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PLN20180033_StaffReportwithAttachments (2)CITY OF EDMONDS !2! srh Avenue North, Edmonds WA 98020 Phone: 425.771,.0220 . Fax: 425.771.0221 ¡ Web:www.edmondswa.sov DEVELOPMENT SERVICES DEPARTMENT r PLANNING DIVISION c. 18 Project: File Number: Date of Report: Reviewed By: Owner: Applicant: PLANNING DIVISION PRELIMINARY SHORT PLAT REVIEW FiNDiNGS, OONCLUSIONS & DEeiSiON Larsen Three-Lot Short Plat P1N20180033 ber 24,20 ð rnen Lien, E nmental Programs Manager Sharon Larsen t. Sharon & Carl Larsen INTRODUCT¡ON The applicant is proposing to subdivide a 68,415 square foot lot located at15729 - 75th Place West into three lots (Attachments L- 4). The site is located within the RS-20 (single-family residential; 20,000 minimum lot size) zone (Attachment 14). There are two existing single family residences located on the property. The proposed subdivision would place each home on its own lot, and create a third vacant lot. The proposed lot layout is shown on the preliminary short plat plans (Attachment 3) and preliminary development plans (Attachment 4). The property is located within the Earth Subsidence and Landslide Hazard Area of North Edmonds and also subject to the requirements of Chapter 19.1-0 ECDC. Consistent with the City's Official Street Map, a ten (10) foot street dedication is required along the 75th Place West property frontage. A. Application 1,. Owner/Aoolicant: Sharon Larsen 2. Site Location: 15729 - 75th Place West, Edmonds, WA (Tax Parcel 00513300002700) 3. Request: To divide one lot with a total area of 68,4L5 square feet into three lots in the RS- 20 zone. 4. Review Process: Short plats are Type ll decisions pursuant to ECDC 20.01.003. Following a public comment period, the Director (or designee) makes an administrative decision B. Attachments: L. Land Use Application 2. Applicant Cover Letter 3. Preliminary Short Plat 4. Preliminary Development Plan 5. Stormwater Drainage Report 6. February 8, 201-8 Nelson Geotechnical Services Geotechnical Report 7. July 25, 2018 Nelson Geotechnical Services Supplemental Geotechnical Report 8. August 9,20t8 Nelson GeotechnicalServices Supplemental Geotechnical Report 9. August 23,2018 Nelson Geotechnical Services Supplemental Geotechnical Report 10. April 30, 20L8 Landau lnc. Geotechnical Peer Review 1L. August 10,2819 La¡dau lnc.Geotechnjcal Peer Review 12. October 15,2018 Landau lnc. Geotechnical Peer Review 1-3. Edmonds Utilities Consortium Form L4. Zoning and Vicinity Map 15. Critical Area Determination CR4201800L2 16. Snohomish Fire District #l- Comment Form 17. Building Division Comments 18. Engineering Memorandum of Compliance and Conditions of Development L9. Public Notification Documentation II. FINDINGS OF FACT AND CONCLUSIONS A. Setting: The site is located within a single-family residential neighborhood in north Edmonds. Refer to Attachment L4 for a zoning and vicinity map indicating the zoning of surrounding properties. The subject property and properties to the north and south, and west are zoned RS-20 (single-family residential; 20,000 square foot minimum lot size). The properties to the east across 72nd Avenue West and west across 75th Place West are zoned RS-L2 (single-family residential, I2,0O0 square foot minimum lot size). B. Topography and Vegetation: Refer to the preliminary short plat and development plans (Attachments 3 and 4) for a depiction of the existing conditions on the site, including the topography of the site and locations of existing trees. The site is part of a larger west facing slope in the Earth Subsidence Landslide Hazard Area. There are three tiers on this slope. The western most portion (Lot 1) is relatively level. Lot L steps up to Lot 2 at approximately 30%. Lot 2 is located at the base of an approximately L00 foot tall bluff with slopes of approxim ately 63%. The third tier is Lot 3 which is located on top of the bluff and will be accessed from 72nd Avenue West. The vegetation on the western half of the site consists of typically residential landscaping. The bluff and Lot 3 are in a more natural condition with a significant amount of trees. Refer to Section ll.C for further discussion on crítical areas on/adjacent to the subject site. C. EnvironmentalAssessment L. CriticalArea: During review and inspection of the subject site in Aprilof 20L8 under File No. CR420180012, it was found that the site contains or is adjacent to critical areas, including Geologically Hazardous Areas (Landslide Hazard Area and Erosion Hazard Area), pursuant to Chapters 23.40 and 23.80 ECDC (Attachment 15). Nearly all of the subject Larsen Short Plat File No. PLN20180033 Page2ofl5 site is located within the mapped North Edmonds Earth Subsidence and Landslide Hazard Area (ESLHA) or buffer. The steepest portion of the bluff is in the middle of the site with somewhat more level areas on the west (below the bluff) and east (above the bluff). According to NRCS soils data, most of the site is underlain by Alderwood-Everett gravely sandy loams, 25-70% slope but the western edge is underlain by Alderwood Gravelly sandy loam (L5-25-% slope) while the eastern edge is Alderwood Urban land complex (2- 8% slope). Given the soils and slopes on and adjacent to the property and its location within the ESLHA, the site is considered to be a potential erosion and landslide hazard a rea. Numerous geotechnical reports have been submitted and peer reviewed (Attachments 6 - L2) consistent with Chapters 1-9.L0 and 23.80 ECDC. Any development associated with the subdivision that was not reviewed with build¡ng permit 81D20180517 for the foundation work on the existing residence on Lot 2 or the related to preliminary approval of the subdivision will be subject to additional geotechnical analysis and peer review consistent with Chapters 19.10 and 23.80 ECDC. An erosion and sediment control plan will be reviewed in conjunction with the civil plans. 2. Native Vegetation Plan: ECDC 23.90.040.C requires subdividable properties in the RS-12 and RS-20 zones to retain or create an area of native vegetation equal to 30% of the total area of the lot. The goal of the 30% native vegetation requirement can be metthrough maintaining existing native vegetation, establishing native vegetation, or a combination of both. This is meant to provide additional protection for fish and wildlife habitat throughout Edmonds. The vegetation management plan could include a combination of retaining existing native trees and vegetation and/or new landscaping consisting of native plants. Any native species will be acceptable provided that a lawn may not count towards the 30% area. The plan must show where the 30% native vegetation area will be located on the site (it does not need to be provided in one contiguous location), specify the native species that will be retained and/or planted within the area, specify any nonnative vegetation that will be removed, and establish ongoing maintenance activities for the native vegetation area. The vegetation management plan must be approved by the Planning Division prior to final approval of the subdivision. The applicant has indicated where the 30% native vegetation area could be provided for on the preliminary short plat and development plans (Attachments 3 and 4). As a condition of this decision, the applicant must submit a vegetation management plan showing how the requirements of ECDC 23.90.040.C will be met, which will be reviewed as part of the civil review. 3. Shoreline: The subject property is not located within shoreline jurisdiction. 4. SEPA: Review under the State Environmental Policy Act (SEPA) is not required for a short plat pursuant to WAC 197-I1.-8OO(6Xd) - Land use decisions. D. Comments L Departmental Comment: This proposal was reviewed by Snohomish County Fire District No. L, and the City of Edmonds Building and Engineering Divisions. Larsen Short Plal File No. PLN20180033 Page 3 of 15 E Snohomish County Fire District No. 1 did not have any comments on the proposed short plat (Attachment 16). The Building Division noted that site lies with the Earth Subsidence and Landslide Hazard Area and that development will be required to meet the requirements of Chapter L9.10 ECDC for new construction or alterations to existing structures (Attachment 17). The Engineering Division approved the proposed subdivision subject to the approval memorandum and Engineering Requirements for the short plat that are included in Attachment 18. The Engineering Division has found the information provided indicates general engineering feasibility; project-specific design, including final utility system design and location, as well as Title 18 Edmonds Community Development Code compliance, will be reviewed during the civil construction phase of this pr:oject. The pr:oposed subdivision is subject to the Engineering Requirements for the short plat included in Attachment l-8. 2. Public Notice and Comment: Chapter 20.03 ECDC provides the City's regulations for public notice of development applications. A "Notice of Application" dated JuneL3, 2018 with a comment period running through June 27,2018 was posted at the subject site, Public Safety Complex, Development Services Department, and Library on June 13, 20L8. The notice was also published in the Herald Newspaper and mailed to property owners within 300 feet of the site on June 13, 20L8 using a mailing list provided by the applicant. Documentation of compliance with the public notice requirements is included as Attachment 19. The City has complied with the public notice requirements of Chapter 20.03 ECDC. No wr¡tten public comments were received during review of the subject proposal. ECDC 20.75.080 General Findings A proposed subdivision may only be approved if all the general findings listed in ECDC 20.75.080 can be made for the proposal as approved or as conditionally approved. Staff's findings in regard to ECDC 20.75.080 are detailed below. L. Subdivision Ordinonce. The proposol is consistent the purposes of this chapter (os listed in ECDC 20.75.020) and meets oll requirements of this chopter. As conditioned, the proposed three lot subdivision is consistent with ECDC 2O.75.020 and allthe requirements of ECDC Chapter 20.75. The proposed subdivision will not negatively impact public health, safety or general welfare, will not negatively impact congestion on streets and highways, will have adequate access to water, utilities, sewerage, storm drainage and will provide proper ingress and egress as well as be uniformly monumented. 2. Comprehensive Plon. The proposol is consistent w¡th the provisions of the Edmonds Comprehensive Plon, or other odopted city policy, and is in the public interest. The subject site is located within the "Single Family Resource" designation of the Comprehensive Plan. The Comprehensive Plan has the following stated goals and policies for Residential Development that apply to this project. Resìd entio I Development A. Gool. High quolity residentiol development which is oppropriote to the diverse Iifestyle of Edmonds residents should be mointoined ond promoted. The options avoilable to the City to influence the quality of housing for oll citizens should be Larsen Short Plat File No. PLN20180033 Page4ofÌ5 opprooched realisticolly in bolancing economic, sociol, oesthetic and e nv i ron m e nto I con si de roti ons. A.7. Encourøge those building custom homes to design ond construct homes with orchitecturol lines which enoble them to hormonize with the surroundings, odding to the community identity ond desirobility. A.3. Minimize encroochment on view of existing homes by new construction or odditions to existing structures. A.4. Support retent¡on ond rehabilitotion of older housing within Edmonds whenever ¡t is economicolly feosible. A.5. Protect residentiai areos from incompotible iand uses through the carefuí control of other types of development ond exponsion bosed upon the following principles: A.5.d. Privote property must be protected from qdverse environmentol impacts of development including noise, drøinoge, troffic, slides, etc. A.6. Require that new residential development be compatible with the notural constraints of slopes, soils, geology, droinoge, vegetotion ond habitat. Compliance with the Residential Development goals and policies: The two existing residences on the site will be retained on Lots 1 and 2. The future residential may be located on Lot 3 on the bluff above the existing residences and should not negatively impact other residences in the area. The future residence will be reviewed for compliance with applicable critical areas regulations at the time of building permit application review. Traffic impact fees consistent with Chapter 3.36 ECDC will be collected with building permit to mitigate traffic impacts. The proposal should not cause any adverse impacts and appears to be consistent with the residential development goals and policies of the Comprehensive Plan. Soíls and Topogrophy Goal B. Development on steep slopes or hazordous soil conditions should preserve the noturolfeotures of the site, in occordance with the following policies: 8.7 Groding and Filling. 8.7.a Groding, filling, and tree cutting shall be restricted to building pods, drivewoys, occess woys and other impervious surfoces. 8.1-.b Groding shall not jeopordize the stobility of ony slope, or of on ødjocent property. 8.7.c Only minimal omounts of cut ond fill on hillsides should be permitted so that the naturol topogrophy con be preserved. Fill sholl not be used to creote o yard on steeply sloped property. 8.1.d Fill ond excovoted dirt sholl not be pushed down the slope. 8.2. Building Construction. 8.2.o Buildings on slopes of 75 percent or greoter sholl be designed to couse minimum disruption to the notural topogrophy. 8.2.b Retaining wolls are discouroged on steep slopes. lf they ore used they should be smoll and should not support construction of improvements which do not conform to the topography. Larsen Short Plat File No. PLN20l80033 Page 5 of I5 8.2.c Woter detention devices shall be used to mointoin the velocity of runoff ot pre deve I op m e nt leve ls. 8.3. Erosion Control. 8.3.o Temporary meosures shall be tqken to reduce erosion during construction. 8.3.b Noturol vegetotion should be preserved wherever possible to reduce erosion ond stobilize slopes, porticulorly on the downhill property line. 8.3.c Slopes should be stobilized with deep rooted vegetation ond mulch, or other moteriols to prevent erosion and siltation of droinoge ways. Compliance with the oils and Topography goals and policies: Grading and filling is minimizgd qs lwo of the proposed lols qre çurrently developed. Since the propert)4 is located in the Earth Subsidence and Landslide Hazard Area, development is subject to Chapter 19.10 ECDC as well at Chapter 23.80 ECDC - Geologically Hazardous Areas. Preliminary geotechnical reports have been prepared for the project (Attachments x - x) which have underwent peer review in accordance with Chapter 19.10 ECDC. Further geotechnical review will be required with the civil review and the building permit associated with the new single family residence on Lot 3. Additionally, ECDC 23.90.040.C requires that 307o of the site be maintain in native vegetation. The steepest portion of the property has been identified as the native vegetation area which will help maintain slope stability. Vegetatìon ond Wildlife A. Gool. The city should ensure thot its woodlønds, morshes ond other oreos contoining naturol vegetotion are preserved, in accordonce with the following policies: A.L Critical oreqs will be designoted ond protected using the best ovoiloble science (BAS). A.2. The removol of trees should be minimized porticulorly when they ore located on steep slopes or hozordous soils. Subdivision loyouts, buildings ond roads should be designed so thot existing trees dre preserved. A.3. Trees thot ore diseased, domaged, or unstoble should be removed. A.4. Groding should be restricted to building pads ond roods only. Vegetotion outside these qreos should be preserved. Compliance with Vegetation and Wildlife goals and policies: For the purposes of the subdivision, tree retention will be reviewed with the civil improvement plans with the subdivision. A condition of preliminary approval is that any tree cutting that is not a hazardous situation and/or not necessary as part of the subdivision improvements shall be reviewed at the time of building permit application review. Any trees retained should be protected during development in accordance with the performance standards in ECDC 18.45.050.H. Any tree cutting on the site is subject to the requirements of Chapter 18.45 ECDC, or as amended. Additionally, ECDC 23.90.040.C requires subdividable properties in the RS-12 and RS-20 zones to retain or create an area of native vegetat¡on equal to 30% of the total area of the lot. As a condition of this decision, the applicant must submit a vegetation management plan showing how the requirements of ECDC 23.90.040.C will be met, which will be reviewed as part of the civil review. Therefore, staff finds that the proposal is consistent with the Comprehensive Plan. Lctrsen Short Plat File No. PLN20180033 Page6ofl5 3. Zoning Ordinance. The proposol meets oll requirements of the zoning ordinonce, or a modificotion hos been approved os provided for in this chopter. The subject property is located in the RS-20 Single-Family Residential zone and is subject to the requirements of Chapter T.6.20 ECDC. Pursuant to ECDC 16.20.030 development standards of the RS-20 zone are as follows: Density means "dwelling units per acre" determined by dividing the total lot area by the density allowed by the underlying zoning; the number of lots or units permitted shall be rounded down to the nearest whole number. Thirty-five feet total of both sides, 10 feet minimum on either side. Minimum Lot Area: The subject site is 68,415 square feet. The RS-20 zone requires a minimum net lot area of 20,000 square feet per lot. Proposed lot area is as follows Proposed Gross sq. ft. Proposed Net sq. ft.* Lot 1 20,o99 20,o99 Lot 2 26,712 26,712 Lot 3 20,400 20,400 *Note: Net lot area excludes the area of any vehicular ingress/egress easements. However, no such easements are indicated with the proposal. As proposed, all lots exceed the minimum required net area of 20,000 square feet per lot, which is compliant with the minimum lot area requirements. Densitv: After a required 1O-foot street dedication, the subject property will contain approximately 67,2IIsquare feet. With 67,ztt square feet, a total of three dwelling units could potentially be developed on the subject property (1.5 acre - 2.2 dwelling units per acre). The subject property currently contains two existing single-family residences. The proposed subdivision would place each home on its own lot, and create a third vacant lot where an additional residence could be constructed. The proposal is compliant with the density requirements. Lot width: Pursuant to ECDC 2L.55.050, lot width is the minimum diameter of a lot width circle that must fit within a lot (100 feet in this instance). A 100-foot diameter lot width circle fits into each of the proposed lots; therefore the proposal is consistent with the minimum lot width requirement. Setbacks: Based on the development standards for the RS-20 zone, setbacks for the proposed lots should be as follows: Larsen Short Plat File No. PLN20lB0033 Page7ofl5 Tone Minimum Lot Area (sq. Ft.) Maximum Densityl Minimum Lot Width Minimum Street Setback Minimum Side Setback Minimum Rea r Setback Maximum Height Maximum Coverage RS-20 20,000 2.2 100'25'35'3 & 10',25 25'35% Lot 1 Lot 2 Lot 3 Street Setbacks (25 feet): Side Setbacks (10/35 feet): Rear Setback (25 feet): Side Setbacks (10/35 feet): Street Setbacks (25 feet): Side Setbacks (10/35 feet): Rear Setback (25 feet): From 75th Pl. W. From the northern and southern property lines From the eastern property line. From allthe property lines. FromT2nd Ave. W. From the northern and southern property lines From the western property line. The existing garage on Lot 1 and the residence on Lot 2 are nonconforming with regards to setbacks; however, the subdivision will not make these buildings more nonconforming and these structures will be compliant with setbacks from the new property lines. Any additions or new development on Lots t and 2 will be required to comply with the zoning setbacks. Compliance with setbacks for any structure on Lot 3 will be review with the associated building permit applications. Corner Lots: None ofthe proposed lots would be considered a corner lot. Elra I ¡+¡. I a+ .) .^,^' 'l.l t ^ -^^-:,{^-^¡ - fl-^ l^+r rqF, LvtJ. Lvt ¿ vvvutu vg çvt tJtuEt Eu o I to6 tvL. Lot Coverage of Existine Buildings on Proposed Lots: Pursuant to ECDC 16.20.030, the maximum coverage of structures in the RS-1"2 zone is 35%. The existing residence and garage on Lot L have a combined footprint of approximately 1-460 square feet. With a lot area of 20,099 square feet, the coverage on Lot l" after the proposed subdivision will be 7.3%. The existing residence on Lot 2 has a footprint of approximately 2350 square feet. With a lot area of 26,712 square feet, the coverage on Lot 2 after the proposed subdivision will be 8.8%. Coverage on Lot 3 will be reviewed with subsequent building permits on that property. Parking: ECDC 17.50.020 requires a minimum of two on-site parking spaces per single- family dwelling. Attachment 3 shows were two off-street parking spaces for the existing single family residences are located. Parking on Lot 3 will be evaluated with future building permits. Staff finds that with the conditions of approval, the proposal is consistent the zoning requirements for the RS-20 zone as contained in ECDC 1,6.20. 4. Flood Ploin Monogement. The proposal meets oll requirements of the Edmonds Community Development code reloting to flood plain monogement. The proposed project is not located within a designated flood plain management area. F. ECDC 20.75.085 - Review Criteria. Pursuant to ECDC 20.75.085, the following criteria shall be used to review proposed subdivisions: L Environmental. o. Where environmental resources exist, such as trees, streoms, ravines or wildlife hobitots, the proposol sholl be designed to minimize significont adverse impocts to the resources. Permanent restrictions moy be imposed on the proposal to avoid impoct. As noted in Section ll.C.1 of this report, the subject property is located within the North Edmonds Earth Subsidence Landslide Hazard Area with steep slopes along the Larsen Short Plat File No. PLN20lB0033 PageBoJl5 western third of the site. The site is also within a mapped fish and wildlife habitat conservation area. The applicant has identified the steep slope in the center of the property and an area approximately 30 feet from the top of the bluff as the location of the native vegetation area required by ECDC 23.90.040.C. ln order to protect the slope and permanently preserve the area, a condition of approval is being added that the native vegetation area be established as a native growth protection easement as provided for in ECDC 23.4O.27O and ECDC 18.45.050.D. The City promotes the retention of as many trees as practicable and encourages the location of building areas with the goal of retaining as many of the trees as possible. For the nurooses of the subdivision. tree retention will be reviewed with the civil improvement plans with the subdivision. A condition of preliminary approval is that any tree cutting that is not a hazardous situation and/or not necessary as part of the subdivision improvements shall be reviewed at the time of building permit application review. Any trees retained should be protected during development in accordance with the performance standards in ECDC 18.45.050.H. Any tree cutting on the site is subject to the requirements of Chapter 18.45 ECDC, or as amended. A condition to this effect has been added as a condition of approval. With the conditions related to protection of existing trees, staff finds that the proposed subdivision is consistent with this criterion. b. The proposol sholl be designed to minimize grading by using shared driveways ond by reloting street, house site ond lot plocement to the existing topography. No grading will be required to retain the two existing residences. Some grading will be required to extend 72nd Ave. W. as a public street for access to Lot 3. The buildable area on Lot 3 is on a relatively level portion of the property which will help mitigate the need for grading when that lot is developed. Therefore, staff finds that the proposed subdivision is consistent with this criterion. c. Where conditions exist which could be hozordous to the future residents of the land to be divided, or to nearby residents or property, such os flood ploins, steep slopes or unstoble soil or geologic conditions, o subdivision of the hozordous lond sholl be denied unless the condition con be permonently corrected, consistent with porogrophs A(1) and (2) of this section (Section ll.F.1.a and ll.F.1.b of this staff report). As has been noted, the subject property contains steep slopes and is located within the North Edmonds Earth Subsidence Landslide Hazard Area. The applicant has identified the steep slope and 25 foot buffer area at the top of the slope as location of the native vegetation area required by ECDC 23.90.040.C. ln orderto permanently protect the steepest slopes on the subject property as required by this criterion, a condition of approval is being added that the native vegetation area be established as a native growth protection easement. As conditioned, staff finds that the proposed subdivision is consistent with this criterion. d. The proposal shall be designed to minimize off-site impacts on droinoge, views ond so forth. Larsen Short Plat File No. PLN20180033 Page9ofl5 The proposed development must be designed to meet current code and minimize stormwater impacts. Stormwater runoff from all new hard surfaces must be mitigated as required by the Engineering Requirements (Attachment L8). The maximum height for new houses in the RS-20 zone is 25 feet from average original grade, which serves to minimize the negative impact to existing views in the vicinity. Aside from the height limits, the Edmonds Community Development Code does not contain specific regulations regarding private view protection within single- family zones. Therefore, staff finds that the proposed subdivision is consistent with this criterion 2. Lot qnd Street Layout. o; Lots shqll be designed to contqin o usoble building orea. lf the building oreo would be difficult to develop, the lot shqll be redesigned or eliminoted, unless speciol conditions can be imposed on the opproval which will ensure thot the lot is developed properly. The existing residences on Lot 1 and Lot 2 will be retained. Should either lot be redeveloped in the future, there is sufficient area within the required setbacks for the RS-20 zone for redevelopment within the relatively level portions of the property. The future house site on Lot 3 is located on a relatively level portion of the property on top of the bluff and should be a developable lot. Based on a review of the project and the analysis in this section, staff agrees that a three-lot short plat may be developed consistent with this requirement. Therefore, staff finds that the proposed subdivision is consistent with this criterion. b. Lots shqll not front on highwoys, orterials or collector streets unless there is no other feosible occess. Speciol occess provisions, such os shored drivewoys, turnorounds or frontoge streets moy be required to minimize troffic hazords Lot L is located on the northeast corner of 75th Pl W and 158th St SW. The existing residence, which is proposed to remain, currently takes access from 75th Pl W. While both streets are designated as local streets, 1-58th St SW has lower traffic volumes. A requirement has been established that upon future redevelopment of Lot 1-, access will be required from 158th St SW. Neither Lot 2 nor Lot 3 will front on an arterial or collector street. Given the topography of the site, shared driveways for all 3 lots is not feasible. As conditioned, staff finds that the proposed subdivision is consistent with this criterion. Eqch lot sholl meet the opplicoble dimensionol requirements of the zoning ordinonce. The subject property is located within the RS-20 zone. Referto Section ll.E.3 of this report for an analysis of the proposal's compliance with the applicable zoning standards. Both of the proposed lots contain at least 20,000 net square feet and are at least 100 feet in width and thus compliant with the dimensional requirements of the RS-20 zone. Therefore, staff finds that the proposed subdivision is consistent with this criterion. d. Pedestrian wolks or bicycle poths sholl be provided to serve schools, porks, public facilities, shorelines and streoms where street occess is not odequote. Larsen Shorl Plat File No. PLN20180033 Page l0ofl5 c Citywide efforts to provide safe transportation include enforcement of traffic regulations, provision of crosswalk and sidewalks for pedestrians, and provision of well-designed streets for safe driving. Safety also involves ongoing coordination with emergency service providers to ensure access for their emergency equipment. Recommendations to address safety issues are based on assessment of historical collision data, focused sub-area or corridor safety studies, or on citizen feedback. The City of Edmonds applies a Walkway Prioritization Process provided in the Transportation Element of the Comprehensive Plan in assessing where sidewalks should be required or upgraded. Criteria has been developed to evaluate and prioritize walkway improvement projects. These criteria (which include distance from schools) are used to prioritize improvements to walkway sections that are identified based on input from public meetings, Walkway Committee meetings, and deficiencies determined from a review of the existing city walkway inventory. The criteria are weighted according to their importance. A system of points evaluate each proposed project against each criterion. The result is a weighted average score that helps to compare and prioritize proposed projects. The City's policy is to consider these criteria in conjunction with City code and the Sidewalk Comprehensive Plan Map in determining sidewa lk req uirements for su bdivisions. Per the City Engineering Division requirements (Attachment L8), no sidewalks are required to be constructed with the proposed subdivision. 