call, 24 hours per day throughout the period of con- struction. . The Construction SWPPP shall include the name, telephone number, fax number, and address of the designated CESCL. . A CESCL may provide inspection and compliance services for multiple con- struction projects in the same geographic region. Duties and responsibilities of the CESCL shall include, but are not limited to the fol- lowing: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 325 Packet Pg. 196 5.1.a . Maintaining permit file on site at all times which includes the Construction SWPPP and any associated permits and plans. . Directing BMP installation, inspection, maintenance, modification, and removal. . Updating all project drawings and the Construction SWPPP with changes made. • Completing any sampling requirements including reporting results using WebDMR. . Keeping daily logs, and inspection reports. Inspection reports should include: . Inspection date/time. . Weather information; general conditions during inspection and approximate amount of precipitation since the last inspection. . A summary or list of all BMPs implemented, including observations of all erosion/sediment control structures or practices. The following shall be noted: 1. Locations of BMPs inspected. 2. Locations of BMPs that need maintenance. 3. Locations of BMPs that failed to operate as designed or intended. 4. Locations of where additional or different BMPs are required. . Visual monitoring results, including a description of discharged stormwater. The presence of suspended sediment, turbid water, discoloration, and oil sheen shall be noted, as applicable. . Any water quality monitoring performed during inspection. • General comments and notes, including a brief description of any BMP repairs, maintenance or installations made as a result of the inspection. . Facilitate, participate in, and take corrective actions resulting from inspections per- formed by outside agencies or the owner. BMP C162: Scheduling Purpose Sequencing a construction project reduces the amount and duration of soil exposed to erosion by wind, rain, runoff, and vehicle tracking. Conditions of Use The construction sequence schedule is an orderly listing of all major land -disturbing activities together with the necessary erosion and sedimentation control measures 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 326 Packet Pg. 197 5.1.a planned for the project. This type of schedule guides the contractor on work to be done before other work is started so that serious erosion and sedimentation problems can be avoided. Following a specified work schedule that coordinates the timing of land -disturbing activ- ities and the installation of control measures is perhaps the most cost-effective way of controlling erosion during construction. The removal of surface ground cover leaves a site vulnerable to accelerated erosion. Construction procedures that limit land clearing provide timely installation of erosion and sedimentation controls, and restore protective cover quickly can significantly reduce the erosion potential of a site. Design Considerations . Minimize construction during rainy periods. Schedule projects to disturb only small portions of the site at any one time. Com- plete grading as soon as possible. Immediately stabilize the disturbed portion before grading the next portion. Practice staged seeding in order to revegetate cut and fill slopes as the work progresses. II-4.2 Runoff Conveyance and Treatment BMPs This section contains the standards and specifications for Runoff Conveyance and Treat- ment BMPs. Table II-4.2.1 Runoff Conveyance and Treatment BMPs by SWPPP Ele- ment (p.327), below, shows the relationship of the BMPs in II-4.2 Runoff Conveyance and Treatment BMPs to the Construction Stormwater Pollution Prevention Plan (SWPPP) Elements described in II-3.3.3 Step 3 - Construction SWPPP Development and Implementation (p.236). Table II-4.2.1 Runoff Conveyance and Treatment BMPs by SWPPP Element Ele- Element Element Ele- Ele- ment #4 Ele- #8 Stab- ment Element ment Element #3 Install ment ilize #10 #13 Protect BMP or Ele- #7 Pro- #9 Con- Con- Sed- #6 Pro- Chan- Control Low Impact ment Name tect trot Pol- trot invent tect nels De- Devel- Drain lutants Flow Con- Slopes and Out- Water- opment Inlets Rates trols lets ing BMP C200: ✓ ✓ Interceptor Dike and Swale (p 331) 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 327 Packet Pg. 198 5.1.a Table II-4.2.1 Runoff Conveyance and Treatment BMPs by SWPPP Element (continued) Ele- Element Element Ele- ment #4 Ele- Ele- #8 Stab- ment Element #3 Install ment ment ilize Element #10 #13 Protect BMP or Ele- #7 Pro- #9 Con- Con- Sed- #6 Pro- Chan- Control Low Impact ment Name tect trot Pol- trot invent tect nels De- Devel- Flow Con- Slopes Drain and Out- lutants Water- opment Inlets Rates trols lets ing BMP C201: ✓ ✓ Grass- Lined Chan- nels (p.333) BMP C202: ✓ Channel Lining tp.3381 BMP C203: ✓ ✓ ✓ Water Bars tp.339) BMP C204: ✓ Pipe Slope Drains tp.3421 BMP C205: ✓ Subsurface Drains (p 346) BMP C206: ✓ ✓ Level Spreader (p 348) BMP C207: ✓ ✓ ✓ ✓ Check Dams tp.352) BMP C208: ✓ ✓ Triangular Silt Dike (TSD) (Geo- 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 328 Packet Pg. 199 5.1.a Table II-4.2.1 Runoff Conveyance and Treatment BMPs by SWPPP Element (continued) Ele- Element Element Ele- Ele- ment #4 Ele- #8 Stab- ment Element ment Element #3 Install ment ilize #10 #13 Protect BMP or Ele- #7 Pro- #9 Con- Con- Sed- #6 Pro- Chan- Control Low Impact ment Name tect trot Pol- trot invent tect nels De- Devel- Drain lutants Flow Con- Slopes and Out- Water- opment Inlets Rates trols lets ing textile - Encased Check Dam .355 BMP C209: ✓ ✓ Outlet Pro- tection (p 356) BMP C220: ✓ Storm Drain Inlet Pro- tection .357 BMP C231: ✓ ✓ Brush Bar- rier (p.365) BMP C232: ✓ Gravel Filter Berm (p 367) BMP C233: ✓ ✓ Silt Fence tp.3671 BMP C234: ✓ ✓ Vegetated Strip (p.375) BMP C235: ✓ ✓ Wattles (p 376) BMP C236: ✓ 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 329 Packet Pg. 200 5.1.a Table II-4.2.1 Runoff Conveyance and Treatment BMPs by SWPPP Element (continued) Ele- Element Element Ele- ment #4 Ele- Ele- #8 Stab- ment Element #3 Install ment ment ilize Element #10 #13 Protect BMP or Ele- #7 Pro- #9 Con- Con- Sed- #6 Pro- Chan- Control Low Impact ment Name tect trot Pol- trot invent tect nels De- Devel- Flow Con- Slopes Drain and Out- lutants Water- opment Inlets Rates trols lets ing Vegetative Filtration (p 379) BMP C240: ✓ ✓ Sediment Trap (p.383) BMP C241: ✓ ✓ Temporary Sediment Pond tp.388) BMP C250: Con- struction Stormwater ✓ ✓ Chemical Treatment (p 396) BMP C251: Con- struction ✓ ✓ Stormwater Filtration tp.404) BMP C252: High pH Neut- ✓ ralization Using CO2 tp.4091 BMP C253: ✓ pH Control 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 330 Packet Pg. 201 5.1.a Table II-4.2.1 Runoff Conveyance and Treatment BMPs by SWPPP Element (continued) Ele- Element Element Ele- Ele- ment #4 Ele- #8 Stab- ment Element ment Element #3 Install ment ilize #10 #13 Protect BMP or Ele- #7 Pro- #9 Con- Con- Sed- #6 Pro- Chan- Control Low Impact ment Name tect trot Pol- trot invent tect nels De- Devel- Drain lutants Flow Con- Slopes and Out- Water- opment Inlets Rates trols lets ing for High pH Water (p 412) BMP C200: Interceptor Dike and Swale Purpose Provide a ridge of compacted soil, or a ridge with an upslope swale, at the top or base of a disturbed slope or along the perimeter of a disturbed construction area to convey storm - water. Use the dike and/or swale to intercept the runoff from unprotected areas and direct it to areas where erosion can be controlled. This can prevent storm runoff from entering the work area or sediment -laden runoff from leaving the construction site. Conditions of Use Where the runoff from an exposed site or disturbed slope must be conveyed to an erosion control facility which can safely convey the stormwater. . Locate upslope of a construction site to prevent runoff from entering disturbed area When placed horizontally across a disturbed slope, it reduces the amount and velo- city of runoff flowing down the slope. . Locate downslope to collect runoff from a disturbed area and direct water to a sed- iment basin. Design and Installation Specifications . Dike and/or swale and channel must be stabilized with temporary or permanent vegetation or other channel protection during construction. Channel requires a positive grade for drainage; steeper grades require channel protection and check dams. . Review construction for areas where overtopping may occur. Can be used at top of new fill before vegetation is established. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 331 Packet Pg. 202 5.1.a . May be used as a permanent diversion channel to carry the runoff. . Sub -basin tributary area should be one acre or less. . Design capacity for the peak volumetric flow rate calculated using a 10-minute time step from a 10-year, 24-hour storm, assuming a Type 1A rainfall distribution, for temporary facilities. Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model. For facilities that will also serve on a per- manent basis, consult the local government's drainage requirements. Interceptor dikes shall meet the following criteria: . Top Width: 2 feet minimum. . Height: 1.5 feet minimum on berm. . Side Slope: 2H:1V or flatter. Grade: Depends on topography, however, dike system minimum is 0.5%, and max- imum is 1 %. . Compaction: Minimum of90 percent ASTM D698 standard proctor. . Horizontal Spacing of Interceptor Dikes: Average Slope Slope Percent Flowpath Length 20H:lV or less 3-5% 300 feet (10 to 20)H:1V 5-10% 200 feet (4 to 1Oft 1V 10-25% 100 feet (2 to 4)H:1V 25-50% 50 feet . Stabilization: depends on velocity and reach . Slopes <5%: Seed and mulch applied within 5 days of dike construction (see BMP C121: Mulching (p.284)). . Slopes 5 - 40%: Dependent on runoff velocities and dike materials. Stabilization should be done immediately using either sod or riprap or other measures to avoid erosion. . The upslope side of the dike shall provide positive drainage to the dike outlet. No erosion shall occur at the outlet. Provide energy dissipation measures as neces- sary. Sediment -laden runoff must be released through a sediment trapping facility . Minimize construction traffic over temporary dikes. Use temporary cross culverts for channel crossing. Interceptor swales shall meet the following criteria: . Bottom Width: 2 feet minimum; the cross-section bottom shall be level. . Depth: 1-foot minimum. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 332 Packet Pg. 203 5.1.a . Side Slope: 2H:1V or flatter. Grade: Maximum 5 percent, with positive drainage to a suitable outlet (such as a sediment pond). . Stabilization: Seed as per BMP C120: Temporary and Permanent Seeding (p.278), or BMP C202: Channel Lining (p.338), 12 inches thick riprap pressed into the bank and extending at least 8 inches vertical from the bottom. Inspect diversion dikes and interceptor swales once a week and after every rainfall. Immediately remove sediment from the flow area. Damage caused by construction traffic or other activity must be repaired before the end of each working day. Check outlets and make timely repairs as needed to avoid gully formation. When the area below the temporary diversion dike is permanently stabilized, remove the dike and fill and stabilize the channel to blend with the natural surface. BMP C201: Grass -Lined Channels Purpose To provide a channel with a vegetative lining for conveyance of runoff. See Figure II- 4.2.1 Typical Grass -Lined Channels (p.336) for typical grass -lined channels. Conditions of Use This practice applies to construction sites where concentrated runoff needs to be con- tained to prevent erosion or flooding. When a vegetative lining can provide sufficient stability for the channel cross sec- tion and at lower velocities of water (normally dependent on grade). This means that the channel slopes are generally less than 5 percent and space is available for a relatively large cross section. Typical uses include roadside ditches, channels at property boundaries, outlets for diversions, and other channels and drainage ditches in low areas. Channels that will be vegetated should be installed before major earthwork and hydroseeded with a bonded fiber matrix (BFM). The vegetation should be well established (i.e., 75 percent cover) before water is allowed to flow in the ditch. With channels that will have high flows, erosion control blankets should be installed over the hydroseed. If vegetation cannot be established from seed before water is allowed in the ditch, sod should be installed in the bottom of the ditch in lieu of hydromulch and blankets. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 333 Packet Pg. 204 5.1.a Design and Installation Specifications Locate the channel where it can conform to the topography and other features such as roads. . Locate them to use natural drainage systems to the greatest extent possible. . Avoid sharp changes in alignment or bends and changes in grade. • Do not reshape the landscape to fit the drainage channel. . The maximum design velocity shall be based on soil conditions, type of vegetation, and method of revegetation, but at no times shall velocity exceed 5 feet/second. The channel shall not be overtopped by the peak volumetric flow rate calculated using a 10-minute time step from a 10-year, 24-hour storm, assuming a Type 1A rainfall distribution. Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model to determine a flow rate which the chan- nel must contain. . Where the grass -lined channel will also function as a permanent stormwater con- veyance facility, consult the drainage conveyance requirements of the local gov- ernment with jurisdiction. . An established grass or vegetated lining is required before the channel can be used to convey stormwater, unless stabilized with nets or blankets. . If design velocity of a channel to be vegetated by seeding exceeds 2 fusec, a tem- porary channel liner is required. Geotextile or special mulch protection such as fiberglass roving or straw and netting provides stability until the vegetation is fully established. See Figure II-4.2.2 Temporary Channel Liners (p.337). . Check dams shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. . If vegetation is established by sodding, the permissible velocity for established vegetation may be used and no temporary liner is needed. . Do not subject grass -lined channel to sedimentation from disturbed areas. Use sed- iment -trapping BMPs upstream of the channel. . V-shaped grass channels generally apply where the quantity of water is small, such as in short reaches along roadsides. The V-shaped cross section is least desirable because it is difficult to stabilize the bottom where velocities may be high. . Trapezoidal grass channels are used where runoff volumes are large and slope is low so that velocities are nonerosive to vegetated linings. (Note: it is difficult to 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 334 Packet Pg. 205 5.1.a construct small parabolic shaped channels.) • Subsurface drainage, or riprap channel bottoms, may be necessary on sites that are subject to prolonged wet conditions due to long duration flows or a high water table. . Provide outlet protection at culvert ends and at channel intersections. . Grass channels, at a minimum, should carry peak runoff for temporary construction drainage facilities from the 10-year, 24-hour storm without eroding. Where flood hazard exists, increase the capacity according to the potential damage. • Grassed channel side slopes generally are constructed 3H:1 V or flatter to aid in the establishment of vegetation and for maintenance. • Construct channels a minimum of 0.2 foot larger around the periphery to allow for soil bulking during seedbed preparations and sod buildup. Maintenance Standards During the establishment period, check grass -lined channels after every rainfall. . After grass is established, periodically check the channel; check it after every heavy rainfall event. Immediately make repairs. . It is particularly important to check the channel outlet and all road crossings for bank stability and evidence of piping or scour holes. Remove all significant sediment accumulations to maintain the designed carrying capacity. Keep the grass in a healthy, vigorous condition at all times, since it is the primary erosion protection for the channel. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 335 Packet Pg. 206 5.1.a Figure II-4.2.1 Typical Grass -Lined Channels Typical V-Shaped Channel Cross -Section With Rock Center i \ee Grass -Lined Filter Fabric Typical Parabolic Channel Cross -Section 6„ - 9" (150-225mm) Key in Fabric With Rock Center for Base Flow 01 A� (150-225mm) / With Channel J Key in Fabric \� Filter Fabric Liner Typical Trapezoidal Channel Cross -Section Overcut channel 2" (50mm) to allow bulking during seedbed preparation and growth of vegetation. DEPARTMENT OF ECOLOGY State of Washington n,. ;__ n--.k Filter Fabric With Rock Center for Base Flow NOT TO SCALE Figure II-4.2.1 Typical Grass -Lined Channels Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 336 1Packet Pg. 207 5.1.a Figure II-4.2.2 Temporary Channel Liners Overlap 6" (150mm) minimum Excavate channel to design grade and cross section �y Design Depth Overcut channel 2' (50mm) to allow bulking during seedbed preparation P Typical installation with \ \ erosion control blankets NIS//� ' or turf reinforcement mats//\ 6,� '6/ Intermittent Check Slot Longitudinal Anchor Trench Shingle -lap spliced ends or begin new roll in an intermittent check slot Prepare soil and apply seed before U installing blankets, mats, or other U_ temporary channel liner system n Notes: . 1. Design velocities exceeding 2 ft/sec (0.5 m/sec) require temporary blankets, mats, or similar liners to protect seed and soil until vegetation becomes established. \T 2. Grass -lined channels with design velocities exceeding 6 ft/sec (2 m/sec) should include turf reinforcement mats. DEPARTMENT OF ECOLOGY State of Washington Figure II-4.2.2 Temporary Channel Liners Longitudinal anchor trench NOT TO SCALE Revised July 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 337 Packet Pg. 208 5.1.a BMP C202: Channel Lining Purpose To protect channels by providing a channel liner using either blankets or riprap. Conditions of Use When natural soils or vegetated stabilized soils in a channel are not adequate to prevent channel erosion. When a permanent ditch or pipe system is to be installed and a temporary measure is needed. In almost all cases, synthetic and organic coconut blankets are more effective than riprap for protecting channels from erosion. Blankets can be used with and without vegetation. Blanketed channels can be designed to handle any expected flow and longevity requirement. Some synthetic blankets have a predicted life span of 50 years or more, even in sunlight. • Other reasons why blankets are better than rock include the availability of blankets over rock. In many areas of the state, rock is not easily obtainable or is very expens- ive to haul to a site. Blankets can be delivered anywhere. Rock requires the use of dump trucks to haul and heavy equipment to place. Blankets usually only require laborers with hand tools, and sometimes a backhoe. . The Federal Highway Administration recommends not using flexible liners whenever the slope exceeds 10 percent or the shear stress exceeds 8 Ibs/ft2. Design and Installation Specifications See BMP C122: Nets and Blankets (p.288) for information on blankets. Since riprap is used where erosion potential is high, construction must be sequenced so that the riprap is put in place with the minimum possible delay. Disturbance of areas where riprap is to be placed should be undertaken only when final preparation and placement of the riprap can follow immediately behind the ini- tial disturbance. Where riprap is used for outlet protection, the riprap should be placed before or in conjunction with the construction of the pipe or channel so that it is in place when the pipe or channel begins to operate. The designer, after determining the riprap size that will be stable under the flow conditions, shall consider that size to be a minimum size and then, based on riprap gradations actually available in the area, select the size or sizes that equal or exceed the minimum size. The possibility of drainage structure damage by children shall be considered in selecting a riprap size, especially if there is nearby water or a gully in which to toss the stones. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 338 Packet Pg. 209 5.1.a Stone for riprap shall consist of field stone or quarry stone of approximately rect- angular shape. The stone shall be hard and angular and of such quality that it will not disintegrate on exposure to water or weathering and it shall be suitable in all respects for the purpose intended. A lining of engineering filter fabric (geotextile) shall be placed between the riprap and the underlying soil surface to prevent soil movement into or through the riprap. The geotextile should be keyed in at the top of the bank. Filter fabric shall not be used on slopes greater than 1-1/2H:1V as slippage may occur. It should be used in conjunction with a layer of coarse aggregate (granular filter blanket) when the riprap to be placed is 12 inches and larger. BMP C203: Water Bars Purpose A small ditch or ridge of material is constructed diagonally across a road or right-of-way to divert stormwater runoff from the road surface, wheel tracks, or a shallow road ditch. See Figure II-4.2.3 Water Bar (p.341). Conditions of Use Clearing right-of-way and construction of access for power lines, pipelines, and other similar installations often require long narrow right-of-ways over sloping terrain. Dis- turbance and compaction promotes gully formation in these cleared strips by increasing the volume and velocity of runoff. Gully formation may be especially severe in tire tracks and ruts. To prevent gullying, runoff can often be diverted across the width of the right-of- way to undisturbed areas by using small predesigned diversions. Give special consideration to each individual outlet area, as well as to the cumu- lative effect of added diversions. Use gravel to stabilize the diversion where sig- nificant vehicular traffic is anticipated. Design and Installation Specifications • Height: 8-inch minimum measured from the channel bottom to the ridge top. . Side slope of channel: 2HA V maximum; 3H:1 V or flatter when vehicles will cross. . Base width of ridge: 6-inch minimum. . Locate them to use natural drainage systems and to discharge into well vegetated stable areas. • Guideline for Spacing: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 339 Packet Pg. 210 5.1.a Slope % Spacing (ft) < 5 125 5 - 10 100 10 - 20 75 20 - 35 50 > 35 Use rock lined ditch Grade of water bar and angle: Select angle that results in ditch slope less than 2 percent. . Install as soon as the clearing and grading is complete. Reconstruct when con- struction is complete on a section when utilities are being installed. . Compact the ridge when installed. Stabilize, seed, and mulch the portions that are not subject to traffic. Gravel the areas crossed by vehicles. Maintenance Standards Periodically inspect right-of-way diversions for wear and after every heavy rainfall for erosion damage. . Immediately remove sediment from the flow area and repair the dike. . Check outlet areas and make timely repairs as needed. . When permanent road drainage is established and the area above the temporary right-of-way diversion is permanently stabilized, remove the dikes and fill the chan- nel to blend with the natural ground, and appropriately stabilize the disturbed area. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 340 Packet Pg. 211 5.1.a Figure II-4.2.3 Water Bar CIO wng Use material excavated from dip to construct hump Deep Water Bar A = 24 to 30 inches B=6to10feet Shallow Water Bar A = 8 to 12 inches B=6to12feet DEPARTMENT OF ECOLOGY State of Washington Figure II-4.2.3 Water Bar NOT TO SCALE Revised July 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. c O c� tv O O O 0 G 0 N 0 N Z J d 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 341 1Packet Pg. 212 5.1.a BMP C204: Pipe Slope Drains Purpose To use a pipe to convey stormwater anytime water needs to be diverted away from or over bare soil to prevent gullies, channel erosion, and saturation of slide -prone soils. Conditions of Use Pipe slope drains should be used when a temporary or permanent stormwater con- veyance is needed to move the water down a steep slope to avoid erosion (Figure II- 4.2.4 Pipe Slope Drain (p.345)). On highway projects, pipe slope drains should be used at bridge ends to collect runoff and pipe it to the base of the fill slopes along bridge approaches. These can be designed into a project and included as bid items. Another use on road projects is to col- lect runoff from pavement and pipe it away from side slopes. These are useful because there is generally a time lag between having the first lift of asphalt installed and the curbs, gutters, and permanent drainage installed. Used in conjunction with sand bags, or other temporary diversion devices, these will prevent massive amounts of sediment from leaving a project. Water can be collected, channeled with sand bags, Triangular Silt Dikes, berms, or other material, and piped to temporary sediment ponds. Pipe slope drains can be: Connected to new catch basins and used temporarily until all permanent piping is installed; . Used to drain water collected from aquifers exposed on cut slopes and take it to the base of the slope; . Used to collect clean runoff from plastic sheeting and direct it away from exposed soil; . Installed in conjunction with silt fence to drain collected water to a controlled area; • Used to divert small seasonal streams away from construction. They have been used successfully on culvert replacement and extension jobs. Large flex pipe can be used on larger streams during culvert removal, repair, or replacement; and, • Connected to existing down spouts and roof drains and used to divert water away from work areas during building renovation, demolition, and construction projects. There are now several commercially available collectors that are attached to the pipe inlet and help prevent erosion at the inlet. 2014 Stormwater Management Manual for Western Washington Volume Att@A"APt J9age 342 1Packet Pg. 213 5.1.a Design and Installation Specifications Size the pipe to convey the flow. The capacity for temporary drains shall be sufficient to handle the peak volumetric flow rate calculated using a 10-minute time step from a 10- year, 24-hour storm event, assuming a Type 1A rainfall distribution. Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model. Consult local drainage requirements for sizing permanent pipe slope drains. . Use care in clearing vegetated slopes for installation. . Re-establish cover immediately on areas disturbed by installation. • Use temporary drains on new cut or fill slopes. . Use diversion dikes or swales to collect water at the top of the slope. • Ensure that the entrance area is stable and large enough to direct flow into the pipe. . Piping of water through the berm at the entrance area is a common failure mode. . The entrance shall consist of a standard flared end section for culverts 12 inches and larger with a minimum 6-inch metal toe plate to prevent runoff from under- cutting the pipe inlet. The slope of the entrance shall be at least 3 percent. Sand bags may also be used at pipe entrances as a temporary measure. . The soil around and under the pipe and entrance section shall be thoroughly com- pacted to prevent undercutting. . The flared inlet section shall be securely connected to the slope drain and have watertight connecting bands. • Slope drain sections shall be securely fastened together, fused or have gasketed watertight fittings, and shall be securely anchored into the soil. . Thrust blocks should be installed anytime 90 degree bends are utilized. Depend- ing on size of pipe and flow, these can be constructed with sand bags, straw bales staked in place, "t" posts and wire, or ecology blocks. . Pipe needs to be secured along its full length to prevent movement. This can be done with steel "t" posts and wire. A post is installed on each side of the pipe and the pipe is wired to them. This should be done every 10-20 feet of pipe length or so, depending on the size of the pipe and quantity of water to divert. . Interceptor dikes shall be used to direct runoff into a slope drain. The height of the dike shall be at least 1 foot higher at all points than the top of the inlet pipe. . The area below the outlet must be stabilized with a riprap apron (see BMP C209: Outlet Protection (p.356), for the appropriate outlet material). . If the pipe slope drain is conveying sediment -laden water, direct all flows into the 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 343 Packet Pg. 214 5.1.a sediment trapping facility. . Materials specifications for any permanent piped system shall be set by the local government. Maintenance Standards Check inlet and outlet points regularly, especially after storms. The inlet should be free of undercutting, and no water should be going around the point of entry. If there are problems, the headwall should be reinforced with compacted earth or sand bags. . The outlet point should be free of erosion and installed with appropriate outlet pro- tection. . For permanent installations, inspect pipe periodically for vandalism and physical distress such as slides and wind -throw. . Normally the pipe slope is so steep that clogging is not a problem with smooth wall pipe, however, debris may become lodged in the pipe. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 344 Packet Pg. 215 5.1.a Figure II-4.2.4 Pipe Slope Drain � f_�} ►_\ � T_�!! T_T_T_T f_�' r T T.1!! T_r H r A! � T} � T f_� 9 Discharge t watercourse, sedirr facility, or ste Provide riprap pad or equivalent energy dissipation NOT TO SCALE ;rceptor dike Notes: 1. Inlet and all sections must be securely fastened together with gasketed watertight fittings Figure II-4.2.4 Pipe Slope Drain DEPARTMENT OF Revised July 2015 ECOLOGY Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 345 Packet Pg. 216 5.1.a BMP C205: Subsurface Drains Purpose To intercept, collect, and convey ground water to a satisfactory outlet, using a perforated pipe or conduit below the ground surface. Subsurface drains are also known as "french drains." The perforated pipe provides a dewatering mechanism to drain excessively wet soils, provide a stable base for construction, improve stability of structures with shallow foundations, or to reduce hydrostatic pressure to improve slope stability. Conditions of Use Use when excessive water must be removed from the soil. The soil permeability, depth to water table and impervious layers are all factors which may govern the use of sub- surface drains. Design and Installation Specifications Relief drains are used either to lower the water table in large, relatively flat areas, improve the growth of vegetation, or to remove surface water. Relief drains are installed along a slope and drain in the direction of the slope. They can be installed in a grid pattern, a herringbone pattern, or a random pattern. . Interceptor drains are used to remove excess groundwater from a slope, stabilize steep slopes, and lower the water table immediately below a slope to prevent the soil from becoming saturated. Interceptor drains are installed perpendicular to a slope and drain to the side of the slope. They usually consist of a single pipe or series of single pipes instead of a patterned lay- out. . Depth and spacing of interceptor drains - The depth of an interceptor drain is determined primarily by the depth to which the water table is to be lowered or the depth to a confining layer. For practical reasons, the maximum depth is usually lim- ited to 6 feet, with a minimum cover of 2 feet to protect the conduit. . The soil should have depth and sufficient permeability to permit installation of an effective drainage system at a depth of 2 to 6 feet. . An adequate outlet for the drainage system must be available either by gravity or by pumping. . The quantity and quality of discharge needs to be accounted for in the receiving stream (additional detention may be required). . This standard does not apply to subsurface drains for building foundations or deep 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 346 Packet Pg. 217 5.1.a excavations. . The capacity of an interceptor drain is determined by calculating the maximum rate of ground water flow to be intercepted. Therefore, it is good practice to make com- plete subsurface investigations, including hydraulic conductivity of the soil, before designing a subsurface drainage system. . Size of drain - Size subsurface drains to carry the required capacity without pres- sure flow. Minimum diameter fora subsurface drain is 4 inches. . The minimum velocity required to prevent silting is 1.4 ft./sec. The line shall be graded to achieve this velocity at a minimum. The maximum allowable velocity using a sand -gravel filter or envelope is 9 ft/sec. . Filter material and fabric shall be used around all drains for proper bedding and fil- tration of fine materials. Envelopes and filters should surround the drain to a min- imum of 3-inch thickness. . The outlet of the subsurface drain shall empty into a sediment pond through a catch basin. If free of sediment, it can then empty into a receiving channel, swale, or stable vegetated area adequately protected from erosion and undermining. . The trench shall be constructed on a continuous grade with no reverse grades or low spots. . Soft or yielding soils under the drain shall be stabilized with gravel or other suit- able material. . Backfilling shall be done immediately after placement of the pipe. No sections of pipe shall remain uncovered overnight or during a rainstorm. Backfill material shall be placed in the trench in such a manner that the drain pipe is not displaced or damaged. . Do not install permanent drains near trees to avoid the tree roots that tend to clog the line. Use solid pipe with watertight connections where it is necessary to pass a subsurface drainage system through a stand of trees. . Outlet - Ensure that the outlet of a drain empties into a channel or other water- course above the normal water level. . Secure an animal guard to the outlet end of the pipe to keep out rodents. • Use outlet pipe of corrugated metal, cast iron, or heavy-duty plastic without per- forations and at least 10 feet long. Do not use an envelope or filter material around the outlet pipe, and bury at least two-thirds of the pipe length. . When outlet velocities exceed those allowable for the receiving stream, outlet pro- tection must be provided. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 347 Packet Pg. 218 5.1.a Maintenance Standards Subsurface drains shall be checked periodically to ensure that they are free -flowing and not clogged with sediment or roots. . The outlet shall be kept clean and free of debris. . Surface inlets shall be kept open and free of sediment and other debris. . Trees located too close to a subsurface drain often clog the system with their roots If a drain becomes clogged, relocate the drain or remove the trees as a last resort. Drain placement should be planned to minimize this problem. . Where drains are crossed by heavy vehicles, the line shall be checked to ensure that it is not crushed. BMP C206: Level Spreader Purpose To provide a temporary outlet for dikes and diversions consisting of an excavated depres sion constructed at zero grade across a slope. To convert concentrated runoff to sheet flow and release it onto areas stabilized by existing vegetation or an engineered filter stri p. Conditions of Use Used when a concentrated flow of water needs to be dispersed over a large area with existing stable vegetation. . Items to consider are: 1. What is the risk of erosion or damage if the flow may become concentrated? 2. Is an easement required if discharged to adjoining property? 3. Most of the flow should be as ground water and not as surface flow. 4. Is there an unstable area downstream that cannot accept additional ground water? Use only where the slopes are gentle, the water volume is relatively low, and the soil will adsorb most of the low flow events. Design and Installation Specifications Use above undisturbed areas that are stabilized by existing vegetation. If the level spreader has any low points, flow will concentrate, create channels and may cause erosion. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 348 Packet Pg. 219 5.1.a . Discharge area below the outlet must be uniform with a slope flatter than 5H:1 V. • Outlet to be constructed level in a stable, undisturbed soil profile (not on fill). . The runoff shall not re -concentrate after release unless intercepted by another downstream measure. . The grade of the channel for the last 20 feet of the dike or interceptor entering the level spreader shall be less than or equal to 1 percent. The grade of the level spreader shall be 0 percent to ensure uniform spreading of storm runoff. . A 6-inch high gravel berm placed across the level lip shall consist of washed crushed rock, 2- to 4-inch or 3/4-inch to 1'/2-inch size. . The spreader length shall be determined by estimating the peak flow expected from the 10-year, 24-hour design storm. The length of the spreader shall be a min- imum of 15 feet for 0.1 cfs and shall increase by 10 feet for each 0.1 cfs thereafter to a maximum of 0.5 cfs per spreader. Use multiple spreaders for higher flows. . The width of the spreader should be at least 6 feet. . The depth of the spreader as measured from the lip should be at least 6 inches and it should be uniform across the entire length. . Level spreaders shall be setback from the property line unless there is an ease- ment for flow. . Level spreaders, when installed every so often in grassy swales, keep the flows from concentrating. Materials that can be used include sand bags, lumber, logs, concrete, and pipe. To function properly, the material needs to be installed level and on contour. BMP C206. Level Spreader .348 and Figure II-4.2.6 Detail of Level Spreader (p 351) provide a cross-section and a detail of a level spreader. A capped perforated pipe could also be used as a spreader. Maintenance Standards The spreader should be inspected after every runoff event to ensure that it is functioning correctly. . The contractor should avoid the placement of any material on the structure and should prevent construction traffic from crossing over the structure. . If the spreader is damaged by construction traffic, it shall be immediately repaired 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 349 Packet Pg. 220 5.1.a Figure II-4.2.5 Cross Section of Level Spreader Densely vegetated for a min. of 100' and slope less than 5:1 DEPARTMENT OF ECOLOGY State of Washington Pressure -treated 2"x10" 1' Min. 3' Min. NOT TO SCALE Figure II-4.2.5 Cross Section of Level Spreader Revised July 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 350 Packet Pg. 221 5.1.a Figure II-4.2.6 Detail of Level Spreader Spreader must be level Treated 2" x 10" may be abutted end DEPARTMENT OF ECOLOGY State of Washington 8' max. spacing Figure II-4.2.6 Detail of Level Spreader NOT TO SCALE Revised July 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 351 Packet Pg. 222 5.1.a BMP C207: Check Dams Purpose Construction of small dams across a swale or ditch reduces the velocity of concentrated flow and dissipates energy at the check dam. Conditions of Use Where temporary channels or permanent channels are not yet vegetated, channel lining is infeasible, and/or velocity checks are required. • Check dams may not be placed in streams unless approved by the State Depart- ment of Fish and Wildlife. Check dams may not be placed in wetlands without approval from a permitting agency. . Do not place check dams below the expected backwater from any salmonid bear- ing water between October 1 and May 31 to ensure that there is no loss of high flow refuge habitat for overwintering juvenile salmonids and emergent salmonid fry. . Construct rock check dams from appropriately sized rock. The rock used must be large enough to stay in place given the expected design flow through the channel. The rock must be placed by hand or by mechanical means (no dumping of rock to form dam) to achieve complete coverage of the ditch or swale and to ensure that the center of the dam is lower than the edges. • Check dams may also be constructed of either rock or pea -gravel filled bags. Numerous new products are also available for this purpose. They tend to be re- usable, quick and easy to install, effective, and cost efficient. . Place check dams perpendicular to the flow of water. . The dam should form a triangle when viewed from the side. This prevents under- cutting as water flows over the face of the dam rather than falling directly onto the ditch bottom. . Before installing check dams impound and bypass upstream waterflow away from the work area. Options for bypassing include pumps, siphons, or temporary chan- nels. . Check dams in association with sumps work more effectively at slowing flow and retaining sediment than just a check dam alone. A deep sump should be provided immediately upstream of the check dam. . In some cases, if carefully located and designed, check dams can remain as per- manent installations with very minor regrading. They may be left as either spill- ways, in which case accumulated sediment would be graded and seeded, or as 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 352 Packet Pg. 223 5.1.a check dams to prevent further sediment from leaving the site. . The maximum spacing between the dams shall be such that the toe of the upstream dam is at the same elevation as the top of the downstream dam. . Keep the maximum height at 2 feet at the center of the dam. . Keep the center of the check dam at least 12 inches lower than the outer edges at natural ground elevation. . Keep the side slopes of the check dam at 2H:1V or flatter. . Key the stone into the ditch banks and extend it beyond the abutments a minimum of 18 inches to avoid washouts from overflow around the dam. • Use filter fabric foundation under a rock or sand bag check dam. If a blanket ditch liner is used, filter fabric is not necessary. A piece of organic or synthetic blanket cut to fit will also work for this purpose. . In the case of grass -lined ditches and swales, all check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale - unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. • Ensure that channel appurtenances, such as culvert entrances below check dams, are not subject to damage or blockage from displaced stones. Figure II-4.2.7 Rock Check Dam (p.354) depicts a typical rock check dam. Maintenance Standards Check dams shall be monitored for performance and sediment accumulation during and after each runoff producing rainfall. Sediment shall be removed when it reaches one half the sump depth. . Anticipate submergence and deposition above the check dam and erosion from high flows around the edges of the dam. . If significant erosion occurs between dams, install a protective riprap liner in that portion of the channel. Approved as Equivalent Ecology has approved products as able to meet the requirements of BMP C207: Check Dams. The products did not pass through the Technology Assessment Protocol — Eco- logy (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http://www.ecy.wa.gov- /programs/wq/stormwater/newtech/equivalent.html 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 353 Packet Pg. 224 5.1.a Figure II-4.2.7 Rock Check Dam View Looking Upstream q 181, _ 12" (0.5m) (150mm) �so�spo/i�24" (0.6m) Note: Key stone into channel banks and extend it//�/�/ beyond the abutments a minimum of 18" (0.5m) to prevent flow around dam. A Section A -A Flow 24" (0.6m) moo o Spacina Between Check Dams DEPARTMENT OF ECOLOGY State of Washington 'L' = the distance such that points 'A' and 'B' are of equal elevation. Figure II-4.2.7 Rock Check Dam NOT TO SCALE Revised July 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 354 1Packet Pg. 225 5.1.a BMP C208: Triangular Silt Dike (TSD) (Geotextile-Encased Check Dam) Purpose Triangular silt dikes may be used as check dams, for perimeter protection, for temporary soil stockpile protection, for drop inlet protection, or as a temporary interceptor dike. Conditions of Use . May be used on soil or pavement with adhesive or staples. . TSDs have been used to build temporary: 1. sediment ponds; 2. diversion ditches; 3. concrete wash out facilities; 4. curbing; 5. water bars; 6. level spreaders; and, 7. berms. Design and Installation Specifications Made of urethane foam sewn into a woven geosynthetic fabric. It is triangular, 10 inches to 14 inches high in the center, with a 20-inch to 28-inch base. A 2—foot apron extends beyond both sides of the triangle along its standard section of 7 feet. A sleeve at one end allows attachment of additional sections as needed. . Install with ends curved up to prevent water from flowing around the ends. . The fabric flaps and check dam units are attached to the ground with wire staples Wire staples should be No. 11 gauge wire and should be 200 mm to 300 mm in length. . When multiple units are installed, the sleeve of fabric at the end of the unit shall overlap the abutting unit and be stapled. • Check dams should be located and installed as soon as construction will allow. • Check dams should be placed perpendicular to the flow of water. . When used as check dams, the leading edge must be secured with rocks, sand- bags, or a small key slot and staples. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript gage 355 Packet Pg. 226 5.1.a . In the case of grass -lined ditches and swales, check dams and accumulated sed- iment shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. Maintenance Standards Triangular silt dams shall be inspected for performance and sediment accu- mulation during and after each runoff producing rainfall. Sediment shall be removed when it reaches one half the height of the dam. Anticipate submergence and deposition above the triangular silt dam and erosion from high flows around the edges of the dam. Immediately repair any damage or any undercutting of the dam. BMP C209: Outlet Protection Purpose Outlet protection prevents scour at conveyance outlets and minimizes the potential for downstream erosion by reducing the velocity of concentrated stormwater flows. Conditions of Use Outlet protection is required at the outlets of all ponds, pipes, ditches, or other con- veyances, and where runoff is conveyed to a natural or manmade drainage feature such as a stream, wetland, lake, or ditch. Design and Installation Specifications The receiving channel at the outlet of a culvert shall be protected from erosion by rock lin- ing a minimum of 6 feet downstream and extending up the channel sides a minimum of 1—foot above the maximum tailwater elevation or 1-foot above the crown, whichever is higher. For large pipes (more than 18 inches in diameter), the outlet protection lining of the channel is lengthened to four times the diameter of the culvert. . Standard wingwalls, and tapered outlets and paved channels should also be con- sidered when appropriate for permanent culvert outlet protection. (See WSDOT Hydraulic Manual, available through WSDOT Engineering Publications). . Organic or synthetic erosion blankets, with or without vegetation, are usually more effective than rock, cheaper, and easier to install. Materials can be chosen using manufacturer product specifications. ASTM test results are available for most products and the designer can choose the correct material for the expected flow. . With low flows, vegetation (including sod) can be effective. . The following guidelines shall be used for riprap outlet protection: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 356 Packet Pg. 227 5.1.a 1. If the discharge velocity at the outlet is less than 5 fps (pipe slope less than 1 percent), use 2-inch to 8-inch riprap. Minimum thickness is 1-foot. 2. For 5 to 10 fps discharge velocity at the outlet (pipe slope less than 3 per- cent), use 24-inch to 48-inch riprap. Minimum thickness is 2 feet. 3. For outlets at the base of steep slope pipes (pipe slope greater than 10 per- cent), an engineered energy dissipater shall be used. . Filter fabric or erosion control blankets should always be used under riprap to pre- vent scour and channel erosion. New pipe outfalls can provide an opportunity for low-cost fish habitat improve- ments. For example, an alcove of low -velocity water can be created by con- structing the pipe outfall and associated energy dissipater back from the stream edge and digging a channel, over -widened to the upstream side, from the outfall. Overwintering juvenile and migrating adult salmonids may use the alcove as shel- ter during high flows. Bank stabilization, bioengineering, and habitat features may be required for disturbed areas. This work may require a HPA. See Volume V 765 for more information on outfall system design. Maintenance Standards . Inspect and repair as needed. . Add rock as needed to maintain the intended function. Clean energy dissipater if sediment builds up. BMP C220: Storm Drain Inlet Protection Purpose Storm drain inlet protection prevents coarse sediment from entering drainage systems prior to permanent stabilization of the disturbed area. Conditions of Use Use storm drain inlet protection at inlets that are operational before permanent sta- bilization of the disturbed drainage area. Provide protection for all storm drain inlets downslope and within 500 feet of a disturbed or construction area, unless conveying run- off entering catch basins to a sediment pond or trap. Also consider inlet protection for lawn and yard drains on new home construction. These small and numerous drains coupled with lack of gutters in new home construction can add significant amounts of sediment into the roof drain system. If possible delay installing lawn and yard drains until just before landscaping or cap these drains to pre- 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 357 Packet Pg. 228 5.1.a vent sediment from entering the system until completion of landscaping. Provide 18- inches of sod around each finished lawn and yard drain. Table 11-4.2.2 Storm Drain Inlet Protection (p 358) lists several options for inlet protection. All of the methods for storm drain inlet protection tend to plug and require a high fre- quency of maintenance. Limit drainage areas to one acre or less. Possibly provide emer- gency overflows with additional end -of -pipe treatment where stormwater ponding would cause a hazard. Table II-4.2.2 Storm Drain Inlet Protection Type of Inlet Emergency Applicable for Protection Overflow Paved/ Earthen Conditions of Use Surfaces Drop Inlet Protection Excavated drop Yes, tem- Applicable for heavy flows. Easy protection inleting porary flood- Earthen to maintain. Large area Require- will occur ment: 30'x30'/acre Block and Applicable for heavy concentrated gravel drop inlet Yes Paved or Earthen flows. Will not pond. protection Gravel and wire Applicable for heavy concentrated drop inlet pro- No flows. Will pond. Can withstand tection traffic. Catch basin fil- Yes Paved or Earthen Frequent Maintenance required. ters Curb Inlet Protection Curb inlet pro- Small capacity Used for sturdy, more compact tection with overflow Paved installation. wooden weir Block and gravel curb inlet Yes Paved Sturdy, but limited filtration. protection Culvert Inlet Protection Culvert inlet Sed 18 month expected life. imenttrap Design and Installation Specifications Excavated Drop Inlet Protection - An excavated impoundment around the storm drain. Sediment settles out of the stormwater prior to entering the storm drain. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 358 Packet Pg. 229 5.1.a . Provide a depth of 1-2 ft as measured from the crest of the inlet structure. • Slope sides of excavation no steeper than 2H:1 V. . Minimum volume of excavation 35 cubic yards. . Shape basin to fit site with longest dimension oriented toward the longest inflow area. . Install provisions for draining to prevent standing water problems. • Clear the area of all debris. • Grade the approach to the inlet uniformly. . Drill weep holes into the side of the inlet. • Protect weep holes with screen wire and washed aggregate. . Seal weep holes when removing structure and stabilizing area. . Build a temporary dike, if necessary, to the down slope side of the structure to pre- vent bypass flow. Block and Gravel Filter- A barrier formed around the storm drain inlet with standard con- crete blocks and gravel. See Figure II-4.2.8 Block and Gravel Filter (p.360). . Provide a height of 1 to 2 feet above inlet. • Recess the first row 2-inches into the ground for stability. • Support subsequent courses by placing a 2x4 through the block opening. . Do not use mortar. . Lay some blocks in the bottom row on their side for dewatering the pool. . Place hardware cloth or comparable wire mesh with 1/2-inch openings over all block openings. . Place gravel just below the top of blocks on slopes of 2H:1 V or flatter. . An alternative design is a gravel donut. . Provide an inlet slope of 3H:1 V. . Provide an outlet slope of 2H:1 V. . Provide all -foot wide level stone area between the structure and the inlet. • Use inlet slope stones 3 inches in diameter or larger. . Use gravel'/2- to 3/4-inch at a minimum thickness of 1-foot for the outlet slope. c 0 3 0 0 3.1 v 0 0 0 N 0 N Z J d 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 359 Packet Pg. 230 5.1.a Figure II-4.2.8 Block and Gravel Filter Drain grate Gravel backfill . . Plan View Concrete block Overflow o water o Water Drop inlet Section A -A crete block Gravel backfill Wire screen or filter fabric Ponding height Notes: 1. Drop inlet sediment barriers are to be used for small, nearly level drainage areas. (less than 5%) 2. Excavate a basin of sufficient size adjacent to the drop inlet. 3. The top of the structure (ponding height) must be well below the ground elevation downslope to prevent runoff from bypassing the inlet. A temporary dike may be necessary on the downslope side of the structure. DEPARTMENT OF ECOLOGY State of Washington Figure II-4.2.8 Block and Gravel Filter NOT TO SCALE Revised August 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. C O cC R 3 0 0 0 0 0 0 N O N Z J d 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 360 1Packet Pg. 231 5.1.a Gravel and Wire Mesh Filter - A gravel barrier placed over the top of the inlet. This struc- ture does not provide an overflow. . Use a hardware cloth or comparable wire mesh with 1/2-inch openings. . Use coarse aggregate. . Provide a height 1-foot or more, 18-inches wider than inlet on all sides. . Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot beyond each side of the inlet structure. . Overlap the strips if more than one strip of mesh is necessary. . Place coarse aggregate over the wire mesh. . Provide at least a 12-inch depth of gravel over the entire inlet opening and extend at least 18-inches on all sides. Catchbasin Filters — Use inserts designed by manufacturers for construction sites. The limited sediment storage capacity increases the amount of inspection and maintenance required, which may be daily for heavy sediment loads. To reduce maintenance require- ments combine a catchbasin filter with another type of inlet protection. This type of inlet protection provides flow bypass without overflow and therefore may be a better method for inlets located along active rights -of -way. . Provides 5 cubic feet of storage. . Requires dewatering provisions. . Provides a high -flow bypass that will not clog under normal use at a construction site. . Insert the catchbasin filter in the catchbasin just below the grating. Curb Inlet Protection with Wooden Weir— Barrier formed around a curb inlet with a wooden frame and gravel. • Use wire mesh with'/2-inch openings. • Use extra strength filter cloth. . Construct a frame. . Attach the wire and filter fabric to the frame. . Pile coarse washed aggregate against wire/fabric. . Place weight on frame anchors. Block and Gravel Curb Inlet Protection — Barrier formed around a curb inlet with concrete blocks and gravel. See Figure II-4.2.9 Block and Gravel Curb Inlet Protection (p.363). 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 361 Packet Pg. 232 5.1.a . Use wire mesh with'/2-inch openings. • Place two concrete blocks on their sides abutting the curb at either side of the inlet opening. These are spacer blocks. • Place a 2x4 stud through the outer holes of each spacer block to align the front blocks. . Place blocks on their sides across the front of the inlet and abutting the spacer blocks. . Place wire mesh over the outside vertical face. • Pile coarse aggregate against the wire to the top of the barrier. Curb and Gutter Sediment Barrier— Sandbag or rock berm (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape. See Figure II-4.2.10 Curb and Gutter Barrier 364 . Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high and 3 feet wide, at least 2 feet from the inlet. . Construct a horseshoe shaped sedimentation trap on the outside of the berm sized to sediment trap standards for protecting a culvert inlet. Maintenance Standards Inspect catch basin filters frequently, especially after storm events. Clean and replace clogged inserts. For systems with clogged stone filters: pull away the stones from the inlet and clean or replace. An alternative approach would be to use the clogged stone as fill and put fresh stone around the inlet. . Do not wash sediment into storm drains while cleaning. Spread all excavated material evenly over the surrounding land area or stockpile and stabilize as appro- priate. Approved as Equivalent Ecology has approved products as able to meet the requirements of BMP C220: Storm Drain Inlet Protection. The products did not pass through the Technology Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 362 Packet Pg. 233 5.1.a Figure II-4.2.9 Block and Gravel Curb Inlet Protection A Catch basin Back of sidewalk 2x4 Wood stud Back of curb Curb inlet cc Concrete block Wire screen or filter fabric s inch (20 mm) A Concrete block Drain gravel Plan View Ponding height Y4 inch (20 mm) Drain gravel Overflow s.: Curb inlet Wire screen or filter fabric 2x4 Wood stud (100x50 Timber stud) \� Catch basin \ j Concrete block Section A -A Notes: 1. Use block and gravel type sediment barrier when curb inlet is located in gently sloping street segment, where water can pond and allow sediment to separate from runoff. 2. Barrier shall allow for overflow from severe storm event. 3. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. NOT TO SCALE Figure II-4.2.9 Block and Gravel Curb Inlet Protection DEPARTMENT OF Revised August 2015 ECOLOGY Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. C O O N R 3 O O O O O O N O N Z J a 2014 Stormwater Management Manual for Western Washington VolumeA t "Plot Page 363 Packet Pg. 234 5.1.a Figure II-4.2.10 Curb and Gutter Barrier Back of sidewalk Burlap sacks to overlap onto curb Back of curb Runoff Curb inlet i Runoff Spillway Catch basin Plan View Gravel filled sandbags stacked tightly Notes: 1. Place curb type sediment barriers on gently sloping street segments, where water can pond and allow sediment to separate from runoff. 