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Edmonds Shops_Geotechnical Report.pdf
GEOTECHNICAL REPORT PROPOSED RETAIL DEVELOPMENT th 8431 244Street Southwest Edmonds, Washington PROJECT NO. 17-057 March 2017 : Prepared for Tekin& Associates, LLC Geotechnical & Earthquake Engineering Consultants APPENDIXA-3 Geotechnical & Earthquake Engineering Consultants March 13, 2017 Project No. 17-057 Mr. Dominic Rambes Tekin & Associates, LLC 8765 Stockard Drive, Suite 203 Frisco, Texas75034 Subject:Geotechnical Report Proposed Retail Development th 8431244Street Southwest,Edmonds, Washington Dear Mr. Rambes: th Please find our attachedgeotechnical report forthe proposed retail developmentat 8431 244 Street Southwest inEdmonds, Washington.In summary,based on the results of our field exploration,the siteis underlain by fill, likely related to the existing development overlying medium dense to very denseVashon till. In our opinion, the proposed building can be supported on a spread footing foundation supported on the existing fill or competent native soils. We appreciate the opportunity to work on this project.Please call if there are any questions. Sincerely, Scott D. Dinkelman, LEG Senior Engineering Geologist ________________________________________________ 3213 Eastlake Avenue East, Suite B Seattle, WA 98102 Tel (206) 262-0370 Fax (206) 262-0374 TABLE OF CONTENTS 1.0 INTRODUCTION...................................................................................................................1 2.0 PROJECT AND SITEDESCRIPTION...............................................................................1 3.0 SUBSURFACE EXPLORATIONS.......................................................................................3 3.1SG.......................................................................................................................3 ITE EOLOGY 3.2SE..................................................................................................3 UBSURFACE XPLORATION 3.3SC...................................................................................................................4 OIL ONDITIONS 3.4G.....................................................................................................................4 ROUNDWATER 4.0 INFILTRATION CONSIDERATIONS...............................................................................5 5.0 GEOTECHNICAL RECOMMENDATIONS.....................................................................5 5.1SDP...............................................................................................5 EISMIC ESIGN ARAMETERS 5.2F........................................................................................................................6 OUNDATIONS 5.2.1 Lateral Resistance..........................................................................................................6 5.2.2 Foundation Subgrade Preparation..................................................................................7 5.3FS.......................................................................................................................7 LOORS LABS 5.4PCFS.......................................................................................8 ERMANENT UT AND ILL LOPES 6.0 EARTHWORK CONSIDERATIONS..................................................................................8 6.1SP.............................................................................................8 TRIPPING AND ROOFROLLING 6.2SFC....................................................................................9 TRUCTURAL ILL AND OMPACTION 6.3TE...................................................................................................9 EMPORARY XCAVATIONS 6.4WWC..........................................................................................10 ET EATHER ONSTRUCTION 6.5EC..................................................................................................10 ROSION ONSIDERATIONS 7.0 ADDITIONAL SERVICES.................................................................................................11 8.0 LIMITATIONS.....................................................................................................................12 9.0 REFERENCES......................................................................................................................14 LA IST OF TTACHMENTS Figure 1Vicinity Map Figure 2Site and Exploration Plan LA IST OF PPENDICES Appendix ASummary Boring Logs Figure A-1Terms and Symbols for Boring and Test Pit Logs Figure A-2Log of Test Boring BH-1 Figure A-3Log of Test Boring BH-2 GR EOTECHNICAL EPORT PRD ROPOSED ETAIL EVELOPMENT TH 8431244SS TREET OUTHWEST E,W DMONDSASHINGTON ______________________________________________________________________________ 1.0 INTRODUCTION This report presents the results of our geotechnical engineering studythat wasundertaken to th support the design and construction of the proposed retail development at 8431 244Street Southwest inEdmonds, Washington.We performed our evaluation in general accordance with thescope of work as outlined in ourmutually agreed proposal datedJanuary 11, 2017and that was approved by you onFebruary 21, 2017.Ourservice scope included reviewing readily available geologic data, conducting a site reconnaissance, drillingtwotest boringsat the site, and developing the conclusions and recommendations presented in this report. 2.0 PROJECTAND SITE DESCRIPTION th The project siteis locatedat 8431 244Street Southwest in Edmonds, Washington, near the junction of State Route 99 and State Route 104at the border between the cities of Edmondsand Shoreline.The approximate project location is shown on Figure 1, Vicinity Map. The irregular shaped property comprises 0.77 acresand is bordered to the north by Edmonds Way,to the east by State Route 99,to the south by a restaurant and parking lot,andto thewest byan ascending slope and multi-family residential buildings. In the central portion of the siteis an existing, one story restaurant buildingconstructed in 1975. The building is surrounded by asphalt paved parking and drive areas. Vegetation consists of lawns and landscaping trees and shrubs located in planting beds. Plates 1 and 2 on the next page show the general site conditions. Thesite and surrounding area slopes down from west to east with about 15feet of elevation change across width of the site. The central portion of the site is relatively flat, having been graded to provide a level area for the existing building and parking areas. It is planned to demolish the existing restaurant and construct a new retail building along with asphalt paved parking and drive areas. The proposed building will be one-story in heightand of lightly-loaded wood-frame constructionwith a slab-on-grade floor.We anticipate the proposed building will be constructed at or near existing site grades, with cuts and fills of less than five feet needed to achieve construction subgrade elevations. Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 Plate 1: View from northeast corner of site to the west. Plate 2: View from north to south of west side of site. 2PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 The conclusions and recommendations in this report are based on our understanding of the proposed development, which is in turn based on the project information provided. If the above project description is incorrect, or the project information changes, we should be consulted to review the recommendations contained in this study and make modifications, if needed.In any case PanGEO should be retained to provide a review of the final design to confirm that our geotechnical recommendations have been correctly interpreted and adequately implemented in the construction documents. 3.0 SUBSURFACE EXPLORATIONS 3.1SG ITE EOLOGY Based on review of theGeologic Map of the Edmonds East and Part of the Edmonds West Quadrangles, Washington complied by James Minard (Minard, 1983), the site is underlain Vashon Till(Geologic Map Unit Qvt).Vashon till is comprised of an unsorted mixture (diamicts) of clay, silt, sand and gravel deposited directly by a glacier. Vashon till has been glacially overridden and is typically dense to very dense. 3.2SE UBSURFACE XPLORATION Our study included drilling twoborings (Borings BH-1and BH-2) at the site on February24, 2017. The approximate test boring locations are shown on Figure 2. The borings were drilled to depths of about 16feet below existing grade Boretec, Inc., under subcontract to PanGEO. The drill rig was equipped with 6-inch outside diameter hollow stem augers. Soil samples were obtained from the borings at 2½-and 5-foot depth intervals in general accordance with Standard Penetration Test (SPT) sampling methods (ASTM test method D-1586) in which the samples are obtained using a 2-inch outside diameter split-spoon sampler. The sampler was driven into the soil a distance of 18 inches using a 140-pound weight falling a distance of 30 inches. The number of blows required for each 6-inch increment of sampler penetration was recorded. The number of blows requiredto achieve the last 12 inches of sample penetration is defined as the SPT N-value. The N-value provides an empirical measure of the relative density of cohesionless soil, or the relative consistency of fine-grained soils. An engineer from our firm was presentduring the field exploration program to observe the drilling, assist in sampling, and to log and document the soil samples obtained from the borings. The completed borings were backfilled with bentonite chipsand the surface sealed with asphalt. 3PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 Thesoil samples retrieved from the borings were described using the system outlined on Figure A-1 of Appendix A. Summary boring logs are included as Figures A-2 andA-3. 3.3SC OIL ONDITIONS Both of our test borings werelocated in asphalt paved areas.At the location of BH-1, approximately 2½ inches of asphalt pavement was encountered, while at the location of BH-2, we encountered about 3½ inches of asphalt pavement was encountered. Below the pavement, we encountered filloverlying Vashon till.A description of the soilsencountered in our test borings is presented below: Fill: Below the pavement, we encountered fill consisting of mediumdense,silty, fineto medium grainedsandwith a varying amount of gravel.It is likely the fill wasplaced as structuralfill to level the site for the existing improvements.The fill extended to a depth of 8 feet below grade at both boring locations. Vashon Till (Qvt): Below the fill, we encountered medium dense to very dense silty sand with graveland sandy silt.We interpret this soil unit as Vashon Till, which is mapped as underlying this area.Both borings were terminated in very dense till. Our subsurface descriptions are based on the conditions encountered at the time of our exploration. Soil conditions between our exploration locations may vary from those encountered. The nature and extent of variations between our exploratory locations may not become evident until construction. If variations do appear, PanGEO should be requested to reevaluate the recommendations in this report and to modify or verify them in writing prior to proceeding with earthwork and construction. 3.4G ROUNDWATER We did not encounter groundwater seepage in our borings to the maximum exploration depth of 16 feet below grade. With the planned improvements being constructed near existing grade, we do not anticipate that groundwater seepage will be a significant construction related issue. However, the designers and contractor should be aware that groundwater elevations are not static and willvary depending on the season, local subsurface conditions, and other factors. Groundwater levels are normally highest during the winter and early spring. 4PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 4.0INFILTRATION CONSIDERATIONS While conducting our field exploration, we evaluated the encountered for suitability as receptor soils for stormwater infiltration. Due to the presence of fill and Vashon till below the site, in our opinion infiltration would not be feasible. 5.0GEOTECHNICALRECOMMENDATIONS 5.1SDP EISMIC ESIGN ARAMETERS The 2012/15 International Building Code (IBC) seismic design section provides a basis for seismic design of structures. Table 1 below provides seismic design parameters for the site that are in conformance with the 2012/15 IBC, which specifies a design earthquake havinga 2 percentprobability of occurrence in 50 years (return interval of 2,475 years), and the 2008 USGS seismic hazard maps. 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. Table 1 –Seismic Design Parameters Design Spectral Spectral Spectral Site Control Periods Response Acceleration Acceleration Site Coefficients\[sec.\] Parameters at 0.2 sec. \[g\]at 1.0 sec. \[g\] Class SS FFSSTT S1 avDSD1OS D1.2610.4931.0001.5070.8400.4950.1180.589 Liquefaction Potential: Liquefaction is a process that can occur when soils lose shear strength for short periods of time during a seismic event. Ground shaking ofsufficient strength and duration results in the loss of grain-to-grain contact and an increase in pore water pressure, causing the soil to behave as a fluid. Soils with a potential for liquefaction are typically cohesionless, predominately silt and sand sized, must be loose, and be below the groundwater table. The subject site is underlain by medium dense to dense silty sand with gravel soils without 5PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 a defined groundwater table. Based on these conditions, in our opinion the liquefaction potential of thesite is low and design considerations related to soil liquefaction are not necessary for this project. 5.2F OUNDATIONS Based on our review and our understanding of the planned improvements, it is our opinion the proposed building may be supported on aspread footing foundation.Footings should bear on the existing fill below the site or on properly compacted structural fill placed to modify site grades. For frost protection considerations, exterior foundation elements should be placed at a minimum depth of 18 inches below final exterior grade. Interior spread foundations should be placed at a minimum depth of 12 inches below the top of concrete slabs. We recommend a maximum allowable soil bearing pressure of 2,500 pounds per square foot (psf) be used forsizing footings. The recommended allowable soil bearing pressure is for dead plus live loads. For allowable stress design, the recommended bearing pressure may be increased by one-third for transient loading, such as wind or seismic forces. Footings designed and constructed in accordance with the above recommendations should experience total settlement of about one inch and differential settlement of less than ½ inch. Most of the anticipated settlement should occur during construction as dead loads are applied. 5.2.1 Lateral Resistance Lateral loads on the structures may be resisted by passive earth pressure developed against the embedded portion of the foundation system and by frictional resistance between the bottom of the foundation and the supporting subgrade soils. For footings bearing on the medium dense silty sand with gravel soils or on structural fill, a frictional coefficient of 0.30may be used to evaluate sliding resistance developed between the concrete and the subgrade soil. Passive soil resistance may be calculated using an equivalent fluid weight of 300 pcf, assuming foundations are backfilled with structural fill. The above values include a factor of safety of 1.5. Unless covered by pavements or slabs, the passive resistance in the upper 12 inches of soil should be neglected. 6PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 5.2.2 Foundation Subgrade Preparation Based on the conditions encountered at our boring location, the foundation subgrade soils will likely consist of previously placed fill. We recommend compacting the foundation subgrade soils in place after they are exposed. The subgrade soils should be in a dense and unyielding condition prior to setting forms and placing rebar. Loose soils encountered at the foundation subgrade elevation should be compacted in-place to the requirements of structural fill. Loose or soft soils that cannot be compacted in-place should be overexcavated and replaced with structural fill. The adequacy of the footing subgrade soils should be verified by a representative of PanGEO prior to placing forms or rebar. FS 5.3 LOORS LABS The floor slab for the proposedbuildingmay be constructed using conventional concrete slab- on-grade floor construction. The floor slabs should be supported on the existing fill encountered below the site or on structural fillused to modify site grades. Any over-excavation, if needed, should be backfilled with structural fill. Interior concrete slab-on-grade floors should be underlain by a capillary break consisting of at least of 4 inches of pea gravel or compacted ¾-inch, clean crushed rock (less than 3 percent fines). The capillary break material should meet the gradational requirements provided in Table 2, below. Table 2 –Capillary Break Gradation Sieve SizePercent Passing ¾-inch100 No. 40–10 No. 100 0–5 No. 2000–3 The capillary break should be placed on the subgrade that has been compacted to a dense and unyielding condition. 7PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 Construction joints should be incorporated into the floor slab to control cracking. Waterproofing and damp proofing measures are the responsibility of the owner. 