75th Pl W and 72nd Ave W street rights-of-way are classified as local streets and per City Code, sidewalks are only required on one side of the street. Sidewalks have already been established on the west side of 75th Pl W and on the east side of 72nd Ave W, both of which are not adjacent to the subject development. Sidewalks are not required along 158th St SW. Therefore, staff finds that the proposed subdivision is consistent with this criterion. 3. Dedicqtions a. The city council møy require dedicotion of lond in the proposed subdivision for public use. b. Only the city council moy opprove o dedicotion of park lond to sotisfy the requirements of ECDC 20.75.090. The council moy request o review ond written recommendotion from the plonning odvisory boord. c. Any opproval of o subdivision sholl be conditioned on appropriote dedication of lond for streets, including those on the officiol street mop and the preliminary plot. Perthe City Engineering Division requirements (Attachment 18), a 10-ft street dedication is required along 75th Place West. See Section ll.G below regarding the dedicat¡on of park land. 4. lmprovements. a. lmprovements which moy be required, but ore not limited to, streets, curbs, pedestrian wolks ond bicycle poths, sidewolks, street landscaping, woter lines, sewqge systems, droinoge systems ond underground utilities. b. The person or body opproving q subdivision sholl determine the improvements necessory to meet the purposes ond requirements of this chopter, qnd the requirements of: Larsen Short Plat File No. PLN20180033 Page l1 of15 ¡. ECDC Title 78, Public Works Requirements; i¡. Chopter 79.75, Fire Code, os to fire hydronts, woter supply and occess. This determination sholl be bosed on the recommendotions of the community development director, the public works director, ond the fire chief. The subject proposal was reviewed by Snohomish County Fire District No. 1 and the Public Works Department - Engineering Division. The Engineering Division identified conditions of approval within the Engineering Requirements provided in Attachment 18. lt was noted that 72nd Ave W, adjacent to the subject development, is currently undeveloped. The public water main will need to be extended, as well as the public road, to serve Lot 3 of the subject subdivision. Staff finds that the proposed subdivision is consistent with this criterion. c. The use of septic systems moy be øpproved if oil of the following conditions ore met: i. lt is more thon 200 feet, multiplied by the number of lots in the proposed subdivision, from the neorest public sewer moin to the neorest boundory of the iond to be divideci. ii. The lond to be divided is zoned RS-20. ¡ii. The public works director ond city heolth officer determine thot soil, droinoge ond slope conditions qre satisfoctory for septic use qnd thot oll requirements of WAC 248-96-090 are met. There are no septic systems included as part of the proposed project. Water and sewer service at the site will be provided through the City's public utility systems. 5. Flood Ptain Monogement. AIt subdivisions shotl compty with the criterio set \orth in the Edmonds community Development code for flood ploin monogement. The subject property is not located within a Flood Plain Management area. G. ECDC 20.75.090 - Park Land Dedication. According to ECDC 20.75.090, before or concurrent with the approval of the final plat of any subdivision, the subdivider shall dedicate land, pay a fee in-lieu of dedication, or do a combination of both, for park and recreational purposes. With the adoption of Ordinance 3934 in 2013, park impacts are now addressed through the assessment of park impact fees in accordance with Chapter 3.36 Edmonds City Code (ECC). No park dedication or fees are required with the subdivision. Park impact fees will be assessed with issuance of the building permits on the new lots consistent with Chapter 3.36 ECC. ilt. DECTSTON ON SUBD|VIS|ON Based upon the Findings of Fact, Conclusions, and Attachments to this staff report, the application for a two-lot short plat on the property located a't L5729 - 75th Place W is APPROVED subject to the following conditions: L. This application is subject to all applicable requirements contained in the Edmonds Community Development Code (ECDC). lt is the responsibility of the applicant to ensure compliance with all applicable requirements. Larsen Short Plat File No. PLN20180033 Page 12 of 15 2. The applicant is responsible for obtaining all local, state, and/or federal permits or approvals applicable to the proposal. 3. As has been noted, the subject property contains steep slopes and is located within the North Edmonds Earth Subsidence Landslide Hazard Area. The applicant has identified the steep slope and an area of approximately 30 feet at the top of the slope as location of the native vegetat¡on area required by ECDC 23.90.040.C. ln order to permanently protect the steepest slopes on the subject property in accordance with ECDC 20.75.085.1-.a, the native vegetation area shall be established as a native growth protect¡on easement. 4. Prior to recording, the applicant must complete the following requirements: ^ ai.,il ^l^^. ñ' '¡+ l.rn ¡nnra.,aÀ nrinr ln ra¡n¡¡lina ln ¡nmnlof ina f ha ¡ir¡il nlrnc rrnr ¡ mr rctq, wtvil PtqttJ tlruJl vç qPPrvvLu yr rvr !v rLLvrvrrró. rÞ !r.! vrerr yrurrr, tvv rr.vJr address the following: i. Complete the Engineering Division conditions listed "Required as a Condition of Subdivision" on Attachment 18. ii. A tree cutting plan shall be submitted and approved with the civil plans for removal of trees impacted by the subdivision improvements. Any tree cutting on the site must be consistent with the requirements of ECDC L8.45 and the 30% native vegetation requirements of ECDC 23.90.040.C. Any tree cutting proposed on the site that is not a hazardous situation and/or not necessary as part of the subdivision improvements shall be reviewed at the time of building permit application or through the appropriate land use permit application and review process. All trees that are to be retained during the development process and trees located on adjacent properties must be protected according to the performance standards found in ECDC 18.45.050.H. lf during construction it is realized that certain trees that were planned to be retained will be damaged due to the construction activities, replacement may be required per ECDC 18.45.050.F. iíi. The applicant must submit a plan that shows how the project complies with the 30% native vegetation requirement of ECDC 23.90.040.C. See Section ll.C.2 of this staff report for further direction regarding the native vegetation plan. iv. Native Growth Protection Easement: (a) ldentify the Native Vegetation Retention Area as a Native Growth Protection Easement on the face of the plat. (b) Provide the following easement language under the Easements Provisions section of the plat document: "No tree(s), shrub(s) or ground cover shall be removed from the native growth protection easement unless documentation is submitted that can demonstrate that the removal will enhance the easement area and will not impact slope stability. Enhancement may include non- mechanical removal of noxious or intrusive species or dead or diseased plants and replanting of appropriate native species. The native growth protect easement may be maintained consistent with the native vegetation plan located in File No. P1N20L80033. " b. Make the following revisions to the plat: i. Ensure that all existing easements are indicated. ii. lndicate the locations of all new easements, and provide easement descriptions and maintenance provisions for all new easements. Larsen Short Plat File No. PLN20180033 Page l3 ofl5 ¡¡i. lndicate the gross and net areas of each lot on the final plat. iv. lnclude the addresses for each of the lots on the final plat (new addresses will be assigned following preliminary approval and provided prior to submitting for final review). v. Add to the face of the plat: "Conditions of approval must be met and can be found in the approval for the short subdivision located in File No. P1N20180033 in the City of Edmonds Planning Division." vi. lnclude on the plat all required information, including owner's certification, hold harmless agreement, and Development Services and Public Works director's approval blocks. vii. Make sure all documents to be recorded meet the Snohomish County Auditor's requirements for, recording. c. Submit an updated copy of the title report (short plat certificate) with the documents proposed to be recorded. The title report must be prepared within 30 days of submittal for final review. d. Submit two copies of the documents to be recorded for the Planning Division and Engineering Division's approval. Once approved, the documents must be recorded with the Snohomish County Auditor's office. 5. After recording the plat and in conjunction with future building permit applications, the applicant must complete the following: a. Complete the Engineering Division conditions listed "Required as a Condition of Building Permit" in Attachment 18. IV. APPEAL Pursuant to ECDC 20.07.004, a party of record may submit a written appeal of a Type ll decision within 14 days after the date of issuance of the decision. The appeal would be heard at an open record public hearing before the Hearing Examiner according to the requirements of Chapter 20.06 ECDC and ECDC 2O.O7.O04. V. LAPSE OF APPROVAL ECDC 20.75.100.8 states, "Approval of a short plat shall expire and have no further validity at the end of seven years if preliminary short plat approval is issued on or before December 3!, 2O!3, and five years if preliminary short plat approval is issued on or afterJanuary I,2O!4, unless the applicant has acquired final short plat approval within the specified time period." Since preliminary approval has been after January 1,,2014, this preliminary short plat approval shall be valid for five years from the date of this staff report. VI. NOTICE TO COUNTY ASSESSOR The property owner may, as a result of the decision rendered by the staff, request a change in the valuation of the property by the Snohomish County Assessor's Office. Larsen Short Plat File No. PLN20180033 Page 14 of I 5 VII. PARTIES OF RECORD City of Edmonds L21--srh Ave. N Edmonds, WA 98020 Sharon & Carl Larson 9832 Marine View Drive Mukilteo, WA 98275 Larsen Short Plat File No. PLN20180033 Page I5 ofl5 City of EdmondsLand Use ApplicationFIIB #PL¡¡rorRoo3Êol;rY l/sy'eYøø û)1cs-ælSrarr !PB nADB UCCzoNE R.g-a()!HEREC'D BY lí¿.. ¡ARECEIPT #Hp¿nr¡lc D¿r¡! ARCHITECTURAL DESIGN RBVISW¡ Covpn¡HBNsIvn PreN AMSNON4BNT¡ CoNInToNAL USE PERMITn HOME OccuperroNN FORMAL SUBDNISTONX Snonr SusotvlstoNI Lor Lr¡w AorusrusNrN PTANNBoRESIDENTIALDEVELOPMENTL--] OTTICK STR¡STMAPAMENDMENTn Srn¡BrVac¡.rtoNI REZONE¡ SHoRÐr¡{n PERrvllr¡ VARIANCE / RBASONAELE USE EXCBPTTONn orseR:. PLEASE N0TE THAT ALL INFoRMATION CONTAINED WITHIN THE APPLICATION IS A PUBLIC RECORD .PROPERTY ADDRESS OR LOCATION15729 75th Pt. W Edmonds WA 98026Pno¡¡cr Nanrn (IF APPLIcABLE)Larsen Short PlatpRop¡Rry OwNnn Sharon LarsenpsoNe# 425-349-1451ADDRESS 9832 Marine View Drive, Mukilteo, WA 98275E-MArL sharon. larsen@frontier. comFex #TaxAccorrr.rr+ 00513300002700Sec. 05 Twp. 27 R*c. 04DESCRrprroN op Pno¡Bcr oRPRoposno Usn (ASee attached cover letterTTACH covER LETTER ls NecnsseRv)DESCzuBE How THE PRoJECT MEETS APPLICABLE CODES (aTTeCU COVER LETTER AS NECESSARSee attached cover letterAppLrcANr Sharon & Carl LarsenpHoNE ¡ 425-349-1451ADDRESS9832 Marine View Drive, Mukilteo, WA 98275E-Mur sharon.larsen@frontier.comFex#CoNr¿,cr PERSoN/AcnNr GGuillenCGE4 425-778-8500ADDRESS250 4lh Ave S. Suite 200 Edmonds WA 98020E-M¡.n grego@cgengineeri ng.comFnx#The undersigned applicant, and his/her/its heirs, and assigns, in consideration on the processing of the application agrees torelease, indemnify, defend and hold the City of Edmonds harmless from any and all damages, including reasonable attorney'sfees, arising from any action or infraction based in whole or part upon false, misleading, inaccurate or incomplete informationfumished 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 knowledgeand that I am authorized to frle thisthe behalf of theas listed belowSTcNeTunT oF APPLICANToorr4=23-6scertify under the penalty of perjury under the laws of the State ofWashington that theis a true and correct statement: I have authorized the above Applicant/Agent to apply for thesubject land useand grant my permission for the public offrcials and the staff of the City of Edmonds to enter thesubject properly for the purposesattendant to thisSIGNATURE OF,o",' 4"-â3-i7CaJJ (azfl111-0220inspectionRevised on 8/22/12B - Land Use ApplicationPage I of IAttachment 1 @e+ CNGINC€RING civil & structural engineering & planning Cover Letter for Larsen Short Plat May 3, 2018 Site lnformation: Address: 1,5729 75th Pl. W, Edmonds 98020 Parcel Number: 00513300002700 Lot Size: 68,415 SF (1.57 acres) Zoning: RS-20 Existing Conditions: The existing site contains two existing houses and an existing detached garage, both on the western half of the site. The site fronts on 75th PL W and also has frontage on 158th ST. SW and on unimproved right- of-way al72nd Ave W. The site slopes up from the road and contains an area of steep slopes at the center of the site. The east and center of the lot have several exísting trees, and the west side of the lot is mostly landscaped with grass, shrubs, and smalltrees. Proiect Proposal: The proposed project includes subdividing the property into (3) separate single-family residential lots, with the two existing houses each occupying a separate lot. Athird house will be constructed on the eastern-most lot at a later date. The two existing houses will retain their existing access to 75th PL W and 158th St. SW, respectively, and the third house will draw access trom72"d Ave W. A 1-0' right-of-way dedication is proposed on 75th PL W. Comprehensive Plan The proposed project supports the Housing Goals of the Comprehensive Plan: r The project allows for infill that is consistent with the character of the surrounding neighborhood (Housing Goal F.2) r The project preserves existing housing stock (Housing Goal D; Residential Goal 4.4) o Access and lot configuration is designed to work with the natural topography of the site (Soils and Topography Goal A; Residential GoalA.6) r The existing and proposed houses are not anticipated to negatively impact the views of neighboring properties (Residential Goal 4.3) 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ph. 42s.778.8500 | f. 42s.778.5536 www.cgengineering.com Attachment 2 Larsen Short Plat Cover Letter May 3, 2018 Page2 of 2 Zonins Code: The proposed uses on site will all be single-family dwelling units. Below is a summary of how the proposed project will address dimensional standards found in Edmonds City Code section 16.20.030 for the RS-20 subdistrict. Because a house has not yet been designed for Lot 3, many of the standards are not able to be confirmed at this time, but we expect they will be addressed at the time of building permit review. Category Code Requirement Proposal Lot 1 Lot 2 Lot 3 Minimum Lot Area (Sq. Ft.) 20,000 20,000 sF 26,8L1SF 20,400 sF Maximum Densitv 2.2 2.r78 1,.625 2.135 Minimum Lot W¡dth 100'720'r20'120', Minimum Street Setback 25 The existing garage does not meet the minimum street setback from 75th PL W. The existing house does not meet minimum street setbacks from 158th St. SW, and encroaches slightly into the street right- of-way 25'; to be confirmed at building permit review for Lot 3 Minimum Side Setback 35'total for both sides; 10'minimum each side Approx. 10' ,52' , and 85', Approx. 22' and 175' 35'/1-0'; to be confirmed at building permit review for Lot 3 Minimum Rear Setback 25'Not applicable, lot is a corner lot (ECC 16.20.040.E) Approx. 55'25'; to be confirmed at building permit review for Lot 3 Maximum Height 25',Existing house and garage are under 25' in heieht. Existing house is under 25' in height. 25'; to be confirmed at building permit review for Lot 3 Maximum Coverage 35%Maximum: 7,000 SF Proposed: 1,465 SF Maximum: 9,383 SF Proposed: 1,856 SF 35%; to be confirmed at building permit review for Lot 3 Minimum Parking Spaces 2 An existing garage with two parking spaces will remain One existing garage space and an outdoor gravel parking area will remain. Min. 2; to be confirmed at building permit review for Lot 3 (Ê(Ê 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ph.425.778.8s00 I f. 42s.778.5s36 www.cgeng¡neering.comCNGIN€€RING Attachment 2 Attachment 3 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 Attachment 5 N Glll. NËLSON GEOTECHNICAL AssocIATEg, INc. GEorËcH NlclLl. ENstr.¡nEns & GËoLo(¡lsrs Ëngíneering-Geology Branch 5526 Industry Lane, #2 Ea^st Wenatchee, WA 98802 (509') 665-1696' FAX (509) 665-7692 Main Office l73l 1 * 135th Ave NE, A-500 Woodinville, WA 98072 {42s) 486-t669 . FAX (425) 481-25 l 0 February 28,2018 RHGffiflVffiÐ MAiT 0 t 20'i8flTTYCÛPY Carl and Sharon Larsen 9832Marine View Drive Mukilteo, Washington 9827 5 DËVE[-OPMENT SERV¡CËS COUNTER Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning 15729 - 75th Place West Edmonds, Washington NGA File No. 999017 Dear Mr. and Mrs. Larsen: We are pleased to submit the attached repoft titled "Preliminary Geotechnical Engineering Evaluation - Larsen Property Short Plat and Residence Underpinning - 15729 - 75th Place West - Edmonds, Washington." This report summarizes the existing surface and subsurface conditions within the project site, and provides geotechnical recommendations for design and construction of the proposed site improvements. Our services were completed in general accordance with the proposal signed by you on June 23,2017 . The site is cunently occupied by an existing single-family residence and detached garage within the lower eastern portion of the properly and an existing single-family residence with a daylight basement within the central portion of the property. The ground surface within the site generally slopes gently to moderately up to the east from 75th Place West along the western property line to the toe of a steep to very steep west-facing slope within the central portion of the properfy. The steep to very-steep west-facing slope ascends up to a relatively level to gently sloping bench area within the very eastem portion ofthe property. We were informed that the existing residence within the central portion of the property has experienced some foundation settlement throughout the years. We understand that the proposed development plan consists of underpinning the central residence foundation to mitigate potential future settlement ofthe structure. A detached garage is also proposed to be constructed along the eastern portion of the central residence location between the toe of the steep slope and the residence. We also understand that you wish to subdivide the existing property into three separate residential parcels. The existing residences within the western and central portion of the property would be located on two of the parcels and the upper bench area would be located on the third parcel. The upper eastern parcel will likely be developed with a new single-family residence sometime in the future. Specific development plans and stormwater handling plans were not available at the time this report was prepared. The site is mapped as part of the large historic/prehistoric Meadowdale Landslide complex area now known as the North Edmonds Earth Subsidence & Landslide Hazard Area (ESHLA). The overall property is located in the designated "Zones B through D" generally located above 75ü Avenue West extending east past the top of the steep to very steep west-facing slope. This report provides information and discussion to fulfill the requirements of the City of Edmonds for construction within this area. Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properly Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Summary -Page2 We explored the site subsurface soil conditions with four drilled soil borings on August 7, 2077. Our explorations indicated that the lower central portion of the site is underlain by undocumented fill and historic landslide debris at shallow depths, with competent native Whidbey Formation deposits at depth. The upper eastern portion of the site is underlain by competent native glacial soils at shallow depths with competent native V/hidbey Formation deposits at depth. Based on our site reconnaissance and explorations, and our understanding ofthe proposed plans, we have concluded that the proposed short plat subdivision, central residence underpinning, central property garage construction and upper eastern lot development on this site should be feasible from a geotechnical standpoint, provided that our recommendations are incorporated into the overall design and construction of this project. We did not observe signs of recent deep-seated slope failures or earth subsidence on the property. The proposed developmenl area appears to be relatively stable under current conditions. The recommendations presented in this report should aid in maintaining and/or improving the current stability conditions observed at the site. Due to the relatively loose nature of the undocumented fiIl soil and landslide debris encountered in our explorations within the lower portion of the site within the vicinity of the existing central residence, it is our opinion that the undocumented fill and landslide debris soils have likely contributed to the settlement and distress that has been observed within the central residence. Without foundation improvements, the settlement and settlement-related distress are likely to continue. To limit future potential impacts to the residence as a result of continued settlement, we recommend that all interior and exterior foundations, along with all interior slabs-on-grade be supported on driven pin piles advancing through the undocumented fill and landslide debris and terminating within the underlying native competent soils. Due to tight access constraints within portions of the residence, some of these improvements may be difficult to implement. We therefore should consult with the structural engineer and contractors on adequate stabilization measures as plans are finalized. In the attached repofi, we have included recommendations for pin pile foundation underpinning support. We also recommend that any new foundations and slabs associated with the proposed garage within the central property be supported on a deep foundation system consisting of driven pin piles. Due to the proposed ga'age being located in close proximity to the toe of the steep slope within the upper eastern portion of the property, we also recommend that the proposed garage be protected against potential slope movement on the eastern uphill side by incorporating some type of a debris wall on that side. This is further discussed in the attached report. For the proposed development within the upper eastem parcel, we recommend that any proposed structure foundations be designed to utilize conventional spread footings extending down to competent native soil or structural fill extending to these soils. We recommend that any proposed structures be set back at least 60 feet from the top of the steep east-facing slope. In the attached report, we have included recommendations for site grading, retaining walls, foundation support, and site drainage. We strongly recommend that all runoff generated within this site, including roof downspouts, driveways, yard and footing drains, and all runoff entering the properly from the road or adjacent properties, be directed into the existing drainage system that is located along the southem portion of the property. No water should be infiltrated or dispersed within the site or near the site slopes. Such activity may lead to instability within the site slopes. We should be retained to review final grading and drainage plans prior to construction. We also recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with contract plans and specifications. Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Summary - Page 3 We appreciate the opportunity to provide service to you on this project. Please contact us if you have any questions regarding this report or require further information. Sincerely, NELSON G EOTECH N ICAL ASSO CI ATES, I N C. Khaled M. Shawish, PE Principal Attachment 6 Table of Contents Surface Conditions..... Subsurface C*¿ltiott .......... Hydrogeologic Conditions.... Seismic Hazard........ Erosion Hazard Landslide HazardlSlope Stability .... CONCLUSIONS AND RECOMMENDATIONS.......... General....... Erosion Control and Slope Protection Measures Site Preparation and Grading....... Temporary and Permanent Slopes ......... Structure Setbacks Foundation Improvements ............ Shallow Foundations Retaining Walls .......... Structural FiII.............. Slab-on-Grade.............. Pavement Subgrade Site Drainage Improvements .......... LIST OF FIGURES Figurel-VicinityMap Figure2-SitePlan Figure 3 - Cross-Section A-A' Figure 4 - Soil Classification Chart Figures 5 through 8 - Boring Logs 2 3 4 4 5 6 7 8 8 NELSON GEOTECHNICAL ASSOCIATES. INC. Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properfy Short Plat and Residence Underpinning 15729 -J5th Place West Edmonds, Washington INTRODUCTION This report presents the results of our preliminary geotechnical engineering evaluation for the proposed Larsen Property Short Plat and Residence Underpinning proj ect. The address for the sile is 15729 - 7 5rh Place West in Edmonds, Washington, as shown on the Vicinity Map in Figure 1. The purpose of the study is to explore and characterizethe surface and subsurface conditions at the site and provide general geotechnical recommendations for site development and improvements. For our use in preparing this report, we have been provided with an undated, untitled boundary and topographic showing the existing site conditions. The site is cupently occupied by an existing single-family residence and detached garage within the lower western portion of the property and an existing single-family residence with a daylight basement within the central portion of the property. The ground surface within the site generally slopes gently to moderately up to the east from 75'h Place West along the western property line to the toe of a steep to very steep west-facing slope within the central portion of the property. The steep to very-steep west-facing slope ascends up to a relatively level to gently sloping bench area within the very eastern portion ofthe property. We were informed that the existing residence within the central portion of the property has experienced some foundation settlement throughout the years. We understand that the proposed development plan consists of underpinning the central residence foundation to mitigate potential future settlement ofthe structure. A detached garage is also proposed to be constructed along the eastern portion of the central residence location between the toe of the steep slope and the residence. We also understand that you wish to subdivide the existing property into three separate residential parcels. The existing residences within the western and central portion of the property would be located on two of the parcels and the upper bench area would be located on the third parcel. The upper eastem parcel will likely be developed with a new single-family residence sometime in the future. Stormwater plans have not been finalized at this time, but we anticipate that runoff generated on this site will be tighlined to discharge into an existing stormwater system within the southem portion of the property. The current site layout is shown on the Site Plan in Figure 2. The site is mapped as part of the large historic/prehistoric Meadowdale Landslide complex area now known as the North Edmonds Earth Subsidence & Landslide Hazard Area (ESHLA). The overall property is located in the designaled "Zones B through D" generally located above 75ú Avenue West extending east past the top of the steep to very steep west-facing slope. Slide movement from the large- scale slide complex and smaller localized slides within the complex can both affect this properfy. This NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page2 report provides information and discussion to fulfill the requirements of the City of Edmonds for construction within this area. SCOPE The purpose of this study is to explore and characterize the site surface and subsurface conditions, and provide opinions and recommendations for the proposed site development. Specifically, our scope of services includes the following: I 2 Review available soil and geologic maps of the area. Explored the subsurface soil and groundwater conditions within the site with four geótechnical borings using a limited access drill rig. The drill rig was subcontracted by NGA. Map the conditions on the slope and evaluate current slope stability conditions and p".io.. hand explorations within the steep slope area and interior portion ofthe central residence, as needed. Perform laboratory classification and analysis ofsoil samples, as necessary. Provide recommendations for earthwork, foundation support, and slabs-on-grade in accordance with the City standards for development in the North Edmonds ESLFIA. Provide recommendations for temporary and petmanent slopes. Provide recommendation for deep foundation support, as needed' Provide recommendations for the existing residence underpinning support. Provide recommendations for retaining walls. Provide recommendations for subgrade preparation. Provide recommendations for site drainage and erosion control. Document the results of our findings, conclusions, and recommendations in a written geotechnical report. 3 4. 5. 6. 7. 8. 9. 10 11 t2 SITE CONDITIONS Surface Conditions The western and central portions of the property are generally situated on gently to moderately sloping ground above and to the east of 75ú Place West. The western portion of the property is occupied within an existing residence and detached garage, while the central portion of the property is occupied with an existing single-family residence with a daylight basement. The ground surface within the western and central portions of the properly slopes gently to moderately up to the east from 75ú Place West to the toe of the steep to very steep west-facing slope within the eastern portion of the properly at gradients in the range of approximately 2 to 18 degrees (3 Io 32 percent). A series of concrete block retaining walls are located within the sloping areas between the existing residences. The western and central portions of the property are generally vegetated with grass and landscaping plants' NELSON GEOTECHNICA L ASSOCIATES. INC,Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properfy Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 3 From the lower central portion ofthe site, the ground surface slopes steeply to very steeply up to the east to a relatively level to gently sloping upper bench areaat gradients in the range of35 to 45 degrees (70 to 100 percent). The existing residence within the central portion of the site is located approximately 37 Io 47 feef.from the toe of the steep to very steep west-facing slope. The overall height of the steep slope is approximately 100 feet. The existing site conditions, site topography, and interpreted subsurface conditions are presented on Cross Sections A-A' in Figure 3. The steep slope and upper bench areaare generally vegetated with dense underbrush and young to mature trees. We did not observe any surface water during our site visit on August 7, 2017. We also did not observe any groundwater emitting from the site slopes, however we were informed that water seepage on the steep slope has been observed in the past. V/e did not observe any indications of recent slope movement such as deep-seated landsliding, however some minor erosion and sloughing was observed within portion of the upper most part of the steep west-facing slope area. The lower western and central portion of the properly is accessed via an existing asphalt driveway located along the southern portion of the property extending from 75ú Place West. The upper eastern portion of the properly is accessed via J2d Avenue West. The site is bordered to the north, south and east by existing residential properties, and to the west by 75'h Place West. The existing and proposed site conditions are shown on the Site Plan in Figure 2' Subsurface Conditions Geology: The geologic units for the site vicinity are shown on the Preliminary Geologic Map of the Edmonds East and Edmonds West Quadrangles. Snohomish and King Counties. Washin$on, by Mackey Smith (U.S.G.S., 1975). The lower western and central portion of the site is mapped as old landslides (Qols) while the upper eastern portion of the properfy is mapped as Esperance Sand deposits (Qe). The old landslide deposits are described as large slumps that occurred during the ablation of the Puget Lobe of the Vashon ice sheet by lowering of water-table level. The Esperance sand is described as thinly bedded sand. We generally encountered undocumented fill and granular landslide debris underlain by fine- grained silt and clay within the lower central portion of the property that we interpreted as native Whidbey Formation soils. Our explorations within the upper eastern portion of the site generally encountered native glacial till and Esperance sand soils with fine-grained sand, silt and clay soils that we interpreted as native Whidbey Formations soils' Explorations: The subsurface conditions within the site were explored on August 7,2011 by drilling four borings using a track-mounted limited-access drill rig to depths of approximately 46.5 to 51.5 feet below the existing ground surface. The approximate locations of our explorations are shown on the Site Plan in Figure 2. A geologist from NGA was present during the explorations, examined the soils and geologic conditions encountered, obtained samples of the different soil types, and maintained logs of the borings. NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 4 A Standard penetration Test (SpT) was performed on each of the samples during drilling to document soil density at depth. The SPT consists of driving a 2-inch outer-diameter, split-spoon sampler 18 inches using a 140-pound hammer with a drop of 30 inches. The number of blows required to drive the sampler the final 12 inches is referred to as the "N" value and is presented on the boring logs. The N value is used to evaluate the strength and density ofthe deposit. The soils were visually classified in general accordance with the Unified Soil Classification System, presented in Figure 4. The logs of our borings are attached to this report and are presented as Figures 5 through 8. We present a brief summary of the subsurface conditions in the following paragraphs. For a detailed description of the subsurface conditions, the boring logs should be reviewed' Underlying the ground surface within Borings B-1 and B-2 within the lower central portion of the property, we generally encountered very loose to medium dense, gray-brown to gray silty fine to medium sand with varying amounts of gravel and organics that we interpreted as surficial undocumented fill and historic granular landslide debris. Underlying the surficial undocumented fill and historic granular landslide debris inB-2 at a depth of approxim ately 40 feet below the ground surface, we encountered very stiff blue-gray silty with varying amounts of fine sand and clay that we interpreted as native Whidbey Formation deposits. Boring B-1 was terminated within the historic granular landslide deposits at a depth of 46.5 feet below the existing ground surface, while Boring B-2 was terminated within the native fine- grained Whidbey Formation deposit at a depth of approximately 51.5 feet below the existing ground surface. Below the ground surface within Borings B-3 and B-4 within the upper eastern porlion of the properly generally encountered approximately 20.0 fo 25.0 feet of medium dense to dense, gray to orange-brown silty fine to medium sand that we interpreted as native glacial soils. Underlying the native glacial soils in Borings B-3 and B-4, we encountered medium dense/very stiff to very dense/very hard blue-gray to gray silty fine sand and silt with varying amounts of sand that we interpreted as native Whidbey Formation Deposits. Borings B-3 and B-4 were terminated within the native fine-grained Whidbey Formation deposit at a depth of approxim ately 46.5 feet below the existing ground surface. Hydrologic Conditions Groundwater seepage was not encountered in our explorations. However, wet soil conditions were encountered within the upper granular soils above the fìne-grained siltier soils encountered at depth. It is our opinion that any groundwater seepage encountered within the site would be perched water. perched water occurs when surface water infiltrates through less dense, more permeable soils and accumulates on top of relatively low permeability materials. The more permeable soils on this site would consist of the granular soils found within the landslide debris and the upper native glacial soils. The low NELSON GEOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Propeffy Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 5 permeability soil consists of underlying siltier soils. Perched water does not represent a regional groundwater "table" within the upper soil horizons. Perched water tends to vary spatially and is dependent upon the amount of rainfall. We would expect the amount of perched groundwater to decrease during drier times of the year and increase during wetter periods. However, due to the large area of recharge, there may be areas of seepage and wet soils on this site even in the drier times of the year. SENSITIVE AREA EVALUATION Seismic Hazard Older landslide debris and medium stiff to hard cohesive soils were encountered underlying the site at depth within the western and central portions of the property, while medium dense/very stiff to very dense/very hard native glacial soils and Whidbey Formation deposits were encountered within the upper eastern portion of the property. Based on the 2015 International Building Code (IBC), the site conditions best fit the description for Site Class E within the lower western and central portions of the property while the site conditions best fit the description for Class D soils within the upper eastern portion of the property. Tables I and 2 below provides seismic design parameters for the site that are in conformance vyith the 2015 IBC, which specifies a design earthquake having a 2%o ptobability of occurîence in 50 years (retum interval of 2,4'7 5 years), and the 2008 USGS seismic hazard maps. Table I -2015IBC Seismic Design Parameters (Lower Western and Central Portions of the Site) Table 2 -2015IBC Seismic Design Parameters (Upper Eastern Portion of the Site) Site Class Spectral Acceleration at 0.2 sec. (g) ss Spectral Acceleration at 1.0 sec. (g) Sr Site Coefficients Design Spectral Response Parameters Fu Fu Sos Spr D 1324 0.521 1.00 1.s00 0.883 0.521 The spectral response accelerations were obtained from the USGS Earthquake Hazards Program Interpolated Probabilistic Ground Motion website (2008 data) for the project latitude and longitude. Site Class Spectral Acceleration at 0.2 sec. (g) SS Spectral Acceleration at 1.0 sec. (g) Sr Site Coefficients Design Spectral Response Parameters Fu F,Sos Spr E 1.323 0.520 0.90 2.40 0.794 0.832 NELSON GEOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properfy Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 6 Hazards associated with seismic activity include liquefaction potential and amplification of ground motion. Liquefaction is caused by a rise in pore pressures in a loose, fìne sand deposit beneath the groundwater table. it is our opinion that the competent glacial and fine-grained soils interpreted to underlie the site have a low potential for liquefaction or amplification of ground motion. The glacial soils interpreted to form the core of the steep slopes within the site are considered stable with respect to deep-seated slope failures. All steep slopes have the potential for shallow sloughing failures during seismic events. Such events should not significantly affect the planned development provided the foundations are designed with the recommended setback values, debris protection systems, and the slope and drainage systems are maintained as described in this report. Erosion Hazard The criteria used for determining the erosion hazard for the site soils includes soil type, slope gradient, vegetation cover, and groundwater conditions. The erosion sensitivity is related to vegetative cover and the specific surface soil types, which are related to the underlying geologic soil units. The Soil Survey of Snohomish County Area. Washington by the Soil Conservation Service (SCS), was reviewed to determine the erosion hazard of the on-site soils. The site surface soils were classified using the SCS classification system as Everett very gravelly sandy loam, 15 to 30 percent slopes within the lower western portion of the site, Alderwood-Everett gravelly sandy loams , 25 1.o 70 percent slopes within the central portion of the site and Alderwood-Urban land complex, 2 To 8 percent slopes within the upper eastern portion ofthe site. These soils are described as having a slight to high erosion hazard- It is our opinion that the site soils should have a slight to moderate hazard for erosion in areas that are not disturbed and where vegetation cover is not removed' Landslide HazardlSlope Stability The criteria used for the evaluation oflandslide hazards include soil type, slope gradient, and groundwater conditions. The western and central portions of the site slope gently to moderately down to the west. A steep west-facing slope is located above and to the east of the existing central residence within the eastem portion of the property. Groundwater seepage was not observed on the sloping portions of the property during site visit, however we understand that groundwater seepage has been observed on the steep slope areainthe past. This site and the overall site vicinity lies within a known ancient landslide area. The site and vicinity have been relatively stable for a very long period of time, and development in the area has taken place in the form of single-family residences, roadways, and underground utilities. Although the likelihood of the ancient slide to become active in the foreseeable future is very low, extreme environmental conditions NELSON GEOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properly Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 PageT coupled with inadequate human practices could, in theory, re-activate the ancient landslide. Such external factors could include severe and elongated weather events andlor significant seismic activity. The site falls within "Zones B through D" of the North Edmonds Earth Subsidence and LandslideHazard Area Report prepared by Landau Associates for the City of Edmonds. This designation requires that certain features be included (or excluded) in the design. Such features include the restriction ofcuts and fills, the need for tightlining runoff into an approved system, the need to design foundations and retaining walls to withstand high lateral earth pressures and potential loss of soil beneath parts of the foundation, the need to vegetate slopes with deeply rooted drought-tolerant vegetation, and the elimination of any and all irrigation systems. We have addressed all of these requirements in the remainder of this report. We encountered what we interpreted as older granular landslide debris to depths of about 40 feet below the existing ground surface within the lower (central) portion of the property. Medium dense/stiff undisturbed native soils were encountered below this material, which we interpret the core of the site slopes at depth to consist primarily of this relatively stable material. Potential deep-seated slide planes were reported to be up to 100 feet deep below ground surface within the area; however, we did not observe signs of recent deep-seated slope failures on the property and do not anticipate that such failures will occur during the expected life of the existing and proposed structures. Localized areas of surface instability and surface sliding can occur on steep slopes, particularly where modified through grading activities. Backwasting (movement of near-surface soil) through soil erosion processes or local surface slides is common to slopes, particularly where the soils are exposed to weathering. Normal surface erosion and shallow sloughing failures should be expected to continue on the steeper portions ofthe site, but we have provided geotechnical recommendations for deep-foundation suppoft, debris catchment, erosion control, structure setbacks and other development considerations that should reduce the potential impact of site development on the site slopes. CONCLUSIONS AND RECOMMENDATIONS General It is our opinion, from a geotechnical standpoint, that the site should be compatible with the proposed development and improvements, provided that the geotechnical recommendations presented in this report are incorporated into project plans and followed during construction. The proposed development area appears to be relatively stable under current conditions. However, the historic landslide mapped at the site could be reactivated by extreme natural conditions andlor poor grading and/or drainage activities by other human activity in the general site vicinity. Vy'e consider this potential to be low. NELSON GEOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 8 In general, the site and steep slopes within the site currently appear generally stable with respect to deep- seated movement. However, the site vicinity is mapped within an older landslide complex and our explorations encountered evidence of past landslide debris and ground movement within the lower central and western portions of the property. The potential for landslide and erosion hazards within this site will greatly depend on how the site is graded and how surface water and near surface water are controlled. We recommend that site grading be kept to a minimum and that grading and site drainage plans be subjected to geotechnical engineering review prior to construction. This review would include specific stability analysis of proposed cuts and fills and would provide recommendations for accomplishing the desired grading while maintaining long-term stability. In our opinion, based on our observations and our understanding ofthe prevailing building conditions, the settlement and distress to the central residence is likely a result of long-term consolidation (settlement) of the relatively loose undocumented fill and landslide debris soils that were encountered in our explorations and is interpreted to underlie portions ofthe residence. It appears that this fill was likely placed during the initial development of this property. Due to the varying nature of the overall density of the fill encountered in our explorations, it is likely that some of the fill material was placed in a loose condition at the time of residence construction, and throughout the years has been settling under the building loads. It is likely that the foundations and slabs-on-grade will continue to experience steady settlement and subsidence under the cunent conditions resulting in additional distress to the foundation, slabs and utilities within the structure. To mitigate this condition, we recommend that the all exterior and interior foundations along with all slabs-on-grade affected by the ongoing settlement be supported on deep foundations consisting of driven pin piles to transfer building loads through the undocumented fiIl and landslide debris down to the underlying competent native soils. Lateral loads on the residence should be resisted by helical anchor tiebacks. The exact location and extent ofthe pin piles and helical anchor tiebacks should be determined by the structural engineer. We should be retained to discuss with the structural engineer the details of the stabilization plans. We have provided recommendations for driven pin piles and helical anchor tiebacks in the Foundation Improvements subsection of this report. We also recommend that aftet the pin pile and helical anchor installation is completed, the remainder of the residence be closely monitored for any signs of further distress, and additional stabilization measures be installed if signs of future distress are observed. We recommend that if a slab-on-grade is utilized in the lower portions of the proposed central residence, that the slab be designed as a structural slab and be supported on the deep foundation system. Other hard surfaces, such as paved areas or walkways that are supported on the existing soil have some risk of future settlement, cracking, and the need for maintenance. To reduce this risk, we recommend over-excavating NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 9 a minimum of two feet of the upper soil from the slab and pavement areas and replacing this material with compacted pit run or crushed rock structural fill. This recommendation is only for hard surfaces to be supported on grade and does not apply for the lower floor structural slab. Even with the recommended treatment, some settlement of the underlying loose material should be anticipated. In addition to the foundation improvements, we recommend that the drainage picture surrounding the existing central residence be improved. Such improvements should include confirming andlor implementing the placement of footing drains around the building, and routing all downspouts and runoff from all hard surfaces into a permanent discharge system. We recommend that these pipes be extended to discharge to an approved system. This is furlher discussed in the Drainage Improvements subsection of this report. It is also our opinion that the proposed garage development along the eastern side ofthe existing central residence is feasible from a geotechnical standpoint. We recommend that the foundations and slabs associated with the proposed garage structure be supported on a deep foundation system consisting of driven pin piles. We understand that the garage will be constructed along or very near the toe of the steep west-facing slope. In our opinion, this should be feasible provided the foundation walls along the upslope side of the garage be designed as recommended in this report. We recommend that the upslope portions of the garage foundation be designed as debris walls and extend a minimum of four feet above finished ground surface to protect the structure against potential failures on this slope. This is intended to provide a catchment measure should any sloughing debris travel towards the garage during extreme weather or as a result ofan earthquake. Alternatively, a separate debris protection structure or fence could be utilized. It is our opinion that the planned residence development within the upper eastem portion of the site is feasible from a geotechnical standpoint. It is also our opinion that the soils that underlie the upper eastern portion of the site and form the core of the steep west-facing slope should be stable with respect to deep- seated earth movements, due to their inherent strength and slope geometry. However, shallow failures could occur on the slopes in the loose surficial soil, especially during adverse weather or a sigrrificant seismic event. Proper structure setbacks along with erosion and drainage control measures as recommended in this report should reduce this potential. Our explorations indicated that the upper eastem portion of the site is underlain by medium dense or better native glacial soils at relatively shallow depths. The native glacial soils within the proposed upper eastern development area should provide adequate support for foundation, slab, and pavement loads. 