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21310 HIGHWAY 99 (2).PDFiiiiiiii lill 11 14073 21310 HWY 99 E TAX ACCOUNT/PARCELNUMBER: BUILDING PERMIT (NEW STRUCTURE) - COVENANTS (RECORDED) FOR: CRITICAL AREAS: DISCRETIONARY PERMIT //'S: DRAINAGE PLAN DATED: PARKING AGREEMENTS DATED: EASEMENT(S) RECORDED FOR: — PERMITS PLANNING DATA CHECKLIST DA SCALED PLOT PLAN DATED: SEWER LID FEE S: SHORT PLAT FILE: SIDE SEWER AS BUILT DATED: SIDE SEWER PERMIT(S),fi: GEOTECB REPORT DATED: 7 STREET USE / ENCROACHMENT PERMIT #: WATER METER TAP CARD DATED: OTHER: kJ DETERMINATION: E] Conditional Waiver E] Study Required [] Waiver LID #: LOT: BLOCK: LATEMP\DSrs\Fonns\Street File Checklist.doc ;1 0 0 Parcel No: 00580700000605 PROPERTYONVNER CONTR�kCTOR MAGIC TOYOTA DAVIS HARDGRAVE FOUSHEE & ASSOCIATES CO INC 21300 HIGHWAY 99 130 LAKESIDE SUITE 250 PO BOX 3767 EDMONDS, WA 98026 SEATTLE, WA 98122 BELLEVUE, WA 98009 42 5-77 5-4422 206-325-2553 425-746-1000 LICENSE #: FOUSHACI 580D EXP:8/12/2007 JOB DESCRIPTION CONSTRUCT NEW TWO STORYENCL)OSED PARKfNGGARAGE USED FOR NVENTORYSTORAGEOF VEHICLES FORA CAR DEALERSHIP. THIS IS PHASE I OF A TWO-PHASE DEVELOPMENT. PARKING GARAGE IS 34,970 SF PER FLOOR, TOTAL FL)DOR AREA 69,9940 SF. VALUATION: $3,636,880 PERMIT TYPE: Commercial PERMIT GROUP: 33 - Garage GRADING: N CYDS: 5530 TYPE OF CONSTRUCTION: IIB RETAININGWALL ROCKERY: N OCCUPANT GROUP: S2 OCCUPANT LOAD: 350 FENCE: N ( 0 X 0 FT.) CODE: 2006 OTHER: N ------- OTHER DESC: ONE: CG 2 INUMBER OF STORIES: 0 VESTED DATE: INUMBER OF DWELLING UNIT S: 0 EX I S TIN G A 11 LA BASEMENT: 0 1 ST FLOOR: 0 2ND FLOOR: 0 PRO 110 SED ARFA BASEMENT: 0 1 ST FLOOR: 34970 2ND FLOOR: 134970 3 RD FLOOR: 0 GARAGE: 0 DECK: 0 OTHER: 0 13RD FLOOR: 0 GARAGE: 0 DECK: 0 OTHER: 0 FRONTSLTBACK SIDESErBACK REARSETBACK REQUIRED: NORTH (212TH): 4' REQUIRED: WEST: 0 PROPOSED: 0 REQUIRED: EAST (HWY 99):4'LANDSCAPED PROPOSED: 300+ PROPOSED: I I HEIGHT ALLOWED:75 PROPOSED:O REQUIRED: SOUTHINE: 0 PROPOSED: 2 SETBACK NOTES: T I AGREE T?�OVPLY WITH CITY AND STATE LAWS REGULATING CONSTRUCTION AND IN DOINGTHE WORK AUTHORIZED '�E 2RE P�MN W I L L BE EM P LOYED IN VIOLAT ION OF T HE LABOR CODE OF T H E ST AT E OF WASHI NGT ON RELAT I NG T 0 WORKMEN'S COMPENSATION INSURANCE AND RCW 18:27. P� p py A THIS A WON IS NOT A PERMIT UNTIL SI.GNED BY THE BUILWN OFFICIAL OR HIS(HER DEPUTY AND ALL FEES ARE PAID. Zd ,,'I'Signat Print Name Releafed Bf Date uv ATTENTION ITIS UNLAWFUL TO USE OR OCCUPY A BUILDING OR STRUCTURE UNTIL A FINAL INSPECTION HAS BEEN MADE AND APPROVAL ORA CERTIFICATE OF OCCUPANCY HAS BEEN GRANTED. UBC[09/ IBCI 10/ IRCI 10. ARCHIVE APPUCANT Lr SESSOR OTHER 0 0 STATMISSUED BLD20070789i CONDiTIONS PURSUANT TO ADB-2007-63: — An itemized landscaping cost estimate wdl be required prior to planning final inspection in order to determine the cost of the landscaping bond(s), pursuant to ECDC 20.13.010. — The landscaping plan shall indicate one of the specific street trees intended for Highway 99, pursuant to the Edmonds Streetscape, Plan (either Acer rubrum"Amistrong" / Armstrong Maple, Acer platanoides "Columnare" / Columnar Norway Maple, orNyssa sylvatica / Tupelo). — With Phase 11 of development, the Applicant shall demonstrate how the project meets the required parking for the entire site, pursuant to BCDC 17.50.020.B. — With Phase 11 of development, the Applicant shall demonstrate how the project meets the required parking lot landscaping for the entire she, pursuant to ECDC 20.13. — Design review is administratively approved with the above conditions for the "Phase I" parking structure and southerly development only. A future "Phase 11" proposal on the northerly portion of the site would require both budding permit review and design review of the proposed newbudding(s). • Seperate Permits and Deferred Submittals: 1) Mechancial 2) Plumbing 3) Electrical (power/lighting plans, and Lighting Sumniary form) 4) Fire Sprinkler 5) Fire A larm 6) Fire Connection 7) Water Meter 8) Side Sewer 9) Shop Drawings 10) Evacuation/1.1fe-safety Plan 11) Maintenance Bonds • REQUIRED SPECIAL INSPECTIONS FOR THIS PROJECT: 1) E�cavation, grading, & site preparation 2) Soil bearing verification 3) Placement of fill & compaction 4) Foundation/Retaining Wall Drainage 5) Concrete Construction 6) Steel Construction 7) Final letter from each Special Inspection Agency CONDITION OF APPROVAL FOR ACCESSIBLE PARKING. The number of required accessible parking stalls for issuance of this Phase I pennit is based on 31 surface parking spaces (2 access ible parking spaces are required). The total number of access ible parking stalls required for the entire s Re (including e)dsting) will be based on the total number of required parking stalls per ECDC 17.50, and must be provided with Phas e 11 of the development. Lot line stakes must be in place at the time of foundation/setback inspection. All new, eAended, re -built or relocated electrical utility and/or service shall be placed underground. Special inspections have been called for on this project and are noted on the approved construction plans and building permit. It is the owner and/or contractors responsibifity to assure that reports are provided to the City on a weekly basis. Be advised — if special inspection reports are not forthcoming, the Budding Official may issue a "Stop Work" and no City inspections Will be provided until such time as the reporting agency has coniplied and reports are reviewed and approved by the City. Obtain Electrical Permit fromState Department,of Labor & Industries. 425-290-1309 Final approval on a project or final occupancy approval must be granted by the Building Official prior to use oroccupancy of the building or structure. Check thejob card for all required City inspections including final project approval and final occupancy inspections. Any request for alternate design, modification, variance or other administrative deviation (hereinafter "variance") from adopted codes, ordinances or policies must be specifically requested in writing and be called out and identified. Processing fees for such request shall be established by Council and shall be paid upon subrnittal and are non-refundable. Approval of any plat or plan containing provisions which do not comply with city code and for which a variance has not been specifically identified, requested and considered by the appropriate city official in accordance with the appropriate provision of city code or state law does not approve any items not to code specification. • Sound/No is e originating from temporary constructions Res as a result of construction activity are exempt from the noise lirnits of ECC Chapter 5.30 only during the hours of 7:00am to 6:00pm on weekdays and 10:00am and 6-.00pm on Saturdays' e2cluding Sundays and Federal Holidays. At all other* times the noise originating firom construction sites/activites must co�� with the noise limits of Chapter 5.30, unless a variance has been granted pursuant to ECC 5.30.120. • Final Locations of iflunfmated e)dt signs & emergency lighting subject to field inspection by the Fire Marshal. I INSPECTIONS THIS PERMIT AUTHORIZES ONLY THE WORK NOTED. THIS PERMIT COVERS WORK TO BE DONE ON PRIVATE PROPERTY ONLY. ANY CONSTRUCTION ON THE PUBLIC DOMAIN (CURBS, SIDEWALKS, DRIVEWAYS, MARQUEES. ETC.) WILL REQUIRE SEPARATE PERMISSION. PERMIT TIME LIMIT: SEE ECDC 19.00.005(A)(6) 131["ING (425) 771-0220 EXT. 1333 1 ENGI[NEUMG (425) 771-0220 EXT. 1326 1 FIRE (425) 771-0215 I PUBUC WOM<S (425) 771-0235 1 PRFTREATNIFNT (425) 672-5755 1 RECYCLING (425) 275-480 1 1 When calling for an inspection please leave the folloyAng information: Permit Number, Job Site Address, Type of Inspection being requested, Contact Name and Phone Number, Date Prefereed, and whether you prefer morning or afternoon. E-Pre-Con &Erosion Control/Mobilization ETraffic Control E-StormTightline FSton-n Connect to Stub E,Storm Detention System E-Footing Drain TL Conveyance &Sewer MH Install on City Main &Sewer MH Channeling E-Sewer Lateral/Main Inspection &Sewer Lateral/Main Pressure Test E,Pre-Water Main Connect, Trench E-Pre-Water Main Con, Valve Cluster FWater Main Connection E-Water Service Purity, >21. &Water Service to Meter,2" or less &Water Service Line E-Double Check Detector Assem Vault F,RPBA with HotBox FFire Hydrant Install/Thrust Block. E-Fire Hydrant Flush &Curb/Gutter Form (comm/multi) E-Sidewalk Form (comm/multi) &Access Slope & Width Verification &Pavement Compaction Test Report &Pavement Striping B-Retaining Wall Forms/Location ERetaining Wall Drainage B-Fire/Aid Address Sign E-Trash Enclosure E-Cross Connection Final E,Fngineering Final B-Setbacks B-Footings B-Foundation Wall B-Isolated Footings/Piers B-Equipment-Mech B-Height Verification B-Framing B-Building Final F-Exinguishers F-Fire Dept Inspection F-Addressing Visibility F-Fire Final P-Planning Final 0 0 CITY OF EDMONDS TRAFFIC IMPACT ANALYSIS WORK SHEET Name of Proposed Project: Magic Toyota Owner/Apolicant: David Broadus Name 21300 Highway 99 Street/Mailing Address Edmonds, WA 98026 City State Telephone: 425-775-4422 Zip Applicant Contact Person: Lance Mueller & Assoc./Arch. Name 130 Lakeside, Suite 250 Street/Mailing Address Seattle, WA 98122 city State Zip Telephone: 206-325-3553 Trafflc Engineer who prepared the Traffic Impact Analysis: TENW Curtis Chin Firm Name Contact Name 206-714-7421 Telephone 1. PROJECT DESCRIPTION R E SUB a. Street address (if known): 21300 Highway 99 OCT 112007 — BU11 n'N"� nEPARFMENT. CrTy OF-IfDi�6NDS b. Location: West side of Highway 99, south of 212th Street SW (see attached vicinity map and site plan) (Attach a vicinity map and siteplan.) c. Specify existing land use: Auto Dealership d. Specify proposed type and size of development: Addition of a two tier, 70,000 sq. ft. parking structure e. When will the project begin construction and when will it be f Define proposed access locations: n.a. - no new ac g. Define propo sed sight distance at site egress locations: a proposed s tar sed r,-.*C:r I ess locations Page 1- --`-��ET AIL�E� 2. TRIP GENERATION a. Existing Site Trip Generation Table: Land Use Daily (ADT) PM Peak -Hour Trips IN OUT b. Proposed Project Trip Generation Table: Land Use Daily (ADT) PM Peak -Hour Trips IN OUT 70,000 sq. ft. No New Daily Trips No New PM No New PM Parking structure Expected Peak Hour Peak Hour Trips Trips Expected Expected c. Net New Pro ect Trip Generation Table: j Land Use Daily (ADT) PM Peak -Hour Trips IN OUT 70,000 sq. ft. No Net New Daily No Net New No Net New Parking structure Trips Expected PM Peak PM Peak Hour Trips Hour Trips Expected Expected d. State assumptions and methodology for internal, link -diverted or passby trips: No internal, link -diverted or passby trips assumed. Page 2 0 3. TRIP DISTRIgUTION n. a. Prepare and attach a graphic showing project trip distributioft percentages and assignments. 4. 81TE ACCESS ROAD WAY/DRIVEWAYS AND SAFETY n. a. a. Have sight distance requirements at egress location been met per AASHTO requirements? b. Intersection Level of Service Analysis:, • Existing Conditions LOS Delays • Year of Opening LOS Delays • Five Years Beyond Change of Land Use LOS I Delays (Intersections to be evaluated shall be determined by the City of Edmonds Traffic Engineer.) c. Describe channelization warrants: d. Vehicle Storage/Queuing Analysis (calculate 50% and 95 % queuing lengths): 50% • Existing Conditions • Year of Opening Five Years Beyond Change of Land Use e. If appropriate, state stop sign and signal warrants: f Summarize local accident history: (Attach stripingplan.) 95% Page 3 5. TRAFFIC VOLUMES n - a. a. Describe existing ADT and peak -hour counts, including turning movements, on street adjacent to and directly impacted by the project. b. Describe the estimated ADT and peak -hour counts, including turning movements, the year the project is fully open (with and without project traffic). c. Describe the estimated ADT and peak -hour counts, including turning movements, five years after the project has been fully open (with and -,irithout project traffic). d. State annual background traffic growth factor and source: 6. LEVEL OF SERVICE ANALYSIS n. a. Summarize Level of Service Analysis below and attach supporting LOS analysis documentation. Provide the following documentation for each arterial street or arterial intersection impacted by ten or more peak - hour trips. Other City -planned developments must also be factored into the LOS calculations. Existing LOS: Existing Condition: Year of Opening LOS: With Project: Without Project: Page 4 E Five Years After Ovenine LOS: With Project: Without Project: Note any assumptions/variations to standard analysis default values and justifications: 7. MITIGATION RECOMMENDATIONS State recommended measures and fees required to mitigate project specific traffic impacts. Traffic impact fee shall be calculated from the Edmonds Road Impact Fee Rate Study Table 4 (attached) and as identified in ECDC 18.82.120, except as otherwise provided for independent fee calculations in ECDC 18.82.130. The proposed parking structure is not expected to generate any new trips or create any additional demand on the roadway system. There ore, no mitigation or traffic impact fees are proposed by the applicant. - SIENGRWmelACity PmjectsXTIA Gtdde1ines%TmflnVAndyWoTk 9-04.doc Page 5 Transportation Magic Toyota - Phase I Engineering Project Vicinity NorthWest I I Edmonds, WA EOTECHNICAL ENGINEERING SERVICES MAGIC TOYOTA 21300 AND 21400 HIGHWAY 99 EDMONDS, WASHINGTON JULY 14, 2006 FOR MAGIC TOYOTA zz-z File No. 11805-001-02 I I I I I I H 'I I I I I I Geotechnical Engineering Services Magic Toyota 21300 and 21400 Highway 99 Edmonds, Washington File No. 11805-001-02 Prepared For: Magic Toyota c/o Carletti Architects, P.S. 1404 East College Way, Suite 103 Mount Vernon, Washington 98273 Attention: Peter Carletti Prepared by: GeoEngineers, Inc. - 2924 Colby Avenue Everett, Washington 98201 (425) 252-4565 July 14, 2006 I fzXPIRES 7/23/n—I -- Debra C. Overbay, PE Senior Geotechnical Engineer -� �-OhAa- &WA&4r-1 ** � &-A v, / J. Robert Gordon, PE Principal JRG:DCO:ta EVERM 1\1 1805001\02\Finals\l 180500102R.doc Two copies submitted Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. CopyrightC 2006 by GeoEngineers, Inc. All rights reserved. IFile No. 11805-001-02 I � I TABLE OF CONTENTS IPage No. IINTRODUCTION AND PROJECT UNDERSTANDING ................................................................................ 1 GEOLOGY..................................................................................................................................................... 1 SITECONDITIONS ....................................................................................................................................... 2 SURFACE CONDITIONS .................................................................................................................... 2 SUBSURFACE CONDITIONS ............................................................................................................ 2 SoilConditions ........................................................................................................................... 2 Groundwater Conditions ............................................................................................................ 2 CONCLUSIONS AND RECOMMENDATIONS ............................................................................................. 3 SUMMARY OF KEY GEOTECHNICAL ISSUES ................................................................................ 