2. Sandbags of either burlap or woven 'geotextile' fabric, are filled with gravel, layered and packed tightly. 3. Leave a one sandbag gap in the top row to provide a spillway for overflow. 4. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. NOT TO SCALE Figure II-4.2.10 Curb and Gutter Barrier DEPARTMENT OF Revised September 2015 ECOLOGYPlease see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 364 1Packet Pg. 235 5.1.a BMP C231: Brush Barrier Purpose The purpose of brush barriers is to reduce the transport of coarse sediment from a con- struction site by providing a temporary physical barrier to sediment and reducing the run- off velocities of overland flow. Conditions of Use . Brush barriers may be used downslope of all disturbed areas of less than one - quarter acre. . Brush barriers are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be con- veyed through the drainage system to a sediment pond. The only circumstance in which overland flow can be treated solely by a brush barrier, rather than by a sed- iment pond, is when the area draining to the barrier is small. . Brush barriers should only be installed on contours. Design and Installation Specifications . Height 2 feet (minimum) to 5 feet (maximum). . Width 5 feet at base (minimum) to 15 feet (maximum). . Filter fabric (geotextile) may be anchored over the brush berm to enhance the fil- tration ability of the barrier. Ten -ounce burlap is an adequate alternative to filter fab- ri c. • Chipped site vegetation, composted mulch, or wood -based mulch (hog fuel) can be used to construct brush barriers. . A 100 percent biodegradable installation can be constructed using 10-ounce bur- lap held in place by wooden stakes. Figure II-4.2.11 Brush Barrier (p.366) depicts a typical brush barrier. Maintenance Standards . There shall be no signs of erosion or concentrated runoff under or around the bar- rier. If concentrated flows are bypassing the barrier, it must be expanded or aug- mented by toed -in filter fabric. . The dimensions of the barrier must be maintained. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 365 Packet Pg. 236 5.1.a Figure II-4.2.11 Brush Barrier If required, drape filter fabric over brush and secure in 4"x4" min. trench with compacted backfill DEPARTMENT OF ECOLOGY State of Washington Min. 5' wide brush barrier with max. 6" diameter woody debris. Alternatively topsoil strippings may be used to form the barrier. Figure II-4.2.11 Brush Barrier Anchor downhill edge of filter fabric with stakes, sandbags, or equivalent NOT TO SCALE Revised September 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. c 0 cC R 3 0 0 0 0 0 0 N O N Z J d 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 366 1Packet Pg. 237 5.1.a BMP C232: Gravel Filter Berm Purpose A gravel filter berm is constructed on rights -of -way or traffic areas within a construction site to retain sediment by using a filter berm of gravel or crushed rock. Conditions of Use Where a temporary measure is needed to retain sediment from rights -of -way or in traffic areas on construction sites. Design and Installation Specifications . Berm material shall be 3/4 to 3 inches in size, washed well -grade gravel or crushed rock with less than 5 percent fines. . Spacing of berms: Every 300 feet on slopes less than 5 percent Every 200 feet on slopes between 5 percent and 10 percent Every 100 feet on slopes greater than 10 percent . Berm dimensions: 1 foot high with 3H:1 V side slopes o 8 linear feet per 1 cfs runoff based on the 10-year, 24-hour design storm Maintenance Standards Regular inspection is required. Sediment shall be removed and filter material replaced as needed. BMP C233: Silt Fence Purpose Use of a silt fence reduces the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. See Figure II-4.2.12 Silt Fence (p.369) for details on silt fence con- struction. Conditions of Use Silt fence may be used downslope of all disturbed areas. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 367 Packet Pg. 238 5.1.a Silt fence shall prevent soil carried by runoff water from going beneath, through, or over the top of the silt fence, but shall allow the water to pass through the fence. . Silt fence is not intended to treat concentrated flows, nor is it intended to treat sub- stantial amounts of overland flow. Convey any concentrated flows through the drainage system to a sediment pond. Do not construct silt fences in streams or use in V-shaped ditches. Silt fences do not provide an adequate method of silt control for anything deeper than sheet or overland flow. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 368 Packet Pg. 239 5.1.a Figure II-4.2.12 Silt Fence Joints in filter fabric shall be spliced at posts. Use staples, wire rings or equivalent to attach fabric to posts 2"x2" by 14 Ga. wire or equivalent, if standard strength fabric used --- rr-------------------------r� Minimum I I 6' max I I 4"x4" trench I u Post spacing may be increased to 8' if wire backing is used 2"x2" wood posts, steel fence posts, or equivalent 2"x2" by 14 Ga. wire or equivalent, if standard strength fabric used Backfill trench with native soil or Y4" - 1.5" washed gravel Filter fabric —T 2' min Minimum 4"x4" trench 2"x2" wood posts, steel fence posts, or equivalent NOT TO SCALE Figure II-4.2.12 Silt Fence DEPARTMENT OF Revised October 2014 ECOLOGY Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 369 Packet Pg. 240 5.1.a Design and Installation Specifications Use in combination with sediment basins or other BMPs. . Maximum slope steepness (normal (perpendicular) to fence line) 1 H:1 V. . Maximum sheet or overland flow path length to the fence of 100 feet. . Do not allow flows greater than 0.5 cfs. . The geotextile used shall meet the following standards. All geotextile properties lis- ted below are minimum average roll values (i.e., the test result for any sampled roll in a lot shall meet or exceed the values shown in Table II-4.2.3 Geotextile Stand- ards (p.370)): Table II-4.2.3 Geotextile Standards 0.60 mm maximum for slit film woven (#30 sieve). Polymeric Mesh AOS 0.30 mm maximum for all other geotextile types (#50 sieve). (ASTM D4751) 0.15 mm minimum for all fabric types (#100 sieve). Water Permittivity 0.02 sec-1 minimum (ASTM D4491) Grab Tensile Strength 180 lbs. Minimum for extra strength fabric. (ASTM D4632) 100 Ibs minimum for standard strength fabric. Grab Tensile Strength 30% maximum (ASTM D4632) Ultraviolet Resistance 70% minimum (ASTM D4355) . Support standard strength fabrics with wire mesh, chicken wire, 2-inch x 2-inch wire, safety fence, orjute mesh to increase the strength of the fabric. Silt fence materials are available that have synthetic mesh backing attached. . Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum of six months of expected usable construction life at a temperature range of 0°F. to 120°F. . One -hundred percent biodegradable silt fence is available that is strong, long last- ing, and can be left in place after the project is completed, if permitted by local reg- ulations. Refer to Figure II-4.2.12 Silt Fence (p.369) for standard silt fence details. Include the following standard Notes for silt fence on construction plans and specifications: 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 370 Packet Pg. 241 5.1.a 1. The contractor shall install and maintain temporary silt fences at the locations shown in the Plans. 2. Construct silt fences in areas of clearing, grading, or drainage prior to starting those activities. 3. The silt fence shall have a 2-feet min. and a 2'/2-feet max. height above the original ground surface. 4. The filter fabric shall be sewn together at the point of manufacture to form fil- ter fabric lengths as required. Locate all sewn seams at support posts. Altern- atively, two sections of silt fence can be overlapped, provided the Contractor can demonstrate, to the satisfaction of the Engineer, that the overlap is long enough and that the adjacent fence sections are close enough together to prevent silt laden water from escaping through the fence at the overlap. 5. Attach the filter fabric on the up -slope side of the posts and secure with staples, wire, or in accordance with the manufacturer's recommendations. Attach the filter fabric to the posts in a manner that reduces the potential for tearing. 6. Support the filter fabric with wire or plastic mesh, dependent on the properties of the geotextile selected for use. If wire or plastic mesh is used, fasten the mesh securely to the up -slope side of the posts with the filter fabric up -slope of the mesh. 7. Mesh support, if used, shall consist of steel wire with a maximum mesh spa- cing of 2-inches, or a prefabricated polymeric mesh. The strength of the wire or polymeric mesh shall be equivalent to or greater than 180 lbs. grab tensile strength. The polymeric mesh must be as resistant to the same level of ultra- violet radiation as the filter fabric it supports. 8. Bury the bottom of the filter fabric 4-inches min. below the ground surface. Backfill and tamp soil in place over the buried portion of the filter fabric, so that no flow can pass beneath the fence and scouring cannot occur. When wire or polymeric back-up support mesh is used, the wire or polymeric mesh shall extend into the ground 3-inches min. 9. Drive or place the fence posts into the ground 18-inches min. A 12—inch min. depth is allowed if topsoil or other soft subgrade soil is not present and 18- inches cannot be reached. Increase fence post min. depths by 6 inches if the fence is located on slopes of 3H:1 V or steeper and the slope is perpendicular to the fence. If required post depths cannot be obtained, the posts shall be adequately secured by bracing or guying to prevent overturning of the fence due to sediment loading. 10. Use wood, steel or equivalent posts. The spacing of the support posts shall 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 371 Packet Pg. 242 5.1.a be a maximum of 6-feet. Posts shall consist of either: . Wood with dimensions of 2-inches by 2-inches wide min. and a 3-feet min. length. Wood posts shall be free of defects such as knots, splits, or gouges. . No. 6 steel rebar or larger. . ASTM A 120 steel pipe with a minimum diameter of 1-inch. • U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft. . Other steel posts having equivalent strength and bending resistance to the post sizes listed above. 11. Locate silt fences on contour as much as possible, except at the ends of the fence, where the fence shall be turned uphill such that the silt fence captures the runoff water and prevents water from flowing around the end of the fence. 12. If the fence must cross contours, with the exception of the ends of the fence, place gravel check dams perpendicular to the back of the fence to minimize concentrated flow and erosion. The slope of the fence line where contours must be crossed shall not be steeper than 3H A V. . Gravel check dams shall be approximately 1-foot deep at the back of the fence. Gravel check dams shall be continued perpendicular to the fence at the same elevation until the top of the check dam intercepts the ground surface behind the fence. Gravel check dams shall consist of crushed surfacing base course, gravel backfill for walls, or shoulder ballast. Gravel check dams shall be located every 10 feet along the fence where the fence must cross con- tou rs. . Refer to Figure II-4.2.13 Silt Fence Installation by Slicing Method (p.374) for slicing method details. Silt fence installation using the slicing method specifications: The base of both end posts must be at least 2- to 4-inches above the top of the filter fabric on the middle posts for ditch checks to drain properly. Use a hand level or string level, if necessary, to mark base points before install- ation. 2. Install posts 3- to 4-feet apart in critical retention areas and 6- to 7-feet apart in standard applications. 3. Install posts 24-inches deep on the downstream side of the silt fence, and as close as possible to the filter fabric, enabling posts to support the filter fabric from upstream water pressure. 4. Install posts with the nipples facing away from the filter fabric. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 372 Packet Pg. 243 5.1.a 5. Attach the filter fabric to each post with three ties, all spaced within the top 8- inches of the filter fabric. Attach each tie diagonally 45 degrees through the fil- ter fabric, with each puncture at least 1-inch vertically apart. Each tie should be positioned to hang on a post nipple when tightening to prevent sagging. 6. Wrap approximately 6-inches of fabric around the end posts and secure with 3 ties. 7. No more than 24-inches of a 36-inch filter fabric is allowed above ground level. Compact the soil immediately next to the filter fabric with the front wheel of the tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact the upstream side first and then each side twice for a total of four trips. Check and correct the silt fence installation for any deviation before compaction. Use a flat -bladed shovel to tuck fabric deeper into the ground if necessary. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 373 Packet Pg. 244 5.1.a Figure II-4.2.13 Silt Fence Installation by Slicing Method Ponding height max. 24" Attach fabric to upstream side of post FLOW - Drive over each side of silt fence 2 to 4 times with device exerting 60 p.s.i. or greater 100% POST SPACING: 7' max. on open runs 4' max. on pooling areas POST DEPTH: As much below ground as fabric above ground 100% No more than 24" of a 36" fabric is allowed above ground Top of Fabric Belt top+8" 1 Diagonal attachment doubles strength Attachment Details: • Gather fabric at posts, if needed. • Utilize three ties per post, all within top 8" of fabric. • Position each tie diagonally, puncturing holes vertically a minimum of 1" apart. • Hang each tie on a post nipple and tighten securely. Use cable ties (50 Ibs) or soft wire. Roll of silt fence Post installed JL4�IIJL Fabric Operation _. MEN1 above compaction ground Horizontal chisel point (76 mm width) Slicing blade (18 mm width) Vibratory plow is not acceptable because of horizontal compaction DEPARTMENT OF ECOLOGY State of Washington F Completed Installation NOT TO SCALE Figure II-4.2.13 Silt Fence Installation by Slicing Method Revised November 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 374 Packet Pg. 245 5.1.a Maintenance Standards . Repair any damage immediately. . Intercept and convey all evident concentrated flows uphill of the silt fence to a sed- iment pond. . Check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. . Remove sediment deposits when the deposit reaches approximately one-third the height of the silt fence, or install a second silt fence. . Replace filter fabric that has deteriorated due to ultraviolet breakdown. BMP C234: Vegetated Strip Purpose Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use . Vegetated strips may be used downslope of all disturbed areas. Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be con- veyed through the drainage system to a sediment pond. The only circumstance in which overland flow can be treated solely by a strip, rather than by a sediment pond, is when the following criteria are met (see Table II-4.2.4 Contributing Drain- age Area for Vegetated Strips (p.375)): Table II-4.2.4 Contributing Drainage Area for Vegetated Strips Average Contributing Area Slope Average Contributing Area Percent Slope Max Contributing area Flowpath Length 1.5H : 1 V or flatter 67% or flatter 100 feet 2H : 1 V or flatter 50% or flatter 115 feet 4H : 1 V or flatter 25% or flatter 150 feet 6H : 1 V or flatter 16.7% or flatter 200 feet 10H : 1 V or flatter 10% or flatter 250 feet 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 375 Packet Pg. 246 5.1.a Design and Installation Specifications The vegetated strip shall consist of a minimum of a 25-foot flowpath length con- tinuous strip of dense vegetation with topsoil. Grass -covered, landscaped areas are generally not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips shall consist of undisturbed native growth with a well -developed soil that allows for infiltration of runoff. . The slope within the strip shall not exceed 4H:1V. . The uphill boundary of the vegetated strip shall be delineated with clearing limits Maintenance Standards Any areas damaged by erosion or construction activity shall be seeded imme- diately and protected by mulch. If more than 5 feet of the original vegetated strip width has had vegetation removed or is being eroded, sod must be installed. If there are indications that concentrated flows are traveling across the buffer, sur- face water controls must be installed to reduce the flows entering the buffer, or addi- tional perimeter protection must be installed. BMP C235: Wattles Purpose Wattles are temporary erosion and sediment control barriers consisting of straw, com- post, or other material that is wrapped in biodegradable tubular plastic or similar encas- ing material. They reduce the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sediment. Wattles are typically 8 to 10 inches in diameter and 25 to 30 feet in length. Wattles are placed in shallow trenches and staked along the contour of disturbed or newly constructed slopes. See Figure II-4.2.14 Wattles (p.378) for typical construction details. WSDOT Standard Plan 1-30.30-00 also provides information on Wattles (http://www.wsdot.wa.gov/Design/Standards/Plans.htm#Sectionl) Conditions of Use . Use wattles: . In disturbed areas that require immediate erosion protection. . On exposed soils during the period of short construction delays, or over winter months. On slopes requiring stabilization until permanent vegetation can be estab- lished. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 376 Packet Pg. 247 5.1.a . The material used dictates the effectiveness period of the wattle. Generally, Wattles are typically effective for one to two seasons. Prevent rilling beneath wattles by properly entrenching and abutting wattles together to prevent water from passing between them. Design Criteria . Install wattles perpendicular to the flow direction and parallel to the slope contour. . Narrow trenches should be dug across the slope on contour to a depth of 3- to 5- inches on clay soils and soils with gradual slopes. On loose soils, steep slopes, and areas with high rainfall, the trenches should be dug to a depth of 5- to 7- inches, or 1/2 to 2/3 of the thickness of the wattle. • Start building trenches and installing wattles from the base of the slope and work up. Spread excavated material evenly along the uphill slope and compacted using hand tamping or other methods. • Construct trenches at intervals of 10- to 25-feet depending on the steepness of the slope, soil type, and rainfall. The steeper the slope the closer together the trenches. . Install the wattles snugly into the trenches and abut tightly end to end. Do not over- lap the ends. . Install stakes at each end of the wattle, and at 4-foot centers along entire length of wattle. . If required, install pilot holes for the stakes using a straight bar to drive holes through the wattle and into the soil. . Wooden stakes should be approximately 3/4 x 3/4 x 24 inches min. Willow cuttings or 3/8-inch rebar can also be used for stakes. Stakes should be driven through the middle of the wattle, leaving 2 to 3 inches of the stake protruding above the wattle. Maintenance Standards Wattles may require maintenance to ensure they are in contact with soil and thor- oughly entrenched, especially after significant rainfall on steep sandy soils. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 377 Packet Pg. 248 5.1.a Figure II-4.2.14 Wattles 3' - 4' Straw rolls must be placed along slope ��� �/ Adjacent rolls — contours `1 shall tightly abut / `r 10' - 25' (3-8m) Spacing depends on soil type and slope steepness Live Stake 7 / DEPARTMENT OF ECOLOGY State of Washington Sediment, organic matter, and native seeds are captured behind the rolls. 3" - 5" (75-125mm) 8" - 10" Dia. > \ZO� (200-250mm) 1" x 1" Stake (25 x 25mm) �\ NOTE: 1. Straw roll installation requires the placement and secure staking of the roll in a trench, 3" - 5" (75-125mm) deep, dug on contour. Runoff must not be allowed to run under or around roll. NOT TO SCALE Figure II-4.2.14 Wattles Revised November 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington VolumeAttgA"AW Page 378 1Packet Pg. 249 5.1.a . Inspect the slope after significant storms and repair any areas where wattles are not tightly abutted or water has scoured beneath the wattles. Approved as Equivalent Ecology has approved products as able to meet the requirements of BMP C235: Wattles. The products did not pass through the Technology Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http://www.ecy.wa.gov- /programs/wq/stormwater/newtech/equivalent.html BMP C236: Vegetative Filtration Purpose Vegetative Filtration may be used in conjunction with BMP C241: Temporary Sediment Pond (p.388), BMP C206: Level Spreader (p.348) and a pumping system with surface intake to improve turbidity levels of stormwater discharges by filtering through existing vegetation where undisturbed forest floor duff layer or established lawn with thatch layer are present. Vegetative Filtration can also be used to infiltrate dewatering waste from foundations, vaults, and trenches as long as runoff does not occur. Conditions of Use . For every five acre of disturbed soil use one acre of grass field, farm pasture, or wooded area. Reduce or increase this area depending on project size, ground water table height, and other site conditions. . Wetlands shall not be used for filtration. • Do not use this BMP in areas with a high ground water table, or in areas that will have a high seasonal ground water table during the use of this BMP. . This BMP may be less effective on soils that prevent the infiltration of the water, such as hard till. • Using other effective source control measures throughout a construction site will prevent the generation of additional highly turbid water and may reduce the time period or area need for this BMP. • Stop distributing water into the vegetated area if standing water or erosion results. Design Criteria Find land adjacent to the project that has a vegetated field, preferably a farm field, or wooded area. . If the project site does not contain enough vegetated field area consider obtaining 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 379 Packet Pg. 250 5.1.a permission from adjacent landowners (especially for farm fields). . Install a pump and downstream distribution manifold depending on the project size. Generally, the main distribution line should reach 100 to 200-feet long (many large projects, or projects on tight soil, will require systems that reach several thou- sand feet long with numerous branch lines off of the main distribution line). . The manifold should have several valves, allowing for control over the distribution area in the field. . Install several branches of 4" schedule 20, swaged -fit common septic tight -lined sewer line, or 6" fire hose, which can convey the turbid water out to various sec- tions of the field. See Fiqure II-4.2.15 Manifold and Branches in a Wooded, Veget- ated Spray Field (p.382). . Determine the branch length based on the field area geography and number of branches. Typically, branches stretch from 200-feet to several thousand feet. Always, lay branches on contour with the slope. On uneven ground, sprinklers perform well. Space sprinkler heads so that spray patterns do not overlap. . On relatively even surfaces, a level spreader using 4-inch perforated pipe may be used as an alternative option to the sprinkler head setup. Install drain pipe at the highest point on the field and at various lower elevations to ensure full coverage of the filtration area. Pipe should be place with the holes up to allow for a gentle weeping of stormwater evenly out all holes. Leveling the pipe by staking and using sandbags may be required. . To prevent the over saturation of the field area, rotate the use of branches or spray heads. Do this as needed based on monitoring the spray field. . Monitor the spray field on a daily basis to ensure that over saturation of any portion of the field doesn't occur at any time. The presence of standing puddles of water or creation of concentrated flows visually signify that over saturation of the field has occurred. . Since the operator is handling contaminated water, physically monitor the veget- ated spray field all the way down to the nearest surface water, or furthest spray area, to ensure that the water has not caused overland or concentrated flows, and has not created erosion around the spray nozzle. . Monitoring usually needs to take place 3-5 times per day to ensure sheet -flow into state waters. Do not exceed water quality standards for turbidity. . Ecology strongly recommends that a separate inspection log be developed, main- tained and kept with the existing site logbook to aid the operator conducting inspec- tions. This separate "Field Filtration Logbook" can also aid the facility in 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 380 Packet Pg. 251 5.1.a demonstrating compliance with permit conditions. Maintenance Standards Inspect the spray nozzles daily, at a minimum, for leaks and plugging from sed- iment particles. . If erosion, concentrated flows, or over saturation of the field occurs, rotate the use of branches or spray heads or move the branches to a new field location. Check all branches and the manifold for unintended leaks. Flowpath Guidelines for Vegetative Filtration Average Slope Average Area % Slope Estimated Flowpath Length (ft) 1.5H:1V 67% 250 2H:1 V 50% 200 4H:1 V 25% 150 6H:1V 16.7% 115 10H:1 V 10% 100 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 381 Packet Pg. 252 5.1.a Figure II-4.2.15 Manifold and Branches in a Wooded, Vegetated Spray Field NOT TO SCALE Figure II-4.2.15 Manifold and Branches in a Wooded, Vegetated Spray Field DEPARTMENT OF Revised November 2015 ECOLOGYPlease see http://www.ecy.wa.govlcopyright.html for copyright notice including permissions, State of Washington limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 382 1Packet Pg. 253 5.1.a BMP C240: Sediment Trap Purpose A sediment trap is a small temporary ponding area with a gravel outlet used to collect and store sediment from sites cleared and/or graded during construction. Sediment traps, along with other perimeter controls, shall be installed before any land disturbance takes place in the drainage area. Conditions of Use Prior to leaving a construction site, stormwater runoff must pass through a sediment pond or trap or other appropriate sediment removal best management practice. Non - engineered sediment traps may be used on -site prior to an engineered sediment trap or sediment pond to provide additional sediment removal capacity. It is intended for use on sites where the tributary drainage area is less than 3 acres, with no unusual drainage features, and a projected build -out time of six months or less. The sediment trap is a temporary measure (with a design life of approximately 6 months) and shall be maintained until the site area is permanently protected against erosion by veget ation and/or structures. Sediment traps and ponds are only effective in removing sediment down to about the medium silt size fraction. Runoff with sediment of finer grades (fine silt and clay) will pass through untreated, emphasizing the need to control erosion to the maximum extent fi rst. Whenever possible, sediment -laden water shall be discharged into on -site, relatively level, vegetated areas (see BMP C234: Vegetated Strip (p.375)). This is the only way to effectively remove fine particles from runoff unless chemical treatment or filtration is used. This can be particularly useful after initial treatment in a sediment trap or pond. The areas of release must be evaluated on a site -by -site basis in order to determine appropriate locations for and methods of releasing runoff. Vegetated wetlands shall not be used for this purpose. Frequently, it may be possible to pump waterfrom the col- lection point at the downhill end of the site to an upslope vegetated area. Pumping shall only augment the treatment system, not replace it, because of the possibility of pump fail- ure or runoff volume in excess of pump capacity. All projects that are constructing permanent facilities for runoff quantity control should use the rough -graded or final -graded permanent facilities for traps and ponds. This includes combined facilities and infiltration facilities. When permanent facilities are used as temporary sedimentation facilities, the surface area requirement of a sediment trap or pond must be met. If the surface area requirements are larger than the surface area of the permanent facility, then the trap or pond shall be enlarged to comply with the surface 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 383 Packet Pg. 254 5.1.a area requirement. The permanent pond shall also be divided into two cells as required for sediment ponds. Either a permanent control structure or the temporary control structure (described in BMP C241: Temporary Sediment Pond (p.388)) can be used. If a permanent control structure is used, it may be advisable to partially restrict the lower orifice with gravel to increase residence time while still allowing dewatering of the pond. A shut-off valve may be added to the control structure to allow complete retention of stormwater in emergency situations. In this case, an emergency overflow weir must be added. A skimmer may be used for the sediment trap outlet if approved by the Local Permitting Authority. Design and Installation Specifications . See Figure II-4.2.16 Cross Section of Sediment Trap (p.386) and Figure II-4.2.17 Sediment Trap Outlet (p.387) for details. . If permanent runoff control facilities are part of the project, they should be used for sediment retention. . To determine the sediment trap geometry, first calculate the design surface area (SA) of the trap, measured at the invert of the weir. Use the following equation: SA = FS(Q2/Vs) where Q2 = Design inflow based on the peak discharge from the developed 2-year runoff event from the contributing drainage area as computed in the hydrologic analysis. The 10-year peak flow shall be used if the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection. If no hydrologic analysis is required, the Rational Method may be used. Vs = The settling velocity of the soil particle of interest. The 0.02 mm (medium silt) particle with an assumed density of 2.65 g/cm3 has been selected as the particle of interest and has a settling velocity (Vs) of 0.00096 ft/sec. FS = A safety factor of 2 to account for non -ideal settling. Therefore, the equation for computing surface area becomes: SA = 2 x Q2/0.00096 or 2080 square feet per cfs of inflow 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 384 Packet Pg. 255 5.1.a Note: Even if permanent facilities are used, they must still have a surface area that is at least as large as that derived from the above formula. If they do not, the pond must be enlarged. . To aid in determining sediment depth, all sediment traps shall have a staff gauge with a prominent mark 1-foot above the bottom of the trap. . Sediment traps may not be feasible on utility projects due to the limited work space or the short-term nature of the work. Portable tanks may be used in place of sed- iment traps for utility projects. Maintenance Standards . Sediment shall be removed from the trap when it reaches 1-foot in depth. . Any damage to the pond embankments or slopes shall be repaired. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 385 Packet Pg. 256 5.1.a Figure II-4.2.16 Cross Section of Sediment Trap Surface area determined at top of weir 1' Min. 1.5 Min. 7 1 Flat Bottom Note: Trap may be formed by berm or by partial or complete excavation. DEPARTMENT OF ECOLOGY State of Washington %4" - 1.5" Washed gravel Geotextile 2" - 4" Rock 4' Min. Overflow 1' Min 7171' Min. 1 F Rip Rap Discharge to stabilized conveyance, outlet, or level spreader NOT TO SCALE Figure II-4.2.16 Cross Section of Sediment Trap Revised November 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. c 0 c� 3 0 0 0 0 0 0 N O N Z J d 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 386 1Packet Pg. 257 5.1.a Figure II-4.2.17 Sediment Trap Outlet Native soil or compacted backfill DEPARTMENT OF ECOLOGY State of Washington 6' Min. 1' Min. depth overflow spillway Geotextile Min. 1' depth 2" - 4" rock Min. 1' depth Y4' - 1.5" washed gravel Figure II-4.2.17 Sediment Trap Outlet NOT TO SCALE Revised November 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 387 1Packet Pg. 258 5.1.a BMP C241: Temporary Sediment Pond Purpose Sediment ponds remove sediment from runoff originating from disturbed areas of the site. Sediment ponds are typically designed to remove sediment no smaller than medium silt (0.02 mm). Consequently, they usually reduce turbidity only slightly. Conditions of Use Prior to leaving a construction site, stormwater runoff must pass through a sediment pond or other appropriate sediment removal best management practice. A sediment pond shall be used where the contributing drainage area is 3 acres or more. Ponds must be used in conjunction with erosion control practices to reduce the amount of sediment flowing into the basin. Design and Installation Specifications . Sediment basins must be installed only on sites where failure of the structure would not result in loss of life, damage to homes or buildings, or interruption of use or service of public roads or utilities. Also, sediment traps and ponds are attractive to children and can be very dangerous. Compliance with local ordinances regard- ing health and safety must be addressed. If fencing of the pond is required, the type of fence and its location shall be shown on the ESC plan. . Structures having a maximum storage capacity at the top of the dam of 10 acre-ft (435,600 ft) or more are subject to the Washington Dam Safety Regulations (Chapter 173-175 WAC). • See Figure II-4.2.18 Sediment Pond Plan View (p.391), Figure II-4.2.19 Sediment Pond Cross Section 6).392), and Figure II-4.2.20 Sediment Pond Riser Detail 393 for details. If permanent runoff control facilities are part of the project, they should be used for sediment retention. The surface area requirements of the sediment basin must be met. This may require temporarily enlarging the permanent basin to comply with the surface area requirements. The permanent control structure must be tem- porarily replaced with a control structure that only allows water to leave the pond from the surface or by pumping. The permanent control structure must be installed after the site is fully stabilized. . Use of infiltration facilities for sedimentation basins during construction tends to clog the soils and reduce their capacity to infiltrate. If infiltration facilities are to be used, the sides and bottom of the facility must only be rough excavated to a min- imum of 2 feet above final grade. Final grading of the infiltration facility shall occur only when all contributing drainage areas are fully stabilized. The infiltration 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 388 1Packet Pg. 259 5.1.a pretreatment facility should be fully constructed and used with the sedimentation basin to help prevent clogging. . Determining Pond Geometry Obtain the discharge from the hydrologic calculations of the peak flow for the 2- year runoff event (Q2). The 10-year peak flow shall be used if the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection. If no hydrologic analysis is required, the Rational Method may be used. Determine the required surface area at the top of the riser pipe with the equation: SA = 2 x Q2/0.00096 or 2080 square feet per cfs of inflow See BMP C240: Sediment Trap (p.383) for more information on the derivation of the surface area calculation. The basic geometry of the pond can now be determined using the following design criteria: . Required surface area SA (from Step 2 above) at top of riser. . Minimum 3.5-foot depth from top of riser to bottom of pond. . Maximum 3HAV interior side slopes and maximum 2HAV exterior slopes. The interior slopes can be increased to a maximum of 2H:1V if fencing is provided at or above the maximum water surface. • One foot of freeboard between the top of the riser and the crest of the emergency spillway. • Flat bottom. . Minimum 1-foot deep spillway. . Length -to -width ratio between 3:1 and 6:1. • Sizing of Discharge Mechanisms. The outlet for the basin consists of a combination of principal and emergency spill- ways. These outlets must pass the peak runoff expected from the contributing drain- age area for a 100-year storm. If, due to site conditions and basin geometry, a separate emergency spill -way is not feasible, the principal spillway must pass the entire peak runoff expected from the 100-year storm. However, an attempt to provide a separate emergency spillway should always be made. The runoff cal- culations should be based on the site conditions during construction. The flow 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 389 Packet Pg. 260 5.1.a through the dewatering orifice cannot be utilized when calculating the 100-year storm elevation because of its potential to become clogged; therefore, available spillway storage must begin at the principal spillway riser crest. The principal spillway designed by the procedures contained in this standard will result in some reduction in the peak rate of runoff. However, the riser outlet design will not adequately control the basin discharge to the predevelopment discharge limitations as stated in 1-2.5.7 Minimum Requirement#7: Flow Control (p.64). However, if the basin for a permanent stormwater detention pond is used for a tem- porary sedimentation basin, the control structure for the permanent pond can be used to maintain predevelopment discharge limitations. The size of the basin, the expected life of the construction project, the anticipated downstream effects and the anticipated weather conditions during construction, should be considered to determine the need of additional discharge control. See Figure 11-4.2.21 Riser Inflow Curves (p.394) for riser inflow curves. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 390 Packet Pg. 261 5.1.a Figure II-4.2.18 Sediment Pond Plan View Key divider into slope to prevent flow around sides The pond length shall be 3 to 6 times the maximum pond width Inflow length Silt fence or equivalent divider Note: Pond may be formed by berm or by partial or complete excavation DEPARTMENT OF ECOLOGY State of Washington Emergency overflow spillway Discharge to stabilized pip conveyance, outlet, or level spreader NOT TO SCALE Figure II-4.2.18 Sediment Pond Plan View Revised November 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AMI Rage 391 1Packet Pg. 262 5.1.a Figure II-4.2.19 Sediment Pond Cross Section Riser pipe (principal spillway) open at top with trash rack Dewatering device (see riser detail) Wire -backed silt fence staked haybales wrapped with filter fabric, or equivalent divider DEPARTMENT OF ECOLOGY State of Washington Dewatering orifice Crest of emergency spillway Concrete base (see riser detail) 6' Min. width. �1' Min. --------_�L Discharge to - - - _ stabilized conveyance outlet or level spreader Embankment compacted 95% pervious materials such as gravel or clean sand shall not be used NOT TO SCALE Figure II-4.2.19 Sediment Pond Cross Section Revised November 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 392 1Packet Pg. 263 5.1.a Figure II-4.2.20 Sediment Pond Riser Detail Polyethylene cap Perforated polyethylene drainage tubing, diameter min. 2" larger than dewatering orifice. Tubing shall comply with ASTM F667 and AASHTO M294. DEPARTMENT OF ECOLOGY State of Washington Watertight coupling Provide adequate strapping Corrugated metal riser 3.5' min. Tack weld T6" min. r------- 18" min. �--- J Concrete base I 2X riser dia. min. Dewatering orifice, schedule 40 steel stub min. diameter per calculations Alternatively, metal stakes and wire may be used to prevent flotation NOT TO SCALE Figure II-4.2.20 Sediment Pond Riser Detail Revised November 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 393 1Packet Pg. 264 5.1.a 1100 to Figure II-4.2.21 Riser Inflow Curves ��i ��■■i ■�ii�i� ir: *AIM 33 ON i 30;�� PFPP'-PP_ Mon r /�..� �■■iiiiiri�/ire■���.�i�..■■�� rr 1190 wool I�f to 0.1 HEAD IN FEET (m easuIred from crest of riser) Qwair=9.739 DN112 0orlNce=3.782 D2 H 112 a in cfs, D and H In feet Slope change occurs at weir -orifice transition DEPARTMENT OF ECOLOGY State of Washington Figure II-4.2.21 Riser Inflow Curves Revised November 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. 2014 Stormwater Management Manual for Western Washington Volume AttgA"AW Page 394 1Packet Pg. 265 5.1.a Principal Spillway: Determine the required diameter for the principal spillway (riser pipe). The diameter shall be the minimum necessary to pass the site's 15-minute, 10- yearflowrate. If using the Western Washington Hydrology Model (WWHM), Version 2 or 3, design flow is the 10-year (1 hour) flow for the developed (unmitigated) site, multiplied by a factor of 1.6. Use Figure II-4.2.21 Riser Inflow Curves (p.394) to determine this dia- meter (h = 1-foot). Note: A permanent control structure may be used instead of a tem- porary riser. Emergency Overflow Spillway: Determine the required size and design of the emer- gency overflow spillway for the developed 100-year peak flow using the method con- tained in Volume III. Dewatering Orifice: Determine the size of the dewatering orifice(s) (minimum 1-inch dia- meter) using a modified version of the discharge equation for a vertical orifice and a basic equation for the area of a circular orifice. Determine the required area of the orifice with the following equation: AS (2h)0" `40 0.6 x 3600Tg" where Ao = orifice area (square feet) AS = pond surface area (square feet) h = head of water above orifice (height of riser in feet) T = dewatering time (24 hours) g = acceleration of gravity (32.2 feet/second2) Convert the required surface area to the required diameter D of the orifice: D=24x Jr.- =13.54xI-A--o The vertical, perforated tubing connected to the dewatering orifice must be at least 2 inches larger in diameter than the orifice to improve flow characteristics. The size and number of perforations in the tubing should be large enough so that the tubing does not restrict flow. The orifice should control the flow rate. . Additional Design Specifications The pond shall be divided into two roughly equal volume cells by a permeable divider that will reduce turbulence while allowing movement of water between cells. The divider shall be at least one-half the height of the riser and a minimum of one foot below the top of the riser. Wire -backed, 2- to 3-foot high, extra strength fil- ter fabric supported by treated 4"x4"s can be used as a divider. Alternatively, 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 395 Packet Pg. 266 5.1.a staked straw bales wrapped with filter fabric (geotextile) may be used. If the pond is more than 6 feet deep, a different mechanism must be proposed. A riprap embank- ment is one acceptable method of separation for deeper ponds. Other designs that satisfy the intent of this provision are allowed as long as the divider is permeable, structurally sound, and designed to prevent erosion under or around the barrier. To aid in determining sediment depth, one -foot intervals shall be prominently marked on the riser. If an embankment of more than 6 feet is proposed, the pond must comply with the criteria contained in Volume III (p.423) regarding dam safety for detention BMPs. . The most common structural failure of sedimentation basins is caused by piping. Piping refers to two phenomena: (1) water seeping through fine-grained soil, erod- ing the soil grain by grain and forming pipes or tunnels; and, (2) water under pres- sure flowing upward through a granular soil with a head of sufficient magnitude to cause soil grains to lose contact and capability for support. The most critical construction sequences to prevent piping will be: 1. Tight connections between riser and barrel and other pipe connections. 2. Adequate anchoring of riser. 3. Proper soil compaction of the embankment and riser footing. 4. Proper construction of anti -seep devices. Maintenance Standards • Sediment shall be removed from the pond when it reaches 1—foot in depth. . Any damage to the pond embankments or slopes shall be repaired. BMP C250: Construction Stormwater Chemical Treatment Purpose This BMP applies when using stormwater chemicals in batch treatment or flow -through treatment. Turbidity is difficult to control once fine particles are suspended in stormwater runoff from a construction site. Sedimentation ponds are effective at removing larger particulate mat- ter by gravity settling, but are ineffective at removing smaller particulates such as clay and fine silt. Traditional erosion and sediment control BMPs may not be adequate to ensure compliance with the water quality standards for turbidity in receiving water. Chemical treatment can reliably provide exceptional reductions of turbidity and asso- ciated pollutants. Chemical treatment may be required to meet turbidity stormwater dis- 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Aage 396 Packet Pg. 267 5.1.a charge requirements, especially when construction is to proceed through the wet sea son. Conditions of Use Formal written approval from Ecology is required for the use of chemical treatment regardless of site size. The Local Permitting Authority may also require review and approval. When approved, the chemical treatment systems must be included in the Con- struction Stormwater Pollution Prevention Plan (SWPPP). Design and Installation Specifications See Appendix II-B: Background Information on Chemical Treatment (p.419) for back- ground information on chemical treatment. Criteria for Chemical Treatment Product Use: Chemically treated stormwater dis- charged from construction sites must be nontoxic to aquatic organisms. The Chemical Technology Assessment Protocol (CTAPE) must be used to evaluate chemicals pro- posed for stormwater treatment. Only chemicals approved by Ecology under the CTAPE may be used for stormwater treatment. The approved chemicals, their allowable applic- ation techniques (batch treatment or flow -through treatment), allowable application rates, and conditions of use can be found at the Department of Ecology Emerging Tech- nologies website: http://www.ecy.wa.gov- /programs/wq/stormwater/newtech/technologies.html. Treatment System Design Considerations: The design and operation of a chemical treatment system should take into consideration the factors that determine optimum, cost-effective performance. It is important to recognize the following: . Only Ecology approved chemicals may be used and must follow approved dose rate. . The pH of the stormwater must be in the proper range for the polymers to be effect ive, which is typically 6.5 to 8.5 . The coagulant must be mixed rapidly into the water to ensure proper dispersion. . A flocculation step is important to increase the rate of settling, to produce the low- est turbidity, and to keep the dosage rate as low as possible. . Too little energy input into the water during the flocculation phase results in flocs that are too small and/or insufficiently dense. Too much energy can rapidly destroy floc as it is formed. • Care must be taken in the design of the withdrawal system to minimize outflow velocities and to prevent floc discharge. Discharge from a batch treatment system should be directed through a physical filter such as a vegetated swale that would catch any unintended floc discharge. Currently, flow -through systems always 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 397 Packet Pg. 268 5.1.a discharge through the chemically enhanced sand filtration system. System discharge rates must take into account downstream conveyance integrity Polymer Batch Treatment Process Description: A batch chemical treatment system consists of the stormwater collection system (either temporary diversion or the permanent site drainage system), a storage pond, pumps, a chemical feed system, treatment cells, and interconnecting piping. The batch treatment system shall use a minimum of two lined treatment cells in addition to an untreated stormwater storage pond. Multiple treatment cells allow for clarification of treated water while other cells are being filled or emptied. Treatment cells may be ponds or tanks. Ponds with constructed earthen embankments greater than six feet high or which impound more than 10 acre-feet require special engineering analyses. The Eco- logy Dam Safety Section has specific design criteria for dams in Washington State (see http://www.ecy.wa.gov/programs/wr/dams/GuidanceDocs.html). Stormwater is collected at interception point(s) on the site and is diverted by gravity or by pumping to an untreated stormwater storage pond or other untreated stormwater holding area. The stormwater is stored until treatment occurs. It is important that the holding pond be large enough to provide adequate storage. The first step in the treatment sequence is to check the pH of the stormwater in the untreated stormwater storage pond. The pH is adjusted by the application of carbon diox- ide or a base until the stormwater in the storage pond is within the desired pH range, 6.5 to 8.5. When used, carbon dioxide is added immediately downstream of the transfer pump. Typically sodium bicarbonate (baking soda) is used as a base, although other bases may be used. When needed, base is added directly to the untreated stormwater storage pond. The stormwater is recirculated with the treatment pump to provide mixing in the storage pond. Initial pH adjustments should be based on daily bench tests. Further pH adjustments can be made at any point in the process. Once the stormwater is within the desired pH range (dependant on polymer being used), the stormwater is pumped from the untreated stormwater storage pond to a treatment cell as polymer is added. The polymer is added upstream of the pump to facilitate rapid mix- ing. After polymer addition, the water is kept in a lined treatment cell for clarification of the sediment -floc. In a batch mode process, clarification typically takes from 30 minutes to several hours. Prior to discharge samples are withdrawn for analysis of pH, flocculent chemical concentration, and turbidity. If both are acceptable, the treated water is dis- charged. Several configurations have been developed to withdraw treated water from the treat- ment cell. The original configuration is a device that withdraws the treated water from just beneath the water surface using a float with adjustable struts that prevent the float 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 398 Packet Pg. 269 5.1.a from settling on the cell bottom. This reduces the possibility of picking up sediment -floc from the bottom of the pond. The struts are usually set at a minimum clearance of about 12 inches; that is, the float will come within 12 inches of the bottom of the cell. Other sys- tems have used vertical guides or cables which constrain the float, allowing it to drift up and down with the water level. More recent designs have an H-shaped array of pipes, set on the horizontal. This scheme provides for withdrawal from four points rather than one. This configuration reduces the likelihood of sucking settled solids from the bottom. It also reduces the tend- ency for a vortex to form. Inlet diffusers, a long floating or fixed pipe with many small holes in it, are also an option Safety is a primary concern. Design should consider the hazards associated with oper- ations, such as sampling. Facilities should be designed to reduce slip hazards and drowning. Tanks and ponds should have life rings, ladders, or steps extending from the bottom to the top. Polymer Batch Treatment Process Description: At a minimum, a flow -through chemical treatment system consists of the stormwater col- lection system (either temporary diversion or the permanent site drainage system), an untreated stormwater storage pond, and the chemically enhanced sand filtration system. Stormwater is collected at interception point(s) on the site and is diverted by gravity or by pumping to an untreated stormwater storage pond or other untreated stormwater holding area. The stormwater is stored until treatment occurs. It is important that the holding pond be large enough to provide adequate storage. Stormwater is then pumped from the untreated stormwater storage pond to the chem- ically enhanced sand filtration system where polymer is added. Adjustments to pH may be necessary before chemical addition. The sand filtration system continually monitors the stormwater for turbidity and pH. If the discharge water is ever out of an acceptable range for turbidity or pH, the water is recycled to the untreated stormwater pond where it can be retreated. For batch treatment and flow -through treatment, the following equipment should be located in a lockable shed- . The chemical injector. . Secondary containment for acid, caustic, buffering compound, and treatment chem- ical. . Emergency shower and eyewash. . Monitoring equipment which consists of a pH meter and a turbidimeter. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 399 Packet Pg. 270 5.1.a System Sizing: Certain sites are required to implement flow control for the developed sites. These sites must also control stormwater release rates during construction. Generally, these are sites that discharge stormwater directly, or indirectly, through a conveyance system, into a fresh water. System sizing is dependent on flow control requirements. Sizing Criteria for Batch Treatment Systems for Flow Control Exempt Water Bodies: The total volume of the untreated stormwater storage pond and treatment ponds or tanks must be large enough to treat stormwater that is produced during multiple day storm events. It is recommended that at a minimum the untreated stormwater storage pond be sized to hold 1.5 times the runoff volume of the 10-year, 24-hour storm event. Bypass should be provided around the chemical treatment system to accommodate extreme storm events. Runoff volume shall be calculated using the methods presented in Chapter III-2 - Hydrologic Analysis (p.429). Worst -case land cover conditions (i.e., pro- ducing the most runoff) should be used for analyses (in most cases, this would be the land cover conditions just prior to final landscaping). Primary settling should be encouraged in the untreated stormwater storage pond. A fore - bay with access for maintenance may be beneficial. There are two opposing considerations in sizing the treatment cells. A larger cell is able to treat a larger volume of water each time a batch is processed. However, the larger the cell the longer the time required to empty the cell. A larger cell may also be less effective at flocculation and therefore require a longer settling time. The simplest approach to siz- ing the treatment cell is to multiply the allowable discharge flow rate times the desired drawdown time. A 4-hour drawdown time allows one batch per cell per 8-hour work period, given 1 hour of flocculation followed by two hours of settling. If the discharge is directly to a flow control exempt receiving water listed in Appendix I-E: Flow Control -Exempt Surface Waters (p.133) or to an infiltration system, there is no dis- charge flow limit. Ponds sized for flow control water bodies must at a minimum meet the sizing criteria for flow control exempt waters. Sizing Criteria for Flow -Through Treatment Systems for Flow Control Exempt Water Bodies: When sizing storage ponds or tanks for flow -through systems for flow control exempt water bodies, the treatment system capacity should be a factor. The untreated storm - water storage pond or tank should be sized to hold 1.5 times the runoff volume of the 10- year, 24-hour storm event minus the treatment system flowrate for an 8-hour period. For a chitosan-enhanced sand filtration system, the treatment system flowrate should be 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 400 Packet Pg. 271 5.1.a sized using a hydraulic loading rate between 6-8 gpm/ft2. Other hydraulic loading rates may be more appropriate for other systems. Bypass should be provided around the chemical treatment system to accommodate extreme storms. Runoff volume shall be cal- culated using the methods presented in Chapter III-2 - Hydrologic Analysis (p.429). Worst -case land cover conditions (i.e., producing the most runoff) should be used for ana- lyses (in most cases, this would be the land cover conditions just prior to final land- scaping). Sizing Criteria for Flow Control Water Bodies: Sites that must implement flow control for the developed site condition must also control stormwater release rates during construction. Construction site stormwater discharges shall not exceed the discharge durations of the pre -developed condition for the range of pre -developed discharge rates from'/2 of the 2-year flow through the 10-year flow as pre- dicted by an approved continuous runoff model. The pre -developed condition to be matched shall be the land cover condition immediately prior to the development project. This restriction on release rates can affect the size of the storage pond and treatment cells. The following is how WWHM can be used to determine the release rates from the chem- ical treatment systems: 1. Determine the pre -developed flow durations to be matched by entering the existing land use area under the "Pre -developed" scenario in WWHM. The default flow range is from'/2 of the 2-year flow through the 10-year flow. 2. Enter the post developed land use area in the "Developed Unmitigated" scenario in WWHM. 3. Copy the land use information from the "Developed Unmitigated" to "Developed Mit- igated" scenario. 4. While in the "Developed Mitigated" scenario, add a pond element under the basin element containing the post -developed land use areas. This pond element rep- resents information on the available untreated stormwater storage and discharge from the chemical treatment system. In cases where the discharge from the chem- ical treatment system is controlled by a pump, a stage/storage/discharge (SSD) table representing the pond must be generated outside WWHM and imported into WWHM. WWHM can route the runoff from the post -developed condition through this SSD table (the pond) and determine compliance with the flow duration stand- ard. This would be an iterative design procedure where if the initial SSD table proved to be inadequate, the designer would have to modify the SSD table outside WWHM and re -import in WWHM and route the runoff through it again. The iteration will continue until a pond that complies with the flow duration standard is correctly sized. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 401 Packet Pg. 272 5.1.a Notes on SSD table characteristics: . The pump discharge rate would likely be initially set atjust below'/2 of the 2- year flow from the pre -developed condition. As runoff coming into the untreated stormwater storage pond increases and the available untreated stormwater storage volume gets used up, it would be necessary to increase the pump discharge rate above'/2 of the 2-year. The increase(s) above'/2 of the 2-year must be such that they provide some relief to the untreated storm - water storage needs but at the same time will not cause violations of the flow duration standard at the higher flows. The final design SSD table will identify the appropriate pumping rates and the corresponding stage and storages. . When building such a flow control system, the design must ensure that any automatic adjustments to the pumping rates will be as a result of changes to the available storage in accordance with the final design SSD table. 