'We recommend that the structures within the upper eastern portion ofthe site be designed utilizing shallow foundations. Footings should extend through any loose surficial soil and be keyed into the underlying competent native soils. These soils should be encountered roughly two to five feet below the existing ground surface within the planned development area, with some potential localized areas of deeper loose soils in unexplored areas of the site. To protect NELSON G EOTECHNICA L ASSOCIA TES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 10 the structures against potential failures on the slopes, we recommend that any proposed structures be set back at least 60 feet from the top of the steep west-facing slopes. We should be retained to review final structure locations and to observe foundation excavations prior to placing forms. The control of surface and near-surface water is very important for the long-term stability of the site and on the steeper portions of the site slopes. We highly recommend that temporary and final site grading be designed to direct surface water away from the structures and away from the site slopes. Final drainage plans have not been developed at this time, but we understand that all stormwater generated on the site will be collected in tightlines and transported into an existing stromwater system along the southern portion of the property. No water should be infiltrated or dispersed within the site. We discuss general site drainage in the Site Drainage subsection of this report. The soils encountered within our explorations are considered extremely moisture sensitive and will disturb easily when wet. We recommend that construction take place during extended periods of dry weather if possible. If construction takes place during wet weather, additional expenses and delays should be expected due to the wet conditions. Additional expenses could include the need to export on- site soil, the import of clean, granular soil for fill, and the need to place a blanket of rock spalls or crushed rock in the construction traffic areas and on exposed subgrades prior to placing structural fill or structural elements. In this report, we have also provided recommendations for drainage, erosion control, and other development considerations intended to reduce the potential impact of development on the site and the site slopes. We should be retained to review final project plans prior to construction. We also recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with contract plans and specifications. Erosion Control and Slope Protection Measures The erosion hazard for the on-site soils is considered moderate to high, but the actual hazard will be dependent on how the site is graded and how water is allowed to concentrate. Best Management Practices (BMPs) should be used to control erosion. Areas disturbed during construction should be protected from erosion. Erosion control measures may include diverting surface water away from the stripped or disturbed areas. Silt fences and/or slope waddles should be erected to prevent muddy water from leaving the site or flowing over the site slopes. Disturbed areas should be planted as soon as practical and the vegetation should be maintained until it is established. The erosion potential for areas not stripped of NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 1 1 vegetation should be low to moderate. Also, inigation systems should not be installed within the property. Protection of the site slopes should be performed as required by the City of Edmonds. Specifically, we recommend that the slopes not be disturbed or modified through placement of any fil1 or future structures outside the planned development areas. No additional material of any kind should be placed on any portion of sloping ground, such as excavation spoils and soil stockpiles. It may be possible for trees to be cut down and removed from the slopes as long as a mitigation plan is developed for maintaining slope stability, such as the replacement of vegetation for erosion protection. A vegetation cover should be preserved onthe slopes. Replacement of vegetation should be performed in accordance withthe City of Edmonds code. Under no circumstances should water be allowed to concentrate on the slopes. Any sloping areas disturbed during construction should be planted with vegetation as soon as practical to reduce the potential for erosion. Site Preparation and Grading Plans for site grading should be devised such that cuts and fills are kept to a minimum. Site preparation should consist of excavating the upper eastern residence and garage footprints down to planned elevations. Site preparation should also consist of stripping any organic topsoil and/or loose/soft soils in areas that will support foundations, slabs-on-grade, pavement, or structural fill. The stripped material should not be stockpiled within the site. If the exposed soils are loose/soft, they should be compacted to a non-yielding condition. Areas observed to pump or weave during compaction should be over-excavated and replaced with rock spalls. If significant surface water flow is encountered during construction, this flow should be diverted around areas to be developed and the exposed subgrade maintained in a semi-dry condition. In wet conditions, the exposed subgrade should not be compacted, as compaction of a wet subgrade may result in further disturbance of the soils. A layer of crushed rock may be placed over the prepared areas to protect them from further disturbance. The site soils are considered extremely moisture sensitive and will disturb easily when wet. We recommend that earthwork construction take place during periods of extended dry weather, and suspended during periods of precipitation. If work is to take place during periods of wet weather, extreme care should be taken during site preparation as to not to disturb the site soils. This can be accomplished by utilizing large excavators equipped with smooth buckets and wide tracks to complete earthwork, and diverting surface and groundwater flow away from the prepared subgrades. Also, construction traffic should not be allowed on the exposed subgrade. A blanket ofrock spalls should be used in construction access areas if wet conditions are prevalent. The thickness of this rock spall layer should be based on subgrade performance at the time of construction. For planning purposes, we recommend a minimum one-foot thick layer ofrock spalls. NELSON G EOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 12 Temporary and Permanent Slopes Temporary cut slope stability is a function of many factors, including the type and consistency of soils, depth of the cut, surcharge loads adjacent to the excavation, length of time a cut remains open and the presence of surface or groundwater. It is exceedingly difficult under these variable conditions to estimate a stable, temporary, cut slope angle. Therefore, it should be the responsibility of the contractor to maintain safe slope configurations since they are continuously at the job site, able to observe the nature and condition of the cut slopes, and able to monitor the subsurface materials and groundwater conditions encountered. The following information is provided solely for the benefit of the owner and other design consultants and should not be construed to imply that Nelson Geotechnical Associates, Inc. assumes responsibility for job site safety. Job site safety is the sole responsibility ofthe project contractor. For planning purposes, we recommend that temporary cuts in the on-site material be no steeper than two units horizontal to one unit vertical (2H:1V). If groundwater seepage is encountered, we would expect that flatter inclinations would be necessary. We should be retained to specifically review proposed geometry for significant cuts planned on this site. We recommend that cut slopes be protected from erosion. Erosion control measures may include covering cut slopes with plastic sheeting and diverting surface water runoff away from the top of cut slopes. We do not recommend vertical slopes for cuts deeper than four feet, if worker access is necessary. We recommend that cut slope heights and inclinations conform to appropriate OSHA/WISHA regulations. Permanent cut and fill slopes should be no steeper than 3H:1V. However, flatter inclinations may be required in areas where loose soils are encountered. Permanent slopes should be covered with erosion control matting and vegetated. The vegetative cover should be maintained until established. We should specifically review all plans for grading on this project. We do not recommend placing irrigation systems near the slopes. Structure Setbacks Uncertainties related to building along steep slopes are typically addressed by the use of building setbacks. The purpose ofthe setback is to establish a "buffer zone" between the structure and the top and toe of the slope so that ample room is allowed for normal slope recession during a reasonable life span of the structure. In a general sense, the greater the setback distance, the lower the risk of slope failures impacting the structure. From a geological standpoint, the setback dimension is based on the slope's physical characteristics, such as slope height, surface angle, material composition, and hydrology. Other factors such as historical slope activity, rate of regression, and the type and desired life span of the development are important considerations as well. NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 13 We recommend that any proposed structures within the upper eastern portion of the property be set back at least 60 feet from the top of the steep west-facing slope. We also understand that a proposed garage structure may be constructed along the toe of the steep west-facing slope within the central portion of the property. In our opinion, this is feasible provided that the uphill eastern side of the garage is designed as a debris catchment wall and extends a minimum of four feet above the sunounding ground surface. We should be retained to review final residence location and to observe foundation excavations prior to placing forms. Any proposed development within the setback area, should be the subject of a specific geotechnical evaluation. Under no circumstances should water be allowed to concentrate on the slopes, during or after construction. Foundation Improvements Driven Pin Piles: We recommend that all interior and exterior foundation lines along with all impacted slabs-on-grade associated with the central residence be supported on driven pin piles to transfer foundation loads to the underlying native competent native materials found below the fill and landslide debris. We also recommend that the foundations and slabs for the proposed garage associated with the central residence also be supported on deep foundations consisting of driven pin piles. Due to the limited access to the existing residence area, we anticipate that all interior areas to be underpinned will be supported on 2-inch pin piles. However, the exterior foundations and foundations for the planned garage could be supported by either 2-inch pin piles or 4'inch pin piles, if larger equipment can access these areas. We recommend that the foundations and slabs associated with the proposed garage be supported on 4-inch pin piles. We have provided recommendations for the two pin pile sizes, in this section' Our explorations did not encounter any significant debris within the existing fill or landslide debris, however there is a possibility that some obstructions within the fill may impede some of the piles. There should be contingencies in the budget and design for additional/relocated piles to replace piles that may be obstructed by debris. We also recommend that excavation equipment be available on site during pile installation so that shallow obstructions can be removed from the planned pile locations. For 2-inch diameter pipe piles driven to refusal using a hand-held, 140-pound jackhammer, we recommend a design axial compression capacity of three tons for each pile. The refusal criterion for this pile and hammer size is defined as less than one inch of movement during 60 seconds of continuous driving. We recommend using galvanized extra strong (Schedule 80) steel pipe for the 2-inch pin piles' 'We recommend that the four-inch pipe piles, if utilized, be driven using a tractor-mounted hydraulic hammer, with an energy rating of at least 1,100 foot-lb. For this pile and hammer size, we recommend a design capacity of eight tons for each pile driven to refusal. The refusal criterion for this pile and hammer size is defined as less than one-inch of movement during 1 5 seconds of continuous driving at a rale of 5 50 blows per minute or higher. We recommend using galvanized schedule 40 pipe for the 4'inch pin piles. NELSON GEOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 14 Maintaining these recommendations for minimum hammer size and refusal criteria is essential for obtaining a successful outcome. Final pile depths should be expected to vary somewhat and will depend on the depth of the loose material and landslide debris, the nature of the underlying competent soils. The pin piles should penetrate a minimum of five feet into the competent native glacial soils below the fill material in order to develop the design capacity. Based on our explorations within the vicinity of the central residence, we anticipate that piles may need to be driven to a minimum depth of 50 feet below the ground surface to achieve the minimum embedment depth into the competent native soils. Piles that do not meet this minimum embedment criterion should be rejected, and replacement piles should be driven after consulting with the structural engineer regarding the new pile locations. The piles should be spaced a minimum of two feet apart to avoid a gfouping effect on the piles. We should also be retained to observe pin pile installation during construction. Due to the relatively small slenderness ratio of pin piles, maintaining pin pile confinement and lateral support is essential in preventing pile buckling. The brackets and pin pile connections to the existing and proposed foundation and slabs should be designed by the structural engineer. Vertically driven pin piles do not provide meaningful lateral capacity. Due to the rigid pile support, friction between the foundation and subgrade soil should not be considered for resisting lateral pressures on this structure. We recommend that all lateral loads be resisted on the helical anchor tiebacks. Shallow Foundations For the upper eastern portion of the development, conventional shallow spread foundations should be placed on undisturbed medium dense or better native soils. Medium dense to dense soils should be encountered roughly two to five feet below the ground surface based on our explorations; however, deeper areas of loose soil may be encountered in unexplored areas of the site. Where undocumented fill or less dense soils are encountered at footing bearing elevation, the subgrade should be over-excavated to expose suitable bearing soil. Footings should extend at least 18 inches below the lowest adjacent finished ground surface for frost protection and bearing capacity considerations. Foundations should be designed in accordance with the 2015 IBC. Footing widths should be based on the anticipated loads and allowable soil bearing pressure. Water should not be allowed to accumulate in footing trenches. All loose or disturbed soil should be removed from the foundation excavation prior to placing concrete. NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properfy Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 15 For foundations constructed as outlined above, we recommend an allowable design bearing pressure of not more than 2,000 pounds per square foot (psf) be used for the footing design for footings founded on the medium dense or better native soils or structural fill extending to the native competent material. The foundation bearing soil should be evaluated by a representative of NGA. We should be consulted if higher bearing pressures are needed. Current IBC guidelines should be used when considering increased allowable bearing pressure for short-term transitory wind or seismic loads. Potential foundation settlement using the recommended allowable bearing pressure is estimated to be less than one inch total and ll2 inch differential between adjacent footings or across a distance of about 20 feet, based on our experience with similar projects. Lateral loads may be resisted by friction on the base of the footing and passive resistance against the subsurface portions of the foundation. A coefficient of friction of 0.3 0 may be used to calculate the base friction and should be applied to the vertical dead load only. Passive resistance may be calculated as a triangular equivalent fluid pressure distribution. An equivalent fluid density of 150 pounds per cubic foot (pcf) should be used for passive resistance design for a level ground surface adjacent to the footing. This level surface should extend a distance equal to at least three times the footing depth. These recommended values incorporate safety factors of 1.5 and 2.0 applied to the estimated ultimate values for frictional and passive resistance, respectively. To achieve this value of passive resistance, the foundations should be poured "neal" against the native medium dense soils or compacted fill should be used as backfill against the front of the footing. We recommend that the upper one-foot of soil be neglected when calculating the passive resistance. Retaining Walls Final grading and development plans were not available at the time this report was prepared but retaining walls will likely be needed for the proposed development. We recommend that the uphill foundation wall for the proposed garage within the central portion of the property be extended a minimum of four feet above the finished ground surface to protect the structure against potential failures from the slope above' This is intended to provide a catchment measure should any sloughing debris travel towards the garage structure during extreme weather or as a result of an earthquake. Alternatively, a separate debris protection structure or fence could be utilized. We also recommend that no window or door openings be located on the uphill eastern side of the proposed garage within the central portion of the property. The lateral pressure acting on subsurface retaining walls is dependent on the nature and density ofthe soil behind the wall, the amount of lateral wall movement which can occur as backfill is placed, wall drainage conditions, the inclination of the backfill, and other possible surcharge loads. For walls that are free to yield at the top at least one thousandth of the height of the wall (active condition), soil pressures will be less than if movement is limited by such factors as wall stiffness or bracing (at-rest condition). We NELSON G EOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 16 recommend that walls supporting horizontal backfill and not subjected to hydrostatic forces be designed using a triangular earth pressure distribution equivalent to that exerted by a fluid with a density of 45 pcf for yielding (active condition) walls, and 65 pcf for non-yielding (at-rest condition) walls. If the uphill side of the proposed garage is intended to act as a debris wall, we recommend the above ground portion of the garage wall be designed to resist an active pressure of 100 pcf' These recommended lateral earth pressures are for a drained granular backfill and are based on the assumption of a maximum 2H:lV backfill inclinations and do not account for additional surcharge loads. Additional lateral earth pressures should be considered for surcharge loads acting adjacent to subsurface walls and within a distance equal to the subsurface height of the wall. This would include the effects of surcharges such as traffic loads, floor slab and foundation loads, or other surface loads. We are available to provide consultation regarding additional loads on retaining walls during final design, if needed. The lateral pressures on walls may be resisted by friction between the foundation and subgrade soil, and by passive resistance acting on the below-grade portion of the foundation. Recommendations for frictional and passive resistance to lateral loads are presented in the Foundations subsection of this report. All wall backfill should be well compacted as outlined in the Structural Fill subsection of this report. Care should be taken to prevent the buildup ofexcess lateral soil pressures, due to over-compaction ofthe wall backfill. This can be accomplished by placing wall backfill in thin loose lifts and compacting it with small, hand-operated compactors within a distance behind the wall equal to at least one-half the height of the wall. The thickness of the loose lifts should be reduced to accommodate the lower compactive energy of the hand-operated equipment. The recommended level of compaction should still be maintained. Permanent drainage systems should be installed for retaining walls. Recommendations for these systems are found in the Subsurface Drainage subsection of this report. We recommend that we be retained to evaluate the proposed wall drain backfill material and drainage systems. Structural Fill General: Fill placed beneath foundations, pavements, and other settlement-sensitive structures, or behind retaining walls should be placed as structural fill. Structural fill, by definition, is placed in accordance with prescribed methods and standards and is monitored by an experienced geotechnical professional or soils technician. Field monitoring procedures would include the performance of a representative number of in-place density tests to document the attainment of the desired degree of relative compaction. The area to receive the fill should be prepared as outlined in the Site Preparation and Grading subsection of NELSON GEOTECHNICAL ASSOCIATES, INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properly Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 17 this report. Sloping areas to receive fill should be benched prior to fill placement. The benches should be level and at least four feet wide. Materials: Structural fill should consist of a good quality, granular soil, free of organics and other deleterious material and be well graded to a maximum size of about three inches. All-weather fill should contain no more than five-percent fines (soil finer than U.S. No. 200 sieve, based on that fraction passing the U.S. 314-inch sieve). We do not anticipate placement of significant volumes of structural fill for this project. The on-site soils consist of moisture-sensitive silty materials and slide debris. We recommend that the on-site material not be used as structural fill. We should be retained to evaluate the suitability of proposed structural fill materials at the time of construction. Fill Placement: Following subgrade preparation, placement of structural fill may proceed. All filling should be accomplished in uniform lifts up to eight inches thick. Each lift should be spread evenly and be thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying building areas and pavement subgrade should be compacted to a minimum of 95 percent of its maximum dry density. Maximum dry density, in this report, refers to that density as determined by the ASTM D-1557 Compaction Test procedure. The moisture content of the soils to be compacted should be within about two percent of optimum so that a readily compactable condition exists. It may be necessary to over- excavate and remove wet soils in cases where drying to a compactable condition is not feasible. All compaction should be accomplished by equipment of a type and size sufficient to attain the desired degree of compaction. Slab-on-Grade As mentioned earlier, we recommend that slabs-on-grade associated with the central portion of the property be designed as a structural slab and fully supported on the deep foundation system consisting of driven pin piles. Slabs associated with the upper eastern portion of the property should be supported on subgrade soils prepared as described in the Site Preparation and Grading subsection of this report. We recommend that all floor slabs be underlain by at least six inches of free-draining gravel with less than three percent by weight of the material passing Sieve #200 for use as a capillary break. We recommend that the capillary