5.4PCFS ERMANENT UT AND ILL LOPES Based on the anticipated soil that will be exposed in the planned excavation, we recommend permanent cut and fill slopes be constructed no steeper than 2H:1V (Horizontal:Vertical). Permanently exposed slopes should be seeded with an appropriate species of vegetation to reduce erosion and improve stability of the surficial layer of soil. 6.0 EARTHWORK CONSIDERATIONS 6.1SP TRIPPING AND ROOFROLLING Building, pavement and areas to receive structural fill should be stripped and cleared of asphalt pavement, surface vegetation, organic matter, and other deleterious material. Existing utility pipes to be abandoned should be plugged or removed so they do not provide a conduit for water and cause soil saturation and stability problems. Based on the thickness of the asphalt pavement encountered inour boring locations, we anticipate a stripping depth of about four to six inches across most of the proposed improvement areas. The actual stripping depth should be based on field observation at the time of construction. Following the stripping operation and excavations necessary to achieve construction subgrade elevations, the ground surface where structural fill, foundations, slabs, orpavements are to be placed should be observed by a representative of PanGEO. Proofrolling may be necessary to identify soft or unstable areasand should be performed under the observation of a representative of PanGEO. Soil in loose or soft areas, if re-compacted and still yielding, should be overexcavated and replaced with structural fill to a depth that will provide a stable base beneath the general structural fill. The optional use of a geotextile fabric placed directly on the overexcavated surface may also help to bridge unstable areas. 8PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 6.2SFC TRUCTURAL ILL AND OMPACTION Structural fill, should be free of organic and inorganic debris, be near the optimum moisture content and be capable of being compacted to the recommendations provided below. If thesite soils cannot be compacted, then an imported structural fill may be needed. Fill for use during wet weather should consist of a well graded soil free of organic material with less than 5 percent fines (silt and clay sized particles passing the U.S. Standard No. 200 sieve). Structural fill should be moisture conditioned to within about 3 percent of optimum moisture content, placed in loose, horizontal lifts less than 8 inches in thickness, and compacted to at least 95 percent maximum density, determined using ASTM D-1557 (Modified Proctor). The procedure to achieve proper density of a compacted fill depends on the size and type of compaction equipment, the number of passes, thickness of the lifts being compacted, and certain soil properties. If the excavation to be backfilled is constricted and limits the use of heavy equipment, smaller equipment can be used, but the lift thickness will need to be reduced to achieve the required relative compaction. Generally, loosely compacted soils are a result of poor construction technique or improper moisture content. Soils with high fines contents are particularly susceptible to becoming too wet and coarse-grained materials easily become too dry, for proper compaction. Silty soils with a moisture content too high for adequate compaction should be aerated during dry weather or moisture conditioned by mixing with drier materials to reduce the moisture content. 6.3TE EMPORARY XCAVATIONS Temporary excavations should be constructed in accordance with Part N of theWAC (Washington Administrative Code) 296-155. The contractor is responsible for maintaining safe excavation slopes and/or shoring. Based on the soil conditions encountered at our boring locations, inour opinion temporary excavations may be cut at a maximum 1H:1V inclination. Temporary excavations should be evaluated in the field during construction based on actual observed soil conditions. If seepage is encountered, excavation slope inclinations may need to be reduced. During wet weather, the cut slopes may need to be flattened to reduce potential erosion or should be covered with plastic sheeting. 9PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 6.4WWC ETEATHER ONSTRUCTION The soils underlying the site are moisture sensitive. These soils will become disturbed and soft when exposed to inclement weather conditions and construction traffic. To avoid disturbance, construction traffic should refrain from travelling on prepared subgrade soils during wet weather. General recommendations relative to earthwork performed in wet weather or in wet conditions are presented below. The following procedures are best management practices recommended for use in wet weather construction: Earthwork should be performed in small areas to minimize subgrade exposure to wet weather. Excavation or the removal of unsuitable soil should be followed promptly by the placement and compaction of clean structural fill. The size and type of construction equipment used may have to be limited to prevent soil disturbance. During wet weather, the allowable fines content of the structural fill should be reduced to no more than 5 percent by weight based on the portion passing the 0.75- inch sieve. The fines should be non-plastic. The ground surface within the construction area should be graded to promote run-off of surface water and to prevent the ponding of water. Geotextile silt fences should be installed at strategic locations around the site to control erosion and the movement of soil. Excavation slopes and soils stockpiled on site should be covered with plastic sheeting. 6.5EC ROSION ONSIDERATIONS Surface runoff can be controlled during construction by careful grading practices. Typically, this includes the construction of shallow, upgrade perimeter ditches or low earthen berms in conjunction with silt fences to collect runoffand prevent water from entering excavations or to prevent runoff from the construction area leaving the immediate work site. Temporary erosion control may require the use of hay bales on the downhill side of the project to prevent water from leaving the site and potential storm water detention to trap sand and silt before the water is discharged to a suitable outlet. All collected water should be directed under control to a positive and permanent discharge system. 10PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 Permanent control of surface water should be incorporated in the final grading design. Adequate surface gradients and drainage systems should be incorporated into the design such that surface runoff is collected and directed away from the structures and to a suitable outlet. Potential issues associated with erosion may also be reduced by establishing vegetation within disturbed areas immediately following grading operations. 7.0 ADDITIONALSERVICES To confirm that our recommendations are properly incorporated into the design and construction of the proposed building, PanGEO should be retained to conduct a review of the final project plans and specifications, and to monitor the construction of geotechnical elements. The City of Edmonds, as part of the permitting process, will also require geotechnical construction monitoringservices. PanGEO can provide you a cost estimate for construction monitoring services at a later date. 11PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 8.0 LIMITATIONS We have prepared this report for use by Tekin & Associatesand itsproject design team. Recommendations contained in this report are based on a site reconnaissance, review of pertinent subsurface information, a subsurface exploration program, and our understanding of the project. The study was performed using a mutually agreed-upon scope of work. Variations in soil conditions may exist between the explorations and the actual conditions underlying the site.The nature and extent of soil variations may not be evident until construction occurs. If any soil conditions are encountered at the site that are different from those described in this report, we should be notified immediately to review the applicability of our recommendations.Additionally, we should also be notified to review the applicability of our recommendations if there are any changes in the project scope. The scope of our work does not include services related to construction safety precautions. 