3 SEISMIC DESIGN CONSIDERATIONS ............................................................................................. 4 Seismicity................................................................................................................................... 4 SeismicZone ............................... ........ r ...................................................................................... 4 LiquefactionPotential ................................................................................................................. 4 OtherConsiderations ................................................................................................................. 5 SHALLOW FOUNDATIONS ................................................................................................................ 5 FLOOR SLAB SUPPORT .................................................................................................................... 5 LATERAL RESISTANCE ..................................................................................................................... 5 RETAINING WALLS ............................................................................................................................ 6 PAVEMENT RECOMMENDATIONS .................................................................................................. 6 EARTHWORK..................................................................................................................................... 7 SitePreparation ......................................................................................................................... 7 StructuralFill .............................................................................................................................. 7 PermanentSlopes ..................................................................................................................... 8 Erosion and Sedimentation Control ................ .......................................................................... 8 DRAINAGE CONSIDERATIONS ........................................................................................................ 8 LIMITATIONS................................................................................................................................................ 9 I d I List of Figures Figure 1. Vicinity Map Figure 2. Site Plan File No. 11805-001-02 Page i GWENGINEER��r Aly 14, 2006 TABLE OF CONTENTS (CONTINUED) APPENDICES Appendix A — Field Explorations and Laboratory and Testing ....................... Appendix A Figures Figure A-1 — Key to Exploration Logs Figures A-2 ... A-5 — Logs of Borings Figure A-6 — Atterberg Limits Test Results Page No. ............... A-1 Appendix B — Report Limitations and. Guidelines for Use ............................................... B-1 ... B-3 AppendixC — Rockeries .................................................................................................. C-1 ... C-2 File No. 11805-001-02 Page U GEoENG1NEERir,,:) July 14, 2006 I I GEOTECHNICAL ENGINEERING SERVICES MAGIC TOYOTA 21300 AND 21400 HIGHWAY 99 EDMONDS, WASHINGTON IINTRODUCTION AND PROJECT UNDERSTANDING This report presents the results of our design geotechnical engineering services for the new building and site improvements at Magic Toyota located at 21300 and 21400 Highway 99 in Edmonds, Washington. The property is located on the south side of 212'h Street Southwest and the along the west side of Highway 99. A vicinity map of the site location is provided as Figure 1. The site 'includes two parcels; the northern parcel is currently developed with the existing dealership and adjacent gravel parking lot, and the southern parcel is a former contractor's site containing a small one-story office building, garage, carport, and yard area. GeoEngineers completed a Phase I ESA for the southern parcel as surnmarized in our report dated January 17, 2006. We understand that the new building will be constructed on the upper, northern lot area, and a parking lot will be located on the southern portion. We anticipate building and floor loads will be typical of facilities of this type with floor loads in the range of 150 to 200 pounds per square foot and column loads in the range of 50 to 100 kips. The purpose of our geotechnical engineering services is to provide recommendations for site preparation and earthwork, pavement design, foundation design, and construction considerations. Our services included drilling four hollow -stem auger borings, coordination with Magic Toyota and subcontractors, completing laboratory testing on samples obtained from the borings, engineering analyses and preparation of a design geotechnical engineering report. G EOLOGY The Puget Sound basin is a region of Quaternary (last 3 million years) sediments that range in thickness between 800 and 2,400 feet. The basin area has been repeatedly overridden by Pleistocene (between 11,000 and 3 million years ago) continental glacial ice depositing till, glacial sand and gravel. As the glacial ice retreated to the north, glaciofluvial sediment was deposited in the outwash channels. The most recent glacial cycle of sediment deposits is referred to as the Vashon Drift, occurring between 13,500 and 15,000 years ago. We reviewed a U.S. Geologic (USGS) map for the project area, "Preliminary Surficial Geological Map of the Edmonds East and Edmonds West Quadrangles, Snohomish and King Counties, Washington" by Mackey Smith (1975). Surficial geologic deposits in the site vicinity are mapped as recessional outwash, glacial till, and advance outwash. Recessional outwash typically consists of sand and gravel with varying amounts of silt that was deposited by meltwater from the stagnating and receding glacier. These soils are typically medium dense. Glacial till is a heterogeneous mixture of sand, gravel, cobbles and occasional boulders in a silt and clay matrix that was.deposited beneath a glacier. Advance outwash typically consists of well -stratified sand with variable amounts of gravel and cobbles. The advance outwash is usually exposed where the overlying glacial till cap has been eroded away, typically in ravines and bluff margins. Both the glacial till and advance outwash have been overridden by thousands of feet of ice, and are typically dense to very dense. The Whidbey Formation underlies the advance outwash and typically consists of dense sands and gravels overlying or interbedded with stiff to hard silts. File No. 11805-001-02 Page I GWENGINEER�.�/_ July 14, 2006 A zone of weathered till typically overlies the dense glacial till to depths of 3 to 6 feet. This weathered zone is somewhat drained, whereas the unweathered till is a barrier to vertical drainage. Water percolating into the weathered till will usually pond and migrate laterally between the weathered and unweathered layers. With the exception of the surficial fill, subsurface soils encountered in our borings are similar to descriptions in the geologic map. Detailed descriptions are provided in the following section. SITE CONDITIONS SURFACE CONDITIONS The site extends approximately 600 feet in the north -south direction and varies from approximately 180 to 375 feet in the east -west direction. Existing structures on the site include the existing dealership located in the north -central area, and an existing house, shop, and sheds in the south construction yard area. Asphalt pavement surrounds the north, west, and east sides of the dealership. A gravel surface parking lot was constructed south of the dealership by placing up to 10 to 12 feet of fill north of the existing construction yard. The fill slope is inclined at approximately 30 to 50 percent and is surfaced with landscape bark. Vegetation within the south