break be hydraulically connected to the footing drain system to allow free drainage from under the slab. A suitable vapor barrier, such as heavy plastic sheeting (6-mil minimum), should be placed over the capillary break material. An additional 2-inch-thick moist sand layer may be used to cover the vapor barrier. This sand layer is optional, and is intended to be used to protect the vapor barrier membrane and to aid in curing the concrete. NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properfy Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page l8 Pavement Subgrade Pavement subgrade preparation should be completed as recommended in the Site Preparation and Grading and Structurat Fill subsections of this report. Depending on the tolerance to pavement cracking, we recommend that the upper two feet of the existing material be removed and replaced with granular structural fill or crushed rock. The pavement subgrade should be proof-rolled with a heavy, rubber-tired piece of equipment, to identify soft or yielding areas that may require repair prior to placing any structural fill and prior to placing the pavement base course. We should be retained to observe the proof-rolling and recommend repairs prior to placement of the asphalt or hard surfaces. The pavement section should be thickened to further reduce the effects of settlement due to the landslide debris, but potential long-term cracking should still be expected. Site Drainage Improvements Surface Drainage: The finished ground surface should be graded such that stormwater is directed to an appropriate stormwater collection system. Water should not be allowed to collect in any area where footings, slabs, or retaining walls are to be constructed. Final site grades should allow for drainage away from the structure and away from the site slopes. We suggest that the finished ground be sloped at a minimum gradient of three percent, for a distance of at least 10 feet away from the structure and slopes. Surface water should be collected by permanent catch basins and drain lines, and be discharged into an appropriate discharge system. Under no circumstances should water be allowed to flow uncontrolled over the site slopes or excavation walls. Existing drains within the property should be investigated and repaired, as needed, to ensure all runoffgenerated on this site is routed away from the building foundation and into the approved discharge system. We recommend that all stormwater generated on the site, including roof downspouts, footing drains, pavement and yard drains, and any water flow from the road, be tightlined to the existing stormwater system within the southern portion of the site. Subsurface Drainage: If groundwater is encountered during construction, we recommend that the contractor slope the bottom of the excavations and collect water into ditches and small sump pits where the water can be pumped out of the excavations and routed into an appropriate outlet. We recommend the use of footing drains around the planned structure and behind retaining walls. Footing drains should be installed at least one-foot below planned finished floor elevation. The drains should consist of a minimum four-inch-diameter, rigid, slotted or perforated, PVC pipe surrounded by free-draining material, such as washed rock, wrapped in a filter fabric. We recommend that an l8-inch- wide zone of clean (less than three-percent fines), granular material be placed along the back of the walls above the drain. Washed rock is an acceptable drain material, or drainage composite may be used instead. NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properfy Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page 19 The free-draining material should extend up the wall to one-foot below the finished surface. The top foot of backfill should consist of low permeability soil placed over plastic sheeting or building paper to minimize the migration of surface water or silt into the footing drain. Footing drains should discharge into tightlines leading to an appropriate collection and discharge point with convenient cleanouts to prolong the useful life of the drains. Roof drains should not be connected to footing drains. Roof drains should also be installed around the structure. Roof drains should consist of gutters and downspouts collecting stormwater runoff from the roof. The downspouts should discharge to catch basins and 4-inch minimum diameter, rigid, PVC tightline pipes. The drains should be directed into catch basins and then into the controlled drainage system. The footing and roof drains should discharge via independent (separate) tightlines into catch basins/cleanouts leading to the stormwater system. Surface water from the driveway and yard areas should also be collected in a catch basin and tightlined separately to the stormwater system. USE OF THIS REPORT NGA has prepared this report for Mr. Carl Larsen and his agents, for use in the planning and design of the development planned on this site only. The scope of our work does not include services related to construction safety precautions and our recommendations are not intended to direct the contractors' methods, techniques, sequences, or procedures, except as specifically described in our report for consideration in design. There are possible variations in subsurface conditions between the explorations and also with time. Our report, conclusions, and interpretations should not be construed as a warranty of subsurface conditions. A contingency for unanticipated conditions should be included in the budget and schedule. We recommend that we be retained to review final project plans and provide consultation regarding specific structure placement, site grading, foundation support, and drainage. We also recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with contract plans and specifications. We should be contacted a minimum of one week prior to construction activities and could attend pre-construction meetings if requested. All people who own or occupy homes on or near hillsides should realize that landslide movements are always a possibility. The landowner should periodically inspect the slope, especially afr.er a winter storm. If distress is evident, a geotechnical engineer should be contacted for advice on remedial/preventative measures as soon as possible. The probability that landsliding will occur is substantially reduced by the NELSON G EOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Property Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page20 proper maintenance of drainage control measures at the site (the runoff from the impervious surfaces should be led to an approved discharge point). Therefore, the homeowner should take responsibility for performing such maintenance. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering practices in effect in this area aI the time this report was prepared. No other waranty, expressed or implied, is made. Our observations, findings, and opinions are a means to identiff and reduce the inherent risks to the owner. o-o-o NELSON G EOTECHNICA L ASSOCIATES. INC.Attachment 6 Preliminary Geotechnical Engineering Evaluation Larsen Properly Short Plat and Residence Underpinning Edmonds, Washington NGA File No. 999017 February 28,2018 Page2l We appreciate the opportunity to provide service to you on this project. If you have any questions or require further information, please call. Sincerely, NEISON GEOTECHNICAI ASSO CIATES, INC. Lee S. Bellah, LG Project Geologist Khaled M. Shawish, PE Principal LSB:KMS:sg Eight Figures Attached ?883 LEE S, BELLAH NELSON GEOTECHNICAL ASSOCIATES. INC.Attachment 6 /\ VICINITY MAP N Not to Scale ',' qa q$!i$l *uu**u 14th Fl $t'l û¿rlct! r:t¡Ê"ll Meadc! Ssacå'\} t { Ð I 2 ì r¡-c -.ã '4r^ 'Ð. zô)r), %us& 66 E€ I*¡trh 3t $¡t q I, {s5ôÞ 6ã F*q. $iloå MeadífrAâb . T ;Ptàvl¡etds i ñi=f,J..--æ'r i63thStSW I { 4 'tt e sd9:e^z $æds3.f*ìrî..*e 5Ar Meadawdale Mlddle Schosl o èsr€.s Edmonds, WA Project Site Project Number 999017 Larsen Property Short Plat Vicinity Map NELsoN GEOTECHNICÄL AssoctÄTES, lNc.N G A GEOTECHNICAL ENGINEERS & GËOLOGISTS wdlnvfle offcê 17311-1slh Aw. NË, Æ Wôôdinúñê. WA s72(425)461æ/Fâx€l-2s10 {w.ndsngeold.6m EalWerdcheoficêsæ lìduêrry Lans. #2 Ead Wonalú66, WAW2 No. Date Rêvision By GK 1 8t10t't7 Original DPN LSB Figure 1 Attachment 6 Approximate Locâtion of Proposed GarageApproximate Top of SlopeExìsting Western Garageþproximale Toe of Slope{NfqExisting Westem ResidenceApprox¡mate 60-footSteep Slope Selback*S..i=r|¡,ll;..*1.' ., l: ,; I '"''"':: r'H'.{.:.,)rrtrll¡'tv,,t),: r ilr ¡rr'.ì r ,(ì(\r ¡i''.r:ra:r1ìr' /: \\;\.{qfìi:.¡r rliiir|- j. ,. :ftExisting Central ResidenceLEGENDProperty lineB-1+-AA't____1Number and approximatelocation of boringApproximate locationof cross-sectionScale: 1 inch = 50 feetRefê€næ: Site Plan based on ân unda'ted, unt¡tled plâñ provided by CG Eng¡neering-o¡E=zçYÈNooo(ûfLoz(toaôcú)cJc-gùoËrDJIz!Ul¡¡Fol¡¡ozooJl¡¡zot-fllıoJo¡¡¡('ðllü¡¡¡¡¡¡auzt!JIztl¡¡Folduúz{¡it¡¡FfUoUI(rÌ^Êåts5ÊËôgËtTItiiiitzodooøof0-oıoNoftrAttachment 6 aÐNooNoÐooÐoo@çooÈåoo¡>!>OG6CıødEpÈCE'-c .QooñvoøE E-Y00*< ã:o;ødÞ5c,gF 6CN:.- *b Érô Èã Our,s,KË6gr-ızØÈD)NouloaÐTooooc?úo6oaoþoooooocñi5ooNotooEoooÞEoıFoc6dÞ'øEEooEgooÞooo.9.oøI()öIEúIoNñËoFñoi¡oLcoxËèèfjoËo6otlL-ç()E(¡)ıffliaao6.9,ı=vıoculoo9Tzãtrit+{-{-'.-+-f-.t>¡.=dÍ()F-trlolaElLIolOJxlu¡l¡01€.9o6ooooNNoa0ooìEaos)(¡ee¡) uone,re¡g eleu¡xolddyao^Iıcài -eË9t ¡íìEeoo1bp;EÞãoqöe*¿ r0666¡equ.¡nN lcelo.¡dv-v uollces-ssoJ3leld uoqs,{uedo.¡d uosle'Iu@ @4æ6!@0ù MÀ 019¿+txaj / SSot{8} (gzt)slzf¿ (M) urÞqtê€q5¡EuÐa ¿¿@6vm ¡olþul@m@ots¿€e (gzt) ¡¡unoc qquoqoüS 0Fv'3N .Àv 49e trl te¿ls¡stoo'lolÐ a s¡{EgNlÐN3 -rYc¡NHÐ3rOE99Nl rSãIV|ÐOSSVvÐN']vtt N Ht3¡oãÐ Nos'rã Na¡Bouolsl^eÈl{g)tctrilgu6PulEpoBSIg ern6¡¡Attachment 6 UNIFIED SOIL CLASSIFICATION SYSTEM MAJOR D¡VISIONS GROUP SYMBOL GROUP NAMË COARSE - GRAINED SOILS MORE THAN 50 % RETAINED ON NO. 200 STEVE GRAVEL MORE THAN 50 % OF COARSE FRACTION RETAINED ON NO.4 SIEVE CLEAN GRAVEL GW WELL-GRADED, FINE TO COARSE GRAVEL GP POORLY-GRADED GRAVEL GRAVEL WITH FINES GM SILry GRAVEL GC CLAYEY GRAVEL SAND MORE THAN 50 % OF COARSE FRACTION PASSES NO.4 SIEVE CLEAN SAND SW WELL-GRADED SAND, FINE TO COARSE SAND SP POORLY GRADED SAND SAND WITH FINES SM SILry SAND SC CLAYEY SAND FINE - GRAINED SOILS MORE THAN 50 % PASSES NO. 2OO SIEVE SILT AND CLAY LIQUID LIMIT LESS THAN 50 % INORGANIC ML SILT CL CLAY ORGANIC OL ORGANIC SILT, ORGANIC CLAY SILT AND CLAY LIQUID LIMIT 50 % OR MORE INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY, FAT CLAY ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: 1) Field classification is based on visual examination of soil in general accordance with ASTM D 2488-93. SOIL MOISTURE MODIFIERS: Dry - Absence of moisture, dusty, dry to the touch 2) Soil classification using laboratory tests is based on ASTM D 24BB-93.Moist - Damp, but no visible water 3) Descriptions of soil density or consistency are based on ¡nterpretat¡on of blowcount data, visual appearance of soils, andior test data. Wet - Visible free water or saturated, usually soil is obtained from below water table Project Number 99901 7 Larsen Propeñy Shott Plat Soil Classification Chad NELSoN GEorEcHNtcAL N G A AssoclATEs, lNc. GEoTEcHNICAL ENGINEERS & GEOLOGISTS Wodlnvlllè Oficê i7311-lSth Aw. NE. Ä-m Woodinülle, WAS72 (425) 4&169 / Faxr 41-2510 w.hel6ohgêotech..om East wénatchêê oflcê 5526 lnduglry Lané. 12 Eâ61Wénåich¿e. WA W2(ru) æ$7ffi / Fax: trt7æ? No. Date Revision By CK at10t17 Original DPN LSB Figure 4 Attachment 6 BORING LOG B-1 Approximate Ground Surface Elevation: ?? Soil Proflle Sample Data Penetration Resistance (Blows/foot - O)10 2,0 3,0 10 5p 50- ç ØoFà ı .o(úJ Piezometer lnstallation - Ground Water Data (Depth in Feet)Description .oco-(!(t oI oo:f, -Õotroı' }E oò ã-o9äe ro-ã95Ø: ßo Moisture Content (Percent - l)10 20 30 40 50 50+rrttt Gray-brown, silty fìne to medium sand with gravel, iron-oxide staining, and trace roots (very loose, moist) -becomes dark brown -becomes dark brown to gray-brown, loose -no organics -becomes gray, moist to wet -becomes gray-brown -becomes gray, medium dense, wet -becomes loose with trace organics, charcoal :.. .. ..'. ' ., | : "- ,-"' -., :- :r-:¡r: t'.--. ,.:4.';;. ..]* _''".-::: ,.. :' SM 3 J 5 7 I I 17 5 Ã 10 15 20I 25I Ã - 10 -15 20 25 LEGEND t: w Solid PVC Pipe Slotted PVC Pipe MonumenU Cap to Piezometer $ffi concrete Bentonite ffi Native So¡l lÏì s¡l¡ca sand ! Water Level M Moisture ContentA Atterberg L¡mitsG Grain-size AnalysisDS Direct ShearPP Pocket Penetrometer Readings, tons/ftP Sample PushedT Triaxial t Depth Driven and Amount Recovered w¡th 2-inch O.D. Split-Spoon Sampler Depth Driven and Amount Recovered * Liquid Limit with 3-inch Shelby Tube Sampler + plastic Limit representative of other t¡mes ând locations- We cannot accept respons¡bility for thê use or interpretation by others of infomation presented on this log. Project Number 99901 7 Larsen Property Short Plat Boring Log NE LSON GEOTECHNICALAssoctÄTEs, lNc.N G A GEoTEcHNIcÄ.L ENGINEERS & GEOLOGISTS Wdlnvlllê Olfcê f7311-1Sth Aw. NE, AS Woodiñüllê, WAse72 Eåst Wêñâichêê otrcê 5526 Indu6lry bn6, #2 Easl Wénatchée, WAW2w.hd6ôngêolech.æm (ru)67ffi/Fax6l76q No. Date Revision By CK 1 atl0tI7 o¡ig¡nal DPN LSB Figure 5 Page 1 of 2 C Attachment 6 BORING LOG B-1 (cont.) Soil Profìle Sample Data Penetration Resistance (Blowsffoot - a)10 2,0 q0 10 5p 50. c ô0)Fào (g o.oG-J Piezometer lnstallation - Ground Water Data (Depth in Feet)Description ,Eè(ú o lt))oıf-Õ o(ä }Eo*c0ı â-oox"E9ÈcF6-=o<ö_:ãg Moisture Content (Percent - l)20 30 4010 I 50 I 50+ Orange-brown to gray-brown, silty fine to medium sand with gravel, irace organics, and charcoal (very loose, wet) -becomes gray to brown, with trace iron-oxide staining, medium dense -no organics or charcoal -becomes gray, with trace gravel -no iron-oxide staining -with trace iron-oxide staining T-:î', .-ì= -.L -*l ,.'t ' : j-- rr :.,-.. .: ".! i*...-- '....-: . SM 2 17 20 l9 l': I40 4! QÃ 40 45 50 -55 Boring terminated below existing grade at 46.5 feet on 817117. Groundwater seepage was not encountered during drilling. 50 55 LEGEND Solid PVC Pipe Slotted PVC Pipe Monument/ Cap to Piezometer Liquid Limit ffil concrete Bentonite ffi trtative Soil ffi silica sand ! water Level M Moisture ContentA Atterberg LimitsG Grain-size AnalysisDS Direct ShearPP Pocket Penetrometer Readings, tons/ftP Sample PushedT Triaxial Depth Driven and Amount Recovered with 2-inch O.D. SplitSpoon Sampler I Depth Driven and Amount Recovered * with 3-inch Shelby Tube Sampler + Plastic Limit NOTE: Subsurface conditions dep¡cted represent our obseruâtions at the time and location of this exploratory hole, modified by eng¡neerjng tests, representative of other t¡mes and locat¡ons. We ænnot accept respons¡bil¡ty for the use or interpretâtion by others of information presented on this analys¡s and judgement. They are not necessarily log. Project Number 99901 7 Larsen Property Short Plat Boring Log NELSoN GEOTECHNICAL N G A AssocrATEs, lNc GEoTEcHNICÃL ENGINEERS & GEOLOGISTS WodlnvllleOtlcê 17311-135h Are. NE, &m Woodinúlle. WA W72 (4?5) 4&1æ / Fax: €1-25i0 w.nelsongeotech.com East wênãlchêe oflcê s26 lndüstry Lâne. #2 Éast W€natchêe. WA W2(ffi) 6$7ffi / Fır: 6F7æ2 No.Date Revision By CK 1 at10t17 Orig¡nal DPN LSB Figure 5 Page2 of 2 co Attachment 6 BORING LOG B-2 Approximate Ground Surface Elevation: ?? Soil Profile Sample Data Penetration Resistance (Blowsfoot - O)10 20 30 40 50 50+ oçEØ(¡)F Þ Go.o(ıJ Piezometer lnstallation - Ground Water Data (Depth in Feet)Description Eo.(ú o oo-J oıJ-ôıço(ä }E:^oı ã-o9bptrı-ıçEØ:8E Moisture Content (Percent20 30tt r)40 50 50+tl10 I Gray-brown, silty fine to medium sand with gravel and roots (very loose to loose, mo¡st) -becomes gray with iron-oxide staining, loose -no roots -becomes gray to orange-brown -becomes gray with trace gravel and roots -becomes gray-brown -becomes medium dense -no roots -becomes wet, with gravel -becomes gray, with trace gravel '.. .:. ' .1': "" I'J.: -*-: ..''" :'.-.. +. '-i+ . ¡ -i-i-' ,.r-rtt..':+ 'j'."t : ...i-,. ' .'.'; " i SM 4 5 ô 7 8 11 13 13 5 10 15 20 I 25 5 - 10 -15 20 -25 LEGEND f:3 I * + Solid PVC Pipe Slotted PVC Pipe MonumenV Cap to Piezometer Liquid Limit Plastic Limit ffil concrete Bentonite ffi Native Soil ffi Silica sand ! Water Level M Moisture ConientA Atterberg LimitsG Grain-size AnalysisDS Direct ShearPP Pocket Penetrometer Readings, tons/ftP Sample PushedT Triaxial I Depth Driven and Amount Recovered with 2-inch O.D. Split-Spoon Sampler Depth Driven and Amount Recovered with 3-inch Shelby Tube Sampler NOTE: Subsurface conditions depìcted represent our obseruations ât the time and Iocåt¡on of th¡s exploratory hole, modified by engineering tests, analysis representative of other timês ând locations. We ænnot accept responsibil¡ty for the use or interpretation by others of intormâtion presented on th¡s log. and judgement. They are not necessarily Project Number 99901 7 Larsen Property Short Plat Boring Log NE LSON GEOTECHNICAL AssocrATEs, lNc.N G A GEorEcHNlcÀL ENGINEERS & GEoLoGIsrs Wôdlnvlllê Oficê 173111ðlh Avê. NE, AS Woodihullê, WAw72(42q 4e1æ / Fåx €1'2510 w.ndsongêotêch.om Eal Wênalchee omce s26lndsstry kne, #2 Eâ6r Wéñárcheé. WA W2(@) 6&76S / F6* 6S7@ No.Date Revision By CK 1 8t10t17 original DPN LSB Figure 6 Pagel of 2 Cô Attachment 6 BORING LOG B-2 (cont.) Soil Profile Sample Data Penetration Resistance (Blows/foot - O) 10 2,0 q0 40 5p 50r CFøo)Fào (5 o.o(tJ Piezometer lnstallation - Ground Water Data (Depth in Feet)Description .oEo.(ú o o)oJ oıf-ooÊ vu) =Eı3 e5 E66YØa oo .ç g do! Moisture Content (Percent - l)20 30 40 50 50,rttt10 I Gray, silty f¡ne to medium sand with gravel, iron-oxide staining, and trace charcoal (loose, wet) -becomes medium dense -no charcoal -.t.- :: ''i"' '.."'r. SM I 24 17 29 30 I 35I I.: I 50 35 40 45 50 -55 Gray-blue silt with fine sand (very stiff, dry) ML Boring terminated below existing grade at 5l.5 feet on 817117. Groundwater seepage was not encouniered during drilling. EÃ LEGEND :: :ã I * + Solid PVC Pipe Slotted PVC Pipe Monument/ Cap to Piezometer Liquid Limit Plastic Limit lffi concrete Bentonite ml Native soil ffi Silica sand ! Water Level M Moisture ContentA Atterberg Lim¡tsG Grain-size AnalysisDS Direct ShearPP Pocket Penetrometer Readings, tons/ftP Sample PushedT Triaxial I Depth Driven and Amount Recovered with 2-inch O.D. Splitspoon Sampler Depth Driven and Amount Recovered with 3-inch Shelby Tube Sampler NOTE: Subsurfacê conditions dep¡cted rêpresent our obseruat¡ons at the time ând locat¡on of th¡s êxploratory hole, modif¡ed by engineêring tests, analysis representat¡vê of other times and locations. We €nnot accept responsib¡lity for the use or interprêtâtion by others of ¡nformâtion presented on this log. and iudgêment. They are not necessarjly Project Number 99901 7 Larsen Property Short Plat Boring Log NELSON GEOTECHNICAL AssocIATEs, lNc.N G A GEoTEcHNIGÀL ENGINEERS & GEOLOGISTS WdlnvllleOtñcê 17311-1slh Avê. NE, As Woodinüll€, WAS72(4ã) 461æ / Fãx:61-2510 w.ndsnseotêch.æn E¡st W¿nâlché omcêsæ lndu6rry kn6, f2 Ea6l Wénaichée, WA W2(re) 667ffi / Fax æ7æ2 No.Date Revision By CK 1 at10t17 O¡iginal DPN LSB Figure 6 Page2 oÍ 2 Cô Attachment 6 BORING LOG B-3 Approximate Ground Surface Elevation: ?? Soil Profile Sample Data Penetration Resistance (Blows/foot - O) 10 2,0 q0 40 5p 50r oc øíJFàoıo.o(uJ Piezometer lnstallation - Ground Water Data (Depth in Feet)Description .o-co.(E o o)ôJ oıf,Oôtrvu) 3E È3 â-oÕ!oã.9 :!6-6!ù<D:* 3- Moisture Content (Percent - l)10 20 30 40 50 50,tttll Gray-brown to orange-brown, silty fìne to medium sand with gravel, iron-oxide weathering, and trace metal/plastic (dense, moist) (FILL) to medium sand w¡th gravel, iron-oxide weathering, and trace roots (very dense, moist) -becomes orange-brown to gray -no roots -becomes gray, medium dense -no iron-oxide staining -becomes gray-brown with iron-oxide staining, dense, wet Gray silt with fine sand (very stiff, moist) SM ML 41 54 50-6' 23 29 32 31 ! t T t 5 10 T 15 t 20 25 .-z' l 5 - 10 -15 20 25 LEGEND ff sotio PVC Pipe ffi concrete M Moisture ContentA Atterberg LimitsG Grain-size AnalysisDS Direct ShearPP Pocket Penetrometer Readings, tons/fiP Sample PushedT Triaxial Depth Driven and Amount Recovered with 2-inch O.D. SpliþSpoon Sampler Depth Driven and Amount Recovered with 3-inch Shelby Tube Sampler l-{ slotte¿ PVC Pipe - Monument/ Cap to Piezometer * Liquid Limit + Plastic Limit Bentonite ffi rr¡ative So¡l ffi silica sand Y Water Level NOTE: Subsurface condit¡ons depicted represent our obseruations at the t¡mê and location of this exploratory hole, modified by engineêring tests, analysis reprêsentat¡ve of other t¡m€s ând tocat¡ons. We cannot accept respons¡b¡l¡ty for the use or inlêrpretation by olhers of infomation presented on th¡s log. and judgement. They are not necessarily Project Number 99901 7 Larsen Property Short Plat Boring Log NELSON GEOTECHNICAL AssoctATEs, lNc.N G A GEoTEcHNIC¡IL ENGINEERS & GEOLOGISTS Wdlnvlll6 oflcê 1 731 i -1 Slh Avê. NE, Â-ru Woodinülle. WAm72 (425) 461@ / Fãxr41-2510 M.nd$ngeotech.6m Eâslwenalchæ oflcê s26lnduBrry bno, #2 Éaâl Wénãtchêé, WA W2(ru) 676s / Fax 6769 No. Date Revision By CK 1 at10t17 orig¡nal DPN LSB Figure 7 Page 1 of 2 Co Attachment 6 BORING LOG B-3 (cont.) Soil Profile Sample Data Penetration Resistance (Blows/foot - O)10 2.o q0 10 5p 50r c øoFà (o ôo(úI Piezometer lnstallation - Ground Water Data (Depth in Feet)Description 'E 6(t o) J oo =9oà }E coı â-o.9 ı'E E!!:6:È<n j *p- Moisture Content (Percent - l)'10 20 30 40 50 50rrtttl Gray-brown, silty flne to medium sand with iron-oxide staining (medium dense to dense, moist) -.!?- .. ..'¡:,-:.: . SM 30 25 45 48 I t': I40 145 35 40 45 50 -55 Gray silt with fìne sand (very stiff, moist) CraV, s¡lty fine sand witn (dense, moist) ng l.. l".."t' .-t j+ j -._..:_+:.. ML SM Boring terminated below exisiing grade at 46.5 feet on 817117 . Groundwater seepage was not encountered during drilling. 50 55 LEGEND l]] solio PVC Pipe ffi concrete M Moisture ContentA Atterberg LimitsG Grain-size AnalysisDS Direct ShearPP Pocket Penetrometer Readings, tons/ftP Sample PushedT Triaxial tests, analysis and ¡udgement. They are not necessarily on this log. t Depth Driven and Amount Recovered with 2-inch O.D. Split-Spoon Sampler Depth Driven and Amount Recovered with 3-inch Shelby Tube Sampler lI stotteo PVC Pipe - Morument/ CaÞ to Piezometer * Liquid Limit + Plastic Limit Bentonite ffi Native Soil lÍl silica sand ! water Level NOTE: Subsurface conditions dep¡cted represent our obseruat¡ons ât the t¡me and representative of other times and locât¡ons. We ænnot accept responsibil¡ty for the locat¡on of this explorâtory hole, mod¡fied by eng¡neering use or interpretat¡on by others of informâtion presented Project Number 99901 7 Larsen Property Short Plat Boring Log NELSON GEOTECHNICAL N G A AssocrÄTEs, lNC. GEoTEcHNICÀL ENGINEERS & GEOLOGISTS WdlnvlllêOfflce 1731 li35th Avé. NE, ÂS Woôdinülle, WAse72 vW.nêlsongeolech.øm Eãsr wendchee ofice 526lndusrry Lane, ð2 EaslWenarcheê, WAw2 .(ffi) @76s / Fa* 6769 No.Date Revision By CK akoll7 Orig¡nal DPN LSB Figure 7 Page2 oÍ 2 cô Attachment 6 BORING LOG B-4 Approximate Ground Surface Elevation: ?? Soil Profile Sample Data Penetration Resistance (Blows/foot - f)10 40 q0 10 50 50, o)c øoFào(! o-o(! -J Piezometer lnstallation - Ground Water Data (Depth in Feet)Description .9,c.o.(5 tt)oJ oı3-Ooç:(rô }Eı3 e5!+E!oØ: oo .c ooE Moisture Content (Percent - l)20 30 40 50 50*10 I Gray-brown, s¡lty fine to medium sand with gravel, iron-oxide stalning, and trace organics (loose, moist) No recovery Gray, silty fine to medium sand with gravel and iron-oxide weathering (dense, moist) -becomes medium dense -becomes gray-brown . l:-i :,..=i- J.: ---:...''" j ¡-- rr i ",_,.¡=: t.-: "'j.'r-r.''i : ,. ..="'::"' 'i¡."-'! '.t-: j1'.'+ .."......' '. ' ' '.':' SM SM 7 2 41 .E 28 35 45 t ! t I 5 10 I 15 I 20 I 25 ¿ 5 -10 -15 -20 *25 Gray silt with fine sand (hard, moist) -interbedded with gray, silty fine to medium sand with gravel ML LEGEND ff sotto PVC Pipe ffi concrete M Moisture ContentA Atterberg LimitsG Grain-size AnalysisDS Direct ShearPP Pocket Penetrometer Readings, tons/ftP Sample PushedT Triaxial têsts, analysis and judgement. They âre not nêcessarily t Depth Driven and Amount Recovered ffi stotteo PVC Pipe with 2-inch o.D. sprit-spoon samprer - |xiåäi8¡t Depth Driven and Amount Recovered * Liquid Limit with 3-inch Shelby Tube Sampler + plastic Limit Subsurface conditions depicted represent our observations at thê time and locat¡on of this Bentonite ffi Native Soil L¡. .1 Silica Sand Y Water Level exploratory hole, modif¡ed by engineeringNOTE: others of infomation prcsented this log.representat¡ve of other t¡m€s ând locat¡ons.ænnot accept respons¡bility for the or interpretation by on Project Number 99901 7 Larsen Property Short Plat Boring Log NELSON GEOTECHNIC,AL AssoctÀTES, lNC.N G A GEoTECHNIC,\L ENGINEERS & GEOLOGISTS Wdlnvlllê Otlco 17311l$lh Av6. NE, AS Woodihüllê, WA9&72 (425) 461æ/Fåx €1-2510 vw nelengeotech.com Eâst Wendchee oñcê s26lñdusrry bnê. #2 Eâst Wånarôhéá, wA m2(æ)67ffi/FE*æ+7s No.Date Revis¡on By CK 1 at10117 oriqinal DPN LSB Figure 8 Pagel of 2 Co Attachment 6 BORING LOG B-4 (cont.) Soil Profile Sample Data Penetration Resistance (Blows/foot - t)10 10 q0 40 5p 50, o)c ûof-à (u o-oıI Piezometer lnstallation - Ground Water Data (Depth in Feet)Description .9 o.(ú(, ÐoJ o.ofCotriñ;=Eı3 â-ü..9 ã'pËËç = o<Ø:3p- Moisture Content lPercent - l) '10 20 30tt 40 50 I 50* Gray s¡lt w¡th fìne sand (very stiff to hard, moist) -interbedded with gray, silty fine to medium sand ML 32 49 53 52 l': I4ù I \ 35 40 -45 -50 55 Boring terminated below existing grade at 46.5 feet on 817117. Groundwater seepage was not encountered during drilling. LEGEND f] sotio PVC Pipe ffil concrete M Moisture ContentA Atterberg LimitsG Grain-size AnalysisDS Direct ShearPP Pocket Penetrometer Readings, tons/ftP Sample PushedT Triaxial Depth Driven and Amount Recovered with 2-inch O.D. SplitSpoon Sampler Depth Driven and Amount Recovered w¡th 3-¡nch Shelby Tube Sampler [îì stotteo PVC Pipe - MorumenU Cap to Prezometer * Liquid Limit + Plastic Limit :.. Benton¡te ffi Nat¡ve Soil ffi sitica sand ! Water Level NOTE:Subsurfåce condit¡ons dêpicted represent our obseruations at the time and location of th¡s explorâtory hole, mod¡f¡ed by engineering tests, ânalysis and use or interpretation by othere of ¡nfomat¡on presented on th¡s log. judgement.They are not necessârily rêpresentative of olher times and locations.We €nnot accept respons¡b¡lity forthe Project Number 99901 7 Larsen Property Short Plat Boring Log NELSON GEOTECHNICAL N G A.Ä.ssoctÄTEs, lNC. GËOTECHNICAL ENGINEERS & GEOLOGISTS WodlnvlllêOtrc€1731liSlh Aw. NE, ffi Woodiñülle, WA S72 {425)4&1æ/Far: €1-2510 w.ndengeotêêhøm EådwêndchêooildèS26lnduslry bnê, P EaÊrwenarchåé, wAw2 No,Date Revision By CK at10t11 orlg¡nal DPN LSB Figure 8 Page2 of 2 co Attachment 6 N G /\ NELsON GEOTECHNIC;IL AssocIATEs, INc. (ãEO.rECHNTCII.L ENCN.