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. Additionally, the scope of our work specifically excludes the assessment of environmental characteristics, particularly those involving hazardous substances. We are not mold consultants nor are our recommendations to beinterpreted as being preventative of mold development. A mold specialist should be consulted for all mold-related issues. This report may be used only by the client and for the purposes stated, within a reasonable time from its issuance. Land use, site conditions (both off and on-site), or other factors including advances in our understanding of applied science, may change over time and could materially affect our findings. Therefore, this report should not be relied upon after 24 months from its issuance. PanGEO should be notified if the project is delayed by more than 24 months from the date of this report so that we may review the applicability of our conclusions considering the time lapse. It is the client’s responsibility to see that all parties tothis project, including the designer, contractor, subcontractors, etc., are made aware of this report in its entirety. The use of information contained in this report for bidding purposes should be done at the contractor’s 12PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 option and risk. Any party other than the client who wishes to use this report shall notify PanGEO of such intended use and for permission to copy this report. Based on the intended use of the report, PanGEO may require that additional work be performed and that an updated report be reissued. Noncompliance with any of these requirements will release PanGEO from any liability resulting from the use this report. Within the limitation of scope, schedule and budget, PanGEO engages in the practice of geotechnical engineering and endeavors to perform its services in accordance with generally accepted professional principles and practices at the time the Report or its contents were prepared. No warranty, express or implied, is made. We appreciate the opportunity to be of service to you on this project. Please feel free to contact our office with any questions you have regarding our study, this report, or any geotechnical engineering related project issues. Sincerely, PanGEO, Inc. Scott D. Dinkelman, LEGSiew L. Tan, P.E. Senior Engineering GeologistPrincipal Geotechnical Engineer 13PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt Geotechnical Report th Proposed Retail Development,8431 244Street Southwest, Edmonds, Washington March 13, 2017 9.0 REFERENCES ASTM International (ASTM), Annual book of standards, Section 04.08 Soil and Rock (I): D420- D5876: West Conshohocken, Pennsylvania International Building Code (IBC), 2012/2015, International Code Council. Minard, J.P.Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangles, , WashingtonUSGS, Miscellaneous Field Studies Map MF-1541,1983. Washington Administrative Code (WAC), 2013, Chapter 296-155-Safety Standards for Construction Work, Part N -Excavation, Trenching, and Shoring, Olympia, Washington. Washington State Department of Transportation (WSDOT), 2016, Standard Specifications for Road, Bridges, and Municipal Construction, Olympia, Washington. 14PanGEO, Inc. 17-057 8431 244th St SW, Edmonds Rpt (8') APPENDIX A SUMMARYBORING LOGS DENNY'S ALTA/NSPS LAND TITLE SURVEY A-4 LEGEND APPENDIX TOPOGRAPHIC & BOUNDARY SURVEY EXISTING SITE CONDITIONS A-5 APPENDIX POST-DEVELOPMENT SITE CONDITIONS B-1 APPENDIX DRAWN BY - CHECKED BY DRAINAGE PLAN GRADING AND PRELIMINARY DEVELOPER: TEKIN & ASSOCIATES PC-2 REVISIONS:April 2017 DATE: SN EDMONDS, WA 98026 VILLAGE 8431 244TH ST. S.W. THE SHOPS @ AURORA PROJECT: B-2 APPENDIX CAP CIFI WH Y 244TH STREET SW ) Y A W S D N O M THE SHOPS BLDG D ARBY'S E ( 9 9 A W DRAWN BY - CHECKED BY CONTROL PHASE 1 EROSION AND DEVELOPER: TEKIN & ASSOCIATES SEDIMENT EC-1 REVISIONS:April 2017 DATE: SN EDMONDS, WA 98026 VILLAGE 8431 244TH ST. S.W. THE SHOPS @ AURORA PROJECT: B-3 APPENDIX AP FIC H CI YW 244TH STREET SW DENNY'S ) Y A W S D N O M D ARBY'S E ( 9 9 A W DRAWN BY - CHECKED BY CONTROL PHASE 2 EROSION AND DEVELOPER: TEKIN & ASSOCIATES SEDIMENT EC-2 REVISIONS:April 2017 DATE: SN EDMONDS, WA 98026 VILLAGE 8431 244TH ST. S.W. THE SHOPS @ AURORA PROJECT: AP FIC H CI YW 244TH STREET SW ) Y A W S D N O M D ARBY'S E ( 9 9 A W WWHM2012 PROJECT REPORT APPENDIXC-1 General Model Information Project Name:Edmonds Shops_04-08-17 Site Name:Shops @ Aurora Site Address:8431 244th St SW City:Edmonds Report Date:4/8/2017 Gage:Everett Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.00 Version:2014/06/18 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Edmonds Shops_04-08-174/8/2017 2:17:53 PMPage 2 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land UseAcres C, Forest, Steep1.08 Pervious Total1.08 Impervious Land UseAcres Impervious Total0 Basin Total1.08 Element Flows To: SurfaceInterflowGroundwater Edmonds Shops_04-08-174/8/2017 2:17:53 PMPage 3 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land UseAcres C, Lawn, Mod0.24 Pervious Total0.24 Impervious Land UseAcres ROOF TOPS FLAT0.23 PARKING FLAT0.31 PARKING MOD0.3 Impervious Total0.84 Basin Total1.08 Element Flows To: SurfaceInterflowGroundwater Vault 1Vault 1 Edmonds Shops_04-08-174/8/2017 2:17:53 PMPage 4 Mitigated Routing Vault 1 Width:32.7962421489375 ft. Length:65.5924842978746 ft. Depth:7 ft. Discharge Structure Riser Height:6 ft. Riser Diameter:18 in. Orifice 1 Diameter:0.64 in.Elevation:0 ft. Orifice 2 Diameter:0.94 in.Elevation:3.372 ft. Orifice 3 Diameter:0.57 in.Elevation:3.87 ft. Element Flows To: Outlet 1Outlet 2 Vault Hydraulic Table Stage(ft)Area(ac)Volume(ac-ft)Discharge(cfs)Infilt(cfs) 0.00000.0490.0000.0000.000 0.07780.0490.0030.0030.000 0.15560.0490.0070.0040.000 0.23330.0490.0110.0050.000 0.31110.0490.0150.0060.000 0.38890.0490.0190.0060.000 0.46670.0490.0230.0070.000 0.54440.0490.0260.0070.000 0.62220.0490.0300.0080.000 0.70000.0490.0340.0090.000 0.77780.0490.0380.0090.000 0.85560.0490.0420.0100.000 0.93330.0490.0460.0100.000 1.01110.0490.0490.0100.000 1.08890.0490.0530.0110.000 1.16670.0490.0570.0110.000 1.24440.0490.0610.0120.000 1.32220.0490.0650.0120.000 1.40000.0490.0690.0120.000 1.47780.0490.0730.0130.000 1.55560.0490.0760.0130.000 1.63330.0490.0800.0130.000 1.71110.0490.0840.0140.000 1.78890.0490.0880.0140.000 1.86670.0490.0920.0140.000 1.94440.0490.0960.0150.000 2.02220.0490.0990.0150.000 2.10000.0490.1030.0150.000 2.17780.0490.1070.0150.000 2.25560.0490.1110.0160.000 2.33330.0490.1150.0160.000 2.41110.0490.1190.0160.000 2.48890.0490.1220.0170.000 2.56670.0490.1260.0170.000 2.64440.0490.1300.0170.000 2.72220.0490.1340.0170.000 2.80000.0490.1380.0180.000 2.87780.0490.1420.0180.000 Edmonds Shops_04-08-174/8/2017 2:17:53 PMPage 6 2.95560.0490.1460.0180.000 3.03330.0490.1490.0180.000 3.11110.0490.1530.0190.000 3.18890.0490.1570.0190.000 3.26670.0490.1610.0190.000 3.34440.0490.1650.0190.000 3.42220.0490.1690.0250.000 3.50000.0490.1720.0280.000 3.57780.0490.1760.0300.000 3.65560.0490.1800.0320.000 3.73330.0490.1840.0340.000 3.81110.0490.1880.0360.000 3.88890.0490.1920.0390.000 3.96670.0490.1950.0420.000 4.04440.0490.1990.0440.000 4.12220.0490.2030.0460.000 4.20000.0490.2070.0480.000 4.27780.0490.2110.0490.000 4.35560.0490.2150.0510.000 4.43330.0490.2180.0530.000 4.51110.0490.2220.0540.000 4.58890.0490.2260.0550.000 4.66670.0490.2300.0570.000 4.74440.0490.2340.0580.000 4.82220.0490.2380.0590.000 4.90000.0490.2420.0610.000 4.97780.0490.2450.0620.000 5.05560.0490.2490.0630.000 5.13330.0490.2530.0640.000 5.21110.0490.2570.0650.000 5.28890.0490.2610.0670.000 5.36670.0490.2650.0680.000 5.44440.0490.2680.0690.000 5.52220.0490.2720.0700.000 5.60000.0490.2760.0710.000 5.67780.0490.2800.0720.000 5.75560.0490.2840.0730.000 5.83330.0490.2880.0740.000 5.91110.0490.2910.0750.000 5.98890.0490.2950.0760.000 6.06670.0490.2990.3280.000 6.14440.0490.3030.8800.000 6.22220.0490.3071.6090.000 6.30000.0490.3112.4800.000 6.37780.0490.3153.4720.000 6.45560.0490.3184.5730.000 6.53330.0490.3225.7720.000 6.61110.0490.3267.0620.000 6.68890.0490.3308.4370.000 6.76670.0490.3349.8910.000 6.84440.0490.33811.420.000 6.92220.0490.34113.020.000 7.00000.0490.34514.690.000 7.07780.0490.34916.430.000 7.15560.0000.00018.230.000 Edmonds Shops_04-08-174/8/2017 2:17:54 PMPage 7 Analysis Results POC 1 + Predevelopedx Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.08 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.24 Total Impervious Area:0.84 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return PeriodFlow(cfs) 2 year0.035693 5 year0.053412 10 year0.066531 25 year0.084667 50 year0.099309 100 year0.114925 Flow Frequency Return Periods for Mitigated. POC #1 Return PeriodFlow(cfs) 2 year0.021149 5 year0.033499 10 year0.044355 25 year0.061774 50 year0.0779 100 year0.097161 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 YearPredevelopedMitigated 19490.0240.017 19500.0410.018 19510.0310.016 19520.0270.015 19530.0230.015 19540.1020.018 19550.0520.029 19560.0430.034 19570.0490.029 19580.0410.017 Edmonds Shops_04-08-174/8/2017 2:17:54 PMPage 8 19590.0390.019 19600.0350.019 19610.0360.028 19620.0310.016 19630.0500.016 19640.0350.015 19650.0300.019 19660.0200.016 19670.0440.016 19680.0520.026 19690.0700.017 19700.0270.016 19710.0410.037 19720.0360.018 19730.0270.018 19740.0570.018 19750.0260.015 19760.0260.018 19770.0230.017 19780.0280.015 19790.0610.018 19800.0340.014 19810.0280.016 19820.0330.036 19830.0540.016 19840.0320.046 19850.0450.032 19860.1070.069 19870.0450.056 19880.0280.034 19890.0260.014 19900.0320.029 19910.0340.019 19920.0290.019 19930.0220.015 19940.0190.019 19950.0340.036 19960.0710.033 19970.1210.214 19980.0240.015 19990.0290.019 20000.0200.043 20010.0080.013 20020.0320.019 20030.0240.019 20040.0390.044 20050.0300.019 20060.0690.033 20070.0620.019 20080.0930.070 20090.0270.019 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 RankPredevelopedMitigated 10.12150.2136 20.10710.0702 30.10150.0688 Edmonds Shops_04-08-174/8/2017 2:18:38 PMPage 9 40.09290.0558 50.07080.0463 60.07020.0437 70.06920.0428 80.06150.0373 90.06080.0361 100.05690.0357 110.05420.0341 120.05250.0336 130.05190.0333 140.04970.0331 150.04890.0316 160.04520.0291 170.04460.0288 180.04440.0287 190.04250.0285 200.04120.0260 210.04100.0194 220.04090.0194 230.03890.0194 240.03860.0193 250.03600.0193 260.03590.0188 270.03510.0188 280.03450.0188 290.03400.0187 300.03400.0187 