construction yard consists primarily of short grass. Existing ground surface elevations range from approximately Elevation 354 to 356 feet in the lower construction yard, to Elevation 388 feet at the north border of the site near 212'h Street SW. Existing site features are shown in the Site Plan, Figure 2. SUBSURFACE CONDITIONS Soil Conditions Subsurface soil and groundwater conditions were evaluated by drilling four borings at the approximate locations shown in Figure 2. Descriptions of the field exploration and laboratory testing procedures and exploration logs are presented in Appendix A. Boring B- I was located in the asphalt pavement on the northwest side of the existing dealership building. The pavement section encountered in boring B-1 consists of 2 inches of asphalt concrete overlying 2 inches of crushed rock base course. Very dense silty sand with gravel (glacial till) underlies the pavement section. Borings B-2 and B-3 were located in the gravel surface parking area south of the dealership. These borings encountered 2 to 3 inches of crushed rock surfacing overlying medium dense silty sand with gravel fill. The fill extends to a depth of approximately 7 to 12 feet and is underlain by glacial till. Hard silt of the Whidbey Formation was encountered beneath the till in both borings at an elevation of approximately 346 feet (20 to 24 feet below existing ground surface). Boring B4 was located in the south construction yard and encountered 10 feet of loose to medium dense fill overlying the hard silt (also encountered at approximately Elevation 346 feet). We understand that the fill was placed in this area following excavation of a former underground storage tank. Groundwater Conditions Groundwater was encountered during drilling at a depth of 17 feet (approximate Elevation 349.5 to 353) in the two borings completed within the gravel surface parking lot (borings B-2 and B-3). Groundwater was not encountered in boring B-1, and was encountered at a depth of 5 feet in boring B-4 (approximately File No. 11805-001-02 Page 2 GMENGINEER�.�r Ady 14, 2006 I Elevation 351 feet). We anticipate that the groundwater is perched on the very dense glacial deposits and will fluctuate as a function of precipitation and other factors. CONCLUSIONS AND RECOMMENDATIONS SUMMARY OF KEY GEOTECHNICAL ISSUES We conclude that the site is suitable for construction of the proposed building provided the reconu-nendations presented herein are followed. Subsurface soils generally consist of loose to medium dense fill overlying medium dense to very dense glacial deposits. Fill was not encountered on the northwest side of the dealership where very dense glacial till is present beneath the pavement section. Groundwater was encountered below an elevation of 353 feet in our borings. The following is a summary of the key geotechnical issues related to site development. Design level recommendations for each of these items, as well as other important geotechnical recommendations for the proposed project, are contained in subsequent sections of this report. The entire Conclusions and Recommendations section should be reviewed to obtain pertinent geotechnical recommendations. 0 We recommend Site Class D in accordance with lBC 2003 be utilized for seismic design. Based on the depth to groundwater encountered in our borings and the consistency of the underlying glacial deposits, there is low risk of liquef�ction at the site. Shallow foundations are suitable for support of the new building. Building footings may be supported on dense native soils or on a minimum 2-foot thickness of structural fill compacted as recommended in this report. Footings supported as recommended above can be designed for an allowable soil bearing pressure of 3,000 psf (pounds per square foot) for dead plus long-term live loads. 0 We recommend slabs -on -grade be supported on a 4-inch-thick granular subbase overlying either the dense native soils or a minimum 18-inch thickness of compacted structural fill. The subbase should consist of clean 3/4-inch minus crushed rock to perform as a capillary break. 0 Lateral loads may be resisted by friction on the base of footings and the floor slab and passive resistance on the sides of the footings. Detailed recommendations for lateral resistance are provided in a following section. 0 We understand that a parking area will be constructed in the south lot area (former construction yard area). Several feet of new fill will be required to raise grade in this area. We recommend that the sod and topsoil layer be stripped and removed prior to placing new fill. 0 Several areas of demolition and removal of subsurface facilities will be required at the site. Following stripping and demolition, the existing subgrade should be compacted to 95 percent of the MDD (maximum dry density). All new fill placed within the building footprint should be compacted to a minimum of 95 percent of the MDD in accordance with ASTMD-1557. New fill placed beneath pavement areas should be compacted to a minimum of 95 percent of the NMD within the upper 2 feet, and to a minimum of 90 percent below 2 feet. 0 We recommend a granular subbase underlie new pavement sections. The subbase should consist of a minimum of 8 inches of sand and gravel containing less than 5 percent passing the U.S. No. 200 sieve. We recommend a minimum pavement section of 3 inches of asphalt concrete overlying 4 inches of crushed surfacing base course in heavy traffic areas. The thickness of the asphalt concrete may be reduced to 2 inches in light service or automobile parking areas. File No.] 1805-001-02 Page 3 GWENGINEER��r Ady 14, 2006 I ISEISmic DESIGN CONSIDERATIONS 11 I I I I I .1 Seismicity The site is located within the Puget Sound region, which is seismically active. Seismicity in this region is attributed primarily to the interaction between the Pacific, Juan de Fuca and North American plates. The Juan de Fuca plate is subducting beneath the North American plate. It is thought that the resulting deformation and breakup of the Juan de Fuca platemight account for the deep focus earthquakes in the region. Hundreds of earthquakes have been recorded in the Puget Sound area. In recent history, four of these earthquakes were large events: (1) in 1946, a Richter magnitude 7.2 earthquake occurred in the Vancouver Island, British Columbia area; (2) in 1949, a Richter magnitude 7.1 earthquake occurred in the Olympia area; (3) in 1965, a Richter magnitude 6.5 earthquake occurred between Seattle and Tacoma; and (4) recently in 2001, a Richter magnitude 6.8 occurred near Olympia. Research is presently underway regarding historical large magnitude subduction-related earthquake activity along the Washington and Oregon coasts. Geologists are reporting evidence that suggests several large magnitude earthquakes (Richter magnitude 8 to 9) have occurred in the last 1,500 years, the most recent of which occurred about 300 years ago. No earthquakes of this magnitude have been documented during the recorded history of the Pacific Northwest. Local design practice in Puget Sound and local building codes are beginning to consider the possible effect of a very large subduction. earthquake in the design of structures. Seismic Zone We understand that the project will be designed utilizing 2003 IBC. We recommend the project site be classified as Site Class D as defined in the IBC. The parameters for the 2003 IBC are summarized in the following table: Spectral Response Accelerations *, Note: 1) Soil Profile Type Description: Stiff Soil Proflle Liquefaction Potential Liquefaction refers to a condition where vibration or shaking of the ground, usually from earthquake forces, results in the development of excess pore pressures in saturated soils and subsequent loss of