¡EENS & GEOLOGISTS Engineerin g-Ceology Branch 552ó lndustry Lane,#2 East ìVenatchee, WA 98802 (509) 665-7696' rAX (509) 665-?692 Main Office l73ll * 135'h Ave NE, A-50t Woodinville, WA 98072 (425) 486-1669 ' FAX (425) 48 I -25 I 0 Iuly 25,2078 Carl and Sharon Larsen 9832 Marine View Drive Mukilteo, Washington 9827 5 Geotechnical Plan Review and Comment Response Letter Larsen Residence Foundation Repair 15729 - 75th Place West Edmonds, Washington NGA File No. 999017 Dear Mr. and Mrs. Larsen: This letter presents the results of our updated geotechnical engineering review of the plans and comment response for your residence underpinning project located at 15729 - 75th Place West in Edmonds, Washington. INTRODUCTION We previously prepared a report for this property that included recommendations for underpinning support of the existing residence dated February 28,2018 and a plan review letter for the proposed improvements dated March 20, 2018. Project plans consist of underpinning the existing residence foundations and supporting associated basement slabs-on-grade and cantilevered portions of the upper floors on driven 2- and 3-inch pin piles. Lateral loads on the eastern portion of the structure are to be restrained by helical anchors. At this time, no additional development is planned within the property. The site falls within *Zones B through D" of bhe North Edmonds Earth Subsidence and Landslide Hazard Area Report prepared by Landau Associates for the City of Edmonds. This designation requires that certain features be included (or excluded) in the design. Such features include the restriction ofcuts and fills, the need for tightlining runoff into an approved system, the need to design foundations and retaining walls to withstand high lateral earth pressures and potential loss of soil beneath parts of the foundation, the need to vegetate slopes with deeply rooted drought-tolerant vegetation, and the elimination of any and all inigation systems. We have addressed all of these requirements in our previous report. Attachment 7 Geotechnical Plan Review and Peer Review Comment Response Letter Larsen Residence Foundation Repair Edmonds, V/ashington NGA File No. 999017 Iuly 25,2018 Page2 PLAN REVIE\il AND CONCLUSIONS We have reviewed the geotechnical aspects of the most recent plans and found the plans to be in general compliance with our recommendations as presented in our previous geotechnical report. We understand that all construction will be performed within the exiting residence footprint. The entire residence structure and any new foundations are to be supported on 2- and 3-inch diameter driven pin piles. Helical anchors are also going to be utilized to restrain lateral loads of the residence along the upper eastern side ofthe residence. The overall size and configuration ofthe anchor is to be determined by the contractor to achieve the design loads as specified on the plans. We recommend that NGA be retained to observe the installation of the pin piles and helical anchors on a full-time basis during construction. We understand that all stormwater runoff associated with this property is to be directed and tightlined to flow into the existing stormwater drainage system located within the southern portion of the property. We understand that this existing system ultimately flows out and discharges to the west of the property. Temporary erosion control measures such as silt fences along the downhill side of the residence are incorporated into the plans. In our opinion, the proposed temporary erosion control measures appear to be feasible. We do not anticipate significant excavations associated with the proposed stabilization of the residence as most of the work will be within the existing residence footprint. Any disturbed soils remaining after the proposed development should be revegetated in accordance with our previous report. Permanent erosion control measures such as compost amended soils, ground cover, and permanent seeding and planting have also been incorporated into the plans. The proposed stabilization is intended to support the existing residence structure and should not adversely impact or decrease the existing stability of the steep slope areas, neighboring properties, or critical areas; and is in compliance with the City of Edmonds Codes 23.80.060 and23.80.070, provided our recommendations are incorporated into the proposed plans and followed during construction. We recommend that all of our recommendations provided in our previous report and letter, and this letter be strictly followed during construction. LANDAU PEER RT,VIEW COMMENTS AND OUR RESPONSES As a part of the City of Edmonds review of this project, Landau Associates performed a peer review of the proposed project and our previous geotechnical report in accordance with Edmonds Community Development Code Chapter 19.10. Landau Associates comments and opinions were presented in a technical memorandum dated April 30, 2018. In the following section, we summarize the relevant geotechnical concerns raised by Landau Associates, followed by our response. NETSON GEOTECHNICAI ASSO CIATES, I NC.Attachment 7 Geotechnical Plan Review and Peer Review Comment Response Letter Larsen Residence Foundation Repair Edmonds, Washington NGA File No. 999017 Iuly 25,2018 Page 3 Comment 1: The vicinity map does not identify existing conditions such as lcnown landslide masses, debris flows, or mudJlows on or near the site. Response: The known historical landslide area has been shown on the most recent plans generated by CG Engineering. We were unabie to fin<Í documentation on any i<nown debris flows or muci flows within the immediate vicinity of the property. Comment 4: The geotechnical report, dated February 28, 2018 by Nelson Geotechnical Associates does not provide analysis ofthe rate ofretreat ofthe bluffnor an estimate ofthe percent risk oflandslide area expansion that recognizes and reflects potential catastrophic evenls such as seismic activity or a 100-year storm event, as required in ECDC 19.10.030(H.6) and ECDC 23.80.050(F.2.e). Response: As discussed in our previous report, this site and the overall site vicinity lie within a known ancient landslide area. The site and vicinity have been relatively stable for a very long period of time, and development in the area has taken place in the form of single-family residences, roads, parks, retaining walls and underground utilities. Although the likelihood of the ancient slide to become active in the foreseeable future is very low, extreme environmental conditions coupled with inadequate human practices could, in theory, re-activate the ancient landslide. Such external factors could include severe and prolonged weather events andlor significant seismic activity. With proper site drainage and maintenance of the drainage systems and protection of steep slopes, we would estimate that the probability of failure on the subject site is likely to be less than 310 percent in 25 years. The proposed improvements do not increase this potential. As we did not observe any indications of recent significant erosion or landsliding within the properfy, we estimate that rate of retreat of the bluff and slopes within the site is on the order of approximately one inch per year or less. NETSON G EOTECHN ICAI ASSO CI ATES, I N C.Attachment 7 Geotechnical Plan Review and Peer Review Comment Response Letter Larsen Residence Foundation Repair Edmonds, Washington NGA File No. 999017 Iuly 25,2018 Page 4 Comment 5: The geotechnical report, dqted February 28, 2018 by Nelson Geotechnical Associates does not describe public and private sewage disposal systems, as required in ECDC 23.80.050(F.2.c). Response: Based on review of the City of Edmonds GIS website and our site observations, existing stormwater and sewer utility pipelines extend down the steep slope area from the upper eastern portion of the site and and ultimately into the main utility lines within 75th Place Vy'est immediately west of the subject property. Sewer from the existing residence is already directed to flow into the existing sewer line. All stormwater associated with the existing residence is also proposed to be directed to flow into the existing stormwater pipe. Comment 6: The geotechnical report, dated February 28, 2018 by Nelson Geotechnical Associates does not consider the run-out hazard oflandslìde debris and/or the impacts oflandslide run-out on downslope properties, as required in ECDC 23.80.050(F.2.Í). Response: Due to the gently sloping nature of the lower westem and central portions of the property along with the fact that approximately 300 feet of level ground is located between the base of the steep west-facing slope within the eastern portion of the property and any down slope properties, it is our opinion that potential adverse impacts to downslope properties as a result of landslide debris runout is low. It is also our opinion that the proposed development does not increase this potential. Comment 7: The geotechnical report, dated February 28,2018 by Nelson Geotechnical Associates does not adequately as,re,Í,r the stability of the slope, as required in ECDC 23.80.050(F.2.g). The geotechnical engìneer should confirm the stability of the slope through modeling or numerical analysis and present the results in the geotechnical report. Response: The site slope within the proposed development area was analyzed for stability along Cross Sections A- A' for the existing conditions using the computer program Slope/W, by Geo-Slope International. Slope/W is a two-dimensional, limit equilibrium slope stability program that generates random potential failure surfaces or specific failure surfaces and determines their corresponding factors of safety with respect to failure. By generating a large number of random surfaces, a critical failure surface with the minimum factor of safety can be identified. 'VELSON GEOTECHNICAT ÂSSO CIATES, I NC.Attachment 7 Geotechnical Plan Review and Peer Review Comment Response Letter Larsen Residence Foundation Repair Edmonds, Washington NGA File No. 999017 Iuly 25,2018 Page 5 The slope stability analyses were performed using information gathered from the field explorations and soil properties were assigned to the soil layers to reasonably reflect their engineering characteristics. Stability analyses were performed localized to the areas along the cross section. Stability analyses were performed for non-seismic and seismic conditions for the existing conditions. Stability analyses were not performed for the proposed conditions as the proposed stabilization measures will be confined to the ^-,:^¿:-^ L.,:ll:-^ c^^+--:-+ ^ -^^1. ^-^,.-l ^^^^l^-^+:^- ^f ^ ô^^ ,,,^- ,,^^l :- +L^ -^:-*:^ ^-^1.,-^- '|.L^tÀt5uilB uullulilË ruutPrlllt, ¡1, Pç<lñ Ëluurlu 4uuçlul¿rlulr ur v,2vË w4J uùlu rrr rrr! rvlJlllrv 4¡r4rJùvù. ¡ rrv soil parameters used in our analyses, along with the results of the analyses, are presented in Figures 1 and 2. The critical slip surfaces for this case achieved factors of safety greater than or equal to 1.53 and 1.12 for the static and seismic cases, respectively indicating relatively stable conditions. It is also our opinion that the proposed stabilization measures for the residence do not reduce the overall factor of safety from the existing site conditions that are present with the site. MINIMUM RISK STATEMENT Provided that the recommendations in this letter, the geotechnical report dated February 28,2018, the letter dated March 12, 2018 and this letter are followed during construction, the areas disturbed by construction should remain stable. Therefore, the risk of damage to the proposed development or to adjacent properties form soil instability should be minimal, and the proposed grading and development should not increase the potential for soil movement. CLOSURE \ffe recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities comply with contract plans and specifications. o-o-o ,VEISO'V G EOT ECH N ICAL ASSO CIATES, I N C.Attachment 7 Geotechnical Plan Review and Peer Review Comment Response Letter Larsen Residence Foundation Repair Edmonds, Washington NGA File No. 999017 July 25,2018 Page 6 We appreciate the opportunity to provide service to you on this project. Please contact us if you have any questions regarding this letter or require further information. Sincerely, wEISOTV GEOTECHN|CAI ASSOCIATES, tNC. Lee S. Bellah, LG Project Geologist Khaled M. Shawish, PE Principal LSB:KMS:dy Two Figures Attached 2883 LEE S. BELLAH NETSO'V GEOTECHNICAT ASSO CIATES, I NC.Attachment 7 o() tût:ta o-aı(,) 'Ë() ûl ûlolôlolololEI ØlEIcl _51 =lñ o ø.Yló o oEl¡nsl:lorO 8l: å:x ı'ı .9gt.Ë = E 5lE; o g'öE> ñ oè -u3oor ;j < E.Y^c ÞoO o< L'E 6f o=5> atro¡I*, Ecoo C)ITIı+, Ø ct)cË .9x l¡J kI g .9+rooo aoot-o I .9a à ctc .Ë t- .ct(ut,Ø o CLo U' (lee¡) uotle^olf 93R33PaeeaoPc{Ë;;_o)¡._rocÐ o¡-ro rotr) ort) o ro oo)s O¡.- oros o* o $ oo)(') o¡.- ort)o ooo (oOoãLLCrl v c)ñ(Jc!(ıñ,aooó(\ o C\l oO) of.- Otr) Õ o Oo)o@oNo@orf)o.+oóoc!o o oN (Ð u? il Øoll E E .E '= oo(ú o cl() 'tro+rØo E oo o-Igt-o ro o'c,) t-o = ØG Èf c)oc(! l-.- o'ıs(, ó èè.-o^oo'9t.. c < c^.; F ı,9È=È LC -lo-E .¡,ooË> c)o,)qÈoaÉ'V,'øuloÍ oroT =(/) c) E rOF- I(ı E XIo-o oL6¡ tıñ (tt 3soH:1 y-o q)zu U) uJt-oz oc)ooooeç)e9ooıñrOO0)È'-60c{ë;; (lae¡) uorle^alf Project Number 99901 7 Larsen Residence Underpinning Cross Section A-A' Existing Static Slope Stability Analysis NELSON GEOTECHNICAL N G A AssocrATES, lNc GEorEcHNtcÀL ENcTNEERS & GEoLocISTS 1731 1¡ 35ih Ave. NE. A-500 Woodiñville. W498072(425)486i669 /Fâx481-2510 Snohom¡sh County (425) 337i669 weñat.hee/chelan (509) 7g'2756sw.nelsongeoleá.øm No.Date Revision By CK 7t20t18 orjginal LSB KMS Figure 1 Attachment 7 oo(út @sØ (úo 'È-() øl =l3l 8lîlpl ølıl 5l .EIÈ I I FI-U R 8CIOrO ,11Í å: ÀlËË fiıl ,: = ç 5lE?3o'xs> N oo -u90oF ij< 7. .u-c.9roo ocEl,q l!E ßJ Èdo:5> a?-oII*r ı? oo /t\/.E ,2oØ ct)c.Ë .9x l¡J kI coa-*,ooU' ooo¡-O I .9,a à(û?- Ë II .ctct+,Ø o CLo Ø (laal) uorle^êlf oooooo:-O)¡.-u)CÕaÕOOO=No)t-r)ct otrrl) oror) o ro o() oó\t of.-s oro.ú Os o <. o)cr) Of.-m Otl) (a_J Õt)c.) O^oc)oıtLc{v c)ñoNC (ı äi .(,Õo N o c{ O) ot- r) o oo)o@ t-o@ no\toO No o oe! C\T;8Øc!oo¡tilÊc =.etr(E :E _þço¡-o-co.Ë (!ìuo=Hd = ct)dtG=.eı't()ofr EH ¡-O 6) 'e-oc'!- Ao-o¿c,t- (go .n :,¿_5= Po = c ı ÈfIJ 0)oc6 ! F ı'ı o tobboèo--o^oo'Þl¿> 8.9.ì oa È=F Ic -le_E.9ooË> oDO-C..= o) .u, pxø)Lll c)É. N.:-o =Ø o) -crf)t- g(! ExIo-o- oLq¡ ro6ø)(JCØ.9oË:;bozu ØIIJFoz oooÕoooooooo!-:O)¡-bOO)È'-tf)(ÐN; (lae¡) uorle^olf Project Number 99901 7 Larsen Residence Underpinning Cross Section A-A' Existing Seismic Slope Stability Analysis NELSoN GEorEcHNtcAL N G A AssoclATEs, lNc. GEorEcHNrcAL ENGTNEERS & GEoLoGrsrs 1 73 1 1 i 35rh Avê. NE, A-500 Snohontsh Couñly (425) 337-1 669woodinúlle, w498072 wènatchee/chetãir i50s) 784-2756ø25) 446-1669 ]F ãx 4ar25l0 ww.netsongeolech.øm No.Date Revision By CK 1 7t20t18 Original LSB KIVS Figure 2 Attachment 7 N G A NELSON GEOTECHNICAL AssocIATEs, INc. GEOTECHNICI|L ENOTNEERS & GEOLOGISTS Main Office I 73 I I - 135'h Avç NE, A-500 Woodinville, WA 98072 (42s) 486-1669 . rAX (42s) 48 I -25 ¡ 0 Ënginoerin g-Geology Branch 5526 Industry L.ane,#2 East ìVenatchee, WA 98802 (509) ó65-7696. rAX (509) 665-7692 August 9,2018 Carl and Sharon Larsen 9832Marine View Drive Mukilteo, Washington 9827 5 Geotechnical Plan Review Letter Larsen Property Short Plat 15729 - 75th Place West Edmondso Washington NGA File No. 999017 Dear Mr. and Mrs. Larsen: This letter presents the results ofour geotechnical engineering review ofthe plans for your property short plat project located a|15729 - 751h Place West in Edmonds, Washington. INTRODUCTION We previously prepared a report for this property that included recommendations for underpinning support of the existing residence dated February 28, 2018. We have also prepared plan review letters for the proposed improvements to the existing residence dated March 20,2018 and July 25,2018. Project plans consist of subdividing the existing property into three separate properties. A new single-family residence is planned for the new upper eastern lot. The site falls within "Zones B through D" of the North Edmonds Earth Subsidence and Landslide Hazard Area Report prepared by Landau Associates for the City of Edmonds. This designation requires that certain features be included (or excluded) in the design. Such features include the restriction ofcuts and fills, the need for tightlining runoff into an approved system, the need to design foundations and retaining walls to withstand high lateral earth pressures and potential loss of soil beneath parts of the foundation, the need to vegetate slopes with deeply rooted drought-tolerant vegetation, and the elimination of any and all irrigation systems. We have addressed all of these requirements in our previous report and previous supplemental letters. For our use in preparing this letter, we were provided with a set of plans titled "Larsen 3-Lot Short Plat," dated May 3,2018, prepared by CG Engineering. Attachment 8 Geotechnical Plan Review Letter Larsen Property Short Plat Edmonds, Washington NGA File No. 999017 August 9,2078 Page2 PLAN REVIEW AND CONCLUSIONS We have reviewed the geotechnical aspects of the most recent plans and found the plans to be in general compliance with our recommendations as presented in our previous geotechnical report. The proposed residence is to be located further than the recommended 60-foot minimum setback provided in our previous report and is planned to be supported on conventional shallow foundations. We understand that all stormwater runoff and sewer associated with this property is to be directed and tifhflinèd 1o flıw ]nto the exisfing sformwaterirainag.and sewer systern pipes located within the southem portion of the property. We understand that this existing system ultimately flows out and discharges to the west of the property. Temporary erosion control measures such as silt fences along the downhill side of the proposed development are incorporated into the plans. In our opinion, the proposed temporary erosion control measures appear to be feasible. Any disturbed soils remaining after the proposed development should be revegetated in accordance with our previous report. Permanent erosion control measures such as compost amended soils, ground cover, and permanent seeding and planting have also been incorporated into the plans. It is our opinion that the proposed residence development associated with the proposed short plat should not adversely impact or decrease the existing stability ofthe steep slope areas, neighboring propeÍies, or critical areas; and is in compliance with the City of Edmonds Codes 23.80.060 and 23.80.070, provided our recommendations are incorporated into the proposed plans and followed during construction. We recommend that all of our recommendations provided in our previous report and letter, and this letter be strictly followed during construction. As discussed in our previous repoft, this site and the overall site vicinity lie within a known ancient landslide area. The site and vicinity have been relatively stable for a very long period of time, and development in the area has taken place in the form of single-family residences, roads, parks, retaining walls and underground utilities. Although the likelihood of the ancient slide to become active in the foreseeable future is very low, extreme environmental conditions coupled with inadequate human practices could, in theory, re-activate the ancient landslide. Such external factors could include severe and prolonged weather events andlor significant seismic activity. With proper site drainage and maintenance of the drainage systems and protection of steep slopes, we would estimate that the probability of failure on the subject site is likely to be less than 30 percent in 25 years. In our opinion, the proposed residence development does not increase this potential. 'VEISO'V G EOTECH N ICAL ASSO CI ATES, I N C. Attachment 8 Geotechnical Plan Review Letter Larsen Property Short Plat Edmonds, Washington NGA File No. 999017 August 9,2018 Page 3 MINIMUM RISK STATEMENT Provided that the recommendations in this letter, the geotechnical report dated February 28,2018 are followed during construction, the areas disturbed by construction should remain stable. Therefore, the risk of damage to the proposed development or to adjacent properties form soil instability should be minimal, and the proposed grading and development should not increase the potential for soil movement. CLOSUR.E Vy'e recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities comply with contract plans and specifications. o-o-o NEISOÍV G EOTECHN ICAL ASSO CI ATES, I NC. Attachment 8 Geotechnical Plan Review Letter Larsen Property Short Plat Edmonds, Washington NGA File No. 999017 August 9,2018 Page 4 We appreciate the opportunity to provide service to you on this project. Please contact us if you have any questions regarding this letter or require further information. Sincerely, ruEtSO'V GEOTECHNICAT ASSO CIATES, INC. Lee S. Bellah, LG Project Geologist Khaled M. Shawish, PE Principal LSB:KMS:dy 2883 LEE S. BELLAH /VEISOil G EOTECH N ICAI ASSO CI ATES, I N C. Attachment 8 N G A NELSON GEO:rECHNIC,AL l!¡'ssoctnTEs, INc. {ãTÕTECHNICJI.L ET.Iç¡INEERã & GEOI.OGISTS Engineerin g-Geol ogy Franch 5526 lndustry [¿ne, #? Sast Wenatchee, WA 98802 (509) ó65-?696 . fAX (s09) 66s-7692 Main ûfficc 1?ll I - 1351h Ave NE, A-500 Woodinville, WA 93072 (4?5) 486-166e' FAX (425) 48 r-25 l0 August 23,2018 Carl and Sharon Larsen 9832 Marine View Drive Mukilteo, Washington 9821 5 Supplemental Geotechnical Plan Review and Comment Response Letter Larsen Residence Foundation Repair 15729 - 75th Place West Edmonds, Washington NGA File No. 999017 Dear Mr. and Mrs. Larsen: This letter presents the results of our updated geotechnical engineering review of the plans and comment response for your residence underpinning project located at 15729 - 75th Place West in Edmonds, Washington. INTRODUCTTON We previously prepared a report for this property that included recommendations for underpinning support of the existing residence dated February 28,2018 and a plan review letter for the proposed improvements dated March 20,2018. We also prepared an initial plan review and comment response letter dated J:uly 25,2018. Project plans consist of underpinning the existing residence foundations and supporting associated basement slabs-on-grade and cantilevered portions ofthe upper floors on driven 2- and 3-inch pin piles. Lateral loads on the eastern portion of the structure are to be restrained by helical anchors. At this time, no additional development is planned within the property. The site falls within "Zoîes B through D" of the North Edmonds Earth Subsidence and Landslide Hazard Area, as indicated in the report prepared by Landau Associates for the City of Edmonds. This designation requires that certain features be included (or excluded) in the design. Such features include the restriction of cuts and fills, the need for tightlining runoff into an approved system, the need to design foundations and retaining walls to withstand high lateral earth pressures and potential loss of soil beneath parts of the foundation, the need to vegetate slopes with deeply rooted drought-tolerant vegetation, and the elimination of any and all irrigation systems. We have addressed all of these requirfi!f; Sru B b {,:å"R"V COPY AUo 24 2or8 ffiorffiggäru, previous report. tE- o5t-7 Attachment 9 Supplemental Geotechnical Plan Review and Comment Response Letter Larsen Residence Foundation Repair Edmonds, Washington NGA File No. 999017 August 23,2018 Page 2 PLAN REVIEW AND CONCLUSIONS We have reviewed the geotechnical aspects of the most recent plans and found the plans to be in general compliance with our recommendations as presented in our previous geotechnical report. We understand that all construction will be performed within the exiting residence footprint. The entire residence structure and any new foundations are to be supported on 2- and 3-inch diameter driven pin piles. Helical anchors are also going to be utilized to restrain lateral loads of the residence along the upper eastern side of the residence. The overall size and configuration of the anchor is to be determined by the contractor to achieve the design loads as specified on the plans. We recommend that NGA be retained to observe the installation of the pin piles and helical anchors on a full-time basis during construction. We understand that all stormwater runoff associated with this property is to be directed and tightlined to flow into the existing stormwater drainage system located within the southem portion of the properfy. We understand that this existing system ultimately flows out and discharges to the west of the property. Temporary erosion control measures such as silt fences along the downhill side of the residence are incorporated into the plans. ln our opinion, the proposed temporary erosion control measures appear to be feasible. We do not anticipate significant excavations associated with the proposed stabilization of the residence as most of the work will be within the existing residence footprint. Any disturbed soils remaining after the proposed development should be revegetated in accordance with our previous report. Permanent erosion control measures such as compost amended soils, ground cover, and permanent seeding and planting have also been incorporated into the plans. The proposed stabilization is intended to support the existing residence structure and should not adversely impact or decrease the existing stability of the steep slope areas, neighboring properties, or critical areas; and is in compliance with the City of Edmonds Codes 23.80.060 and 23.80.070, provided our recommendations are incorporated into the proposed plans and followed during construction. We recommend that all of our recommendations provided in our previous report and letter, and this letter be strictly followed during construction. LANDAU PEER REVIEW COMMENTS AND OUR RESPONSES As a part of the City of Edmonds review of this project, Landau Associates performed a peer review of the proposed project and our previous geotechnical report in accordance with Edmonds Community Development Code Chapter 19.10. Landau Associates comments and opinions were presented in a technical memorandum dated August 10, 2018. In the following section, v/e summarize the relevant geotechnical concerns raised by Landau Associates, followed by our response. NEISON GEOTECHNICA¿ ASSO CIATES, INC. Attachment 9 Supplemental Geotechnical Plan Review and Comment Response Letter Larsen Residence Foundation Repair Edmonds, Washington