310.03390.0186 320.03330.0185 330.03200.0184 340.03190.0182 350.03190.0182 360.03150.0180 370.03140.0180 380.03010.0180 390.03000.0176 400.02910.0172 410.02870.0169 420.02820.0167 430.02800.0167 440.02760.0164 450.02720.0163 460.02690.0163 470.02670.0162 480.02670.0161 490.02640.0159 500.02610.0158 510.02590.0157 520.02420.0154 530.02420.0153 540.02380.0151 550.02350.0150 560.02270.0150 570.02220.0150 580.02000.0147 590.01970.0145 600.01900.0145 610.00840.0128 Edmonds Shops_04-08-174/8/2017 2:18:38 PMPage 10 Duration Flows The Facility PASSED Flow(cfs)PredevMitPercentagePass/Fail 0.0178149141172778Pass 0.018713353680850Pass 0.019511907380731Pass 0.020310617308429Pass 0.02119441294731Pass 0.02208397284333Pass 0.02287495275536Pass 0.02366663267640Pass 0.02445916258843Pass 0.02535217249647Pass 0.02614624236151Pass 0.02694100222254Pass 0.02773679211257Pass 0.02853260195459Pass 0.02942926179361Pass 0.03022631168363Pass 0.03102372158366Pass 0.03182143143867Pass 0.03271946128465Pass 0.03351790115764Pass 0.03431619107766Pass 0.03511468102069Pass 0.0359133893770Pass 0.0368122888371Pass 0.0376112185175Pass 0.0384103482179Pass 0.039294479584Pass 0.040186677289Pass 0.040981274591Pass 0.041775571895Pass 0.042570969097Pass 0.043467165998Pass 0.044262862699Pass 0.045060360299Pass 0.045858357197Pass 0.046656654095Pass 0.047554952595Pass 0.048352651096Pass 0.049150249298Pass 0.049948447798Pass 0.050846846098Pass 0.051645644697Pass 0.052444243297Pass 0.053242841897Pass 0.054142040195Pass 0.054940937591Pass 0.055739835689Pass 0.056538534288Pass 0.057337233188Pass 0.058235431990Pass 0.059034430287Pass 0.059833028385Pass 0.060631226384Pass Edmonds Shops_04-08-174/8/2017 2:18:38 PMPage 12 0.061529624984Pass 0.062328823782Pass 0.063127922580Pass 0.063927221378Pass 0.064726620275Pass 0.065625818772Pass 0.066425417066Pass 0.067224915261Pass 0.068024513354Pass 0.068923911447Pass 0.06972329942Pass 0.07052258638Pass 0.07132188338Pass 0.07222147535Pass 0.07302105224Pass 0.07382034723Pass 0.07461973718Pass 0.07541923116Pass 0.0763188179Pass 0.0771183179Pass 0.0779179179Pass 0.0787175179Pass 0.07961681710Pass 0.08041571710Pass 0.08121451711Pass 0.08201411712Pass 0.08291351712Pass 0.08371301713Pass 0.08451231613Pass 0.08531171613Pass 0.08611121614Pass 0.08701071614Pass 0.08781031615Pass 0.0886971616Pass 0.0894911617Pass 0.0903861618Pass 0.0911741621Pass 0.0919651624Pass 0.0927561628Pass 0.0935521630Pass 0.0944471634Pass 0.0952421638Pass 0.0960391641Pass 0.0968381642Pass 0.0977321650Pass 0.0985271659Pass 0.0993231669Pass Edmonds Shops_04-08-174/8/2017 2:18:38 PMPage 13 Appendix Predeveloped Schematic Edmonds Shops_04-08-174/8/2017 2:19:16 PMPage 17 Mitigated Schematic Edmonds Shops_04-08-174/8/2017 2:19:17 PMPage 18 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2013; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Edmonds Shops_04-08-174/8/2017 2:19:17 PMPage 28 Appendix C-2 Operation and Maintenance Manual Maintain Stormwater Facilities The owner or operator of the project shall be responsible for maintaining the stormwater facilities in accordance with local requirements. Proper maintenance is important for adequate functioning of the stormwater facilities. See the LID Manual and Volume III and Volume V of the Stormwater Manual for guidance on operation and maintenance measures for BMPs. The following maintenance program is recommended for this project: Table 10 Maintenance Checklist for Catch Basins and Inlets Frequency Drainage Problem Conditions To Check For Conditions That Should Exist System Feature Trash or debris in front of the No trash or debris located M,S General Trash, debris, and sediment in or on catch basin opening is blocking immediately in front of catch basin capacity by more than 10%. basin opening. Grate is kept clean and allows water to enter. M Sediment or debris (in the basin) No sediment or debris in the that exceeds 1/3 the depth from catch basin. Catch basin is the bottom of basin to invert of the dug out and clean. lowest pipe into or out of the basin. M,S Trash or debris in any inlet or pipe Inlet and Outlet pipes free of blocking more than 1/3 of its trash or debris. height. M Structural damage Corner of frame extends more than Frame is even with curb. to frame and/or top ¾ inch past curb face into the slab street (if applicable). M Top slab has holes larger than 2 Top slab is free of holes and square inches or cracks wider than cracks. ¼ inch (intent is to make sure all material is running into the basin). M Frame not sitting flush on top slab, Frame is sitting flush on top i.e., separation of more than ¾ slab. inch of the frame from the top slab. A Cracks in basin Cracks wider than ½ inch and Basin replaced or repaired to walls/bottom longer than 3 feet, any evidence of design standards. Contact a soil particles entering catch basin professional engineer for through cracks, or maintenance evaluation. person judges that structure is unsound. A Cracks wider than ½ inch and No cracks more than ¼ inch longer than 1 foot at the joint of wide at the joint of any inlet/outlet pipe or any inlet/outlet pipe. Contact a evidence of soil particles entering professional engineer for catch basin through cracks. evaluation. A Settlement/ Basin has settled more than 1 inch Basin replaced or repaired to misalignment or has rotated more than 2 inches design standards. Contact a out of alignment. professional engineer for evaluation. M,S Fire hazard of other Presence of chemicals such as No color, odor, or sludge. pollution natural gas, oil, and gasoline. Basin is dug out and clean. Obnoxious color, odor, or sludge noted. M,S Outlet pipe is Vegetation or roots growing in No vegetation or root growth clogged with inlet/outlet pipe joints that is more present. vegetation than 6 inches tall and less than 6 inches apart. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: A = Annual (March or April, preferred) M = Monthly S = After major storms (use 1-inch in 24 hours as a guideline) TABLE 10 (CONTINUED) Maintenance Checklist for Conveyance Systems (Pipes) Frequency Drainage Problem Conditions To Check For Conditions That Should Exist System Feature M,S Pipes Sediment & Accumulated sediment that exceeds Pipe cleaned of all sediment and debris 20% of the diameter of the pipe. debris. M Vegetation Vegetation that reduces free movement All vegetation removed so water of water through pipes. flows freely through pipes. A Damaged Protective coating is damaged; rust is Pipe repaired or replaced. (rusted, bent, causing more than 50% deterioration to or crushed) any part of pipe. M Any dent that significantly impedes Pipe repaired or replaced. flow (i.e., decreases the cross section area of pipe by more than 20%). M Pipe has major cracks or tears allowing Pipe repaired or replaced. groundwater leakage. Maintenance Checklist for Detention Vault Frequency Drainage Problem Conditions To Check For Conditions That Should Exist System Feature M,S Plugged Air One-half of the cross section of a vent Vents open and functioning. Vents is blocked at any point or the vent is damaged. M Debris and Accumulated sediment depth exceeds All sediment and debris Sediment 10% of the diameter of the storage area removed from storage area. for 1/2 length of storage vault or any Storage point depth exceeds 15% of diameter Area M,S Vault Structure Cracks wider than 1/2-inch and any Vault replaced or repaired to Includes Cracks evidence of soil particles entering the design specifications and in Wall, Bottom, structure through the cracks, or is structurally sound. No cracks Damage to maintenance/ inspection personnel more than 1/4-inch wide at the joint Frame and/or determines that the vault is not of the inlet/outlet pipe. Top Slab structurally sound. Cracks wider than 1/2-inch at the joint of any inlet/outlet pipe or any evidence of soil particles entering the vault through the walls. M Cover Not in Cover is missing or only partially in Manhole is Place place. Any open manhole requires closed. maintenance. M Locking Mechanism cannot be opened by one Mechanism Mechanism maintenance person with proper tools. opens with Not Working Bolts into frame have less than 1/2 inch proper tools.. of thread (may not apply to self-locking lids). Manhole M Cover Difficult One maintenance person cannot Cover can be removed and to Remove remove lid after applying normal lifting reinstalled by one maintenance pressure. Intent is to keep cover from person. sealing off access to maintenance. A Ladder Rungs Ladder is unsafe due to missing rungs, Ladder meets design standards. Unsafe misalignment, not securely attached to Allows maintenance person safe structure wall, rust, or cracks. access. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: A = Annual (March or April, preferred) M = Monthly S = After major storms (use 1-inch in 24 hours as a guideline) TABLE 10 (CONTINUED) Maintenance Checklist for Flow Control Structure Frequency Drainage Problem Conditions To Check For Conditions That Should Exist System Feature A Trash and Material exceeds 25% of Control structure orifice is Debris sump depth or 1 foot below not blocked. All trash and (Includes orifice plate. debris removed. Sediment General A Structural Structure is not securely attached to Structure securely attached to Damage manhole wall. Structure is not in upright wall and outlet pipe. position (allow up to 10% from plumb). Structure in correct position. Connections to outlet pipe are not Connections to outlet pipe watertight and show signs of rust. are water tight; structure Any holes - other than designed holes - repaired or replaced and in the structure. works as designed. Structure has no holes other than designed holes. M Damaged or Cleanout gate is not watertight or is Gate is watertight and works Missing missing. Gate cannot be moved up as designed. Gate moves up Cleanout and down by one maintenance and down easily and is Gate person. Chain/rod leading to gate is watertight. Chain is in place missing or damaged. Gate is rusted over and works as designed. 50% of its surface area. Gate is repaired or replaced to meet design standards. M Damaged or Control device is not working properly Plate is in place and works as Missing due to missing, out of place, or bent designed. Orifice orifice plate. Plate M,S Obstructions Any trash, debris, sediment, or Plate is free of all vegetation blocking the plate. obstructions and works as designed. M,S Overflow Obstructions Any trash or debris blocking Pipe is free of all obstructions Pipe (or having the potential of and works as designed. blocking) the overflow pipe. M,S Cover Difficult One maintenance person cannot Cover can be removed and to Remove remove lid after applying normal lifting reinstalled by one pressure. Intent is to keep cover from maintenance sealing off access to maintenance. person. Manhole M,S Ladder Rungs Ladder is unsafe due to missing rungs, Ladder meets design Unsafe misalignment, not securely attached to standards. Allows structure wall, rust, or cracks. maintenance person safe access. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: A = Annual (March or April, preferred) M = Monthly S = After major storms (use 1-inch in 24 hours as a guideline) TABLE 10 (CONTINUED) Maintenance Checklist for Manufactured Media Filters Frequency Drainage Problem Conditions To Check For Conditions That Should Exist System Feature M,S Sediment Sediment depth exceeds 0.25- No sediment deposits which Accumulation inches. would impede permeability on media of the compost media. M Sediment Sediment depth exceeds 6-inches No sediment deposits in vault Accumulation in first chamber. bottom of first chamber. in Vault A Trash/Debris Trash and debris accumulated on Trash and debris removed from Accumulation compost filter bed. the compost filter bed. M Sediment in When drain pipes, clean-outs, become Sediment and debris removed. Drain full with sediment and/or debris. Pipes/Clean- Outs M Damaged Any part of the pipes that are Pipe repaired and/or Pipes crushed or damaged due to corrosion replaced. and/or settlement. Access Cover Cover cannot be opened; one person Cover repaired to proper working Below Damaged/Not cannot open the cover using specifications or replaced. Ground Working normal lifting pressure, corrosion/ Vault deformation of cover Vault Structure Cracks wider than 1/2-inch or evidence Vault replaced or repairs made so Includes of soil particles entering the that vault meets design Cracks in structure through the cracks, or specifications and is structurally Wall, maintenance/inspection personnel sound. Vault repaired so that Bottom, determine that the vault is not no cracks exist wider Damage to structurally sound. than 1/4-inch at the Frame and/or Cracks wider than 1/2-inch at the joint of the inlet/outlet Top Slab joint of any inlet/outlet pipe or pipe. evidence of soil particles entering through the cracks. Baffles Baffles corroding, cracking warping, Baffles repaired or and/or showing signs of failure replaced to specifications as determined by maintenance/ inspection person. Access Ladder Ladder is corroded or deteriorated, Ladder replaced or Damaged not functioning properly, not repaired and meets securely attached to structure wall, specifications, and is missing rungs, cracks, and misaligned. safe to use as determined by inspection personnel. Below Media Drawdown of water through the Media cartridges Ground media takes longer than 1 hour, replaced. Cartridge and/or overflow occurs frequently. Type Short Flows do not properly enter filter Filter cartridges Circuiting cartridges. replaced. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: A = Annual (March or April, preferred) M = Monthly S = After major storms (use 1-inch in 24 hours as a guideline) TABLE 10 (CONTINUED) Maintenance Checklist for Grounds (Landscaping) Frequency Drainage Problem Conditions To Check For Conditions That Should Exist System Feature M General Weeds Weeds growing in more than 20% of Remove trash and debris and (nonpoisonous) the landscaped area (trees and shrubs dispose as prescribed by the only). County. M Insect hazard Any presence of poison ivy or other Ditch cleaned of all sediment poisonous vegetation or insect nests. and debris so that it matches design. M,S Trash or litter Dumping of yard wastes such as grass Remove trash and debris and clippings and branches onto grounds. dispose as prescribed by the Unsightly accumulation of County. nondegradable materials such as glass, plastic, metal, foam, and coated paper. M,S Erosion of Noticeable rills are seen in landscaped Causes of erosion are Ground Surface areas. identified and steps taken to slow down/spread out the water. Eroded areas are filled, contoured, and seeded. A Trees and Damage Limbs or parts of trees or shrubs that are Trim trees/shrubs to restore shrubs split or broken which affect more than shape. Replace trees/shrubs 25% of the total foliage of the tree or with severe damage. shrub. M Trees or shrubs that have been blown Replant tree, inspecting for down or knocked over. injury to stem or roots. Replace if severely damaged. A Trees or shrubs which are not Place stakes and rubber-coated adequately supported or are leaning ties around young trees/shrubs over, causing exposure of the roots. for support. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: A = Annual (March or April, preferred) M = Monthly S = After major storms (use 1-inch in 24 hours as a guideline) INSPECTION AND MAINTENANCE GUIDE November 4, 2015 Version 1 oldcastlestormwater.com (800) 579-8819 stormcapture.com | Inspection and Maintenance Guide PerkFilter PerkFilter Media Filtration System Description surfaces and other urban and suburban landscapes generate a variety of contaminants that can enter device designed to capture and retain sediment, gross solids, metals, nutrients, hydrocarbons, and trash and debris. As with any stormwater treatment system, the PerkFilter requires regular periodic maintenance to sustain optimum system performance. Function the cylindrical cartridges from the outside surface, through the media for treatment, and into the center of the cartridge. At the center of the cartridge is a center tube assembly designed to distribute the hydraulic built into each cartridge allows the treatment chamber to dewater between storm events. Filter cartridge treatment chamber Precast concrete vault Access Covers Inlet chamber Outlet hood Inlet pipe Outlet pipe Outlet chamber Concrete false floor Bypass assembly Figure 1. Schematic of the PerkFilter system. ©2015 Oldcastle Precast, Inc. 11/4/2015_V1 2 | Inspection and Maintenance Guide PerkFilter chamber directly to the outlet chamber, bypassing the treatment chamber to prevent sediment and other in the outlet chamber for discharge by a single outlet pipe. Vent tube Outer media layer Center tube assembly Inner media layer Outer screen Connection to outlet chamber (with draindown) Figure 2. Schematic of the PerkFilter cartridge. may be fabricated from concrete or steel. Internal components including the PerkFilter cartridges are manufactured from durable plastic and stainless steel components and hardware. All cartridges are 18 inches in diameter and are available in two heights: 12-inch and 18-inch. Cartridges may be used alone or may be stacked (Figure 3) to provide 24-inch and 30-inch combinations. The capacity of each cartridge or cartridge combination is dictated by the allowable operating rate of the media and the outer surface area of the cartridge. Thus, taller cartridges have greater treatment capacity than shorter cartridges but they also standard mix is composed of zeolite, perlite, and carbon (ZPC). Access to an installed PerkFilter system is typically provided by ductile iron castings or hatch covers. The ©2015 Oldcastle Precast, Inc. 11/4/2015_V1 3 | Inspection and Maintenance Guide PerkFilter Vent tube (4 dia.) Top stacked cartridge Inner interconnector coupling (2 dia.) Outer interconnector coupling (4 dia.) Single or bottom stacked cartridge Urethane bottom cap Slip coupler (2 dia.) Figure 3. Schematic of stacked cartridges and connector components. ©2015 Oldcastle Precast, Inc. 11/4/2015_V1 4 | Inspection and Maintenance Guide PerkFilter Maintenance Overview State and local regulations require all stormwater management systems to be inspected on a regular basis and maintained as necessary to ensure performance and protect downstream receiving waters. Maintenance prevents excessive pollutant buildup that can limit system performance by reducing the Inspection and Maintenance Frequency The PerkFilter should be inspected on a regular basis, typically twice per year, and maintained as required. Initially, inspections of a new system should be conducted more frequently to help establish an appropriate pollutant loading encountered by a given system. In most cases, the optimum maintenance interval will be one to three years. Inspection and maintenance activities should be performed only during dry weather periods. Inspection Equipment The following equipment is helpful when conducting PerkFilter inspections: Recording device (pen and paper form, voice recorder, iPad, etc.) Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) Socket and wrench for bolt-down access covers Manhole hook or pry bar Flashlight Tape measure Measuring stick or sludge sampler Long-handled net (optional) Inspection Procedures PerkFilter inspections are visual and may be conducted from the ground surface without entering the unit. covers are removed. Once the covers have been removed, the following items should be checked and recorded (see form provided at the end of this document) to determine whether maintenance is required: Inspect the internal components and note whether there are any broken or missing parts. In the unlikely event that internal parts are broken or missing, contact Oldcastle Stormwater Solutions at (800) 579-8819 to determine appropriate corrective action. Note whether the inlet pipe is blocked or obstructed. The outlet pipe is covered by a removable outlet hood and cannot be observed without entering the unit. ©2015 Oldcastle Precast, Inc. 11/4/2015_V1 5 | Inspection and Maintenance Guide PerkFilter may be used to retrieve the bulk of trash and debris at the time of inspection if full maintenance due Observe, quantify, and record the average accumulation of sediment in the inlet chamber and treatment chamber. A calibrated dipstick, tape measure, or sludge sampler may be used to determine the amount of accumulated sediment in each chamber. The depth of sediment may be determined the accumulated sediment and the measurement from the rim of the PerkFilter to the bottom of the PerkFilter structure. Finding the top of the accumulated sediment below standing water takes some practice and a light touch, but increased resistance as the measuring device is lowered toward the bottom of the unit indicates the top of the accumulated sediment. Finally, observe, quantify, and record the amount of standing water in the treatment chamber around the cartridges. If standing water is present, do not include the depth of sediment that may have settled out below the standing water in the measurement. Maintenance Triggers Internal components are broken or missing. Inlet piping is obstructed. There is more than 6 of accumulated sediment in the inlet chamber. There is more than 4 of accumulated sediment in the treatment chamber. There is more than 4 of standing water in the treatment chamber more than 24 hours after end of rain event. The system has not been maintained for 3 years (wet climates) to 5 years (dry climates). Maintenance Equipment The following equipment is helpful when conducting PerkFilter maintenance: Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) Socket and wrench for bolt-down access covers Manhole hook or pry bar ©2015 Oldcastle Precast, Inc. 11/4/2015_V1 6 | Inspection and Maintenance Guide PerkFilter Flashlight Tape measure Vacuum truck with water supply and water jet Contact Oldcastle Stormwater Solutions at (800) 579-8819 four weeks is recommended. Maintenance Procedures the access covers may be removed and the following activities may be conducted to complete maintenance: extension nozzle on the end of the boom hose of the vacuum truck. Continue using the vacuum truck to completely dewater the inlet chamber and evacuate all accumulated sediment from the inlet chamber. Some jetting may be required to fully remove sediment. The inlet chamber does not need storm event occurs. cartridge (the top is held on by four 9/16 bolts) and use the vacuum truck to evacuate the spent sediment and debris from being washed into the outlet chamber during washdown. Once all the spent cartridges have been removed from the structure, the vacuum truck may be used to evacuate all accumulated sediment from the treatment chamber. Some jetting may be required to fully remove sediment. Take care not to wash sediment and debris through the openings in the including the spent media must be disposed of in accordance with local, state, and/or federal regulations. In most cases, the material may be handled in the same manner as disposal of material removed from sumped catch basins or manholes. Place a fresh cartridge in each cartridge position using the existing slip couplers and urethane bottom caps. If the vault is equipped with stacked cartridges, the existing outer and inner interconnector couplers must be used between the stacked cartridges to provide hydraulic connection. Transfer the existing vent tubes from the spent cartridges to the fresh cartridges. Finally, Securely replace access covers, as appropriate. Make arrangements to return the empty spent cartridges to Oldcastle Stormwater Solutions. ©2015 Oldcastle Precast, Inc. 11/4/2015_V1 7 | Inspection and Maintenance Guide PerkFilter PerkFilter Inspection and Maintenance Log Location_____________________________________________________________ Structure Configuration and Size: Inspection Date______________ Vault_____ feet x _____ feet Manhole _____diameter Catch Basin _____ feet x _____ feet Number and Height of Cartridges: Count _____each 12” 18” 24” 30” Media Type: ZPC Perlite Other _______________ Notes: Condition of Internal Components Good Damaged Missing Notes: Inlet PipeBlockage or Obstruction Yes No Notes: Floating Trash and Debris Significant Not Significant Notes: Floating Oils Significant Not Significant Spill Notes: Sediment Depthin Inlet Chamber Inches of Sediment: __________ Notes: Sediment Depthin Treatment Chamber Inches of Sediment: __________ Notes: Standing Water in Treatment Chamber Inches of Standing Water: __________ Maintenance Required Yes –Schedule Maintenance No–Inspect Again in _____ Months ©2015 Oldcastle Precast, Inc. 11/4/2015_V1 8 STORMWATER POLLUTION PREVENTION PLAN FOR CONSTRUCTION ACTIVITIES Shops @ Aurora Village th St SW 8431 244 Edmonds, WA 98026 Operator(s): Tekins & Associates Day-to-Day Operator 2727 LBJ Freeway Contractor TBD Suite 785 Dallas, Texas 75234 (469) 458-0485 Prepared by: PACLAND 10135 SE Sunnyside, Suite 200 Clackamas, OR 97015 Phone: (503) 659-9500 Email: snguy@pacland.com Attention: Shawn Nguy, P.E. SWPPP Preparation Date: 04/10/2017 Estimated Project Dates: Start of Construction: December 2017 Completion of Construction: September 2017 SWPPP ÏShops @ Aurora Village Page 1 of 5 Edmonds, WA APPENDIXD Introduction This SWPPP includes the elements necessary for construction activities administered by the U.S. Environmental Protection Agency (EPA) under the National Pollutant Discharge Elimination System (NPDES) program and all local governing agency requirements. This SWPPP must be implemented at the start of construction. Construction phase pollutant sources anticipated at the site are disturbed (bare) soil, vehicle fuels and lubricants, chemicals and coatings associated with site or building construction and pavement installation, construction- generated litter and debris, and building materials. Without adequate control there is a potential for each type of pollutant to be transported by stormwater. Project construction will consist primarily of demolition, site grading, paving, storm drainage, water supply, sewage collection, utilities, site lighting, etc. located within the project area. There is no work proposed beyond the project area noted on the Erosion and Sediment Control Plan. Project Description The project proposes to develop an approximate 10,000 square foot Retail Shop at 8431 244 SW in the fall of 2017. th The site is currently an existing DennyÔs Restaurant and parking lot with a total area of approximately 1.08 acres in size. In addition to the new building, there will be parking, landscaping, lighting, pedestrian access and circulation, stormwater, and utility infrastructure, to serve the proposed use in accordance with the city of Edmonds development codes and standards. Runoff currently flows to onsite catchbasins and is conveyed to a water quality treatment manhole and an underground detention system. A new runoff treatment and detention system is proposed for this project as the site currently does not have one. Roof downspouts will be piped to the detention facility on site. Site Description A. Site Location Address: 8431 244 St SW, Edmonds, WA th Latitude: N 47°46'42" (Center of Site) Longitude: W 122°20'50" (Center