strength. This can result in vertical oscillations and/or lateral spreading of the affected soils with accompanying surface subsidence and/or heaving. In general, soils, which are susceptible to liquefaction, include loose to medium dense clean to silty sands which are saturated (i.e., below the water table). Based on the groundwater table and soil consistency encountered in our borings, the risk of liquefaction at the site is low. File No. / 1805-001-02 Page 4 GEoENG1NEERir,./) Ady 14, 2006 I Other Considerations We strongly recommend that all connections to the building be flexible to allow differential movements to occur between the building and the adjacent ground during and after an earthquake. In particular, it is important that gas, sewer and water lines be fitted with flexible connections at the building. We also recommend that automatic shut-off values, triggered by seismic accelerations, be installed in gas and water lines leading to the building. SHALLow FOUNDATIONS Shallow footings may be founded on dense native soils or on a minimum 2-foot thickness of structural fill compacted as recommended in the Earthwork section of this report. Footings supported as recommended above can be designed using an allowable soil bearing value of 3,000 psf. All column and continuous footings should have minimum widths of 3 feet and 1-1/2 feet, respectively. The footings should be founded at least 18 inches below the lowest adjacent grade for frost protection. We estimate that the settlement of continuous strip and isolated column footings will be on the order of 1/4 to 1/2 inch, depending on the loading conditions. Differential settlements should not exceed about 1/2 inch in about 40 to 50 feet. These settlements should occur rapidly after applying load to the footings due to the granular nature of the bearing soils. We estimate differential settlement between comparably loaded footings founded on similar soil will be on the order of one-half the total settlement. Additional differential settlement may occur between footings supporting different loads or between footings underlain by different subgrade soils. The allowable bearing values presented above apply to the total of dead and long-term live loads exclusive of the weight of the footing and any overlying backfill. An increase in these values of one-third may be used when considering wind or seismic loading. FLOOR SLAB SUPPORT All slab subgrade areas should be stripped and proofrolled or otherwise evaluated as recommended in Site Preparation before placing any fill. We recommend slabs -on -grade be supported on a 4-inch-thick granular subbase overlying either the dense native soils or compacted structural fill. The subbase should consist of clean 3/4-inch minus crushed rock to perform as a capillary break. If fill placement and slab construction will proceed during extended periods of dry weather, the import fill placed below the upper 4 inches of slab subgrade can contain an increased percentage of fines, provided the fill can be compacted as recommended in the Earthwork section of this report. If moisture sensitive floor coverings will be used, we also recomr nend a vapor barrier with bonded seams. LATERAL RESISTANCE The soil resistance available to resist lateral loads is a function of the frictional resistance which can develop on the base of footings and slabs, and the passive resistance which can develop on the face of below -grade elements of the structure as these elements tend to move into the soil. For footings and floor slabs founded on structural fill placed and compacted in accordance with our recommendations, the allowable frictional resistance can be computed using a coefficient of friction of 0.35 applied to vertical dead -load forces. The allowable passive resistance on the face of footings, grade beams or other embedded foundation elements can be computed using an equivalent fluid density of 300 pcf (triangular distribution) if all soil extending out from the face of the foundation element for a distance at least equal to two and one-half times the depth of the element consists of structural fill compacted to at File No.] 1805-001-02 Page 5 GMENGINEERir.P Ady 14, 2006 I I I I I I I I I I I I I I I least 95 percent of maximum dry density (ASTM D-1557). This value should be reduced to 250 pcf if the face of foundation elements are located within the existing loose fill soils. The above coefficient of friction and passive equivalent fluid density values include a factor of safety of about 1.5. RETAINING WALLS Conventional cast -in -place concrete retaining walls may be required to construct the receiving dock portion of the building, or in areas of grade transitions. Guidelines for rockery wall construction are provided in Appendix C. Lateral earth pressures for permanent retaining walls depend on the type of backfill material, ground water levels, compactive effort on backfill and amount of wall yielding. Additional lateral earth pressure due to seismic loading should also be included in the design. For walls that are free to yield at the top at least one one -thousandth of the height of the wall, soil pressures will be less than if movement is limited by such factors as wall stiffness or bracing. Assuming that the walls are backfilled and drainage is provided as outlined in the following paragraphs, we recommend that yielding walls supporting horizontal backfill be designed using an equivalent fluid density of 35 pcf (triangular distribution), while non -yielding walls supporting horizontal backfill be designed using an equivalent fluid density of 55 pcf (triangular distribution). We recommend a uniform seismic pressure of 8H be used in design of permanent walls. The earth pressure values presented above assume that hydrostatic pressure does not build up against the wall. For conventional retaining walls, we recommend that a minimum 24-inch-thick layer of rock or sand and gravel with less than 5 percent fines be placed behind the wall. This layer of rock or sand and gravel should extend from the base of the wall to within I foot of the finished ground surface; the upper I foot should consist of relatively impen-neable on -site native soil or pavement. Smooth -walled perforated drainpipe having a minimum diameter of 6 inches should be embedded within the zone of free -draining material at the base of the wall along its entire length. This drainpipe should discharge to a tightline collection system. We recommend fill against the wall be compacted to between 90 and 92 percent of maximum dry density determined in accordance with ASTM D-1557. Hand operated compactors should be used within a 5-foot zone behind the walls. Over -compaction near the. wall should be avoided to reduce lateral pressures against the back of the wall. PAVEMENT RECOMMENDATIONS Pavement subgrade areas should be stripped and proofrolled, or otherwise evaluated, as recommended in the Site Preparation section of the report. Assuming that proper site preparation is accomplished and a -relatively firm subgrade can be achieved, we recommend a minimum 8-inch-thick subbase layer be provided beneath the base course of the pavement section to enhance site drainage. The subbase should consist of free -draining sand and gravel with less than five percent fines (that portion passing the U.S. NO. 200 sieve). The subbase may not be necessary in the southern fill area depending on the gradation of the import material. We recommend the necessity for the pavement subbase be confirmed by the geotechnical engineer during construction. File No. 11805-001-02 Page 6 GWENGINEER��r July 14, 2006 I I I Recommendations pavement design sections are provided in the table below: Pavement Section Asphalt Surfacing Thickness (inches)' Crushed Rock Base Course (inches)2 Subbase Thickness (inches)2 Automobile Parking 2 4 8 Truck and Drive Aisles 3 4 8 1 Asphalt Surfacing should consist of !