NGA File No. 999017 August 23,2018 Page 3 Comment 1: The slope stability analysis performed by NGA does not appear to factor in the effect of groundwater on the stability of the slope. Our experience suggests that groundwater can impact the stability of slopes within the North Edmonds ESLHA and it is our opinion that NGA's slope stability model should consider the effect of groundwater on the stability of the slope. Response: As a part of our previous evaluation, we did not encounter any groundwater seepage or table within our explorations performed throughout the site. We agree that groundwater within the North Edmonds ESLHA can impact the stability of the steep slopes within this area, but we did not encounter any within our previous explorations. In our opinion, some perched groundwater conditions within the upper slope area could occur but we would anticipate this condition within this site is likely minor and would not significantly impact the existing slope stability conditions within the proposed site development. Comment 2: The slope stability analysis performed by NGA uses a seismic coefficient (kr') equal to 0.20. Standard of practice in limit equilibrium slope stability modeling is to use a lc, value equal to one half of the peak ground acceleration (PGA). Per the online USGS Seismic Hazard Design Tool, the PGA at the site is equal to 0.5439. Response: The site slope within the proposed development area was reanalyzed for stability along Cross Sections A- A' for the existing conditions using the computer program Slope/W, by Geo-Slope International. Slope/W is a two-dimensional, limit equilibrium slope stability program that generates random potential failure surfaces or specific failure surfaces and determines their corresponding factors of safety with respect to failure. By generating a large number of random surfaces, a critical failure surface with the minimum factor of safety can be identified. The slope stabitity analyses were performed using information gathered from the field explorations and soil properties were assigned to the soil layers to reasonably reflect their engineering characteristics. Stability analyses were performed localized to the areas along the cross section. Stability analyses were performed for a seismic condition for the existing conditions. Stability analyses were not performed for the proposed conditions as the proposed stabilization measures will be confined to the existing building footprint. A horizontal ground acceleration of 0.27gwas used in the seismic analysis which is 0.5 of the peak ground acceleration of 0.543 as determined by the USGS Seismic Hazard Design Tool. The soil parameters used in our analysis, along with the results of the analysis, are presented in Figures 1. NEISON G EOTECHNICAI ASSO CIATES, I NC. Attachment 9 Supplemental Geotechnical Plan Review and Comment Response Letter Larsen Residence Foundation Repair Edmonds, Washington NGA File No. 999017 August 23,2018 Page 4 The critical slip surfaces for this case achieved factors of safefy greater than or equal to 1.028 for the updated seismic case, indicating marginally stable conditions during a seismic event. It is also our opinion that the proposed stabilization measures for the residence do not reduce the overall factor of safety from the existing site conditions that are present with the site. As such, the critical failure surface would need to shear through the proposed deep foundation improvements for the existing residence foundation, therefore the deep foundation should enhance deep-seated stability. Comment 3: NGA states that "lítith proper site drainage and maintenance of the drainage systems and protection of steep slopes, we would estimate that the probability of failure on the site is likely to be less than 310 percent in 25 years." If an event will never occur, its probability of occuffence is 0 (or 0 percent). If an event is absolutely certain to occur, its probability of occurrence is I (or 100 percent). Therefore, we do not understand what is meant by a probability of /ess than 3 l0 percent. Response: This is a typographical error. This sentence should read as swh "With proper site drainage and maintenance of the drainage systems and protection of steep slopes, we would estimate that the probability offailure on the site is likely to be less than I0 percent in 25 years." MINIMUM RISK STATEMENT Provided that the recommendations in this letter, the geotechnical report dated February 28,2018, the letters dated March 12,2018 and July 25,2018, and this letter are followed during construction, the areas disturbed by construction should remain stable. Therefore, the risk of damage to the proposed development or to adjacent properties form soil instability should be minimal, and the proposed grading and development should not increase the potential for soil movement. CLOSURE We recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide reconìmendations for design changes should the conditions revealed differ from those anticipated, and to evaluate whether or not earthwork activities comply with contract plans and specifications. o-o-o A/ËLSON G EOTECHNICAT ASSO CIATES, INC, Attachment 9 Supplemental Geotechnical Plan Review and Comment Response Letter Larsen Residence Foundation Repair Edmonds, Washington NGA File No. 999017 August 23,20t8 Page 5 We appreciate the opporrunity to provide service to you on this project. Please contact us if you have any questions regarding this letter or require further information. Sincerely, NEtSOru G EOTECH N ICAL ASSOC/A TES,'A'C, Lee S. Bellah, LG Project Geologist Maher A. Shebl, PE Senior Engineer LSB:MAS:dy One Figure Attached 2883 LEE S. BELLAH NETSON G EOTECH N ICA¿ ASSO CIA,T ES, I N C. Attachment 9 r! cı zrlll-ooz o FIo{tÍoIz ñ l. o aq(nØ9 -o J EÊæ(n3 9.qPö =>d€mo>x_caøf .=f o ø*!,f= l@ı' zn uloo!{FIjrt 2o s:ì PqıÉís ìÉó e€i ò;e ã-3ç 4¡ ã sÉ .9 Bê -&å ono{noI =or rrlzIzüF¡o ÞllF aoIa{o :! e oqg @ ? (o(o(o _.1 zo oÐo 7os. ı' (D ox Slope Stability Analysis- Gross Section A-A' Exisitng Seismic Conditions Morgenstern-Price most critical surface with minimum FOS ='1.028 with a seismic coefficient of ground acceleration = 0.279 210 190 170 '150 rso $5't1o cos0Ë 70# 50 ooLL c .F (! o uJ 210 190 170 1s0 130 110 90 70 50 30 10 -10 1,0e8 Glac¡al Tll/Advance Outwash lntemal Fric[on Angle: 36" Nrcfst tJnit We¡ght 130pcf Cohesion: 0 psf 75th Ave SW Existing Residence o 102030405060708090 .110 l3o 150 170 190 210 230 250 270 290 310 330 350 370 390 410 430 450 470 490 510 530 550 570 Distance (Feet) 30 '10 -10 -20 NOTES: Not to scale Elevations are Approximate Cohedoru 0 tntemd Fñclion Angle 28' MdsiUn¡lWeiqhÈ 110 pcf Critical Slip Surface Whidbev Formation lntemal Friclíon Angle: 32' Mo¡st Unitweight 120 pcf Cohedon: 1000 psf Attachment 9 Technical Memorandum TO: FROM: DATE: RE: Linda Thornquist, Senior Permit Coordinator City of Edmonds Development Services Department, Building Division Sean Gertz, EIT and Steven Wright, PE April 30, 2018 Geotechnical Peer Review Submittal Package for Structural lmprovements in a Critical Area Larsen Residence - L5729 75th Place West Edmonds, Washington SCANNET APR i;fi r,fffr This technical memorandum summarizes the results of our geotechnical peer review of the permit submittal package that was submitted to the City of Edmonds (City) for proposed structural improvements to the above referenced residence, which is located within a critical area in Edmonds, Washington. The purpose of our geotechnical peer review is to review portions of the submittal package and assess its compliance with the City's development and building permit requirements as contained in Edmonds Community Development Code (ECDC)Chapter L9.10 for sites designated within or near the North Edmonds Earth Subsidence and Landslide Hazard Area (ESLHA). This review also assesses the submittal's compliance with the requirements of Chapter 23.80 of the ECDC as required or noted in Chapter L9.10, This geotechnical peer review was accomplished in accordance with Task Order No. 18-02 of Landau Associates' On-Call Geotechnical and Environmental Engineering Services Agreement with the C¡ty. We reviewed the following information forwarded by the City . Completeness Review Pre-Application Form for Earth Subsidence Landslide Hazard Area projects, stamped Received March 1,,2OL8 ¡ Affidavit of "Notice of Application posted at Job Site" (signed by Applicant/Owner), dated February 26,201,8 . Applicant/Owner Covenant to Notify and Hold Harmless, dated February 26,2OtB o Structural Engineer Declaration, prepared by CG Engineering on February 26,2018 r Lead Design Professional Designation and Statement and Geotechnical Hazard ldentification/Declaration, prepared by CG Engineering on February 26,2018 o Geotechnical Hazard ldentification/Declaration and Mitigation Statement of Risk from Geotechnical Engineer, prepared by Nelson GeotechnicalAssociates, lnc. on March 20,20L8 . Applicant/Owner Liability and Landslide Acknowledgment, dated Febru ary 26,2018 o Structural Design Calculations (stamped by Structural Engineer), prepared by CG Engineering on March 1-,2018 ¡ CriticalArea Determination (CR420180012), stamped Received March 1,,20L8 LANDAU AssoCHrESA 130 2nd Avenue South . Edmonds, Washington 99020 . (4251779_0907 Attachment 10 Landau Associates o North Edmonds Earth Subsidence and Landslide Hazard Areas Map with signed signatory block, dated February 26,20L8 ¡ Vicinity Map, prepared by CG Engineering on February 26,20L8 o Topographical Map and Survey, prepared by A.S.P.l. Land Surveying and Planning on February L4,2018 o Preliminary Geotechnical Engineering Evaluation (stamped by Geotechnical Engineer), prepared by Nelson Geotechnical Associates, lnc. on February 28,2Ot8 o Building Construction Plans (stamped by Engineer), prepared by CG Engineering on February 21,2018. Based on our review of the information that was submitted, it is our opinion that the geotechnical report that was prepared and submitted for this project provides a good discussion of site conditions and risks, and provides geotechnical recommendations that appear to be appropriate for design. ln addition, the report appears to adequately document existing site conditions based upon field reconnaissance and subsurface explorations, and acknowledges the presence of, and adequately evaluates, seismic, erosion and landslide hazards on the property. The submittal package that we reviewed includes the majority of the information in Sections l-9,10 and 23.80 of the ECDC that is identified as being required. However, we found the following deficiencies in the information that was submitted: The vicinity map does not identify existing conditions such as known landslide masses, debris flows, or mud flows on or near the site. The topographic survey does not show distances to existing habitable structures on or near the site, as required in ECDC L9.1-0.030(D). The applicant did not submit a separate topographical drawing showing proposed grade contours at 2-foot intervals, as required in ECDC 1-9.10.030(E.7). The geotechnical report, dated February 28,20L8 by Nelson Geotechnical Associates does not provide analysis of the rate of retreat of the bluff nor an estimate of the percent risk of landslide area expansion that recognizes and reflects potential catastrophic events such as seismic activ¡ty or a 1-00-year storm event, as required in ECDC 19.1-0.030(H.6) and ECDC 23.80.050(F.2.e). The geotechnicalreport, dated February28,2018 by Nelson GeotechnicalAssociates does not describe public and private sewage disposal systems, as required in ECDC 23,S0.050(F.2.c). The geotechnical report, dated February 28,20L8 by Nelson Geotechnical Associates does not consider the run-out hazard of landslide debris and/or the impacts of landslide run-out on downslope properties, as required in ECDC 23.80,050(F.2.f). The geotechnical report, dated Febru ary 28,201-8 by Nelson Geotechnical Associates does not adequately assess the stability of the slope, as required in ECDC 23.80.050(F.2.g). The geotechnical engineer should confirm the stability of the slope through modeling or numerical analysis and present the results in the geotechnical report. a a a o a a a Geotechnical Peer Review Larsen Residence-15729 75th Pl W 2 April 30, 20L8 Attachment 10 Landau Associates . The applicant did not submit documentation of required bonds, frozen funds, or adequate instrument of credit, nor did they submit a copy of the contractor's general public liability insurance, as required by ECDC 19.10.030(J). This technical memorandum has been prepared for use by the City in evaluating the adequacy of permit submittal documents related to the proposed structural improvements to the residence at 15729 75th Place West in Edmonds, Washington. The focus of this review was the geotechnical aspects of the application, The purpose of the review was to assess the adequacy of the application documents for compliance with City requirements contained in ECDC 19.10, ECDC 23.80, and conformance with conventionally accepted geotechnical engineering practices. This geotechnical peer review by Landau Associates does not lessen the requirements forthe applicant's geotechnical consultant to serve as the project's Geotechnical Engineer of Record and other design professionals to prepare an appropriate des¡gn for the site conditions. We appreciate this opportunity to be of service to the City. Please contact us if you have any questions or if we may be of further service. LANDAU ASSOCIATES, INC. Sean Gertz, EIT Senior Staff Geotechnical EIT S/^D"/r{ Steven R. Wright, PE Principal SMG/SZWrgm [\\EDMDAfAOI\PROj ECIS\o74\196\R\PEERREVI EW_f M.DOCX] Geotechnical Peer Review Larsen Residence-15729 75th Pl W 3 April 30, 2018 Attachment 10 Technical Memorandum 130 2nd Avenue South • Edmonds, Washington 98020 • (425) 778-0907 TO: Kristin Johns, Senior Permit Coordinator City of Edmonds Development Services Department, Building Division FROM: Sean Gertz, EIT and Steven Wright, PE DATE: August 10, 2018 RE: Supplemental Geotechnical Peer Review Submittal Package for Structural Improvements in a Critical Area Larsen Residence – 15729 75th Place West Edmonds, Washington This technical memorandum summarizes the results of Landau Associates’ (LAI) supplemental geotechnical peer review of the permit submittal package that was submitted to the City of Edmonds (City) for proposed structural improvements to the above-referenced residence, which is located within a critical area in Edmonds, Washington. The purpose of our geotechnical peer review is to review portions of the submittal package and assess its compliance with the City’s development and building permit requirements as contained in Edmonds Community Development Code (ECDC) Chapter 19.10 for sites designated within or near the North Edmonds Earth Subsidence and Landslide Hazard Area (ESLHA). This review also assesses the submittal’s compliance with the requirements of Chapter 23.80 of the ECDC as required or noted in Chapter 19.10. This geotechnical peer review was conducted in accordance with Task Order No. 18-03 of Landau Associates’ On-Call Geotechnical and Environmental Engineering Services Agreement with the City. LAI previously completed a geotechnical peer review for this project and our initial review comments are contained in a technical memorandum dated April 30, 2018. The applicant’s design team has addressed these comments (and other review comments by others) and prepared a revised permit application submittal. This supplemental geotechnical peer review focuses on the revised permit application submittal. LAI reviewed the following information forwarded by the City:  Cover letter prepared by CG Engineering, dated June 26, 2018  Building Construction Plans (stamped by Engineer) prepared by CG Engineering on February 21, 2018, revised on June 26, 2018  Geotechnical Plan Review and Comment Response Letter prepared by Nelson Geotechnical Associates, Inc. (NGA), dated July 25, 2018. The following briefly reiterates our review comments that are contained in our April 30, 2018 technical memorandum and states how each comment was addressed in the most recent submittal. Attachment 11 Landau Associates Geotechnical Peer Review Larsen Residence – 15729 75th Place West 2 August 10, 2018 Review Comment: The vicinity map does not identify existing conditions such as known landslide masses, debris flows, or mud flows on or near the site. Response: The vicinity map has been updated on Sheet S0.1 of the Building Construction Plans to show the known slide area. NGA was unable to find documentation on any known debris flows or mud flows within the immediate vicinity of the property. Review Comment: The topographic survey does not show distances to existing habitable structures on or near the site, as required in ECDC 19.10.030(D). Response: Distances have been added to the site plan presented on Sheet S0.1 of the Building Construction Plans. Review Comment: The applicant did not submit a separate topographical drawing showing proposed grade contours at 2-foot intervals, as required in ECDC 19.10.030(E.7). Response: All work is within the footprint of an existing building and site grades will not change. As a result, there are no proposed grade contours for the applicant to present. Review Comment: The geotechnical report, dated February 28, 2018 by NGA does not provide analysis of the rate of retreat of the bluff nor an estimate of the percent risk of landslide area expansion that recognizes and reflects potential catastrophic events such as seismic activity or a 100-year storm event, as required in ECDC 19.10.030(H.6) and ECDC 23.80.050(F.2.e). Response: The supplemental geotechnical response by NGA provides results of this analysis. Review Comment: The geotechnical report, dated February 28, 2018 by NGA does not describe public and private sewage disposal systems, as required in ECDC 23.80.050(F.2.c). Response: The supplemental geotechnical response by NGA provides this information. Review Comment: The geotechnical report, dated February 28, 2018 by NGA does not consider the run-out hazard of landslide debris and/or the impacts of landslide run-out on downslope properties, as required in ECDC 23.80.050(F.2.f). Response: The supplemental geotechnical response by NGA addresses run-out hazard and potential impacts on downslope properties. Review Comment: The geotechnical report, dated February 28, 2018 by NGA does not adequately assess the stability of the slope, as required in ECDC 23.80.050(F.2.g). The geotechnical engineer should confirm the stability of the slope through modeling or numerical analysis and present the results in the geotechnical report. Attachment 11 Landau Associates Geotechnical Peer Review Larsen Residence – 15729 75th Place West 3 August 10, 2018 Response: The supplemental geotechnical response by NGA provides results of this analysis. Review Comment: The applicant did not submit documentation of required bonds, frozen funds, or adequate instrument of credit, nor did they submit a copy of the contractor’s general public liability insurance, as required by ECDC 19.10.030(J). Response: It is our understanding that the City will collect the above listed items prior to permit issuance. The submittal package that LAI reviewed generally addresses the comments in our April 30, 2018 technical memorandum and includes the majority of the information in Sections 19.10 and 23.80 of the ECDC that is identified as being required. However, LAI found the following deficiencies in the information that was submitted:  The slope stability analysis performed by NGA does not appear to factor in the effect of groundwater on the stability of the slope. Our experience suggests that groundwater can impact the stability of slopes within the North Edmonds ESLHA and it is our opinion that NGA’s slope stability model should consider the effect of groundwater on the stability of the slope.  The slope stability analysis performed by NGA uses a seismic coefficient (kh) equal to 0.20. Standard of practice in limit equilibrium slope stability modeling is to use a kh value equal to one half of the peak ground acceleration (PGA). Per the online USGS Seismic Hazard Design Tool, the PGA at the site is equal to 0.543g.  NGA states that “With proper site drainage and maintenance of the drainage systems and protection of steep slopes, we would estimate that the probability of failure on the site is likely to be less than 310 percent in 25 years.” If an event will never occur, its probability of occurrence is 0 (or 0 percent). If an event is absolutely certain to occur, its probability of occurrence is 1 (or 100 percent). Therefore, we do not understand what is meant by a probability of less than 310 percent. This technical memorandum has been prepared for use by the City of Edmonds in evaluating the adequacy of permit submittal documents related to the proposed residential structure located at 15729 75th Place West in Edmonds, Washington. The focus of this review was the geotechnical aspects of the resubmitted application. The purpose of the review was to assess the adequacy of the application documents for compliance with City requirements contained in ECDC 19.10 and conformance with conventionally accepted geotechnical engineering practices. This geotechnical peer review by Landau Associates does not lessen the requirements for the applicant’s geotechnical consultant to serve as the project’s Geotechnical Engineer of Record and other design professionals to prepare an appropriate design for the site conditions. Attachment 11 Landau Associates Geotechnical Peer Review Larsen Residence – 15729 75th Place West 4 August 10, 2018 We appreciate this opportunity to be of service to the City. Please contact us if you have any questions or if we may be of further service. LANDAU ASSOCIATES, INC. Sean M. Gertz, EIT Project EIT Steven R. Wright, PE Principal SMG/SZW/rgm [\\EDMDATA01\PROJECTS\074\196\R\SUPPLEMENTAL PEER REVIEW_TM.DOCX] Attachment 11 Technical Memorandum 130 2nd Avenue South • Edmonds, Washington 98020 • (425) 778-0907 TO: Kernen Lien, Environmental Programs Manager City of Edmonds, Planning Division FROM: Sean Gertz, EIT and Steven Wright, PE DATE: October 15, 2018 RE: Geotechnical Peer Review Submittal Package for Short Plat in a Critical Area Larsen Residence – 15729 75th Place West Edmonds, Washington This technical memorandum summarizes the results of our geotechnical peer review of the permit submittal package that was submitted to the City of Edmonds (City) for a proposed short plat subdivision of property located at the above-referenced address, which is located within a critical area in Edmonds, Washington. The purpose of our geotechnical peer review was to review portions of the submittal package and assess whether or not enough geotechnical information has been submitted to evaluate if the proposed short plat is geotechnically feasible. This geotechnical peer review was accomplished in accordance with Task Order No. 18-06 of Landau Associates’ On-Call Geotechnical and Environmental Engineering Services Agreement with the City. We reviewed the following information that was forwarded to us by the City:  Civil Plans (stamped by Engineer), prepared by CG Engineering, dated May 3, 2018 and last update August 20, 2018.  Preliminary Geotechnical Engineering Evaluation, Larsen Property Short Plat and Residence Underpinning (stamped by Geotechnical Engineer), prepared by Nelson Geotechnical Associates, Inc., dated February 28, 2018.  Geotechnical Plan Review Letter, Larsen Property Short Plat (stamped by Geotechnical Engineer), prepared by Nelson Geotechnical Associates, Inc., dated August 9, 2018.  Preliminary Short Plat (Stamped by Surveyor), prepared by ASPI Land Surveying and Planning, dated April 23, 2018. Based on our review of the information that was submitted, it is our opinion that the applicant has submitted enough preliminary information to conclude that the proposed short plat is feasible from a geotechnical perspective. However, as noted in Nelson Geotechnical Associates’ February 28, 2018 report, site grading should be kept to a minimum and grading and site drainage plans should be subjected to further geotechnical engineering review prior to construction. Furthermore, we concur with Nelson Geotechnical Associates’ statement in their February 28, 2018 report that this review should include specific stability analysis of proposed cuts and fills, and provide specific recommendations for accomplishing the desired grading while maintaining long-term slope stability. This analysis should also include an analysis of the two retaining walls that are proposed along the western portion of 72nd Avenue West that will be extended to provide access to the upper proposed Attachment 12 Landau Associates Geotechnical Peer Review Larsen Residence Short Plat – 15729 75th Pl W 2 October 15, 2018 lot, as well as all underground utilities that are proposed in close proximity to the site’s steep slope and associated buffer. This technical memorandum has been prepared for use by the City in evaluating the adequacy of short plat submittal documents related to the proposed subdivision at 15729 75th Place West in Edmonds, Washington. The focus of this review was the geotechnical aspects of the application. This geotechnical peer review by Landau Associates does not lessen the requirements for the applicant’s geotechnical consultant to serve as the project’s Geotechnical Engineer of Record and other design professionals to prepare an appropriate design for the site conditions. We appreciate this opportunity to be of service to the City. Please contact us if you have any questions or if we may be of further service. LANDAU ASSOCIATES, INC. Sean Gertz, EIT Project EIT Steven R. Wright, PE Principal SMG/SZW/rgm [\\EDMDATA01\PROJECTS\074\196\050\R\PEERREVIEW_TM.DOCX] Attachment 12 #F,28 H€$C CUSTOMER EUC CONTACT FormFJnonds Utilitis Consoftium A coordinated utitity environment which maximizes joint utility opportunÌties to provide quality service for the citizens of Edmonds YOU WLL BE GIVENT A CONFIRMATION NUMBER BY E,4CHUTILITY ONCE YOU HAVE INFORMED THEM OF YOUR PROJECT. SITE ADDRESS:15729 75th Pl. W THIS FORM MUST BE COMPLETED AND GIVEN TO DEVELOPMENT SERVICES STAFF AT THE TIME OF PERMIT SUBMITTAL Rev. 10/1/13 ¡ ', "¡q {-t 3 ':.'¡t'r: " ';"r l.'