5. It should be noted that the above procedures would be used to meet the flow con- trol requirements. The chemical treatment system must be able to meet the runoff treatment requirements. It is likely that the discharge flow rate of/2 of the 2-year or more may exceed the treatment capacity of the system. If that is the case, the untreated stormwater discharge rate(s) (i.e., influent to the treatment system) must be reduced to allow proper treatment. Any reduction in the flows would likely result in the need for a larger untreated stormwater storage volume. If the discharge is to a municipal storm drainage system, the allowable discharge rate may be limited by the capacity of the public system. It may be necessary to clean the municipal storm drainage system prior to the start of the discharge to pre- vent scouring solids from the drainage system. If the municipal storm drainage sys- tem discharges to a water body not on the flow control exempt list, the project site is subject to flow control requirements. Obtain permission from the owner of the col- lection system before discharging to it. If system design does not allow you to discharge at the slower rates as described above and if the site has a retention or detention pond that will serve the planned development, the discharge from the treatment system may be directed to the permanent reten- tion/detention pond to comply with the flow control requirement. In this case, the untreated stormwater storage pond and treatment system will be sized according to the sizing criteria for flow -through treatment systems for flow control exempt water bodies described earlier except all discharge (water passing through the treatment system and stormwater bypassing the treatment system) will be directed into the permanent reten- tion/detention pond. If site constraints make locating the untreated stormwater storage pond difficult, the permanent retention/detention pond may be divided to serve as the untreated stormwater storage pond and the post -treatment flow control pond. A berm or barrier must be used in this case so the untreated water does not mix with the treated water. Both untreated stormwater storage requirements, and adequate post -treatment 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 402 Packet Pg. 273 5.1.a flow control must be achieved. The post -treatment flow control pond's revised dimen- sions must be entered into the WWHM and the WWHM must be run to confirm com- pliance with the flow control requirement. Maintenance Standards Monitoring: At a minimum, the following monitoring shall be conducted. Test results shall be recorded on a daily log kept on site. Additional testing may be required by the NPDES permit based on site conditions. Operational Monitoring: . Total volume treated and discharged. . Flow must be continuously monitored and recorded at not greater than 15-minute intervals. . Type and amount of chemical used for pH adjustment. . Amount of polymer used for treatment. • Settling time. Compliance Monitoring: . Influent and effluent pH, flocculent chemical concentration, and turbidity must be continuously monitored and recorded at not greater than 15-minute intervals. pH and turbidity of the receiving water. Biomonitorin Treated stormwater must be non -toxic to aquatic organisms. Treated stormwater must be tested for aquatic toxicity or residual chemicals. Frequency of biomonitoring will be determined by Ecology. Residual chemical tests must be approved by Ecology prior to their use. If testing treated stormwater for aquatic toxicity, you must test for acute (lethal) toxicity. Bioassays shall be conducted by a laboratory accredited by Ecology, unless otherwise approved by Ecology. Acute toxicity tests shall be conducted per the CTAPE protocol. Discharge Compliance: Prior to discharge, treated stormwater must be sampled and tested for compliance with pH, flocculent chemical concentration, and tur- bidity limits. These limits may be established by the Construction Stormwater General Permit or a site -specific discharge permit. Sampling and testing for other pollutants may also be necessary at some sites. pH must be within the range of 6.5 to 8.5 standard units and not cause a change in the pH of the receiving water of more than 0.2 standard units. Treated stormwater samples and measurements shall be taken from the discharge pipe or another location representative of the nature of the treated stormwater discharge. Samples used for determining compliance with the water quality standards in the 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 403 Packet Pg. 274 5.1.a receiving water shall not be taken from the treatment pond prior to decanting. Com- pliance with the water quality standards is determined in the receiving water. Operator Training: Each contractor who intends to use chemical treatment shall be trained by an experienced contractor. Each site using chemical treatment must have an operator trained and certified by an organization approved by Ecology. Standard BMPs: Surface stabilization BMPs should be implemented on site to prevent significant erosion. All sites shall use a truck wheel wash to prevent tracking of sediment off site. Sediment Removal and Disposal: . Sediment shall be removed from the storage or treatment cells as necessary. Typ- ically, sediment removal is required at least once during a wet season and at the decommissioning of the cells. Sediment remaining in the cells between batches may enhance the settling process and reduce the required chemical dosage. . Sediment that is known to be non -toxic may be incorporated into the site away from drainages. BMP C251: Construction Stormwater Filtration Purpose Filtration removes sediment from runoff originating from disturbed areas of the site. Background Information: Filtration with sand media has been used for over a century to treat water and wastewa- ter. The use of sand filtration for treatment of stormwater has developed recently, gen- erally to treat runoff from streets, parking lots, and residential areas. The application of filtration to construction stormwater treatment is currently underdevelopment. Conditions of Use Traditional BMPs used to control soil erosion and sediment loss from sites under devel- opment may not be adequate to ensure compliance with the water quality standard for turbidity in the receiving water. Filtration may be used in conjunction with gravity settling to remove sediment as small as fine silt (0.5 pm). The reduction in turbidity will be dependent on the particle size distribution of the sediment in the stormwater. In some cir- cumstances, sedimentation and filtration may achieve compliance with the water quality standard for turbidity The use of construction stormwater filtration does not require approval from Ecology as long as treatment chemicals are not used. Filtration in conjunction with polymer treat- ment requires testing under the Chemical Technology Assessment Protocol — Ecology (CTAPE) before it can be initiated. Approval from the appropriate regional Ecology office 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 404 Packet Pg. 275 5.1.a must be obtained at each site where polymers use is proposed prior to use. For more guidance on stormwater chemical treatment see BMP C250: Construction Stormwater Chemical Treatment (p.396). Design and Installation Specifications Two types of filtration systems may be applied to construction stormwater treatment: rapid and slow. Rapid sand filters are the typical system used for water and wastewater treatment. They can achieve relatively high hydraulic flow rates, on the order of 2 to 20 gpm/sf, because they have automatic backwash systems to remove accumulated solids In contrast, slow sand filters have very low hydraulic rates, on the order of 0.02 gpm/sf, because they do not have backwash systems. Slow sand filtration has generally been used to treat stormwater. Slow sand filtration is mechanically simple in comparison to rapid sand filtration but requires a much larger filter area. Filtration Equipment. Sand media filters are available with automatic backwashing fea- tures that can filter to 50 pm particle size. Screen or bag filters can filter down to 5 pm. Fiberwound filters can remove particles down to 0.5 pm. Filters should be sequenced from the largest to the smallest pore opening. Sediment removal efficiency will be related to particle size distribution in the stormwater. Treatment Process Description. Stormwater is collected at interception point(s) on the site and is diverted to an untreated stormwater sediment pond or tank for removal of large sediment and storage of the stormwater before it is treated by the filtration system. The untreated stormwater is pumped from the trap, pond, or tank through the filtration sys- tem in a rapid sand filtration system. Slow sand filtration systems are designed as flow through systems using gravity. Maintenance Standards Rapid sand filters typically have automatic backwash systems that are triggered by a pre-set pressure drop across the filter. If the backwash water volume is not large or sub- stantially more turbid than the untreated stormwater stored in the holding pond or tank, backwash return to the untreated stormwater pond or tank may be appropriate. However, other means of treatment and disposal may be necessary. Screen, bag, and fiber filters must be cleaned and/or replaced when they become clogged. Sediment shall be removed from the storage and/or treatment ponds as necessary Typically, sediment removal is required once or twice during a wet season and at the decommissioning of the ponds. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 405 Packet Pg. 276 5.1.a Sizing Criteria for Flow -Through Treatment Systems for Flow Control Exempt Water Bodies: When sizing storage ponds or tanks for flow -through systems for flow control exempt water bodies the treatment system capacity should be a factor. The untreated stormwater storage pond or tank should be sized to hold 1.5 times the runoff volume of the 10-year, 24-hour storm event minus the treatment system flowrate for an 8-hour period. For a chitosan-enhanced sand filtration system, the treatment system flowrate should be sized using a hydraulic loading rate between 6-8 gpm/ft2. Other hydraulic loading rates may be more appropriate for other systems. Bypass should be provided around the chemical treatment system to accommodate extreme storms. Runoff volume shall be calculated using the methods presented in Chapter III-2 - Hydrologic Analysis (p.429). Worst -case conditions (i.e., producing the most runoff) should be used for analyses (most likely con- ditions present prior to final landscaping). Sizing Criteria for Flow Control Water Bodies: Sites that must implement flow control for the developed site condition must also control stormwater release rates during construction. Construction site stormwater discharges shall not exceed the discharge durations of the pre -developed condition for the range of pre -developed discharge rates from 1 /2 of the 2-year flow through the 10-year flow as predicted by an approved continuous runoff model. The pre -developed condition to be matched shall be the land cover condition immediately prior to the development project. This restriction on release rates can affect the size of the storage pond, the filtration sys- tem, and the flow rate through the filter system. The following is how WWHM can be used to determine the release rates from the fil- tration systems: 1. Determine the pre -developed flow durations to be matched by entering the land use area under the "Pre -developed" scenario in WWHM. The default flow range is from'/2 of the 2-year flow through the 10-year flow. 2. Enter the post developed land use area in the "Developed Unmitigated" scenario in WWHM. 3. Copy the land use information from the "Developed Unmitigated" to "Developed Mit- igated" scenario. 4. There are two possible ways to model stormwater filtration systems: a. The stormwater filtration system uses an untreated stormwater storage pond/tank and the discharge from this pond/tank is pumped to one or more fil- ters. In -line filtration chemicals would be added to the flow right after the pond/tank and before the filter(s). Because the discharge is pumped, WWHM can't generate a stage/storage /discharge (SSD) table for this system. This 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 406 Packet Pg. 277 5.1.a system is modeled the same way as described in BMP C250: Construction Stormwater Chemical Treatment (p.396) and is as follows: While in the "Developed Mitigated" scenario, add a pond element under the basin element containing the post -developed land use areas. This pond ele- ment represents information on the available untreated stormwater storage and discharge from the filtration system. In cases where the discharge from the filtration system is controlled by a pump, a stage/storage/discharge (SSD) table representing the pond must be generated outside WWHM and imported into WWHM. WWHM can route the runoff from the post -developed condition through this SSD table (the pond) and determine compliance with the flow duration standard. This would be an iterative design procedure where if the initial SSD table proved to be out of compliance, the designer would have to modify the SSD table outside WWHM and re -import in WWHM and route the runoff through it again. The iteration will continue until a pond that enables compliance with the flow duration standard is designed. Notes on SSD table characteristics: The pump discharge rate would likely be initially set atjust below'/2 if the 2-year flow from the pre -developed condition. As runoff coming into the untreated stormwater storage pond increases and the available untreated stormwater storage volume gets used up, it would be neces- sary to increase the pump discharge rate above '/z of the 2-year. The increase(s) above'/2 of the 2-year must be such that they provide some relief to the untreated stormwater storage needs but at the same time they will not cause violations of the flow duration standard at the higher flows. The final design SSD table will identify the appropriate pumping rates and the corresponding stage and storages. When building such a flow control system, the design must ensure that any automatic adjustments to the pumping rates will be as a result of changes to the available storage in accordance with the final design SSD table. b. The stormwater filtration system uses a storage pond/tank and the discharge from this pond/tank gravity flows to the filter. This is usually a slow sand filter system and it is possible to model it in WWHM as a Filter element or as a combination of Pond and Filter element placed in series. The stage/stor- age/discharge table(s) may then be generated within WWHM as follows: i. While in the "Developed Mitigated" scenario, add a Filter element under the basin element containing the post -developed land use areas. The length and width of this filter element would have to be the same as the bottom length and width of the upstream untreated stormwater storage pond/tank. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 407 Packet Pg. 278 5.1.a In cases where the length and width of the filter is not the same as those for the bottom of the upstream untreated stormwater storage tank/ - pond, the treatment system may be modeled as a Pond element fol- lowed by a Filter element. By having these two elements, WWHM would then generate a SSD table for the storage pond which then grav- ity flows to the Filter element. The Filter element downstream of the untreated stormwater storage pond would have a storage component through the media, and an overflow component for when the filtration capacity is exceeded. WWHM can route the runoff from the post -developed condition through the treatment systems in 4b and determine compliance with the flow duration standard. This would be an iterative design procedure where if the initial siz- ing estimates for the treatment system proved to be inadequate, the designer would have to modify the system and route the runoff through it again. The iteration would continue until compliance with the flow duration standard is achieved. 5. It should be noted that the above procedures would be used to meet the flow con- trol requirements. The filtration system must be able to meet the runoff treatment requirements. It is likely that the discharge flow rate of/2 of the 2-year or more may exceed the treatment capacity of the system. If that is the case, the untreated storm - water discharge rate(s) (i.e., influent to the treatment system) must be reduced to allow proper treatment. Any reduction in the flows would likely result in the need for a larger untreated stormwater storage volume. If system design does not allow you to discharge at the slower rates as described above and if the site has a retention or detention pond that will serve the planned development, the discharge from the treatment system may be directed to the permanent reten- tion/detention pond to comply with the flow control requirements. In this case, the untreated stormwater storage pond and treatment system will be sized according to the sizing criteria for flow -through treatment systems for flow control exempt waterbodies described earlier except all discharges (water passing through the treatment system and stormwater bypassing the treatment system) will be directed into the permanent reten- tion/detention pond. If site constraints make locating the untreated stormwater storage pond difficult, the permanent retention/detention pond may be divided to serve as the untreated stormwater discharge pond and the post -treatment flow control pond. A berm or barrier must be used in this case so the untreated water does not mix with the treated water. Both untreated stormwater storage requirements, and adequate post -treatment flow control must be achieved. The post -treatment flow control pond's revised dimen- sions must be entered into the WWHM and the WWHM must be run to confirm com- pliance with the flow control requirement. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 408 Packet Pg. 279 5.1.a BMP C252: High pH Neutralization Using CO2 Purpose When pH levels in stormwater rise above 8.5 it is necessary to lower the pH levels to the acceptable range of 6.5 to 8.5, this process is called pH neutralization. pH neutralization involves the use of solid or compressed carbon dioxide gas in water requiring neut- ralization. Neutralized stormwater may be discharged to surface waters under the Gen- eral Construction NPDES permit. Neutralized process water such as concrete truck wash -out, hydro -demolition, or saw -cut ting slurry must be managed to prevent discharge to surface waters. Any stormwater con- taminated during concrete work is considered process wastewater and must not be discharged to surface waters. Reason for pH Neutralization: A pH level range of 6.5 to 8.5 is typical for most natural watercourses, and this neutral pH is required for the survival of aquatic organisms. Should the pH rise or drop out of this range, fish and other aquatic organisms may become stressed and may die. Calcium hardness can contribute to high pH values and cause toxicity that is associated with high pH conditions. A high level of calcium hardness in waters of the state is not allowed. The water quality standard for pH in Washington State is in the range of 6.5 to 8.5. Ground water standard for calcium and other dissolved solids in Washington State is less than 500 mg/I. Conditions of Use Causes of Hiah aH: High pH at construction sites is most commonly caused by the contact of stormwater with poured or recycled concrete, cement, mortars, and other Portland cement or lime con- taining construction materials. (See BMP C151: Concrete Handling (p.313) for more information on concrete handling procedures). The principal caustic agent in cement is calcium hydroxide (free lime). Advantages of CO2 Sparging: . Rapidly neutralizes high pH water. . Cost effective and safer to handle than acid compounds. • CO2 is self -buffering. It is difficult to overdose and create harmfully low pH levels. . Material is readily available. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Aage 409 Packet Pg. 280 5.1.a The Chemical Process: When carbon dioxide (CO2) is added to water (H2O), carbonic acid (H2CO3) is formed which can further dissociate into a proton (H+) and a bicarbonate anion (HCO3-) as shown below: CO2 + H2O H H2CO3 H H+ + HCO3- The free proton is a weak acid that can lower the pH. Water temperature has an effect on the reaction as well. The colder the water temperature is the slower the reaction occurs and the warmer the water temperature is the quicker the reaction occurs. Most con- struction applications in Washington State have water temperatures in the 50°F or higher range so the reaction is almost simultaneous. Design and Installation Specifications Treatment Process: High pH water may be treated using continuous treatment, continuous discharge sys- tems. These manufactured systems continuously monitor influent and effluent pH to ensure that pH values are within an acceptable range before being discharged. All sys- tems must have fail safe automatic shut off switches in the event that pH is not within the acceptable discharge range. Only trained operators may operate manufactured systems System manufacturers often provide trained operators or training on their devices. The following procedure may be used when not using a continuous discharge system: 1. Prior to treatment, the appropriate jurisdiction should be notified in accordance with the regulations set by the jurisdiction. 2. Every effort should be made to isolate the potential high pH water in order to treat it separately from other stormwater on -site. 3. Water should be stored in an acceptable storage facility, detention pond, or con- tainment cell prior to treatment. 4. Transfer water to be treated to the treatment structure. Ensure that treatment struc- ture size is sufficient to hold the amount of water that is to be treated. Do not fill tank completely, allow at least 2 feet of freeboard. 5. The operator samples the water for pH and notes the clarity of the water. As a rule of thumb, less CO2 is necessary for clearer water. This information should be recor- ded. 6. In the pH adjustment structure, add CO2 until the pH falls in the range of 6.9-7.1. Remember that pH water quality standards apply so adjusting pH to within 0.2 pH units of receiving water (background pH) is recommended. It is unlikely that pH can be adjusted to within 0.2 pH units using dry ice. Compressed carbon dioxide gas should be introduced to the water using a carbon dioxide diffuser located near the 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 410 Packet Pg. 281 5.1.a bottom of the tank, this will allow carbon dioxide to bubble up through the water and diffuse more evenly. 7. Slowly discharge the water making sure water does not get stirred up in the pro- cess. Release about 80% of the water from the structure leaving any sludge behind. 8. Discharge treated water through a pond or drainage system. 9. Excess sludge needs to be disposed of properly as concrete waste. If several batches of water are undergoing pH treatment, sludge can be left in treatment struc- ture for the next batch treatment. Dispose of sludge when it fills 50% of tank volume. Sites that must implement flow control for the developed site must also control storm - water release rates during construction. All treated stormwater must go through a flow control facility before being released to surface waters which require flow control. Maintenance Standards Safety and Materials Handling: . All equipment should be handled in accordance with OSHA rules and regulations. . Follow manufacturer guidelines for materials handling. Operator Records: Each operator should provide: . A diagram of the monitoring and treatment equipment. . A description of the pumping rates and capacity the treatment equipment is cap- able of treating. Each operator should keep a written record of the following: • Client name and phone number. . Date of treatment. • Weather conditions. . Project name and location. . Volume of water treated. . pH of untreated water. . Amount of CO2 needed to adjust water to a pH range of 6.9-7.1. . pH of treated water. . Discharge point location and description. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 411 Packet Pg. 282 5.1.a A copy of this record should be given to the client/contractor who should retain the record for three years. BMP C253: pH Control for High pH Water Purpose When pH levels in stormwater rise above 8.5 it is necessary to lower the pH levels to the acceptable range of 6.5 to 8.5, this process is called pH neutralization. Stormwater with pH levels exceeding water quality standards may be treated by infiltration, dispersion in vegetation or compost, pumping to a sanitary sewer, disposal at a permitted concrete batch plant with pH neutralization capabilities, or carbon dioxide sparging. BMP C252: High pH Neutralization Using CO2 (p.409) gives guidelines for carbon dioxide sparging. Reason for pH Neutralization: A pH level range of 6.5 to 8.5 is typical for most natural watercourses, and this pH range is required for the survival of aquatic organisms. Should the pH rise or drop out of this range, fish and other aquatic organisms may become stressed and may die. Conditions of Use Causes of High pH: High pH levels at construction sites are most commonly caused by the contact of storm - water with poured or recycled concrete, cement, mortars, and other Portland cement or lime containing construction materials. (See BMP C151: Concrete Handling .313 for more information on concrete handling procedures). The principal caustic agent in cement is calcium hydroxide (free lime). Design and Installation Specifications Disposal Methods: Infiltration . Infiltration is only allowed if soil type allows all water to infiltrate (no surface runoff) without causing or contributing to a violation of surface or ground water quality standards. . Infiltration techniques should be consistent with Chapter V-7 - Infiltration and Biore- tention Treatment Facilities (p.957) Dispersion Use BMP T5.30: Full Dispersion (p.939) Sanitary Sewer Disposal . Local sewer authority approval is required prior to disposal via the sanitary sewer. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Pipt Page 412 Packet Pg. 283 5.1.a Concrete Batch Plant Disposal . Only permitted facilities may accept high pH water. . Facility should be contacted before treatment to ensure they can accept the high pH water. Stormwater Discharge Any pH treatment options that generate treated water that must be discharged off site are subject to flow control requirements. Sites that must implement flow control for the developed site must also control stormwater release rates during construction. All treated stormwater must go through a flow control facility before being released to sur- face waters which require flow control. 2014 Stormwater Management Manual for Western Washington VolumeA t4 Ript Page 413 Packet Pg. 284 5.1.a C. Correspondence Ecology EPA Local Government a Page 131 Attachment 9 Packet Pg. 285 5.1.a D. Site Inspection Form Create your own or download Ecology's template: http://www.ecy.wa.gov/programs/wq/stormwater/construction/index.html Select Permit, Forms and Application to find the link to the Construction Stormwater Site Inspection Form. Page 132 Attachment 9 Packet Pg. 286 5.1.a E. Construction Stormwater General Permit (CSWGP) Download the CSWGP: http://www.ecy.wa.gov/programs/wq/stormwater/construction/index. html Page 133 Attachment 9 Packet Pg. 287 5.1.a F. 303(d) List Waterbodies / TMDL Waterbodies Information Proposed New Discharge to an Impaired Water Body form SWPPP Addendum addressing impairment G. Contaminated Site Information Administrative Order Sanitary Discharge Permit Soil Management Plan Soil and Groundwater Reports Maps and Figures Depicting Contamination H. Engineering Calculations Sediment Trap 2090 SA= FS (Q2/ Vs) (Q2) FS= 2 Factor of Safety Vs 0.00096 ft/sec Settling Velocity Q2 15-min Peak from WWHM12 WWHM Input Landcover Basin A Type (AC) Imp. Area 0.38 Pervious (LS) 0.12 Total Area 0.50 Soil Type = Till WWHM12 = 15 min. Time series Results Basin A Q2 (cfs) 0.12 SA (ft2) 250 c 0 �a �a 3 0 0 0 0 O 0 N O N z J a Page 134 Attachment 9 Packet Pg. 288 5.1.a #P71 CITY OF EDMONDS ENVIRONMENTAL CHECKLIST Purpose of Checklist. RECEIVED Aug 04 2020 CITY OF EDMONDS DEVELOPMENT SERVICES DEPARTMENT The State Environmental Policy Act (SEPA), chapter 43.21C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An environmental impact statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help you and the agency identify impacts from your proposal (and to reduce or avoid impacts from the proposal, if it can be done) and to help the agency decide whether an EIS is required. Instructions for Applicants: This environmental checklist asks you to describe some basic information about your proposal. Governmental agencies use this checklist to determine whether the environmental impacts of your proposal are significant, requiring preparation of an EIS. Answer the questions briefly, with the most precise information known, or give the best description you can. You must answer each question accurately and carefully, to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or does not apply". Complete answers to the questions now may avoid unnecessary delays later. Some questions ask about governmental regulations, such as zoning, shoreline, and landmark designations. Answer these questions if you can. If you have problems, the governmental agencies can assist you. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. Use of checklist for nonproject proposals: For nonproject proposals complete this checklist and the supplemental sheet for nonproject actions (Part D). the lead agency may exclude any question for the environmental elements (Part 13) which they determine do not contribute meaningfully to the analysis of the proposed nonproject actions, the references in the checklist to the words "project," "applicant," and "property or site" should be read as "proposer," and "affected geographic area," respectively. A. BACKGROUND Name of proposed project, if applicable: WoodWay Station 2. Name of applicant: CDA + Pirscher Architects Inc. 3. Address and phone number of applicant and contact person: 23114 1001h W Edmonds, WA 98020 Carl F. Pirscher AIA, LEED AP 206-368-9668 Revised on 9116116 P71_ - SEPA_Checklist Woodway Station Design Review 2020.doc Page 1 of 28 Attachment 10 Packet Pg. 289 5.1.a 4. Date checklist prepared: July 25, 2020 5. Agency requesting checklist: City of Edmonds 6. Proposed timing or schedule (including phasing, if applicable): The project will commence construction upon completion of the processing and approvals of all relevant materials approximately fall of 2020. (STAFF COMMENTS) 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. Additional permits will be required for interior tenant improvements. (STAFF COMMENTS) 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. A Phase I and Phase II Environmental Site Assessment has been conducted and attached for review. A traffic report and impact analysis has also been prepared and is attached for review. A soils report has been prepared and is attached for review. (STAFF COMMENTS) 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. None Revised on 9119116 P71-_SEPA_Checklist Woodway Station Design Review_ 2020.doc Page 2 of 2h Attachment 10 1Packet Pg. 290 5.1.a (STAFF COMMEN 10. List any government approvals or permits that will be needed for your proposal, if known. This SEPA checklist is being submitted for approval. The project will also be submitted for Architectural Design Review and building permit documentation will also be submitted following SEPA approval. (STAFF C 11. Give brief, complete description of your proposal, including the proposed uses and size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. The project consists of the demolition of an existing gas station and associated two story convenience%ffice facility and the construction of a new approximately 11,168 GSF (2) story structure devoted primarily to _-ggeneral office uses. The site area is approximately 20,505 SF in area and at present almost fully developed as a _gas station convenience store. The site will be extensively relandscaped to meet current development _guidelines as part of the new Class A office development. (STAFF COMM 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide range or boundaries of the site(s). Provide legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. The project is located at 23726 100th Ave. W., Edmonds, WA. See attached property survey for le_aal description, tax parcel number and additional information. Revised on 9119116 P71_ _SEPA_Checklist Woodway Station Design Review_ 2020.doc Page 3 of 2R Attachment 10 Packet Pg. 291 5.1.a (STAFF COMMENTS) TO BE COMPLETED BY APPLICANT B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one): Flat, rolling, hilly, steep slopes, mountainous, other: The site is almost flat with a slight change in elevation from the NE property corner to the SW property corner. See attached property survey for more information. (STAFF COMMENTS) b. What is the steepest slope on the site (approximate percent slope)? The slite slopes, as noted above, approximately 2.5% from the NE corner to the SW corner of the site. (STAFF COMMENTS) C. What general types of soils are found on the site (for example, clay, sand, gravel, peat, and muck)? If you know the classification of agricultural soils, specify them and note any agricultural land of long term commercial significance and whether the proposal results in removing any of these soils. The existinq soils are considered quite sandy with __good infiltration characteristics. See attached geotechnical report for specific information. (STAFF COMMENTS) Revised on 9119116 P71-_SEPA_Checklist Woodway Station Design Review_ 2020.doc Page 4 of 28 Attachment 10 1Packet Pg. 292 5.1.a d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. There is at present no history of unstable soils on the subject site. Please review the attached geotechnical report for additional information. (STAFF COMMENTS) e. Describe the purpose, type, total area and approximate quantities and total affected area of any filling, excavation, and grading proposed. Indicate source of fill. Cut & Fill is expected to be minimal as there will be no underground gara_ge, The project will be slab on existing _-ggrade. See attached preliminary _gradin_g and drainage plans for more information. (STAFF COMMENTS) f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. An erosion control plan will be prepared alon_q with a SWPPP report at the time of engineering submittals to the City. (STAFF COMMENTS) g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? The total pervious area for the completed project will be 5,235 SF which will total approcxmmately 24% of the site. The impervious area will total 16,271 SF and will be approximately 76% of the site. (STAFF COMMENTS)r h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: A temporary erosion and sedimentation control plan will be prepared and implemented in accordance with City of Edmonds standards. Revised on 9119116 P71_ _SEPA_Checklist Woodway Station Design Review_ 2020.doc Page 5 of 28 Attachment 10 Packet Pg. 293 5.1.a (STAFF COMMENTS) 2. AIR a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, and industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. During construction there will be temporary mechanical emissions from the operations of clearin_g and _gradin_g with heavy equipment and material deliveries and the arrival and departures of construction personnel. Also during construction there may on occasion be the potential for soil particulates related to excavation and gradin_q of the site. Post construction the normal operations of human activity and the utilization of motor vehicles associated with this project may __generate normal air emissions. (STAFF COMM Are there any off -site sources of emissions or odor that may effect your proposal? If so, generally describe None identified. (STAFF COMM C. Proposed measures to reduce or control emissions or other impacts to the, if any: During construction the temporary mechanical emissions from the operations of clearing and gradin_q equipment and material deliveries will be limited by City of Edmonds code to specific hours of operation and the equipment itself will have tail pipe emissions regulated by state and national standards. Efforts will be maintained durinq construction to control the potential for soil particulates by maintainin_g erosion control measures as will be approved and periodically hydrating any exposed soils to restrict wind erosion (STAFF COMMENTS) 3. WATER Revised on 9119116 P71-_SEPA_Checklist Woodway Station Design Review 2020.doc Page 6 of 28 Attachment 10 1Packet Pg. 294 5.1.a a. Surface: Revised on 9119116 (1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, and wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. There are no surface water bodies on the site or in the immediate vicinity. (STAFF COMMENTS) (2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. None (STAFF COMMENTS) (3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. None (STAFF COMMENTS) _ (4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. No withdrawals or diversions (STAFF COMMENTS) (5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. No P71-_SEPA_Checklist Woodway Station Design Review 2020.dm Paxe 7 01'2R 0 r cc w to 0 3 0 0 0 0 0 0 N O N Z J a Attachment 10 Packet Pg. 295 5.1.a (STAFF COMMENTS) (6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No waste material will be discharged to surface waters as a result of the proiect. Sewer effluent will be conveyed to the sanitary sewer system. Pollutants in surface runoff (from parking areas) will be treated within bioretention planters along the front property line. (STAFF COMMENTS) b. Ground: (1) Will ground water be withdrawn from a well for drinking water or other purposes? If so, give a general description of the well, proposed uses and approximate quantities withdrawn from the well Will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. No Ground water withdrawals (STAFF COMMENTS) (2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemicals...; agricultural; etc.). Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. The project will be served by a public sanitation system. (STAFF COMMENTS) C. Water Runoff (including storm water): Revised on 9119116 P71-_SEPA_Checklist Woodway Station Design Review 2020.doc Page 8 of 28 Attachment 10 1Packet Pg. 296 5.1.a (1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. The primary source of runoff for the subject parcel at present is atmospheric precipitation. Runoff will be collected in catch basins throughout the site and in roof drain pipes and conveyed to an underground detentionfinfiltration vault. An overflowfcontrol structure will attenuate site discharge to the existin_g stormdrainage system within city right of way. Stormwater water quality mitigation will be provided. (STAFF COMMENTS) (2) Could waste materials enter ground or surface waters? If so, generally describe. There are no surface waters in the subject sites vicinity. The project will be served by a public sanitation system. (STAFF COMMENTS) (3) Does the proposal alter or otherwise affect drainage patterns in the vicinity of the site? If so, describe. No, the existin_a drainage Patten will be maintained. (STAFF COMMENTS) d. Proposed measures to reduce or control surface, ground, runoff water, and drainage pattern impacts, if any: During construction, silt fence, interceptor ditches, sediment traps, and Baker tanks will be used as necessary. In the permanent condition, an underground detentionfinfiltration vault will be used to comply with DOE standards for flow control, water quality and on site stormwater management will be implemented. Revised on 9119116 P71_-_SEPA—Checklist Woodway Station Design Review_ 2020.doc Page 9 of 28 Attachment 10 Packet Pg. 297 5.1.a 4. Plants a. b. Revised on 9119116 (STAFF Check or circle types of vegetation found on the site: deciduous tree: alder, maple, aspen, other: evergreen tree: fir, cedar, pine, other: X shrubs _ X grass pasture crop or Brain Orchards, vineyards or other permanent crops wet soil plants: cattail, buttercup, bulrush, skunk cabbage, other: water plants: water lily, eelgrass, milfoil, other: other types of vegetation: (STAFF COMMENTS What kind and amount of vegetation will be removed or altered? Existing scrub -growth _-ggrasses, shrubs, will be removed durin_g construction. (STAFF COMMENTS) P71_-_SEPA_Checklist Woodway Station Design Review 2020.doc Page 10 of 2,1, c O co Cn 3 0 O 0 0 0 0 N 0 N Z J a. Attachment 10 Packet Pg. 298 5.1.a C. List threatened or endangered species known to be on or near the site. None (STAFF COMMENTS) d. Proposed landscaping, use of native plants, or other materials to preserve or enhance vegetation on the site, if any: New landscaping will include trees, shrubs and ground cover as required by the City Code, usinq native and ornamental plant material suited for this region. See attached proposed landscape plan. (STAFF COMMENTS) e. List all noxious weeds and invasive species known to be on or near the site. None (STAFF COMMENTS) 5. Animals a. List any birds and other animals that have been observed on or near the site or are known to be on or near the site. Examples include: birds: hawk, heron, eagle, SONGBIRDS, other: mammals: deer, bear, elk, beaver, other: RODENTS fish: bass, salmon, trout, herring, shellfish, other: Revised on 9119116 P71_-_SEPA_Checklist Woodway.Station Design Review _ 2020.doc Page 11 of 2N Attachment 10 Packet Pg. 299 5.1.a (STAFF COMMENTS) List any threatened or endangered species known to be on or near the site. None (STAFF COMMENTS) C. Is the site part of a migration route? If so, explain. The site is in the path of the Pacific Flyway migratory bird route that extends from Alaska to Patagonia. (STAFF COMMENTS) d. Proposed measures to preserve or enhance wildlife, if any: The proposed project includes a detailed landscape plan that describes materials and methods to enhance the site with new plantings. This will enhance the opportunity for wildlife to forage and find shelter. See attached landscape plan for more information. (STAFF COMMENTS) e. List any invasive animal species known to be on or near the site. None Revised on 9119116 P71-_SEPA_Checklist Woodway Station Design Review_ 2020.doc Page 12 of 28 Attachment 10 1Packet Pg. 300 5.1.a (STAFF COMMENTS) 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. Electricity will be used for lighting, heating and equipment within the buildin_g's commercial space. (STAFF COMMENTS) b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. The proposed project would have negligible impact on the ability of adioininp properties to install and operate solar energy facilities due to the buildin_a setbacks and buildin-g height regulations associated with the City's zonin_q code. (STAFF COMMENTS) C. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: Light fixtures will have energy efficient bulbs and ballasts. HVAC equipment will have economizers where required by code. The development will be designed to meet or exceed the current WSEC compliance requirements. (STAFF COM Revised on 9119116 P71- SEPA _Checklist Woodway Station Design Review 2020.doc Page 13 of 28 Attachment 10 Packet Pg. 301 5.1.a 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so describe. None (STAFF COMMENTS) (1) Describe any known or possible contamination at the site from present or past uses. None c (STAFF COMM (2) Describe existing hazardous chemicals/conditions that might affect project development and design. This includes underground hazardous liquid and gas transmission pipelines located within the project area and in the vicinity. None (STAFF COMMENTS) (3) Describe any toxic or hazardous chemicals that might be stored, used, or produced during the project's development or constructions, or at any time during the operating life of the project. NONE. Revised on 9119116 P71-_SEPA_Checklist Woodway Station Design Review_ 2020.doc Page 14 of 28 Attachment 10 1Packet Pg. 302 5.1.a (STAFF COM (4) Describe special emergency services that might be required. Public Safety, Fire Suppression and emer_gency medical services is anticipated for this project that is normally associated with new construction and human occupancy. (STAFF COMMENTS) (5) Proposed measures to reduce or control environmental health hazards, if any: Measures to reduce or control environmental health hazards include providing safe and well lighted vehicular and pedestrian access pathways; desipnin_g the buildings to meet or exceed the minimal standards for life safety as re_-gulated through local, state and national building codes and providing on site management. (STAFF COMMENTS) b. Noise (1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? The current volumn of vehicular traffic associated with 10011, Ave W. Way will be the primary noise generator for this site. (STAFF COMMENTS) Revised on 9119116 P71 - SEPA_Checklist Woodway Station Design Review_ 2020.doc Page l5 of 28 Attachment 10 Packet Pg. 303 5.1.a (2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hour's noise would come from the site. As noted above the site is primarily impacted by vehicular noise from the sites location adjacent to a well trafficked arterial. Additional short term noise will be associated with the construction of the new facility. Thereafter, traffic noise will again become the predominant noise generator. The new development will --generate additional traffic that will mimic the current patterns of peak use. (STAFF COMMENTS) (3) Proposed measures to reduce or control noise impacts, if any: Short term noise _generation will be limited to dayli_ght hours as defined by local (STAFF COMMENTS) Revised on 9119116 P71_-_SEPA_Checklist Woodway Station Design Review 2020.doc Page 16 of 28 Attachment 10 1Packet Pg. 304 5.1.a 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? Will the proposal affect current land uses on nearby or adjacent properties? If so, describe. A commercial gas station and convenience store%ffice facility is located on the subject site. West and north and east of the subject parcel are located sinqle family homes that are separated from the subject parcel by neighborhood collecter streets and arterial streets. South of the subject parcel is located a cell tower and a small commercial structure that are separated from the site by a collecter street. Due to the associated setbacks from adjacent streets in the BN Zone, the landscapin_g requirements for the BN zone and the 25' height limit for a structure in the BN zone it is felt that a well designed class A office facility at this location will enhance the the neighborhood aesthetics and improve service opportunities for the neighborhood. (STAFF COM b. Has the project site been used as working farmlands or working forest lands? If so, describe. How much agricultural or forest land of long-term commercial significance will be converted to other uses as a result of the proposal, if any? If resource lands have not been designated, how many acres in farmland or forest land tax status will be converted to nonfarm or nonforest use? No (STAFF COMMENTS) (1) Will the proposal affect or be affected by surrounding working farm or forest land normal business operations, such as oversize equipment access, the application of pesticides, tilling, and harvesting? If so, how: No. (STAFF COMMENTS) _ C. Describe any structures on the site. Revised on 9119116 P71 _ _SEPA_Checklist Woodway Station Design Review 2020.doc Page 17 of 28 Attachment 10 Packet Pg. 305 5.1.a d. e. f. 9. None (STAFF COMMENTS) Will any structures be demolished? If so, what? Yes the exiting _gas canopy and the existing convenience store%ffice will be removed in their entirety alon_g with related accessory structures. (STAFF COMMENTS) What is the current zoning classification of the site? BN — Neighborhood Business (STAFF COMMENTS) What is the current comprehensive plan designation of the site? Commercial (STAFF COMMENTS)VI? I? If applicable, what is the current shoreline master plan designation of the site? N/A (STAFF COMMENTS) Revised on 9119116 P71 - SEPA_Checklist Woodway Station Design Review 2020.doc Page 18 of 28 c 0 ca 0) 3 0 0 0 0 0 0 N O N Z J a Attachment 10 Packet Pg. 306 5.1.a h. Has any part of the site been classified critical area by the city? If so, specify. k. No. (STAFF COMMENTS) Approximately how many people would reside or work in the completed project? Approximately 20 people will work in the proposed office building. (STAFF COMMENTS) Approximately how many people would the completed project displace? None. (STAFF COMMENTS) Proposed measures to avoid or reduce displacement impacts, if any: N/A (STAFF COMMENTS) Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The proposed project is designed to meet the criteria of the Citv's zonin_q and building codes including a proposed height under the maximum allowed for its zone. (STAFF COMM Revised on 9119116 P71 - SEPA_Checklist Woodway Station Design Review_ 2020.doc Page 19 of'28 Attachment 10 Packet Pg. 307 5.1.a 9. M. Proposed measures to reduce or control impacts to agricultural and forest lands of long-term commercial significance, if any: N/A (STAFF COMMENTS) Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. None (STAFF COMMENTS) b. Approximately how many units, if any would be eliminated? Indicate whether high, middle, or low-income housing. N/A as there ar no on -site units currently. (STAFF COMMENTS) C. Proposed measures to reduce or control housing impacts, if any: N/A (STAFF COMMENTS) 10. Aesthetics Revised on 9/19/16 P71-_SEPA_Checklist Woodway Station Design Review 2020.doc Page 20 of 28 c 0 co 0) 3 0 0 0 0 0 0 N O N Z J a. Attachment 10 1Packet Pg. 308 5.1.a a. What is the tallest height of any proposed structure(s), not including antennas; what is the principle exterior building material(s) proposed? The proposed office buildin_g will not exceed the allowable 25' hei_ght limit established for the BN zone by City decree. The exterior will be clad in City preferred materials such as wood, architectural metal and -glass, and products such as brick and fiber cement board finishes that replicate preferred materials. (STAFF COMMENTS) b. What views in the immediate vicinity would be altered or obstructed? The 2 story, 25' height of the development and proposed setbacks from property lines minimizes potential view disruption. (STAFF COMMENTS) C. Proposed measures to reduce or control aesthetic impacts, if any: The project is designed to blend into the character of the neighborhood through a variety of measures. Through the use of a hi_gh/y modulated system of wall forms, the use of exterior finish materials that would be comfortably associated with residential structures (i.e. brick claddin_a, horizontal board siding, residential style windows, board trim for accent bands and window trim) and a complimentary landscape plan, the buildin_g forms and massin_g will be strongly compatible with its environmental (STAFF COMMENTS) 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Building lighting fixtures will use full cutoff fixtures which shine the light mostly down. This will minimize illumination spillin_g beyond the walkin_g surface intended to be illuminated. (STAFF COMMENTS) Revised on 9119116 P71= _SEPA_Checklist Woodway Station Design Review 2020.doc Page 21 of 28 Attachment 10 Packet Pg. 309 5.1.a b. Could light or glare from the finished project be a safety hazard or interfere with views? No. (STAFF COMMENTS) C. What existing off -site sources of light or glare may affect your proposal? None (STAFF COMMENTS) d. Proposed measures to reduce or control light and glare impacts, if any: The exterior Iightin_g standards will utilize cut off fixtures to limit the "spilla_ge" of light past the property line. 12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity? There is the Scriber Lake High School facility several blocks to the north of the site. There is the Woodvale Community Park, the JP Patches Playground, the Hickman Park and the Klahava Swim and Tennis Club a couple of blocks west of the subject property. (STAFF COMMENTS) Revised on 9119116 P71-_SEPA_Checktist Woodway Station Design Review_ 2020.doc Page 22 of 28 Attachment 10 Packet Pg. 310 5.1.a b. Would the proposed project displace any existing recreation uses? If so, describe. No. (STAFF COMM C. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: None required. 13. Historic and Cultural Preservation a. Are there any buildings, structures, or sites located on or near the site that are over 45 years old listed in, or eligible for listing in national, state, or local preservation registers? If so, specifically describe. None that have been identified. (STAFF C MME TS) n cr v V-- A o L ✓ �. b. Are there any landmarks, features, or other evidence of Indian or historic use or occupation? This may include human burials or old cemeteries. Are there any material evidence, artifacts, or areas of cultural importance on or near the site? Please list any professional studies conducted at the site to identify such resources. None (STAFF COM Revised on 9119116 P71_- SEPA_Checklist Woodway Station Design Review 2020.doc Puke 23 of'28 c 0 c� to c� 3 0 0 0 v 0 0 0 N 0 N Z J d Attachment 10 Packet Pg. 311 5.1.a C. Describe the methods used to assess the potential impacts to cultural and historic resources on or near the project site. Examples include consultation with tribes and the Department of Archeology and Historic Preservation, archaeological surveys, historic maps, GIS date, etc. The site has been fully developed in the recent past. The site has been surveyed (see attached survey) and geo/ogica1 reports and Phase I evaluations of the site have been conducted. No cultural or historic resources have been identified by these reports. (STAFF COMMENTS) d. Proposed measures to avoid, minimize, or compensate for loss, changes to, and disturbance to resources. Please include plans for the above and any permits that may be required. None believed necessary 14. Transportation a. Identify public streets and highways serving the site or affected geographic area, and describe proposed access to the existing street system. Show on site plans, if any. The site is a corner site with current primary access to 100t" Ave. W-and secondary access to the subject property from 2381n St. SW and informal access from 101st Ave. W. We are proposin_q a primary access from 1001 Ave W near the NE corner of the site and a secondary access from 238th St. SW per the attached site plan. (STAFF COMMENTS) b. Is the site or affected geographic area currently served by public transit? If so, generally describe. If not, what is the approximate distance to the nearest transit stop? Revised on 9119116 P71-_SEPA_Checklist Woodway Station Design Review 2020.doc 1' .,, "' a/?x Attachment 10 1Packet Pg. 312 5.1.a Yes. Snohomish Transit operates public bus service on 100th Ave. W in both directions via route 130 with stops in the immediate vicinity.. (STAFF COMMENTS) _ C. How many additional parking spaces would the completed project or nonproject proposal have? How many would the project or proposal eliminate? The existing developed property lot currently has several demarcated parking spaces and substantial site area paved informally for additional numbers of stalls. The new development will provide 23 total stalls. (STAFF COMMENTS) d. Will the proposal require any new or improvements to existing roads, streets, pedestrian, bicycle or state transportation facilities not including driveways? If so, generally describe (indicate whether public or private). Frontage improvements along 100th Ave W. will include a pedestrian sidewalk, landscape strip with street trees, and City standard curb cut that are consistant with the City of Edmonds development guidelines. A new curbcut is proposed to replace an existin_o curbcut on the 238th St. SW frontage. An additional exiting curb cut along 2381h St SW will be removed and replaced with new sidewalk. Street curbing will be installed along the 101s' Ave. W frontage. (STAFF COMMENTS) e. Will the project or proposal use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. Revised on 9119116 P71 _- SEPA_Checklist Woodway Station Design Review_ 2020.doc Page 25 of 28 Attachment 10 Packet Pg. 313 5.1.a (STAFF COMMENTS) f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur and what percentage of the volume would be trucks (such as commercial and passenger vehicles). What data or transportation models were used to make these estimates? The development will _-ggenerate approximately 174 average daily trips with 8 AM peak - hour trips and 18 PM peak -hour trips. This data was determined usin_g the ITE Trip Generation 101h Edition. It would be anticipated that the truck percentage would not exceed that of the adjacent roadway or approximately 2%. See attached traffic memo. (STAFF COMMENTS) g. Will the proposal interfere with, affect or be affected by the movement of agricultural and forest products on roads or streets in the area? If so, generally describe. No. (STAFF COMMENTS) h. Proposed measures to reduce or control transportation impacts, if any: Revised on 9119116 The development will provide its share of traffic impact mitigation fees. See attached traffic memo. P71_-_SEPA—Checklist Woodway Station Design Review 2020.doc Page 26 of 2h Attachment 10 Packet Pg. 314 5.1.a 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, public transit, health care, schools, other)? If so, generally describe. The project will require additional public services such as community policing, emergency medical services, fire protection, health care, public transit and educational services consistant with a an expansion of the built environment. (STAFF COMMENTS) b. Proposed measures to reduce or control direct impacts on public services, if any: The buildin_g will be fully sprinklered and designed to meet or exceed building code standards for new construction. Additional tax revenues associated with this project's completion should offset the added costs for emergency services. (STAFF COMMENTS) 16. Utilities a. Circle utilities currently available at the site: ELECTRICITY, NATURAL GAS, WATER, REFUSE SERVICE, TELEPHONE, SANITARY SEWER, septic system, other: Electricity, gas, water, sewer, refuse service, telephone, sewer, storm. (STAFF COMMENTS) b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. City of Edmonds manages the storm. Olympic View is in charge of water and sewer. Sno PUD provides electricity. Revised on 9119116 P71-_SEPA_Checklist Woodway Station Design Review 2020.doc Page 27 of 28 Attachment 10 Packet Pg. 315 5.1.a (STAFF COMMENTS) C. SIGNATURE I declare under penalty of perjury laws that the above answers are true and correct to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature of Proponent BMWIN� Date Submitted Revised on 9119116 P91_- SEPA_Checklist Woodway Station Design Review_ 