/�-inch HMA (PG 58-22) in accordance with WSDOT Sections 5-04 and 9-03. Crushed rock base course should meet WSDOT specification 9-03.9(3). We recommend the subbase consist of free -draining sand and gravel with less than five percent fines. The above pavement recommendations assume placement of structural fill as previously recommended and an R value of 45 (CBR of approximately 15). EARTHWORK Site Preparation We understand that approximately 8 to 10 feet of fill may be placed in the southern site area to raise grades to form the new south parking lot. Site development in this area will require removal of the existing shop and house, buried utilities and other potential subsurface facilities. Site preparation should also include stripping the sod and topsoil present in the south yard area and placing the stripped material in landscaping areas or removing it from the site. Based on our exploration and site observations, we expect that the depth of stripping will generally be less than 2 to 4 inches, and little to no stripping will be required in the central yard area where vehicle travel has occurred. The existing surficial soils consist primarily of silty sand and contain high fines (silt) content such that repeated construction traffic will result in considerable disturbance during wet weather construction. If wet weather construction occurs, it may be necessary to provide a layer of quarry spalls, crushed rock or pit run sand and gravel if the on -site soils become wet and begin to pump. We recommend that the exposed subgrade be proofrolled with heavy rubber -tired construction equipment if work is done during extended dry weather. Any soft, loose or otherwise unsuitable areas identified during proofrolling should be recompacted, if practical, or removed and replaced with structural fill as described subsequently. We recommend that proofrolling of the subgrade be observed by a representative from our firm to assess the adequacy of the subgrade conditions and to identify areas needing remedial work. If site preparation is performed during wet weather, stripping should be done using lightweight construction equipment. Trafficability at the site under wet conditions is expected to be difficult and could result in considerable disturbance to exposed subgrade areas if not done carefully. Structural Fill During dry weather, structural fill placed below the recommended pavement and slab subbase can contain an increased fines content, provided, that the minimum compaction cr iteria can be achieved. The maximum particle size for general site grading should be limited to about six inches. The pavement subbase and the upper four inches of building pad fill (capillary break material) should consist of a well -graded, free -draining sand and gravel free of organic matter and debris. The sand and gravel fill should contain less than five percent fines by weight relative to the fiaction passing the 3/4-inch sieve. File No. 11805-001-02 Page 7 GEoENG1NEERUrP July 14, 2006 I I I The maximum particle size should be limited to 1 V2 inches. We should be provided samples of the proposed capillary break material for evaluation prior to approving it as acceptable material. Structural fill should be placed in horizontal lifts which are 10 inches or less in loose thickness. Within the building footprint areas and within two feet of the finished subgrade surface for pavement areas, each lift should be uniformly compacted to at least 95 percent of the maximum dry density as determined in accordance with the ASTM D-1557 test method. For fill more than two feet below the finished pavement subgrade surface, the compaction criteria can be reduced to 90 percent of the maximum dry density (ASTM D-1557). The moisture content of the fill material may need to be adjusted to achieve the specified compaction. Structural fill placed on the existing slope should be 'keyed' into the slope by excavating a series of horizontal benches. The benches are typically cut into the slope gradient a minimum of 3 feet wide and structural fill is placed in horizontal lifts. We recommend that a representative from our staff be present at the site to observe and evaluate fill placement and compaction operations, and to complete a representative number of in -place density tests to determine if compaction criteria are being achieved. Permanent Slopes We recommend permanent slope inclinations no steeper than 2H: 1 V (horizontal to vertical) in medium dense to dense existing soils or in structural fill placed in accordance with our recommendations. Structural fill should meet the cr-iten*a described in the previous section, "Structural Fill." Fill should be carefully compacted on the slope face as described in the previous section. Erosion and Sedimentation Control The site soils have a moderate to high susceptibility to erosion when disturbed. Temporary erosion control measures should be used during construction depending on the water, location, soil type, and other factors. Surface water should be prevented from flowing across disturbed areas and not directed toward the slopes during construction. Temporary erosion protection (e.g., straw, plastic, or rolled erosion control products [RECPs]) may be necessary to reduce sediment transport until vegetation is established or permanent surfacing applied. Appropriate best management practices (BMPs) should be incorporated into the temporary erosion and sediment control plan by the civil engineer. We are available to provide input if desirable. DRAINAGE CONSIDERATIONS We recommend that pavement surfaces be sloped so that surface drainage flows away from the building. We recommend that all roof drainage be collected in tight lines for diversion into the storm drain system. Because of the potential for a perched groundwater condition to develop above the native glacial deposits, we recommend a perimeter footing drain be constructed around the new building. Grading in all areas should be accomplished to avoid concentration of runoff onto fill, cut slopes, natural slopes steeper than 10 percent or other erosion -sensitive areas. File No. 11805-001-02 Page 8 GMENGINEER��r July 14, 2006 I I I .1 I LIMITATIONS We have prepared this report for use by Magic Toyota for use in design and construction of the proposed addition at the existing dealership in Edmonds, Washington. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted geotechnical practices in this area at the time the report was prepared. No warranty or other conditions, express or implied, should be understood. Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Please refer to the appendix titled Report Limitations and Guidelines for Use for additional information pertaining to use of this report. We appreciate this opportunity to be of service to Magic Toyota and the design team on this project. Please call if you have any questions regarding this report or we can provide additional assistance. File No. 11805-001-02 Page 9 GMENGINEERi-rP July 14, 2006 f�-j T7 �193,d a isw 192nd PI S Park Way 19 PI W 91 : P jq �r 3: — SW 193rd PI 194th PI SW 19 h St SW& 193rd a- 194th St SW 19 th tsW < Wilc== P 196th St SW 198 St W 3: dz;: E b Q-7 Scriot"!'T'.ke x 1 IhS S1W -S st SW thsts Ff Z it 2 Ist St SW 2DOth St :2 < ynrwood P/ St 9 202nd P11 :2 nd S1 S Ist PI SW 203rd Sd P1 SW SIS 204th P11 �!