of Site) Adjacent surrounding properties: North Ï Highway 104 offramp o West Ï Multi Family Residents o South Ï ArbyÔs Restaurant o East Ï Highway 99E o B.Site Topography Lowest elevation on project site: 421.2 Ï southeast corner of site along Highway 99E. Highest elevation on project site: 451 Ïsouthwest corner of site along 244th Percent slope variation: 1.0% to 50% slope across the site. Topography changes: The existing site has moderate to steep slopes with existing rockery walls along the west property line. The site generally drains from west to east of the property. Vegetation: The existing site is paved with limited vegetation area. Existing rockery walls will be protected in place, while limited vegetation that are within the proposed improvement areas will be cleared and replaced. The developed condition will provide site landscaping that covers approximately 22% of the entire site. C.Rainfall Information Jan Feb March April May June July Aug Sept Oct Nov Dec Total Average rainfall 4.9 4.2 3.5 2.3 1.5 1.5 1.0 1.1 1.9 3.2 4.9 5.8 36.0 in inches (Rainfall data is based on a WRCC Monthly Climate Summary) SWPPP ÏShops @ Aurora Village Page 2 of 5 Edmonds, WA The total average annual rainfall for the project area is: 36.0 inches The design rain event for this project is based on City/State requirement using hourly precipitation data through water year 2009 provided with the WWHM2012 continuous runoff simulation software. Infiltration of stormwater runoff is not a feasible option for this site due to a thick layer of engineer fill and dense to very dense Vashon till soils. Runoff flow control for the site will be accomplished via an underground detention system. D. Site Soils According to the Natural Resources Conservation Services (NCRS), the native soil underlying the site consists of Alderwood-Urban Land Complex (2-15% slopes). The Geotechnical Engineering Investigation report by GeoTest, dated 3/24/2017, found that soils below the existing pavement are composed of fill consisting of medium dense, silty, fine to medium grained sand and medium dense to very dense Vashon till. The fill and Vashon till soils are categorized within the Soil Conservation Service (SCS) hydrologic soil group C. Average depth to groundwater: groundwater was not encountered in geotechnical borings down to depths of 16 ft below ground surface. E. Total Area to be Disturbed The project site contains: 0.99 acres F. Receiving Surface Waters Receiving waters: Lake Ballinger, located approximately 0.83 miles east of the site. 13 ELEMENTS of Construction SWPPP Element #1: Preservation Vegetation / Mark Clearing Limits This element applies only to the west side of the project because the project proposes to protect in place the existing rockery walls and vegetation on the steep slopes of the site. The majority of the site east of the existing walls was previously cleared as part of a prior development. Paved surface covers the majority of the site. Clear and grubbing of existing minor vegetation is anticipated only in areas needed to accommodate the proposed development. Element #2: Construction Access This element applies to the project. Even though pavement cover is dominant across the site, a stabilized construction exit will be installed to help minimize track-out onto public streets during pavement removal, regrading, excavation and filling activities. The location on the construction exit is shown on the SWPPP plans. BMP Implemented: C105 Stabilized Construction Entrance. Element #3: Flow Control Rates This element does not apply to the project. due to the size and existing stabilized conditions of the project area, it is not anticipated that a temporary sediment pond will be required. However, the post-developed conditions of the site will include an underground stormwater detention facility to control post-develop flow rates to the pre-forested condition discharge rates. Element #4: Install Sediment Control This element applies to the project. Sediment will be controlled on-site to prevent any potential for discharge to adjacent public streets. Sediment fence will be installed at the locations shown on the SWPPP plans for both sediment and perimeter site control. BMP Implemented: C233 Silt Fence. Element #5: Stabilize Soils SWPPP ÏShops @ Aurora Village Page 3 of 5 Edmonds, WA This element applies to the project. Exposed soils shall be worked during the week until they have been stabilized. Excavated soils will be stockpiled and located within the project limit of disturbance as shown on the SWPPP. No soils shall remain exposed and unworked for more than 2 days from October 1 to April 30 and for more than 7 days from May 1 to September 30. Temporary stabilize soils at the end of the shift before holiday or weekends, if needed based on weather forecast. Once the disturbed landscape areas are graded, the grass areas will be seeded or sodded in accordance with the Landscape Plan. All stockpiles will be covered in plastic if left unworked. BMPs Implemented: C123 Plastic Covering C124 Sodding C125 Topsoiling C140 Dust Control Element #6: Protect Slopes This element applies to a portion of the project. 2:1 fill slopes along the north side of the site building the building and the existing pedestrian path will require temporary seeding and blankets for stabilization until permanent landscaping and mulching can be installed. BMPs Implemented: C120 Temporary and Permanent Seeding C121 Mulching C122 Nets and Blankets C123 Plastic Covering C 125 Topsoiling Element #7: Protect Permanent Drain Inlets This element applies to the project. There are existing storm drain catch basins in the existing parking area and along public streets. Temporary inlet protection measures will be installed at the locations and per details shown on the SWPPP plans. BMPs Implemented: C220 Storm Drain Inlet Protection Element #8: Stabilize Channels and Outlets This element does not apply to the project. No storm drainage channels or ditches are proposed to be constructed either temporarily or permanently. Runoff from the developed site conditions will flow to the underground detention facility. Element #9: Control Pollutants This element applies to the project. Any and all pollutants, chemicals, liquid products, and other material materials that have the potential to pose a threat to human health or the environment will be covered, contained, or protected from vandalism. All such products will be kept in a secured location onsite. Concrete handling shall follow BMP C151. BMPs Implemented: C151 Concrete Handling C152 Sawcutting and Surfacing Pollution Prevention C153 Material Delivery, Storage and Containment. Element #10: Control De-Watering This element does not apply to the project. No dewatering of the site is anticipated as groundwater was not encountered in any geotechnical boring to depths of 16 ft below ground surface. Element #11: Maintain BMPs This element applies to the project. BMPs shall be inspected and maintained during construction and repaired as needed. Remove temporary BMPs within 30 days after City inspector or Engineer determines that the site is stabilized and that BMPs are no longer needed. SWPPP ÏShops @ Aurora Village Page 4 of 5 Edmonds, WA Element #12: Manage the Project This element applies to the project. This SWPPP shall be implemented at all times. BMPs will be implemented in the following sequence. Phase I 1.Conduct pre-construction meeting with city engineering division. 2.Mark clearing and grading limits 3.Install silt fence for sediment and perimeter control 4.Install catch basin protection 5.Establish temporary parking and staging areas 6.Begin grading, clearing, grubbing, and removal activities as needed to accommodate project improvements. 7.Start construction of building pad, structures, and site improvements. Phase II 1.Temporarily stabilize all denuded areas that will be inactive for more than 7 days during dry season (May 1 Ï Sept. 30) and more than 2 days during wet season (Oct 1 Ï April 30). Temporary stabilize soils at the end of the shift before holiday or weekends, if needed based on weather forecast. 2.Install utilities, storm system, curbs and gutters. 3.Permanently stabilize areas to be vegetated as they are brought to final grade. 4.Prepare site for paving. 5.Complete final grading and installation of permanent stabilization over all areas 6.Contact city engineering division for approval of permanent erosion protection and site grades 7.Remove erosion control methods as permitted by the city engineering division and repair permanent erosion protection as necessary. 8.Monitor and maintain permanent erosion protection until fully established. Element #13: Protect LID BMPs This element does not apply to the project. Infiltration facilities and permeable pavement are not included with the project. Stormwater runoff will be managed with a stormwater filter manhole and underground detention facility. Contractor to install stormfilters in manhole only after site is permanently stabilized and ready for operations. SWPPP ÏShops @ Aurora Village Page 5 of 5 Edmonds, WA