2020. doc Page 28 of 28 Attachment 10 Packet Pg. 316 5.1.a O� ED,y 0 41 CITY OF EDMONDS �S[ ISco 1215TH AVENUE NORTH, EDMONDS, WA 98020 (425) 771-0220 DETERMINATION OF NONSIGNIFICANCE Description of proposal: The applicant is proposing to demolish the existing structure that was formerly used as convenience store and gas station and construct a new two-story, approximately 11,000 square foot commercial building. The project (Woodway Station) will also provide 22 parking spaces and new landscaping. Proponent: CDA Pirscher Architects Location of proposal, including street address if any: 23726 1001 Avenue West, Edmonds, WA. Tax Parcel Number 27033600400500 Lead agency: City of Edmonds The lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.21C.030 (2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. The City of Edmonds has determined that the requirements for environmental analysis and protection have been adequately addressed in the development regulations and comprehensive plan adopted under chapter 36.70A RCW, and in other applicable local, state, or federal laws or rules, as provided by RCW 43.21C.240 and WAC 197-11-158 and/or mitigating measures have been applied that ensure no significant adverse impacts will be created. There is no comment period for this DNS. This DNS is issued after using the optional DNS process in WAC 197-11-355. There is no further comment period on the DNS. XX This DNS is issued under 197-11-340(2); the lead agency will not act on this proposal for 14 days from the date below. Comments must be submitted by January 21, 2021. Project Planner: Kernen Lien, Environmental Programs Manager Responsible Official: Rob Chave, Planning Manager Contact Information: City of Edmonds 1 1215th Avenue North, Edmonds WA 98020 1 425-771-0220 Date: January 7, 2021 Signature:_�'�/� XX You may appeal this determination to Robert Chave, Planning Manager, at 121 5th Avenue North, Edmonds, WA 98020, by filing a written appeal citing the specific reasons for the appeal with the required appeal fee, adjacent property owners list and notarized affidavit form no later than January 28, 2021. You should be prepared to make specific factual objections. Contact Rob Chave to read or ask about the procedures for SEPA appeals. XX Posted on January 7, 2021, at the Edmonds Public Library and Edmonds Public Safety Building. Published in the Everett Herald. Emailed to the Department of Ecology SEPA Center (SEPAunit@ecy.wa.gov). Mailed to property owners within 300 feet of the site. XX Distribute to "Checked" Agencies below. Information on this development application can be obtained online at http://edmondswa.gov/public-notices- text/development-notices.html under the development notice for application number PLN2020-0040, by emailing the City contact listed below, or by calling the City of Edmonds at 425-771-0220. . Page 2 of 2 SEPA DETERMNAnON_REVISED 20190311 Attachment 11 vsi21.SEPA Packet Pg. 317 5.1.a Distribution List: This DNS and SEPA checklist were distributed to the following: ❑X Applicant ❑X Dept. of Ecology ❑ City of Everett ❑X Parties of Record ❑ Dept. of Ecology - Shorelands ❑ City of Lynnwood ❑ Dept. of Natural Resources ❑ City of Mountlake Terrace ❑ US Army Corps of Engineers ❑ Dept. of Commerce ❑ City of Mukilteo ❑ US Fish and Wildlife ❑ WSDOT ❑ City of Shoreline ❑ WSDOT— Ferries ❑ Town of Woodway ❑X Puget Sound Energy ❑ Dept. of Fish & Wildlife ❑X Snohomish PUD ❑ Dept. of Health — Drinking Water ❑ Snohomish Co. Public Works ❑X Olympic View Water & Sewer ❑X Dept. of Arch. & Historic Pres. ❑ Snohomish Co. PDS ❑ Alderwood Water District ❑ Dept. of Parks and Rec. Commission ❑ Snohomish Co. Health Dist. ❑ Edmonds School District ❑ Port of Edmonds ❑X Puget Sound Clean Air Agency ❑ King County - Transit ❑X South County Fire ❑ Puget Sound Regional Council ❑ King County — Environ. Planning ❑ Swedish Hospital ❑ Puget Sound Partnership ❑ Community Transit ❑X Tulalip Tribe ❑ Other pc: File No. PLN2020-0040 SEPA Notebook Page 2 of 2 SEPA DETERMINATION_PLN2020-0040 Attachment 11 Ii6i2LSEPA Packet Pg. 318 5.1.a d0> r Ln 2351 0 2351 �o Ln LO.O L RSM 00 00 00 NLn rn 23605 c�CO6,o2360723 g1 Y 236TH PL SW 23611 ?36)0 6' 23611 ' N 23611 2361 cc 23620 3621 N N c 2361 23618 23619 N U 23628 '1�ry 2361 2361 3629 O$Mr 23627 Q Q� LO N 2362 012 1� 23632 ,�� `�61 t° 3701 O "' a 2370 632 W 23633 ►= 23706 °� co"'� o� N N 23 6 3707 O'� '�'� 2370 23 Q 23707 Ocb`v °' 62 �"� H- ey °� oO CO 00 � c 4 o� 23712 23715 23� c� (Mn 01 cCD N N ^0� CO 23718 c o°� � 9804 r . O r r 23721 23726 23720: �N CO 9808 N r 238TH ST SW ' ' ' ' 0 0 9812 23806 23805 23808 1Bt� 23803 r M ti M LU a)MCD N 23814 23813 23816 �`b > 23813 °' 0 M 0 0 0 � 23820 23821 238TH ST SW 3828 23828 M W Z�a30 ?3g29 23 MVN Q Q c 00 00 N oo CDc 3830 Q 830 N� � � o a, 0 0 0 CO 3902 9 23832 0 • ; • 997 9905 N Cn — 15 910 y�N 0 9�, O� � � ; � 0 00 0� 0 9� 23924 �� 23915 23916 2391 991 99 J'� 9813 9 4 07 9821 23923 Nto 23920 99 A8 CD �9 �`' w 00 CO >> 23928 a 23927 N 23926 9904 9822 M M Tii;V) 9914 r rN N T- r �L4002 r O) O O O O ^ O Ln r M Ln `,7e. ig9l Zoning and Vicinity Map PLN2020-0040 Woodway Station 23726 100th Ave. W Attachment 12 0 0 0 0 0 O 0 N O N Z J a Scale 1 inch = 200 feet Packet Pg. 319 5.1.a FILE NO.: PLN2020-0040 Applicant: CDA Pirscher Architects DECLARATION OF POSTING On the 10th day of September, 2020, the attached Notice of Application was posted at the subject property in accordance with Edmonds Community Development Code (ECDC) 20.03.002. I, Kernen Lien, hereby declare under penalty of perjury under the laws of the State of Washington that the foregoing is true and correct this 101h day of September, 2020, at Edmonds, Washington. Signed: {BFP747893.DOC;1\00006.900000\ } Attachment 13 Packet Pg. 320 5.1.a FILE NO.: PLN2020-0040 Applicant: CDA Pirscher Architects DECLARATION OF MAILING On the I Ot" day of September, 2020, the attached Notice of Application was mailed by the City of Edmonds to property owners within 300 feet of the property that is the subject of the above - referenced application. The adjacent property owners list was provided by the applicant. I, Debbie Rothfus, hereby declare under penalty of perjury under the laws of the State of Washington that the foregoing is true and correct this lOt" day of September, 2020, at Edmonds, Washington. Signed: ' {BFP747887.DOC;1\00006.900000\ } Attachment 13 Packet Pg. 321 5.1.a CITY OF EDMONDS NOTICE OF APPLICATION `nC. i0V PROJECT DESCRIPTION: The applicant is proposing to demolish the existing structure has was formerly used as convenience store and gas stations and construct a new two-story, 10,966 square foot commercial building. The project will also provide 23 parking spaces and a new landscaping. The site is zoned Neighborhood Business (BN). PROJECT LOCATION: 23726 —100'h Avenue West, Edmonds, WA. Tax Parcel Number 27033600400500 NAME OF APPLICANT: CDA Pirscher Architects FILE NUMBER: PLN2020-0040 DATE OF APPLICATION: August 4, 2020 DATE OF COMPLETENESS: September 1, 2020 DATE OF PUBLIC NOTICE: September 10, 2020 REQUESTED PERMIT: Design Review (Type III -A Permit Process). A public hearing before the Architectural Design Board will be scheduled at a future date. A Notice of Public Hearing will be issued once the ADB date has been scheduled. OTHER REQUIRED PERMITS: Building Permit, SEPA Determination. EXISTING ENVIRONMENTAL DOCUMENTS: Critical Area Determination, Preliminary Stormwater Report, Phase I & Phase II Environmental Assessments, SEPA Checklist COMMENTS ON PROPOSAL DUE: September 24, 2020 Any person has the right to comment on this application during public comment period, receive notice and participate in any hearings, and request a copy of the decision on the application. The City may accept public comments at any time prior to the closing of the record of an open record predecision hearing, if any, or, if no open record predecision hearing is provided, prior to the decision on the project permit. Only parties of record as defined in ECDC 20.06.020 have standing to initiate an administrative appeal. Information on this development application can be obtained online at http://edmondswa.gov/public- notices-text/development-notices.html under the development notice for application number PLN2020- 0040, by emailing the City contact listed below, or by calling the City of Edmonds at 425-771- 0220. Please refer to the application number for all inquiries. Attachment 13 Packet Pg. 322 CITY CONTACT: KernenLien, Environmental Programs Manager kernen]ien@ednnondsvva.Qov 425'771-0220 mmvms HOOP V I-N,,',[- r'rr��� L3 � 5.1.a Everett Daily Herald Affidavit of Publication State of Washington } County of Snohomish } ss Dicy Sheppard being first duly sworn, upon oath deposes and says: that he/she is the legal representative of the Everett Daily Herald a daily newspaper. The said newspaper is a legal newspaper by order of the superior court in the county in which it is published and is now and has been for more than six months prior to the date of the first publication of the Notice hereinafter referred to, published in the English language continually as a daily newspaper in Snohomish County, Washington and is and always has been printed in whole or part in the Everett Daily Herald and is of general circulation in said County, and is a legal newspaper, in accordance with the Chapter 99 of the Laws of 1921, as amended by Chapter 213, Laws of 1941, and approved as a legal newspaper by order of the Superior Court of Snohomish County, State of Washington, by order dated June 16, 1941, and that the annexed is a true copy of EDH908236 PLN2020-0040 as it was published in the regular and entire issue of said paper and not as a supplement form thereof for a period of 1 issue(s), such publication commencing on 09/10/2020 and ending on 09/10/2020 and that said newspaper was regularly distributed to its subscribers during all of said period. The amount of the fee for Uuchhublication is $61.60. :::�� Subscribed and sworn b e me on this day o Q� D Nota Public in and for the State of Washington. City of Edmonds - LEGAL ADS 1 14101416 KERNEN LIEN Attachment 13 U ndo ps lic Washington s08129l2021 .t Packet Pg. 324 Classified Proof CITY OF EDMONDS NOTICE OF APPLICATION PROJECT DESCRIPTION: The applicant Is proposing to demolish the existing structure has was formerly used as convenience store and gas stations and construct a new two-story, 10,966 square foot commercial building. The project will also provide 23 = parking spaces and a new landscaping. The site is zoned 0 Neighborhood Business (BN), r PROJECT LOCATION: (� 23726 — 100th Avenue West, Edmonds, WA. Tax Parcel Number 27033600400500 NAME OF APPLICANT: CDA Pirscher Architects FILE NUMBER: PLN2020-0040 DATE OF APPLICATION: August 4, 2020 DATE OF COMPLETENESS: September 1, 2020 DATE OF PUBLIC NOTICE: September 10, 2020 REQUESTED PERMIT: Design Review (Type III -A Permit 0 Process). A public hearing before the Architectural Design Board 0 will be scheduled at a future dale. A Notice of Public Hearing will be issued once the ADB date has been scheduled. OTHER REQUIRED PERMITS: Building Permit, SEPA o Determination. EXISTING ENVIRONMENTAL DOCUMENTS: Critical Area o Determination, Preliminary Stormwaler Report, Phase I & Phase II Environmental Assessments, SEPA Checklist COMMENTS ON PROPOSAL DUE: September 24, 2020 CD Any person has the right to comment on this application during N comment period, receive notice and participate In any CDtearings, Public and request a copy of the decision on the application, N The City may accept public comments at any time prior to the Z closing of the record of an open record predecision hearing, if any, J or, if no open record predecision hearing is provided, prior to the a decision on the project permit. Only parties of record as defined in ECDC 20.06.020 have standing to Initiate an administrative appeal. Information on this development apprication can be obtained online U) at http:/fedlnondswa.gov/public-notices-text/development- 4+ notices.html under the development notice for application number = PLN2020-0040, by emailing the City contact listed below, or by N calling the City of Edmonds at 425-771-0220. Please refer to the E application number for all Inquiries. CITY CONTACT: Kernen Lien, Environmental Programs Manager kemeii.lien@ediiioiidswa.gov 425-771-0220 fC Published: September 10, 2020. EOH908236 Q i w 3 0 a ro c� 0 v 0 0 CD N 0 N Z J a a� E 0 r r a Proofed by Sheppard, Dicy, 09/10/2020 09:28:12 am Page: 2 Attachment 13 Packet Pg. 325 5.1.a FILE NO.: PLN2020-0040 Applicant: CDA Pirscher Architects DECLARATION OF POSTING On the 24th day of September, 2020, the attached REVISED Notice of Application was posted at the subject property in accordance with Edmonds Community Development Code (ECDC) 20.03.002. I, Kernen Lien, hereby declare Washington that the foregoing Edmonds, Washington. under penalty of perjury under the laws of the State of is true and correct this 241h day of September, 2020, at Q Signed: {BFP747893.DOC;1\00006.900000\ } Attachment 14 Packet Pg. 326 5.1.a File No.: PLN2020-0040 Applicant: CDA Pirscher Architects Type III -A Permit Process Design Review Revised Notice DECLARATION OF MAILING On the 25th day of September, 2020, the attached Notice of application and virtual public hearing as prescribed by Ordinance to property owners within 300 feet of the site that is the subject of this application. I, Michelle Martin, hereby declare under penalty of perjury under the laws of the State of Washington that the foregoing is true and correct this 25th day of September, 2020, at Edmonds, Washington. Signed: WIGc� Attachment 14 Packet Pg. 327 5.1.a CITY OF EDMONDS REVISED NOTICE OF APPLICATION Revised to provide public notice in compliance with ECDC 20.03.002.D. `n C. 1 89\,) PROJECT DESCRIPTION: The applicant is proposing to demolish the existing structure has was formerly used as convenience store and gas stations and construct a new two-story, 10,966 square foot commercial building. The project will also provide 23 parking spaces and a new landscaping. The site is zoned Neighborhood Business (BN). PROJECT LOCATION: 23726 —100th Avenue West, Edmonds, WA. Tax Parcel Number 27033600400500 NAME OF APPLICANT: CDA Pirscher Architects FILE NUMBER: PLN2020-0040 DATE OF APPLICATION: August 4, 2020 DATE OF COMPLETENESS: September 1, 2020 DATE OF PUBLIC NOTICE: September 25, 2020 REQUESTED PERMIT: Design Review (Type III -A Permit Process). A public hearing before the Architectural Design Board will be scheduled at a future date. A Notice of Public Hearing will be issued once the ADB date has been scheduled. OTHER REQUIRED PERMITS: Building Permit, SEPA Determination. EXISTING ENVIRONMENTAL DOCUMENTS: Critical Area Determination, Preliminary Stormwater Report, Phase I & Phase II Environmental Assessments, SEPA Checklist COMMENTS ON PROPOSAL DUE: October 9, 2020 Any person has the right to comment on this application during public comment period, receive notice and participate in any hearings, and request a copy of the decision on the application. The City may accept public comments at any time prior to the closing of the record of an open record predecision hearing, if any, or, if no open record predecision hearing is provided, prior to the decision on the project permit. Only parties of record as defined in ECDC 20.06.020 have standing to initiate an administrative appeal. Information on this development application can be obtained online at http://edmondswa.gov/public- notices-text/development-notices.html under the development notice for application number PLN2020- 0040, by emailing the City contact listed below, or by calling the City of Edmonds at 425-771-0220. Please refer to the application number for all inquiries. Attachment 14 Packet Pg. 328 5.1.a CITY CONTACT: Kernen Lien, Environmental Programs Manager kernen.lien@edmondswa.gov 425-771-0220 NI-W (q' 111:)11 wc; r'P HI-1 Irp AIONr, 11II"51 1 01 111,11 F4 N1-W 6' 1I101I I; IIGLSr vLnnn I-rwr.r V .. ....... . L"I I' Attachment 14 Packet Pg. 329 5.1.a Everett Daily Herald RECEIVED 012020 PLANNING DEPT. Affidavit of Publication State of Washington } County of Snohomish } ss Dicy Sheppard being first duly sworn, upon oath deposes and says: that he/she is the legal representative of the Everett Daily Herald a daily newspaper. The said newspaper is a legal newspaper by order of the superior court in the county in which it is published and is now and has been for more than six months prior to the date of the first publication of the Notice hereinafter referred to, published in the English language continually as a daily newspaper in Snohomish County, Washington and is and always has been printed in whole or part in the Everett Daily Herald and is of general circulation in said County, and is a legal newspaper, in accordance with the Chapter 99 of the Laws of 1921, as amended by Chapter 213, Laws of 1941, and approved as a legal newspaper by order of the Superior Court of Snohomish County, State of Washington, by order dated June 16, 1941, and that the annexed is a true copy of EDH909460 PLN2020-0040 as it was published in the regular and entire issue of said paper and not as a supplement form thereof for a period of 1 issue(s), such publication commencing on 09/25/2020 and ending on 09/25/2020 and that said newspaper was regularly distributed to its subscribers during all of said period. The ount of the fee o such publicati n is $63.00. Subscribed and sworn re me on this �� F da Phillips dayo tarypublic f Washington ra Expires 08/29/2021 1 Notary Public in and for the State of Washington. City of Edmonds -LEGAL ADS 114101416 KERNEN LIEN Attachment 14 Packet Pg. 330 Classified Proof 5.1.a CITY OF EDMONDS REVISED NOTICE OF APPLICATION Revised to provide public notice in compliance with ECDC 20.03.002.D. PROJECT DESCRIPTION: The applicant Is proposing to demolish the existing structure has was formerly used as convenience i store and gas stations and construct a new two-story, 10,966 0 square foot commercial building. The project will also provide 23, parking spaces and a new landscaping. The site is zoned Neighborhood Business (81\1J_ r+ PROJECT LOCATION: 23726 — 100th Avenue West, Edmonds, (n WA. Tax Parcel Number 27033600400500 NAME OF APPLICANT: CDA Pirscher Architects FILE NUMBER: PLN2020-0040 DATE OF APPLICATION: August 4, 2020 DATE OF COMPLETENESS: September 1, 2020 'a DATE OF PUBLIC NOTICE: September 25, 2020 0 REQUESTED PERMIT: Design Review (Type III -A Permit 0 Process). A public hearing before the Architectural Design Board will be scheduled at a future date. A Notice of Public Hearing will I be Issued once the ADB date has been scheduled. o OTHER REQUIRED PERMITS. Building Permit, SEPA Determination. EXISTING ENVIRONMENTAL DOCUMENTS: Critical Area Determination, Preliminary Stonmwater Report, Phase I R Phase 9 II Environmental Assessments, SEPA Checklist p COMMENTS ON PROPOSAL DUE: October 9, 2020 I;V Any person has the right to comment on this application during public comment period, receive notice and participate in any N hearings, and request a copy of the decision on the application. Z The City may accept public comments at any time prior to the J closing of the record of an open record predecislon hearing, if any, or, If no open record predecision hearing is provided, prior to the d decision on the Project permit. Only parties of record as defined In ECDC 20.06.020 have standing to Initiate an administrative appeal. Information on this development application can be obtained online y at hltp://edmondswa.gov/public-notices-text/development- notices.html under the development notice for application number PLN2020-0040, by emalling the City contact listed below, or by calling the City of Edmonds at 425-771-0220. Please refer to the application number for all inquiries. CITY CONTACT: Kernen Lien, Environmental Programs Manager tJ kernen.lien@edmondswa.gov r 425-77 1-0220 �.. Published: September 26, 2020. EDH909460 a t r-+ 3 0 a a� 0 0 0 0 0 N CD N Z J a r c m E z c� ..r Proofed by Sheppard, Dicy, 09/25/2020 12:59:26 pm Page: 2 Attachment 14 Packet Pg. 331 5.1.a FILE NO.: PLN2020-0040 Applicant: CDA Pirscher Architects DECLARATION OF POSTING On the 7th day of January, 2021, the attached notice of public hearing and SEPA determinations was posted at the subject property in accordance with Edmonds Community Development Code (ECDC) 20.03.002. I, Kernen Lien, hereby declare under penalty of perjury under the laws of the State of Washington that the foregoing is true and correct this 7th I day of January, 2021, at Edmonds, Washington. Signed: {13FP747893.DOC;1\00006.900000\ } Attachment 15 Packet Pg. 332 5.1.a File No.: PLN2020-0040 Applicant: CDA Pirscher Architects Notice of Public Hearing SEPA Threshold Determination DECLARATION OF MAILING On the 7th day of January, 2021, the attached Notice of application and virtual public hearing as prescribed by Ordinance to property owners within 300 feet of the site that is the subject of this application. I, Michelle Martin, hereby declare under penalty of perjury under the laws of the State of Washington that the foregoing is true and correct this 7th day of January, 2021 at Edmonds, Washington. A Signed: � Attachment 15 Packet Pg. 333 5.1.a CITY OF EDMONDS NOTICE OF PUBLIC HEARING AND SEPA THRESHOLD DETERMINATION `11C. l S9'J PROJECT DESCRIPTION: The applicant is proposing to demolish the existing structure that was formerly used as convenience store and gas station and construct a new two-story, approximately 11,000 square foot commercial building. The project (Woodway Station) will also provide 22 parking spaces and new landscaping. The site is zoned Neighborhood Business (BN). The proposed development is subject to the zoning standards in Chapter 16.45 Edmonds Community Development Code (ECDC) and general design standards in Chapter 20.11 ECDC. PROJECT LOCATION: 23726 100th Avenue West, Edmonds, WA Tax Parcel Number 27033600400500 NAME OF APPLICANT: CDA Pirscher Architects FILE NO.: PLN2020-0040 REQUESTED PERMIT: Design Review (Type III -A Permit Process, Public Hearing and Decision by the Architectural Design Board) COMMENTS ON PROPOSAL DUE: February 3, 2021 Any person has the right to comment on this application during public comment period, receive notice and participate in any hearings, and request a copy of the decision on the application. The City may accept public comments at any time prior to the closing of the record of an open record predecision hearing, if any, or, if no open record predecision hearing is provided, prior to the decision on the project permit. Information on this development application can be obtained online at htto://edmondswa.Rov/public-notices-text/development-notices.html under the development notice for application number PLN2020-0040, by emailing the City contact listed below, or by calling the City of Edmonds at 425-771-0220. Please refer to the application number for all inquiries. A copy of the staff report will be available at least seven days prior to the hearing. PUBLIC HEARING INFORMATION: Due to COVID-19, a virtual public hearing will be held by the Architectural Design Board on February 3, 2021 at 7 p.m. Join the Zoom meeting at: https://zoom.us/i/96385160252?pwd=OGtCNDNGQkllMzVNZ*JgMkNJYlZGQT09 Or via phone by dialing 253-215-8782 Meeting ID: 963 8516 0252 Password: 944947 SEPA DETERMINATION: Notice is Hereby Given that the City of Edmonds has issued a Determination of Nonsignificance under WAC 197-11-340 for the above project. DATE OF ISSUANCE: January 7, 2021 SEPA COMMENTS: Comments regarding the SEPA determination are due January 21, 2021. Attachment 15 Packet Pg. 334 5.1.a SEPA APPEAL: This SEPA determination may be appealed by filing a written appeal citing the specific reasons for appeal with the required appeal fee no later than January 28, 2021 by 4:00 p.m. Only parties of record as defined in ECDC 20.06.020 have standing to initiate an administrative appeal. CITY CONTACT: Kernen Lien, Environmental Programs Manager kernen.lien@edmondswa.gov 425-771-0220 L� J[#��ff ► t� 40 Attachment 15 1Packet Pg. 335 5.1.a Everett Daily Herald Affidavit of Publication State of Washington } County of Snohomish } ss Dicy Sheppard being first duly sworn, upon oath deposes and says: that he/she is the legal representative of the Everett Daily Herald a daily newspaper. The said newspaper is a legal newspaper by order of the superior court in the county in which it is published and is now and has been for more than six months prior to the date of the first publication of the Notice hereinafter referred to, published in the English language continually as a daily newspaper in Snohomish County, Washington and is and always has been printed in whole or part in the Everett Daily Herald and is of general circulation in said County, and is a legal newspaper, in accordance with the Chapter 99 of the Laws of 1921, as amended by Chapter 213, Laws of 1941, and approved as a legal newspaper by order of the Superior Court of Snohomish County, State of Washington, by order dated June 16, 1941, and that the annexed is a true copy of EDH917087 PLN2020-0040 as it was published in the regular and entire issue of said paper and not as a supplement form thereof for a period of 1 issue(s), such publication commencing on 01/07/2021 and ending on 01/07/2021 and that said newspaper was regularly distributed to its subscribers during all of said period. The amount of the fee for such publication is .