—Sw 204h —M22 —SW St ;W rL CL th SW 4 n St C 12 Mth P1 77 2084 St 3W th PI SW dmonds L 5 2 2th SIT Hall a a 213th S1 5W 213th PI N 215th St SW" 1W 5 21 �th St W 3: CL 3: ?16th St SW 21 Ith St S ti rF < 21ft St W 1L- 3 > i 0) 110 3: cl. co 2294 st SW 3: 22nd 41 JW Z22M St -S-11 -R�! r r 224OWS 26th St::;;W CL, 3: < 'L E t, 28th St E th st, Nh St SW 230th�l SW 231stSISW hP 231LIS SW [ 14 jP, x 232nd P1 SW E 2.33rd,PI,SW. L5 th Sw LL kbdrona Ln 'Lake, ... I CD 7, C) I t Skagit Lr) Co Ln chf.. Jft� C14 M— Kwn C> C, Notes: 1. The locations of all features shown are appro)dmate. CL 2- This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master EL file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. 3. It is unlawful to copy or reproduce all or any part thereof, whether for personal use or resale, without permission. LLJ LLJ Data Sources: Interstates, state routes. and roads from TIGER 2000. hi County boundaries. cities, and waterbodies from Department of Ecology. Lamben Conformal Conic, Washington State Flane North, North American Datum 1983 St SW St 22 t St SW St St MO ritlak Te ce 22 St SW IV 24th- 1L S1214 J�2 Sth St S V 22ft Pr W 226th PI S Qaii!tp svv 3-- 28thjTsrj---- th St sw 7 SS :5 N W-*E 2,000 0 2,000 I - - - =9 Feet Vicinity Map Magic Toyota 21300 & 21400 Hwy 99 Edmonds, Washington GEoENGINEER ��r Figure I I GEoENGINEERS Lrad I I I I I APPENDIxA PELD ExpLoRA TION AND LABORATORY TEsTING I I I I F I I I I I F I I I I I I I H I I APPENDIX A FIELD EXPLORATION AND LABORATORY TESTING EXPLORATION PROGRAM Subsurface soil and groundwater conditions were evaluated by drilling four borings. The borings were completed to depths of 15.5 to 41.5 feet below the existing ground surface (bgs). The approximate locations of the explorations are shown in Figure 2. The borings were continuously monitored by a geotechnical engineer from our firm who examined and classified the soils encountered, obtained representative soil samples, observed groundwater conditions, and prepared a detailed log of each exploration. Soils were visually classified in general accordance with ASTM D 2488-90, which is described in Figure A-1. An explanation of our boring log symbols is also shown in Figure A-1. The samples were obtained using an SPT -sampler driven into the soil with a 140-pound harnmer free -falling 30 inches. The number of blows required to drive the sampler the last 12 inches or other indicated distances are recorded on the boring log. The logs of the borings are presented in Figures A-2 and A-5. The exploration logs are based on our interpretation of the field and laboratory data and indicate the various types of soils encountered. They also indicate the depths at which these soils or their characteristics change; although the change might actually be gradual. LABORATORY TESTING All soil samples were brought to our laboratory for further examination. Selected samples were tested to determine their moisture content, percent fines, and Atterberg limits characteristics. The results of the moisture content and percent fines tests are presented on the logs. The Atterberg limits test results are included as Figure A-6. File Mo. 11805-001-02 Page A-1 Ady 14,2006 GWENGMEER��r I SOIL CLASSIFICATION CHART ADDITIONAL MATERIAL SYMBOLS I I I I I I I I I I I I I I I I MAJOR DIVISIONS SYMBOLS TYPICAL DESCRIPTIONS GRAPH LETTER CLEAN F777 0& a GW wELL-GRADED GRAVELS. GRAVEL - SAND MIXTURES GRAVEL GRAVELS AND GRAVELLY SOILS CUTTLE OR NO FINES) DOOOOC 3 0 0 GP POORLY -GRADED GRAVELS. GRAVEL - SAND MIXTURES GRAVELS WITH FIN 4ES 0 0 GM S LTY GRAVELS GRAVEL - SAND - SILT MIXTURES' COARSE GRAINED SOILS MORE THAN SD% OF COARSE FRACTION Mo GC. CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES RETAINED ON NO. 4 SIEVE (APPRECIABLE AMOUNT OF FINES) CLEAN SANDS SW WELL -GRADED SANDS, GRAVELLY SANDS MOR THAN 50% RETAINED ON NO. 200 SIEVE SAND AND SANDY (LITTLE OR NO FINES) sp POORLY -GRADED SANDS. GRAVELLY SAND SOILS SANDS WITH FINES SM SILTY SANDS. SAND - SILT MIXTURES MORE THAN 50% OFCOAR SE FRACTION PASSING NO. 4 SIEVE (APPRECIABLE AMOUNT OF FINES) sc CLAYEY SANDS. SAND - CLAY MIXTURES INORGANIC SILTS, ROCK FLOUR ML CLAYEY SILTS WITH SLIGHT PLASTICITY FINE GRAINED SILTS AND LIQUID LIMIT LESS THAN 50 CLAYS CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY GRAVELLY CLA YS, SANDY CLAY'� SILTY CLAYS. LEAN CLAYS OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY SOILS MORE THAN 60% PASSING NO , 200 MH INORGANIC SILTS. MICACEOLIS OR DIATOMACEOUS SILTY SOILS SIEVE CH INORGANIC CLAYS OF HIGH PLASTICITY SILTS AND LIQUID LIMIT CLAYS GREATER !HAN 50 OH ORGANIC CLAYS AND SILTS OF MEDIUM TO HIGH PLASTICITY HIGHLY ORGANIC SOILS PT P 'AT, HUMUS, SWAMP SOILS WITH HFIGH ORGANIC CONTENTS NOTE: Multiple symbols are used to indicate borderline or dual soil classifications SairnDler Svmbol Descrit)tions 2.44nch I.D. split barrel Standard Penetration Test (SPT) Shelby tube Piston Direct -Push V\j Bulk or grab Blowcount is recorded for driven samplers as the number of blows required to advance sampler 12 inches (or distance noted). See exploration log for hammer weight and drop. A "P" indicates sampler pushed using the weight of the drill rig. SYMBOLS TYPICAL DESCRIPTIONS GRAPH LETTER CC Cement Concrete AC Asphalt Concrete CIR Crushed Rock/ Quarry Spalls TS Topsoil/ Forest Duff/Sod Measured groundwater level in _V1 exploration, well, or piezometer VGroundwater observed at time of exploration Perched water observed at time of exploration Measured free product in well or T piezometer Straticiranhic Contact Distinct contact between soil strata or geologic units Gradual change between soil strata or geologic units — — — — Approximate location of soil strata change within a geologic soil unit Laboratory / Field Tests %F Percent fines AL Afterberg limits CA Chemical analysis CP Laboratory compaction test CS Consolidation test DS Direct shear HA Hydrometer analysis Mc Moisture content MID Moisture content and dry density 0C Organic content PM Permeability or hydraulic conductivity Pp Pocket penetrometer SA Sieve analysis TX Triaxial compression UC Unconfined compression Vs Vane shear Sheen Classification ISIS No Visible Sheen ss Slight Sheen MS Moderate Sheen HS Heavy Sheen NT Not Tested NOTE: The reader must refer to the discussion in the report text and the logs of explorations for a proper understanding of subsurface conditions. Descriptions on the logs apply only at the specific exploration locations and at the time the explorations were made; they are not warranted to be representative of subsurface conditions at other locations or times. KEY TO EXPLORATION LOGS GMENGINEERS FIGURE A-1 L�� I I I I I I I I I I I I I I I I I I I Date(s) 03/15/06 Logged JH Checked By DCO Drilled By Drilling Boretec Drilling Hollow -stem Auger Sampling SPT Contractor Method Methods Auger 3.25-inch ID Hammer 140 lb hammer/30 in drop Drilling EC55 Volvo Data Data automatic Equipment Total Depth (ft) 15.4 Surface Elevation (ft) 385 Groundwater Elevation (ft) Not Encountered Vertical Daturn/ Easting(x): Datum System Northing(y): LOG OF BORING B-1 Project: Magic Toyota 0 ca GMENGINEER�� Project Location: Edmonds, Washington Figure A-2 Project Number: 11805-001-02 Sheet 1 of 1 Date(s) 03/15/06 Logged JH Checked By DCO Drilled By Drilling Contractor Boretec Drilling Method Hollow -stem Auger Sampling Methods SPT Auger 3.25-inch ID Hammer 140 lb hammer/30 in drop Drilling EC55 Volvo Data Data automatic Equipment Total 41.5 Surface 370 Groundwater 353 Depth (ft) I Elevation (ft) Elevation (R) Vertical Daturn/ Easting(x): Datum I System Northing(y): SAMPLES 0 �R > MATERIAL DESCRIPTION 0 (n OTHER TESTS = M - CD > '2 "�s E Z ca A? CU -J U 2 - 0 3 C !� AND NOTES CL 0 1 0 U) CL �6 E 1! CM C1. 2 E a) 00 D Cl) Fn C�n UO) 0 (3 -J 0 U) 370 6- CR -\3-inches crushed rock surfacing SM Gray silty fine to medium sand with gravel (dense, moist) (fill) 12 36 8 -365 5-1 5 21 2 Grades to loose to medium dense. 