*i I lshi"i\f-'; _,,,,rr-i,,jiffitn You will need to provide PUD with a site plan and a completed New Service Questionnaire. # PUD -0019-2018 Íit{(}1 lr,}¡*,tt5t I c:r}Lt N r Y Mary McAilister - 425-670-3216 Call to verifu gas availability and to coordinate service install. You will need to provide parcel number, contact phone number and mailing address. # sOsB34s43 New Customer Construction Department, I'BB8-321-7 7 7 9 PUG ÊT SqU\D ENERGY You will need to provide Frontier with the location of your project, total line requirement, and the date in which service is required. A copy o{ your development plan may be required. # 420ffi"gr Jeremy Fallt - 425-263-4024 # 283156 You will need to provide Comcast with the location of your project, a copy of your development and site plan (digital copy if available.) The date in which service is required and a list of contact names, phone numbers & mailing addresses. John'Warrick 425 263-5328 cümcüst. You will need to provide OWVSD with the survey map of your site and complete a development information form. # N/A 425.77 +77 69 For customers in Olympic View Service Area Attachment 13 PRD-1989-1 RS-20 CW RS-12 RS-20 RS-12 MEADOWDALEMARINA 15518 15433 161171610315814 15800 15805 1 6 0 0 9 16118 16120 16122 16121 15719 15902 15926 1612316 1 1 5 1 6 2 1 7 15824 15912 15910 15908 16000 7429 15927 15925 15825158217400 16131 16115 160047220 16111 1572215714 15824 15730 16105161121610016215 16209 16008 16010 160201570815728 15732 15712 1580515917 15 9 3 1 15910 15920 15915 7309 15917 732415808 15806 15812 16116 16105 160311601216010 16008 16006 161071612116119 1610916010 15729 15701 15709 15731711915711 70301570215715 7120 7117 7029 7110 7100 7026156027124 1560115515710515508 15621 15631 15703 7018702270191560015514711171077101710370317025700970037215 15516 15620 15706 7222 15625 15615 15605 15631 1552415808 15900 1600716001 1611 9 15730 15724 15604 16124COUNTY 15911 1551515520 15500 16106 16007 15722 15718 15712 15724 15716 72ND AVE W70TH AVE W7 5 T H P LW 73RDPLW74TH PL W156TH ST SW 74TH PL W72ND AVE W157TH ST SW 76TH PL W75THPLWNMEADOWDALERD 162ND STSW 71STAVEW158TH ST SW H Project Location Zoning and Vicinity MapPLN2018003315729 - 75th Place West 1 inch = 300 feetScale Attachment 14 CITY OF EDMONDS !2! sth Avenue North, Edmonds WA 98020 Phone: 425.771.0220 . Fax: 425J7Lß221 . Web:www.edmondswa.sov DEVELOPMENT SERVICES DEPARTMENT . PLANNING DIVISION c. 189o Critica I Area Determ ¡nation (CR4201800 12l. Based on a review and inspection of the subject site, staff has determined that one or more critical areas are located on or near the site. Critical areas are ecologically sensitive or hazardous areas that are protected in order to maintain their functions and values. Site Description Nearly allof the subject site is located within the mapped North Edmonds Earth Subsidence and LandslideHazardArea(ESLHA)orbuffer. Thesteepestportionofthebluff isinthemiddleof the site with somewhat more level areas on the west (below the bluff) and east (above the bluff). According to NRCS soils data, most of the site is underlain by Alderwood-Everett gravely sandy loams, 25-70% slope but the western edge is underlain by Alderwood Gravelly sandy loam (15-25-% slope) while the eastern edge is Alderwood Urban land complex (2-8% slope). Given the soils and slopes on and adjacent to the property and its location within the ESLHA, the site is considered to be a potential erosion and landslide hazard area. What does this mean? The critical area regulations are only triggered when an alteration is proposed to a critical area or its buffer. However, once an alteration in or near critical area is proposed, critical area studies and City review and approval may be required. Site Locotion Tax Account Number Property Owner Applicant Critical Areo(s) Present 15729 75th Place West 00513300002700 Sharon & Carl Larsen Dennis Titus - CG Engineering I Wetlonds (ECDC 23.50) tr Frequently Flooded Areas (ECDC 23.70) X Geologicolly Hazardous Areas (ECDC 23.80) X Erosion Hazard Areos X Londslide Hazard Areas n Seismic Hozord Areas n Fish & Wildlife Hobitot Conservation Areas (EcDc 23.90) tr Streoms Attachment 15 What is an 'Alteration'? According to Section 23.40.005 of the Edmonds Community Development Code (ECDC): "Alteration" means any human-induced action which changes the existing conditions of a critical area or its buffer. Alterations include, but are not limited to: grading, fil ling; d redging; d raining; chan nelizing; cutting, pruning, limbing or topping, clearing, relocating or removing vegetation; applying herbicides or pesticides or any hazardous or toxic substance; d isch arging pol lutants; pavi ng, construction, application of gravel; modifying for surface water management purposes; or any other human activity that changes the existing landforms, vegetation, hydrology, wildlife or wildlife habitat value of critical areas. Mike Clugston, AICP, Associate Planner February 1,2,2078 Name, Title Signature Date Cited sections of the Edmonds Community Development Code (ECDC) can be found ot htt p : //www. cod e p u b I i sh i n g. co m /W A/ E d m o n d s Environmentolly Critical Areos Generol Provisions (ECDC 23.40) Wetlonds (ECDC 23.50) Frequently Flooded Areos (ECDC 23.70) Geologicolly Hozordous Areos (ECDC 23.80) Fish and Wildlife Hobitat Conservotion Areas (ECDC 23.90) Buitding permits - Eorth Subsidence and Londslide Hozord Areos (ECDC 19.10) City of Edmonds GIS map tool with approximate location of critical areas: htt p :// m o ps. e d m o n d sw o. g ov flt/ Unpermitted alteration of o criticol oreo ar buffer (including tree trimming or topping, dumping yord waste, or application of pesticides or fertilizers) can lead to enforcement action and fines. Before undertaking any work, please contact the City to verify whether critical areo studies and City review is necessary. Page | 2 Attachment 15 City of Edmonds CR420180012¡Notes1572975th HaæW1'.2,2570ILegendi_lTOeeksSisrnic Hazard Areashrth $bsidence and Landdide IMinimum Buffer Adjacent to Ha;WetlandsWetlands BoundaryWetland Boundaries Not Completel: Wetland Known ËxtentsHoodplainsSorm Catdr BasinsSorm ManholesDetention FacilitiesOrlvertFacìlity Feature(leeksSorm LineFacility LinesSorm Dtdrùntour Lines1050r 1 00ArcÐE G S SIFEEI_CENIEF{I N E- <all other values>12mIo+0 94.04 188.1 FeetEWGS_1 9 84_Web_[vl ercât o r_rAux¡ I i ary_S h ere@ City of EdmondsThis me is a user gimerated Sat¡c output from an lntemet mapp¡ng dte and isforreferenæ only. Dáa layers that appear on this mæ may or may not be arrate,ilrrent, or otheM¡se rel¡able.THIS I\¡AP IS NOT TO BE USED FOR DESGN OR CONSTRUCTIONAttachment 15 GriticalAreas File Cßft zo t oo [2- ,il'ln¡tiul Determination - $100 I Subsequent ination - $50 Date Received I Date Mailed to APPlicant #P20 City of Edmonds Development Services DePartment Planning Division Phone: 425.111.0220 www.edmondswa.gov ac. 18 CRITICAL ARE,AS CHECKLIST The purpose of this checklist is to enable City staff to determine whether any critical areas and/or buffers are located on or adjacent to the subject property. Critical areas, such as wetlands, streams and steep slopes, are ecologically sensitive or hazardous areas that are regulated to protect their functions and values. The City's critical area regulations are contained within Edmonds Community Development Code (ECDC) Chapters 23.40 through 23.90. A property owner, or an authorized representative, must fill out the checklist, sign and date it, and submit it to the City. Staff will review the checklist, conduct a site visit, and make a determination of whether there are critical areas and/or critical area buffers on or near the site. If a "Critical Area Present" determination is issued, a report addressing the applicable critical area requirements of ECDC Chapters 23.40 through 23.90 may be required depending on the scope of the proposed activity. Property Owner's Authorization By my signature, I certify that the information and exhibits herewith submitted are true and correct to the best of my knowiedge and grant mypermission for the public officials and the staff of the City of Edmonds to enter the subject propertylor the purposãs of inspection attenàant to this application. The undersigned owner, and his/her/its heirs, and ãssigns, in consiãerãtion on the processing of the application agrees to release, indemnify, defend and hold the City of Edmonds harmless from any anã all damages, incluàing reasonable attorney's fees, arising from any action or infraction based in whole or part upol fulr", misleading, inaccurate or incomplete information furnished by the applicant, hislher/its agents or employees. DATESrcNerune oF OwNER PLEASE PRINT CLEARLY Owner: Slz.e.rt¡r 1c,,1 L,,¡st.' Applicant/Agent: c6 ì.re¿r ir - Þer. ..ìs T¡ i.¡S Name ZSo 1'4 Ave 5, sv|*e- 'loo Name 1 bzz lne,cil.¿ V¡c- Þriv¿ Street Address Av Itìl l¿o WA 16L?ç Street Address Ela"^oLs VA laozo City State zip City Telephone: State ,ILS - Tì8. ESO O zip Telephone:'|Lç-?79-8Çoo Email address . ãh..ro^ .l".r r.n C k"¡fier. Cov: Email Address ì,r êêf ìr1. cou,. Revised on 1/4/17 P20 - Critical Areas Checklist chanis t @ c1.^s Page I of2Attachment 15 CA File No: Site Information 1. Site Address/Location:lç ?21 ?ç" PI v), êeln,otoll , wA lEozb CA4TatK oo (?- #pzo Critical Areas Checklist 2. Property Tax Account Number:oo5t77ooÒo z+oo 3. Approximate Site Size (acres or square feet)l.55 Acu€S 4. Is this site currently developed? p Yes tr No If yes, how is the site develoPed?gt-s;{e..lia.l 5. Describe the general site topography. Check all that apply' n Flat to Rolling: No slope on/adjacent to the site or slopes generally less than 15% (a vertical rise of 10-feet over a horizontal distance of 66-feet)' n Moderate: Slopes present onf adjacent to site of more than 15% and less than 40% (a vertical rise of lO-feet over a horizontal distance of 25 to 66-feet)' E Steep: Slopes of greater ttran40% present on/adjacent to site (a vertical rise of l-O-feet over a horizontal distance of less than 25-feet). 6. FIave there been landslides on or neaï the site in the past? M Yes n No If yes, please describe:SiÈe o.¡ìÈtrì^ 6SLHA 7. Site contains areas of year-round standing water? n Yes (approx. depth: ) B. Site contains areas of seasonal standing water? n Yes (approx. depth: ) If yes, what season(s) of the Year? g. Site is in the floodway or floodplain of a water course? E Floodway n Floodplain 10. Site contains a creek or an area where water flows across the grounds surface? n Yes E No If yes, are flows year-round or seasonal? n Year-round n Seasonal (time of year: ) 11,. Obvious wetland is present on site? [1 Yes FNo Et No ENo {¡ w ovl t¿v() fu9t Site within d.esignated North Edmonds Earth Subsidence and Landslide Hazatd Area (ESHLA)? For City Staff Use Only WAIVER oç I Date:Reviewed z 1. J. J. 4. SCS mapped soil tical or C.A. map indicates Critical Area on site: Zornng: DETERMINATION AREAS PRESENT Revised on l/4/17 P20 - Critical Areas Checklist Page 2 of 2Attachment 15 o!nooz9{Iô-Ior¡r9(¡<{g3F;{€-Þ¡¡p l-8=N)ol-ÐU'r¡z.Ðm¡ll0mz.e)f¡rlocz.I-loz7)Irt!aInéz@tIa@zCNI]\)I!noo@I1U)=rrlTrzã10*10IuÐ 9 áì.- =.5=,,.1Lr ool.106=ô0513300002502. :.:rr'li ! - -..,"101.u*#-'¿ ùr-i:{¡",,"iti:'rlirr-s t.,j,ìf"- . ,"r.r/,/1: i.--q ¡, i-""î;- rlII-¿rr /-\.- 'lÃrBRI*\/llF/\$¡$!tt\tt\\.'\ Ni-iIl(ì¡ltI.l..lIPLAI]TEFiP0gfs-a\o,Á.LLOl 1*20,000KETSiTOI]EREMOVÊREPIACE EXISTON GRADE0051LOT 2r26,811EIÍABILIZE EXISTW PIPE PILES & ANCHORSfaiç?r/ \//r]RlNl= I02.48'lE=97.57 (11" tlvlP v{)lE=98..rô (ll LlllP E)("nJ02550I\EY5Tf-IiE VIÁLL3ìlrruwzrsJ/j'-lfl-,d'SITE PLANSCALE: l-" = 50'-0"O50100><>,<><><>><><t\r,r7ióHCilJSEFF=1 42. IGARAGEr/-1, ^.."--*HOtr5EFF=1û4 7'FF=11 2.t)CARÁGEFF=1A7 5t:t-tIoFr1zAttachment 15 LARSEN RESIDENCE FOUNDATION REPAIR L5729 75TH PLW EDMONDS, WA 98026 OWNER CONSULTANTS SHARON & CARL LARSEN 9832 MARINE VIEW DRIVE MUKILTEO, WA 98275 425.349.145t SHARON.LARSEN @ FRONTIER.COM PROPERTY INFORMATION EX BUILDING FOOTPRINT PROPOSED BUILDING FOOTPRINT STRUCTURAL ENGINEER CG ENGINEERING 250 4TH AVE S, SUITE 2OO EDMONDS, WA 98020 425.77 8.8500 FAX 778.5536 CONTACT: DENNIS TITUS, PE. SE GEOTECHNICAL ENGINEER N ELSON GEOTECHNICAL ASSOCIATES, INC T73TT 1.35TH AVENUE NE A-5OO WOODINVILLE, WA 98072 425.486.7669 CONTACT: LEE S. BELLAH LEGAL DESCRIPTION ALL OF TRACT 27 MEADOWDALE BEACH SUPPLEMENTAL PLAT, SNOHOMISH COUNTY, WASHINGTON = 1904 SQFT = NOT TO CHANGE PARCEL NUMBER 00513300002700 SCOPE OF WORK THIS PROJECT INVOLVES THE STABILIZATION OF AN EXISTING HOME THAT HAS EXPERIENCED SOME SETTLEMENT. WILL UNDERPIN THE EXISTING FOUNDATION WITH 2" DIAMETER PIN PILES TO SUPPORT FUTURE LOADS OF THE PLANNED ADDITIONAL FLOOR. PR N otval PLOI DÀfE:s0.3 NCIT F XX/ XX/ XX DATE xx/xx/xx r 71 45.10PROJECÍ NO. SCALE LARSEN RESIDENCE FOUNDATION REPAIR 1s729 75TH PL W EDMONDS, WA 98026 DRAWN BY JCP CHECKED BY NAL s0.3 SHEET APPROVED BY DMÌ SITE PLAN IITLE +€NGIN€€RING 2s0 41H AVÊ. S., SUITE 200 EOMONDS, WASHINGÍON 98020 PHoNE (425) 77A-A5OO FAX (125) 778-5536 - tb (E Attachment 15 C¡TY OI EDMONDS - PLANNING DIVISION STATF COMMENT FORM E Rw-rngineering E r¡r" E pw - Mointenonce E ruilaing Project Number PLN201 80033 Annlicenf'c Name"rr"-"'SHARON + CARL LARSEN Property Location: 15729158TH St Date Application Received RS.2O 05.03.18 Date Application Routed 05.04.18 Zoning: Project Description 3 LOT SUBDIVISION lf you have any questions or need clarification on this project, please contact Responsible KERNEN LIEN 1223 Name of lndividual Submitting Comments: T¡tIE Karl Fitterer Deputy Fire Marshal D^¡o.05-21-2018 lã t how reviewed this tand use proposalfor my deportment and I do not have any comments. My deportment may olso review this project during the building permit process (if applicoble) ond reserves the right to provide additionol comments ot that time. E t hor" reviewed this tand use proposolfor my deportment ond have the following comments or conditions: Attachment 16 Project Numbe PLN201 80033 Applicant's Name SHARON + CARL LARSEN Property Location 15729 75TH PL WEST Date Application Received RS-20 Date Application Routed 05.04.1805.03.18 Zoning: Project Description:3 LOT SUBDIVIS¡ON lf you have any questions or need clarification on this project, please contact Responsible KERNEN LIEN Ext 1223 LEIF BJORBACKName of lndividual Submitting Comments BUILDING OFFICIAL r.rare. 511812018Title E t hor" reviewed this tand use proposølfor my deportment and I do not have anY comments. My department moy also review this project during the building permit process (if applicoble) ond reserves the right to provide additional comments at thot time. E t hor" reviewed this tand use proposolfor my department and have the following co m m e nts or co n d iti ons : Site lies within the ESLHA and development will need to meet the requirements of ECDC 19.10, both for new construction or alterations to existing structure foundations Attachment 17 City of Edmonds Date: October 23, 2018 To: Kernen Lien, Environmental Programs Manager From: Jeanie McConnell, Engineering Program Manager Subject: PLN20180033, Larsen 3 lot short plat 15729 75th Pl W Engineering has reviewed the preliminary short plat application for the Larsen property at 15729 75th Pl W. The information provided indicates general engineering feasibility. As part of the preliminary short plat review, requirements regarding development of the adjacent public infrastructure were determined. Street Right-of-Way Dedication: Consistent with the City’s Official Street Map, a 10-ft street dedication to the City of Edmonds is required along the property frontage on 75th Pl W. Lot and Street Layout and Sidewalks: Lot 1 is a corner lot at 75th Pl W and 158th St SW. The existing residence, which is proposed to remain, currently takes access from 75th Pl W. While both streets are designated as local streets, 158th St SW has lower traffic volumes. A requirement has been established that upon future redevelopment of Lot 1, access will be required from 158th St SW. 75th Pl W and 72nd Ave W street rights-of-way are classified as local streets and per City Code, sidewalks are only required on one side of the street. Sidewalks have already been established on the west side of 75th Pl W and on the east side of 72nd Ave W, both of which are not adjacent to the subject development. Sidewalks are not required along 158th St SW. Improvements: 72nd Ave W adjacent to the subject development is currently undeveloped. The public water main will need to be extended, as well as the public road, to serve Lot 3 of the subject subdivision. MEMORANDUM ENGINEERING MEMO OF COMPLIANCE Attachment 18 The project-specific design, including final utility system design and location, as well as Title 18 Edmonds Community Development Code compliance, will be reviewed during the civil construction phase of this project. Preliminary approval shall not be interpreted to mean approval of the improvements as shown on the preliminary plans. Please find attached the Engineering Requirements for the subject developent. The applicant will be required to satisfy these requirements as a condition of short plat approval. Subsequent to obtaining a preliminary short plat determination of approval from the Planning Division, the applicant will be required to submit revised civil construction plans addressing all short plat conditions. Plans are to be submitted to the Engineering Division. A civil plan review fee is to be paid at the time of submittal. At this time, the review fee is $2785. Thank you. Attachment 18 ENGR RQMNTS PLN20180033-Larsen 3 lot SP 1 of 3 printed 10/23/2018 Planning Division PLN20180033 Jeanie McConnell, Engineering Program Manager Engineering Division Date:October 23, 2018 Larsen - 3 Lot SP Address:15729 75th Pl W Required as a Condition of Subdivision Requirement Already Satisfied 1.Right-of Way Dedication for Public Streets: a)X 2. a)X b)X c)X d)X e)X f)X g) X h)X 3. a) X b)X c)X d)X CITY OF EDMONDS 121 - 5TH AVENUE NORTH, EDMONDS, WA 98020 Provide 10-foot right-of-way dedication to the City of Edmonds along the property frontage on 75th Pl W. Provide asphalt or concrete driveway approaches on each lot per City Code. Curb and/or curb and gutter shall be provided along property frontage(s) as required to comply with City standards and requirements. Lot 2 shall take access off 158th St SW and Lot 3 shall take access off 72nd Ave W. i. Access road curb cut shall be constructed to meet City standards and ADA requirements. Cross slope of public road shall not exceed 2% PUBLIC WORKS DEPARTMENT - ENGINEERING DIVISION REQUIREMENTS FOR SHORT PLATS 75th Pl W to be widened along property frontage as needed to comply with City code and standards. 72nd Ave W shall be improved as a public street to provide access to Lot 3. 158th St SW to be widened along property frontage as needed to comply with City code and standards. File Number: From: Project: Required as a Condition of Building Permit Public Street Improvements & Access (Asphalt, curb, gutter and sidewalks): To: Slope of driveway shall not exceed 14% per ECDc 18.80.060. X Private Access Requirements & Improvements: Individual driveway access points shall meet sight distance requirements set forth by the American Association of State Highway and Transortation Officials (AASHTO). Existing residence on Lot 1 can continue to take access off 75th Pl W. Should the existing residence be demollished in the future, access will be required from 158th St SW. i. Driveway curb cut shall be constructed to meet City standards and ADA requirements. Driveway entrance for each point of access shall be provided to City standards Provide asphalt or concrete driveway approaches on each lot per City Code. Attachment 18 ENGR RQMNTS PLN20180033-Larsen 3 lot SP 2 of 3 printed 10/23/2018 Required as a Condition of Subdivision Requirement Already Satisfied Required as a Condition of Building Permit 4. a)X 5. a)X 6. 7. 8. a)X b)X c)X d)X e)X 9. a)X b)X 10. a) X b)X c)X d)X e)X f)X 11. a)X 12. a)X X X XSubmit a grading plan as part of engineered site plan. Required for all new services. ii. Where sewer lateral provides servcie to more than one lot, it shall be a minimum of 6". Provide storm sewer stub to all proposed lots, as applicable. Connect to public storm system, as applicable. i. Provide 4" side sewer to individual lots. Connect all new hard surfaces to stormwater management system(s) as required. Stormwater System Improvements: Provide all easements as required - access, utility, etc. Construct turnaround at south end of 72nd Ave W per City standards Easements (City utilities, private access, other utilities): Street Turnaround: Public water main shall be extended in 72nd Ave W to provide water service to Lot 3. N/A Street Lights: Street Trees/Planting Strip: Public hydrant spacing shall meet requirements of ECDC 19.25. Sanitary Sewer System Improvements: i.Stormwater management design shall account for proposed short plat improvements, including improvements within the right-of-way, and future lot development. X Underground Wiring (per Ord. 1387): Excavation and Grading (per IBC) N/A Provide water service stub to each Lot Provide 6" service lateral from City's sanitary sewer main to development. Connect to public sewer system. Provide a Stormwater Management Report and Site Plan that shows compliance with the 2014 Department of Ecology Stormwater Manual as amended by ECDC 18.30 and the Stormwater Addendum. X X X Water System Improvements: Connect to public water system. Install storz adapter on existing fire hydrant, as required. ii. Stormwater management system to be located on private property. Construct privately owned and maintained stormwater management system as required. Storm catch basins shall be installed in flow line in 72nd Ave West and 158th St SW, as required. X Attachment 18 ENGR RQMNTS PLN20180033-Larsen 3 lot SP 3 of 3 printed 10/23/2018 Required as a Condition of Subdivision Requirement Already Satisfied Required as a Condition of Building Permit b) 13. a)X b)X 14. a)X 15.a)X 16.a)X b)X c)X d)X e)X f)X g) 17. a)Storm system general facility charge for shared hard surface areas X b)Storm system general facility charge for each new lot c) d) e) f) g) h)X i)X j)XInspection fees X Engineering Fees: X Survey Monumentation (per Ord., Sect. 12.10.120): As-built Drawings (per City Engineer): Install fire and aid address signage. Maintenance agreements Legal documents for each lot Field stake utility stubs at property lines Plat showing lots, easements, legals, survey information Transportation Impact Fee Analysis X Parks impact fees Mailbox location per Postmaster X Signage and Striping (per City Engineer): Field stake lot corners (by professional surveyor) Provide street monumentation as required. Provide an as-built drawing of all street and utility improvements in electronic format. Water meter fee X X Submit grading plan for foundations with building permit. X X All signs shall be vinyl letters and to City standards. X Sewer general facility charge Transportation impact fee per each new SFR X Short Plat civil plan review fee Right-of-Way Construction Permit Water general facility charge Other Requirements: Attachment 18 Fl[E NO.: PtN201080033 Applicont lorsen DECTARATION OF POSTING On the 13th doy of June, 2018, the ottoched Notice of Applicoiion wos posted of the subject property, Civic Holl, Librory ond Public Sofety buildings. l, Kernen Lien, hereby declore under penolty of perjury under the lows of the Stote of Woshington thot the fo 2018, of Edmonds, Woshington. regoing is lrue o this 13 doy of June, Ò Signed {BFP747893.DOC; 1\00006.900000\ }Attachment 19 FILE NO.: PLN20180033 Applicant: Larsen DECLARATION OF MAILING On the 13th day of June, 2018, the attached Notice of Public Hearing was mailed by the City to property owners within 300 feet of the property that is the subject of the above-referenced application. I, Denise Nelson, hereby declare under penalty of perjury under the laws of the State of V/ashington that the foregoing is true and correct this 13th day of June, 2018, at Edmonds, Washington. Signed {BFP747887.DOC; l\00006.900000\ }Attachment 19 c. 189s PROJECT DESCRIPTION PROJECT LOCATION NAME OF APPLICANT; FILE NUMBER: DATE OF APPLICATION: DATE OF COMPLETENESS DATE OF PUBLIC NOTICE: REQUESTED PERMIT: CITY OF EDMONDS NOTICE OF APPLICATION The applicant is proposing to subdivide a single 68,4!5 square foot lot into three lots. Each lot will contain a minimum of 12,000 square feet of lot area. The site is zone RS- 20 (Single-family residential; 20,000 sq. ft. minimum lot size). !5729 - 75th Place W, Edmonds, WA. Tax Parcel Number 0013300002700 Sharon and Carl Larsen PLN20r_80033 May 3, 2018 May 31, 2018 June 13,2018 Short Subdivision (Type ll-A Permit Process) OTHER REQUIRED PERMITS:None EXISTI NG ENVI RON M ENTAL DOCUMENTS: Critical Area Determination, Geotechnical Report, Preliminary Storm Drainage Report COMMENTS ON PROPOSAL DUE:June 27,2O18 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 prìor 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 20,07.oo3 have standing to initiate an administrative appeal. lnformation on this development application can be viewed or obtained at the C¡ty of Edmonds Development Services Department, 121 sth Ave North, Edmonds, WA 98020 between the hours of 8:00 A.M. and 4:30 P.M. Monday, Tuesday, Thursday and Friday; between the hours of 8:30 AM and Noon on Wednesday; or online through the City's website at https://permits.edmonds.wa.us/citizen through the Online Permits link. Search for permit P1N20180033. Kernen Lien, Environmental Programs Manager kernen.lien @ edmondswa.gov 425-771-0220 CITY CONTACT: Attachment 19 15701 7åTH n- WÉ0H0i.lD5. t/,û. 9me6Ï,{I,1Ë.LA E sTÉ,VCN ZAHPÉEþ'¡1ã73+ 72ND ÂVE !{ÊÐfioNcs" wA 9ôû¿6adffii8iLIttIIåJ0r-lN ÊerÊs7$¿,+ r58TH 5T 5wÉCOTT OATESa!ô(vr-:t:Attachment 19 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 Eve¡ett 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 EDH8I2120 PLN20180033 as it was published in the regular and entire issue of said paper and not as a supplement form thereof for a period of I issue(s), such publication commencing on 0611312018 and ending on 0611312018 and that said neu/spaper was regularly distributed to its subscribers during all ofsaid period. The amount of the fee such publication is Subscribed and me on th¡s Æ davor Jzã Public in and for the State of Washington. City of Edmon& - LEGALADS | 14101416 KËRNEN LIBN l1 Attachment 19 Classified Proof clTY oF ËolloNos NOTICE OF APPLICATION PROJECT DESCRIPTION: The applicant is øoposing to rubdlvidea slnqlê 68,415 squêre foot tot lflto three lols. Each lot v¡ll contal-n a mlnimum of 12,000 square leet of lot area. The sile ¡s zône RS-20 (single-family residenìi8h 20;000 sq. ñ- mln¡num lot size). PROJÊCT LOCATION: 15729 - 75th Placs W, Ectnonds, wA.fax Pårcel Nqmber 0013300ù02700 NAMÊ OF APPLICANT: Sharon ånd caí Laßen FILE NUMBËR: P1N20180033 OATE OFAPPLICATION: MaY 3.2018 ÞATE OF COMPLETENeSS: MaY 31, 2018 DATE OF PUSLIC NOTICE; JUNS 13,2T18REOUESTEDPÊRMÍ: StìsrtSubdivision(Type ll-A Pemil Procesg) OTHËR REQUIRED PEFITMITS: NONE. EXISTING ENVIRONMENTAL DOCUMENTS: CÍIIiCAI ATEä Deteminatio¡, Geolechn¡cål Report, Preliminary Stom Publ¡shed: June 13, 2018: comments attecord to the lf any, to the EDH8121?0 Proofed by Sheppard, Dicy,0611312018 08:45:12 am Page:2 Attachment 19