� $82��j Subscribed and sworn efore me on this day of71 \ r Notary Public in and for the State of Washington. City of Edmonds - LEGAL ADS 114101416 KERNEN LIEN i,ln U Phllllps Notary Public State of Washington MYAPPott�tmOM fiesoa/29/2py� Art`. RECEIVE,. BAN 2 0 2021 PLAtM O DEPT. . Attachment 15 Packet Pg. 336 Classified Proof 5.1.a City of Edmond NOTICE OF PUBLIC HEARING AND SEPA THRESHOLD DETERMINATION PROJECT DESCRIPTION: The applicant is proposing to demolish the existing structure that was formerly used as convenience store and gas station and construct a new two-story, approximately 11,000 square foot commercial building. The project (Woodway Station) will also provide 22 parking spaces and new landscaping. The site is zoned Neighborhood Business (BN). The proposed development Is subject to the zoning standards In Chapter 16.45 Edmonds Comrnunky Development Code (ECDC) and general design standards in Chapter 20.11 ECDC. PROJECT LOCATION: 23726 100th Avenue West, Edmonds, WA Tax Parcel Number 27033600400500 NAME OF APPLICANT: CDA Pirscher Architects FILE NO.: PLN2020-0040 REQUESTED PERMIT: Design Review (Type III -A Permit Process, Public Hearing and Decision by the Architectural Design Board) COMMENTS ON PROPOSAL DUE: February 3, 2021 Any person has the right to comment on this application during public comment period, receive notice and participate in any hearings, and request a copy of the decision on the applicatlon. The City may accept public comments at any time prior to the closing of the record of an open record predecision hearing, it any, or, if no open record predecision hearing is provided, prior to the decision on the project permit. Information on this development application can be obtained online at http://edmondswa.gov/pubric-notices-texYdevelopment- notices.html under the development notice for application number PLN2020-0040, by ernaliing the City contact listed below, or by calling the City of Edmonds at 425-771-0220. Please refer to the application number for all inquiries. A copy of the staff report will be available at least seven days prior to the hearing. PUBLIC HEARING INFORMATION: Due to COVID-19, a virtual public hearing will be held by the Architectural Design Board on February 3, 2021 at 7 p.m. Join the Zoom meeting at: https:llzoom.us/1/96386160252?pwd=OGICNDNGQkll MzVNZjJ gMkNJYlZGQT09 Or via phone by dialing 253-215-8782 Meeting ID: 963 8516 0262 Password: 944947 SEPA DETERMINATION: Notice is Hereby Given that the City of Edmonds has issued a Determination of Nonsignificance under WAG 197-11-340 for the above project DATE OF ISSUANCE: January 7, 2021 SEPA COMMENTS: Comments regarding the SEPA determination are due January 21, 2021. SEPA APPEAL: This SEPA determination may be appealed by fling a written appeal citing the specific reasons for appeal with the required appeal fee no later than January 28, 2021 by 4:00 p.m. Only parties of record as defined in ECDC 20.06.020 have standing to initiate an administrative appeal. CITY CONTACT: Kamen Lien, Environmental Programs Manager kernen.Ilen@eclmondswa.gov 425-771-0220 Published: January 7, 2021. EDH917087 Proofed by Sheppard, Dicy, 01/07/2021 09:18:17 am Page: 2 Attachment 15 Packet Pg. 337 5.1.a From: SUSAN FRODSHAM To: Lien, Kernen Subject: Development notice Date: Wednesday, September 23, 2020 5:08:12 PM Hello, I have concerns about the development notice for application number PLN2020-0040. My concern is the placement of the fence on the backside of the property along 101st Ave W. extending to 238th S.W. The fence can't be placed up to the sidewalk on 238th S.W. without causing disruption of visibility that is needed. With increase of daily traffic,along with the speed of the cars making the turns from 100th Ave. A clear visual sight is needed to pull out into traffic from 101 st Ave W. At the present time when the Salon customers from across the street park in the lot next to sidewalk. The visibility is impaired and dangerous. My other comment is concerning the material of the fence. It should be made out of material that will discourage persons from using the fence for graffiti. This is a Family neighborhood first! Thank you for your, Sue Frodsham 206-542-3456 suefrodsham@comcast.net Attachment 16 Packet Pg. 338 5.1.a From: Danielle Hursh To: Lien, Kernen Subject: Public comment on PLN2020-0040 Date: Tuesday, September 22, 2020 11:15:40 AM Hello, I would like to submit my public comment for Project PLN2020-0040 - Woodway Station. The proposed development does not fit in with the existing neighborhood or commercial structures at all. All of the surrounding buildings - both residential and commercial - are one story in height and reflect a more casual development style with wood siding and minimal glazing. The proposed project, while meeting City of Edmonds setbacks and design guidelines, will loom over the quiet single family residential neighborhood. Design materials such as metal siding and extensive glazing do not compliment the neighborhood. In addition, the project is specifically designed to have rear facing decks overlooking 101st Ave W on the second story of the project - further intruding into the residential neighborhood and peering into adjacent properties. Such design does not maintain privacy for the existing residents and businesses. As a resident on 101 st Avenue W, I am extremely concerned about the amount of parking provided for this project and the number of daily trips associated with this development. Currently 101 st Ave W is a quiet, dead-end street. We have minimal traffic except for residents of the street and delivery vehicles. This project will be providing office/retail space for potentially 4 different businesses. That is a huge change from the current use of the site - a single business utilizes the property to park garbage trucks. There currently is minimal traffic associated with the site and its current use. The new development will have approximately 20 employees on site and will generate 174 average daily trips between Sam and 6pm, yet there are only 23 parking spaces available on site. I anticipate this will cause employees to park off- street in the adjacent neighborhood in order to preserve parking on -site for customers. That is unacceptable. I am also concerned that the increased number of daily trips generated by this development will increase traffic and noise on 101 st Ave W. Vehicles bound for this location may miss the turn for the parking lot and will then utilize 101 st Ave W to turn around - representing a potential increase in traffic on a residential street that is unacceptable. The proposed plan to add a curb along 101 st Ave W, but no sidewalk, further encourages on -street parking along the west side of the project and creates additional impacts to the neighborhood. The current project site is underutilized and has been for years. Adjacent businesses and private clubs have utilized the site for additional parking - minimizing their impact on the surrounding residential neighborhood. With the redevelopment of this site, we are also concerned with on -street parking impacts on residential streets from the Woodway Barbershop and the Klahaya swim and tennis club will increase. I am also concerned about the plants selected to landscape the site. The plans state that the plants chosen will complement the local flora, however they are not native species and are not drought tolerant. They will provide minimal privacy and screening from this huge commercial building located in a small residential neighborhood. Changes to the planting plan should be considered - including larger trees that will grow up to provide a better screen and privacy between this project and the single story homes adjacent. In addition to the specific project issues I've mentioned above, I am extremely concerned Attachment 17 Packet Pg. 339 5.1.a about the impact on the surrounding residential neighborhood during construction. We are currently dealing with COVID-19 restrictions. Many people are stuck at home, teleworking, doing remote learning, etc. We are already stressed and dealing with much change and upheaval in our lives. Many folks in my neighborhood are dealing with mental health issues and emotions are running high. It's challenging to function well during most days, let alone when we are impacted by traffic from construction vehicles - which may park on local residential streets near the project - or noise and impacts from demolition and construction. I have been teleworking for the past six months and am already challenged by the weekly visit from my neighbor's gardener. I cannot imagine the impact construction noise will have on my ability to effectively make phone calls, video conference, or do other essential work and thanks to COVID, I have no ability to relocate. In addition, a project of this size will need to have utility work done - which may impact the neighborhood by shutting off water, electricity, and/or internet access. All of these potential impacts would make telework and remote learning impossible. If this project is approved and proceeds, the City of Edmonds needs to work carefully with the property owner/project manager to ensure minimal impacts on the neighborhood. Properties adjacent to the site should be given clear communication about when the project will start and which days will impact the neighborhood most severely. Care should be taken to minimize impacts of construction workers parking on residential streets and to decrease the noise as much as possible. This neighborhood has no need for specialty retail facilities or commercial office space, and this project will further harm our neighborhood, not improve it. In addition, I am concerned that the property will be redeveloped, only to sit vacant for years as the economy struggles to recover from COVID. That creates an additional blight to the neighborhood. If the property owner and CIty of Edmonds wish to redevelop the site, I urge you to consider rezoning this parcel for a residential use - not townhomes that would loom over the existing single family residences, but perhaps a single story duplex would provide a good use of the site while minimizing traffic and environmental impacts on the neighborhood. Or perhaps the City of Edmonds could purchase the site and redevelop it as a neighborhood park. Danielle Hursh 23627 101 st Ave W Edmonds, WA 98020 206-218-8695 Attachment 17 Packet Pg. 340 5.1.a From: K Keefe To: Lien. Kernen Subject: Public Comment PLN 2020-040 Date: Tuesday, September 22, 2020 1:54:30 PM Good afternoon, please accept the below as my public comment on the application for redevelopment of the property located at 23726 100th Ave W. in Edmonds, PLN 2020-0040. I am against the redevelopment in it's current proposal. The building design is wholly out of scale with the buildings (both business and residential) in the vicinity. There are no close businesses that are two stories, and few two story residential homes. The building materials and overall appearance of the building do not reflect or compliment existing business or homes in the area. It will look out of place and will be much larger than anything within a few blocks and will dominate the landscape. The majority of structures close to this property are residential, single story, single family homes on quiet residential streets, with a few smaller, one story businesses nearby. A two story, nearly 11,000 square foot commercial building comprised of new building materials and a modern design DOES NOT blend in to a neighborhood consisting primarily of homes built in the 1950's and 1960's. The homes surrounding this property currently enjoy a quiet residential neighborhood lifestyle. I live on 101 st Ave W and purchased my home for this reason. A structure and businesses of this scale, at this site, will change all of that and make it difficult for me to be able to stay in my home. The selected vegetation for this site -with the exception of Attachment 18 1Packet Pg. 341 5.1.a Oregon Grape- are not native to the area and will do very little to provide a visual barrier from the commercial building and neighboring homes. The application documents submitted estimate 174 trips daily in correspondence with the "Woodway Station" property. Currently, the predominate traffic on 101 st Ave W is limited to residents and delivery trucks. 174 daily trips to and from this site would be an ENORMOUS increase from what currently is seen on this street that is in no way designed to accommodate that amount of traffic. Further, from the application documents, it is estimated that the building will have 20 people working on site after completion. 23 parking spaces will be provided on site. If all 20 people each drive a vehicle and park on site, that leaves only 3 available parking spaces for others doing business. What happens if all of the parking spaces are full? The parking will naturally overflow onto the neighboring residential streets, chiefly 101 st Ave W, as both 100th Ave W and 23 8th Street have none -or very limited- on street parking. 101 st Ave W, a dead end street with only 16 houses on it cannot accommodate that, especially when residents of these houses already use what limited parking that is available. I have concerns about the timing of this redevelopment as well. With COVID restrictions, and many people at home, a huge construction project will have impacts on the residents nearby. The noise, air pollution and traffic from such a development will make it challenging for those working from home or using telehealth or schooling from home, to conduct their work effectively. 0 3 0 0 0 0 G 0 N O N Z J d Attachment 18 1Packet Pg. 342 5.1.a I am disabled, and restricted to my home much of the time, and the stress of a massive construction project during an already stressful time, is going to be a huge challenge for me. I am worried about the negative impact this will have on my health, as I am not able to leave my home easily to escape the construction. Overall, this project is completely out of scale with the surrounding neighborhood, a visual blight and will completely change -negatively- the feel, livability and character of the area. Please do not move forward with this project as it has been proposed. Sincerely, Killy Keefe 23 627 101 st Ave W Killy wheekawheek()amail.com "When the power of love overcomes the love of power, the world will know peace." Jimi Hendrix "Dawn is breaking everywhere. Light a candle, curse the glare." Touch of Grey, The Grateful Dead. "She knew how animals would act, she understood what animals thought, but you could never be sure about people." From "The Long Winter" by Laura Ingalls Wilder What is man without the beasts? If all the beasts were gone, man would die from a great loneliness of the spirit. For whatever happens to the beasts, soon happens to man. All things are connected. N Chief Seattle Attachment 18 1Packet Pg. 343 5.1.a a Attachment 18 Packet Pg. 344 5.1.a From: vanessa mark To: Lien, Kernen Subject: Public comment Date: Tuesday, September 22, 2020 7:06:53 PM Hello, I would like to submit a public comment on the development project at 23726 -100th Ave W, Edmonds, WA. One ofy concerns with this project is that the building is in-between two intersections which may become quite congested in traffic increases. One intersection at 100th and 238th St. is already controlled by a traffic light, but the other at 101st Ave W and 238th St is just a 2 way stop. The space between 100th Ave W and 101st Ave W is not a full city block, it is quite small. I want to make sure traffic is controlled in a way that will allow cars to turn out from 101st Ave and cross it or turn onto 238th St. My other concern is that ample parking be included in the building plans So that cars will not park on 101st Ave W to access the businesses in the building. That lot is sometimes used for parking even though no business occupies it. Vanessa Mark Attachment 19 Packet Pg. 345 5.1.a From: Kristine Wear To: Lien. Kernen Subject: Proposal to redevelop Edmonds property, Permit PLN2020-0040 Date: Thursday, October 8, 2020 1:40:00 PM To Kernen Lien: I have serious concerns with the proposed development of property at 23726 100th Ave. W. I live on the north side of 101 st Ave. W. The 2 story building is too large for our neighborhood location. Now there is already too much traffic congestion and noise on 100th with dangerous incidents occurring at the intersection of 100th and 238th. It has been estimated that 174 trips will be generated daily in & out of this building increasing traffic immensely. Traffic on 238th St. heading west has increased twofold in the past year. A 25 mph. speed limit on 238th St is rarely followed or enforced. In the proposal I saw no street access analysis for the north or south side of 101 st Ave. W. which is divided by 238th St. If there is a 6 foot fence on the entire west side of the building we will not be able to see around it. As neighbor residents we need to be able to safely head east or west on 238th St. The situation will be exacerbated by increased traffic leaving the building on to 238th. Parking will be another big issue for us on 101 st. The proposal has 23 parking places for a projected 20 people working in the building. Half the complex is designed for retail. That means only 3 other people will be able to park on site. That's not realistic. The overflow of parking will end up mostly on the north side of my street. Also where will all the workers park during the period of time the building is being constructed? They can't park on the property site. As you know there is no parking available on 100th or 238th so where is everyone going to park? I have a permanent disability and so do several of my friends who visit me. I need the parking space in front of my house to be available. Please scale back this project. It will create undue harm to our neighborhood with increased traffic congestion, traffic safety problems and overflow parking issues. Sincerely, Kristine Wear Attachment 20 1Packet Pg. 346 5.1.a From: Chris Johnson To: Lien, Kernen Subject: Petition against proposal to redeveop Edmonds property, Permit PLN2020-0040 Date: Wednesday, September 23, 2020 9:31:07 PM Attachments: Petition aaainst commercial building redevelooment.Ddf To Kemen Lien: We are Edmonds residents of 101st Ave W and the surrounding neighborhood, and we have serious problems with the proposal to develop the property at 23726 100th Ave W as currently proposed. 101St Ave W above 238th St, behind the proposed project, is a quiet cul-de-sac where its residents value their peaceful, non -through street. The proposed development will increase the nearby traffic significantly, at a corner that is already dangerous and congested, due to the jog that 238th St takes, and the two close -together traffic lights that jog requires. We are very concerned that this large a building, with its estimated 174 trips generated, will vastly overflow the planned 23 parking spaces. Since people cannot park on 100th Ave W or 238th St SW, they will be coming and going constantly on our quiet cul-de-sac, leaving us no space for our own vehicles or those of our guests. The scale of this project is far greater than that of a neighborhood business! We are certain that the scale of this project will place an undue burden upon the surrounding residents, and are registering our official complaints against it. Please reconsider this project, taking into account the residents of our neighborhood and the potentially dangerous increase of traffic at an already dangerously congested intersection. Thank you, The residents of 101 st Ave W and surrounding streets. Attachment 21 Packet Pg. 347 5.1.a Petition against the proposal to redevelop the property at 23726 100th Ave W to a two story 10,966 square foot commercial building called "Woodway Station." Permit File Number: PLN2020-0040 • This building will be out of scale and character to existing structures in the neighborhood (2 story, nearly 11, 000 square feet) • The proposed building/businesses are estimated to generate 174 trips daily • It is estimated that 20 people will work in the building, but only 23 parking spaces will be provided. This could mean overflow parking onto quiet residential streets By signing, I am expressing my disapproval to the City of Edmonds of the proposed project and the potential negative effects it will have on the neighborhood, the character and feel of the neighborhood, and the negative impacts it will have on the livability of residents in the vicinity of this project. Signed: NAME SIGNATURE L9�-_ ADDRESS DATE 34 27 tot sF A,c ,e/ Z z� z Lr - 0,0 Attachment 21 1Packet Pg. 348 5.1.a Petition against the proposal to redevelop the property at 23726 100th Ave W to a two story 10,966 square foot commercial building called "Woodway Station." Permit File Number: PLN2020-0040 • This building will be out of scale and character to existing structures in the neighborhood (2 story, nearly 11, 000 square feet) • The proposed building/businesses are estimated to generate 174 trips daily • It is estimated that 20 people will work in the building, but only 23 parking spaces will be provided. This could mean overflow, parking onto quiet residential streets By signing, I am expressing my disapproval to the City of Edmonds of the proposed project and the potential negative effects it will have on the neighborhood, the character and feel of the neighborhood, and the negative impacts it will have on the livability of residents in the vicinity of this project. Signed: NAME I.' et�V\� SI -J=0 7- ADDRESS DATE �1 1S v 1st- Ao-e J 3a6-qOn Zgrl" --O� 18' 10 (� IJ��M%l Attachment 21 1Packet Pg. 349 5.1.a Petition against the proposal to redevelop the property at 23726 100th Ave W to a two story 10,966 square foot commercial building called "Woodway Station." Permit File Number: PLN2020-0040 • This building will be out of scale and character to existing structures in the neighborhood (2 story, nearly 11, 000 square feet) • The proposed building/businesses are estimated to generate 174 trips daily • it is estimated that 20 people will work in the building, but only 23 parking spaces will be provided. This could mean overflow parking onto quiet residential streets By signing, I am expressing my disapproval to the City of Edmonds of the proposed project and the potential negative effects it will have on the neighborhood, the character and feel of the neighborhood, and the negative impacts it will have on the livability of residents in the vicinity of this project. Signed: Sao Real, Q W A W � � I Attachment 21 1Packet Pg. 350 v STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office • 3190 160th Avenue SE • Bellevue, Washington 98008-5452 • (425) 649-7000 711 for Washington Relay Service • Persons with a speech disability can call (877) 833-6341 January 21, 2021 Kernen Lien, Environmental Programs Manager City of Edmonds 121 5th Ave N Edmonds, WA 98020 Re: Woodway Station File# PLN2020-0040, Ecology SEPA# 202100086 Dear Kernen Lien: Thank you for the opportunity to provide comments on the State Environmental Policy Act (SEPA) determination of nonsignificance (DNS) process for the Woodway Station. Based on review of the checklist associated with this project, the Department of Ecology (Ecology) has the following comments: This property appears in Ecology databases as follows: Underground Storage Tank (UST)Database Site Name: Edmonds Liquor & Gas UST ID 100015 Site Status: USTs removed Facility/Site Database Texaco Gas Mart CSID 7972 Site Status: NFA Determination by Ecology 6/5/2012 Edmonds Liquor & Gas South Dispenser Cleanup Site ID (CSID) 14897 Site Status: No Further Action (NFA) Determination by Ecology 2/6/2019 The NFA determinations by Ecology were based on documentation regarding removal of seven USTs, cleanup of contaminated soil, and absence of groundwater in UST excavations and site borings. However, the UST system removal activities did not assess the following: Attachment 22 Packet Pg. 351 5.1.a Kernen Lien January 21, 2021 Page 2 A 500-gallon waste oil UST associated with the original gas station that was constructed in 1961. The location of this UST was never verified. Two hydraulic hoists located in the floors of the former gas station service bay. Potential contamination associated with the arson fire that destroyed the original gas station in 1993. If soil or groundwater with concentrations of chemicals above Model Toxics Control Act (MTCA) cleanup levels is encountered during the course of the proposed action, a new release report must be submitted to Ecology (see https:Hecoloay.wa.aov/About-us/Get-involved/Report- an-environmental-issue/Report-a-spill ) and all contaminated materials must be managed and cleaned up in accordance with the MTCA regulation (https:Hecolog_y.wa.aov/Spills- Cleanup/Contamination-cleanup/Rules-directing-our-cleanup-work/Model-Toxics-Control-Act ) Thank you for considering these comments from Ecology. If you have any questions or would like to respond to these comments, please contact Michael Warfel from the Toxics Cleanup Program at (425) 649-7257 or by email at michael.warfelgecy.wa.gov. Sincerely, f 4iQ� r Katelynn Piazza SEPA Coordinator Sent by email: Kernen Lien, kernen.liengedmondswa.gov ecc: Michael Warfel, Ecology Attachment 22 Packet Pg. 352 5.1.a SOUTH COUNTY FIRE 12425 Meridian Ave S., Everett WA 98208 tel (425) 551-1200 • fax (425) 551-1249 www.southsnofire.org Cities of Brier, Edmonds and Mountlake Terrace Department of Fire Prevention Plan Review DATE: 08/20/2020 PERMIT #: PLN2020-0040 JOB NAME/ADDRESS: Woodway Station 23726 100t" Ave W CONTACTS: Carl Pirscher 206-368-9667 carlp@cdaarch.com Two story Commercial Office building, Approved, Additional comments: 1. Fire Sprinkler and Fire Alarm required, separate permits. 2. Required an additional hydrant at site and within 50 feet of new FDC 3. Riser room needs an outside entrance, FDC within 50 feet of hydrant 4. Signing and/or stripping "NO PARKING FIRE LANE" in parking area 4. Knox key box entry Thank you, Karl Fitterer CFI, FPE Assistant Fire Marshal Fire Prevention Services 121 5th Ave N Edmonds, WA 98020 0: (425)771-0213 VM: (425)551-1980 kfittererCcD.southsnofire.org SERVING SOUTH SNOHOMISH COUNTY • BRIER • EDMONDS • LYNNWOOD • MOUNTLAKE TERRACE Page 1 of 1 Attachment 23 Packet Pg. 353 5.1.a % LJ Date: To: MEMORANDUM January 12, 2021 Kernen Lien, Environmental Programs Manager From: Jeanie McConnell, Engineering Program Manager Zachary Richardson, Stormwater Engineer Bertrand Hauss, Transportation Engineer Subject: PLN2020-0040 —Design Review Woodway Station — 23726100' Ave W Engineering has reviewed the subject application and found the information provided is consistent with Title 18 Edmonds Community Development Code & Engineering standards. Compliance with Engineering codes and construction standards will be reviewed with the building permit application for development of the site. Approval of the design review phase of the project does not constitute approval of the improvements as shown on the submitted plans. The following comments are provided in response to public comments received related to the proposed development: • Access to the site will be from 1001h Ave W and 2381h St SW. The development will not have access from 101" Ave W. • Fencing and vegetation will be reviewed to ensure proposed locations do not create sight distance issues. • Landscaping will be installed along the western property boundary, between the property line and the roadway which will prevent vehicles from parking in this area. • City regulations restrict construction related noise to the hours of 7am-6pm M-F and 10am-6pm on Saturdays. Activity that exceeds allowable noise levels is not permissible on Sundays and Federal Holidays. • A pre -construction meeting will be held with the developer prior to the start of construction. Discussions will be had at that time to help minimize impacts to the neighborhood and ensure proper coordination/communication for any street or utility disturbances. The comments below are provided to assist with preparation of the civil construction plans associated with the building permit phase of development. Attachment 24 Packet Pg. 354 5.1.a Stormwater Engineer Review: Refer to attached plan review comments by City Stormwater Engineer, Zachary Richardson. Please contact Zack directly at 425-771-0220 or by email at Zachary.richardson(&edmondswa.gov with any specific questions you may have regarding his comments. Please note, the memo is dated August 28, 2020 and a resubmittal received by the City on November 20, 2020 included a TIR. The TIR was reviewed by Zack in part and the project continues to be feasible. Transportation Engineer Review: The following comments are provided by the City Transportation Engineer, Bertrand Hauss. Please contact Bertrand directly at 425-771-0220 or by email at Bertrand.hauss(d),edmondswa.gov with any specific questions you may have regarding his comments. A Transportation Memo was prepared by Gibson Traffic Consultants, Inc., dated November 18, 2020. The memo indicates an existing land use of General Office, however, City records show the previous use as a Gas Station. Please update the memo accordingly at the building permit phase of the project. General Engineering Review: The following comments are provided by the Engineering Program Manager, Jeanie McConnell. \Please contact Jeanie directly at 425-771-0220 or by email at Jeanie.mcconnellgedmondswa.gov with any specific questions you may have regarding his comments. 1. Frontage Improvements, Access and Parking: a) The subject development will take access from two access points as depicted on the preliminary plans. One access on 100th Ave W and one access on 2381h St SW. b) Sidewalk improvements: i. 5-ft sidewalks required along 2381h St SW. The existing sidewalk can remain, except for that it shall be modified as needed to address the location of the new driveway approach as well as remove and replace the easterly driveway cut in accordance with City/ADA standards. ii. 5-ft wide landscape buffer with street trees and 7-ft wide sidewalk required along 100th Ave W. iii. Public pedestrian access easement required for those portions of the sidewalk that extend onto private property. c) Provide offset from curb on west side of ADA parking stall (the extension of the stall into the drive aisle) to provide better turning movement out of the parking stall. 2. Water and Sewer: a. Water and sewer utilities fall under the purview of the Olympic View Water & Sewer District. The project development will need to meet the requirements of OVWSD. Attachment 24 Packet Pg. 355 I 5.1.a I of Ebb STORMWATER REVIEW COMMENTS City of Edmonds Engineering Division To: Applicant & Project File Date: August 18, 2020 Project Name: Woodway Station Permit Number: PLN2020-0040 Address: 23726 100th Ave W Review Type: Design Review (Preliminary) Submittal Date: 8/4/2020 Reviewer: Zack Richardson, PE City of Edmonds, Stormwater Engineer Recommendation: While the project has not submitted a complete drainage report at this phase, sufficient information is shown to demonstrate that the project site has a sizeable infiltration rate and plenty of exterior surface space to allow for potential modification to the drainage improvements as the project progresses to construction design. Accordingly, I recommend that PLN2020-0040 be preliminarily approved with conditions to comply with ECDC 18.30. Infiltration of stormwater will be required. Significant additional information or revision is anticipated prior to building permit submittal for the next phase; the comments below are provide to assist in addressing reviewer concerns at that time, and do not necessarily need to be addressed prior to preliminary approval. Review Comments: 1. Include drainage report, compliant with ECDC 18.30, with next submittal; future submittals should be rejected without a drainage report. 2. It is currently unclear what extents the drywell has been sized for, explain/clarify. a. If pervious pavements are proposed to address pavement surfaces, then this effort needs to address how the overlapping footprints are accounted for (ie. Is the drywell sized to account for the roof and direct rain fall within its footprint?) 3. It is unclear how water quality treatment (MR #6) is currently being satisfied. a. Geotech report does not appear to indicate if soils have cation exchange capacity sufficient to meet this requirement, update as needed or provide appropriate BMPs. 4. If roof is not considered pollution generating, include a description of how the engineer determined that the roof conditions were not pollution generating (metal Pa Attachment 24 Packet Pg. 356 5.1.a roofs treated to prevent leaching, internal spill controls on all mechanical/HVAC equipment, etc) and the coordination mechanism to ensure this is maintained throughout design process. 5. Very little information is provided on grading for the site, but it is unclear that enough collection devices have been provided to collect and treat runoff from all new plus replaced impervious surfaces, including frontage improvements in the ROW. a. Ensure all surfaces are either adequately collected and conveyed to the facility OR ensure that the model correctly reflects bypass areas as such in a point of compliance analysis. b. Note that MR #5 still applies to areas bypassed for flow control (MR #7) to the maximum extent feasible and has allowances to only bypass up to 1,000 SF maximum and only after demonstrating that collection of these areas is infeasible. 6. Particular to this project, the report should address the potential for interaction between runoff and subsurface contaminates, or lack thereof as the case may be. a. If any additional mitigation measures are proposed (impervious liners on sidewalls, over excavation at time of construction, etc) include plans and/or details as needed for construction. 7. Ensure report addresses source control requirements for the trash enclosure area for the trash enclosure area. 8. Include in report or downstream analysis a description of how the engineer determined the on -site storm pipe proposed for re -use as an overflow, was in adequate condition for re -use. Attachment 24 Page Packet Pg. 357