15 8 3 -360 10-1 18 18 4 25 SP-SM Gray fine to coarse sand with silt and gravel (dense, moist to wet) (glacial till) -355 15- 12 42 5 % F=14.5 13 SM Z' Gj7aTsili�-fin-e io- ;;�IjirFsZCN;i�tg��el Tdense, wet) -350 20 18 43 6 T.' ME Gray elastic silt (hard, moist) (VAidbey formation) W 0- 1 345 25 - 18 48 7 CL -340 301 S Notes: See Figure A- I for explanation of symbols. LOG OF BORING B-2 Project: Magic Toyota GEoENGINEER Project Location: Edmonds, Washington Figure A-3 Project Number: 11805-001-02 Sheet I of 2 I I .1 I I I I I I I F1 I I I I I I I 0. LOG OF BORING B-2 (continued) 0 Z 0: Project: Magic Toyota 0 Ca GEoENGINEER Project Location: Edmonds, Washington Figure A-3 I Project Number: 11805-001-02 Sheet 2 of 2 1� . I I I I I . I I I I I Date(s) 03/15/06 Logged JH Checked By DCO Drilled By Drilling Boretec Drilling Hollow -stem Auger Sampling SPT Contractor Method Methods Auger 3.25-inch ID Hammer 140 lb hammer/30 in drop Drilling EC55 Volvo Data Data automatic Equipment Total Depth (ft) 26.5 Surface Elevation (ft) 366 Groundwater Elevation (ft) 349.5 Vertical Daturn/ Easting(x): Datum System Northing(y): SAMPLES -6 E z > MATERIAL DESCRIPTION U) .0 OTHER TESTS > CL > 2 E z 0 _J .0 0 Mn 2 Z :!:: - AND NOTES 2! C' cx 2 S 2 C1 a) :3 E A —C C;) Lu Q) x 0 3-3 M U) U) M 0 J 2 0 U) 00 2 5 0 3: CR —\2-inches crushed rock surfacing —365 SM Brown gray silty fine to medium sand with gravel (medium dense, moist) (fill) 5 25 10 0 6 Grades to loose —360 2 SM Brown gray silty fine to medium sand with occasional 10 31 ITT 1, 1 gravel (dense, moist) (weathered glacial till) LOU OF ESORINU B-3 Project: Magic Toyota Project Location: Edmonds, Washington GWENGINEER��r Figure A-4 Project Number: 11805-001-02 Sheet 1 of 1 lo Date(,) 03/15/06 Logged JH Checked By DCO Drilled By Drilling Boretec Drilling Hollow -stem Auger Sampling SPT Contractor Method Methods Auger 3.25-inch ID Hammer 140 lb hammer/30 in drop Drilling EC55 Volvo Data Data automatic Equipment Total Depth (ft) 21.5 Surface Elevation (ft) 356 Groundwater Elevation (ft) 351 Vertical Daturn' Easting(x): Datum System Northing(y): SAMPLES C M E > MATERIAL DESCRIPTION Cc > a) CL 4) > U) z z 0 an W Q) 0 8 4) 3: 0 CL E CL E2 3 :3 E 2 >, .S of in- u) u) 3:1 (3 -1 0 u) E)--T SOD F\1 -inch grass/sod -355 SM Brown gray silty fine to medium sand (medium dc moist) (fill) 3. 330 a C 9 1 20 1 SP Gray fine to medium 5— 2 3 7 1 28 3 sm Gray silty fine to me( 0 dense, wet) (fill?) to _J§ 18 1 65 1 4 15—tV 181 37 1 ' 2')—tl 181 56 1 6 25� ML 30 —J Notes: See Figure A- I for explanation of symbols. OTHER TESTS AND NOTES C '15 8 27 wo LOG OF BORING B-4 Project: Magic Toyota GMENGINEER Project Location: Edmonds, Washington Figure A-5 Project Number: 11805-001-02 Sheet 1 of 1 11805-001-02 DCO : CTS : jvj 3-29-06 (Atterbergs.ppt) n PLASTICITYCHART m 0 60 m 50 m m CH or OH :0 x 40- tA UJI 11-100' Z 30 - OH or MH 20- CL c r > 10- .000 oe m CL-ML 1 '..'00, IVIL or OL ;a w 0-1/ m X 0 10 20 30 40 50 60 70 80 90 100 C) LIQUID LIMIT r- ic X —4 m CA > -4 m EXPLORATION SAMPLE MOISTURE LIQUID PLASTICITY SYMBOL NUMBER DEPTH CONTENT(%) LIMIT (%) INDEX(%) SOIL DESCRIPTION X m CA I= B-2 30.0' 26 52 22 Gray elastic silt (MH) Ca B-4 15.0' 27 62 31 Gray elastic silt (MH) I GEoENGINEERS I I I I H APPENDixB REPORT LimiTA TIONS AND GUIDELINES FOR USE I I I I I I I I I I I I .1 I I I I I I H I I APPENDIX B REPORT LIMITATIONS AND GUIDELINES FOR USE' This appendix provides information to help you manage your risks with respect to the use of this report. GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES, PERSONS AND PROJECTS This report has been prepared for the exclusive use of Magic Toyota, Carletti Architects and their authorized agents. This report is not intended for use by others, and the information contained herein is not applicable to other sites. GeoEngineers structures our services to meet the specific needs of our clients. For example, a geotechnical or geologic study conducted for a civil engineer or architect may not fulfill the needs of a construction contractor or even another civil engineer or architect that are involved in the same project. Because each geotechnical or. geologic study is unique, each geotechnical engineering or geologic report is unique, prepared solely for the specific client and project site. Our report is prepared for the exclusive use of our Client. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. This is to provide our firm with reasonable protection against open-ended liability claims by third parties with whom there would otherwise be no contractual limits to their actions. Within the limitations of scope, schedule and budget, our services have been executed in accordance with our Agreement with the Client and generally accepted geotechnical practices in this area at the time this report was prepared. This report should not be applied for any purpose or project except the one originally contemplated. A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT Is BASED ON A UNIQUE SET OF PROJECT-SPECIFIc FACTORS This report has been prepared for the proposed building addition to the existing Magic Toyota dealership located at 21300 Highway 99 in Edmonds, Washington. GeoEngineers considered a number of unique, project -specific factors when establishing the scope of services for this project and report. Unless GeoEngineers specifically indicates otherwise, do not rely on this report if it was: • not prepared for you, • not prepared for your project, • not prepared for the specific site explored, or • completed before important project changes were made. For example, changes that can affect the applicability of this report include those that affect: • the function of the proposed structure; • elevation, configuration, location, orientation or weight of the proposed structure; • composition of the design team; or • project ownership. Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org. File No. 11805-001-02 Page B-1 GWENGINEERir.) July 14, 2006 If important changes are made after the date of this report, GeoEngineers should be given the opportunity to review our interpretations and recommendations and provide written modifications or confirmation, as appropriate. SUBSURFACE CONDITIONS CAN CHANGE This geotechnical or geologic report is based on conditions that existed at the time the study was performed. The findings and conclusions of this report may be affected by the passage of time, by manmade events such as construction on or adjacent to the site, or by natural events such as floods, earthquakes, slope instability or groundwater fluctuations. Always contact GeoEngineers before applying a report to determine if it remains applicable. MOST GEOTECHNICAL AND GEOLOGIC FINDINGS ARE PROFESSIONAL OPINIONS Our interpretations of subsurface conditions are based on field observations from widely spaced sampling locations at the site. Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data and then applied our professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. GEOTECHNICAL ENGINEERING REPORT RECOMMENDATIONS ARE NOT FINAL Do not over -rely on the preliminary construction recommendations included in this report. These recommendations are not final, because they were developed principally from GeoEngineers' professional judgment and opinion. GeoEngineers' recommendations can be finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or liability for this report's recommendations if we do not perform construction observation. Sufficient monitoring, testing and consultation by GeoEngineers should be provided 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 are completed in accordance with our recommendations. Retaining GeoEngineers for construction observation for this projectis the most effective method of managing the risks associated with unanticipated conditions. A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT COULD BE SUBJECT To MISINTERPRETATION Misinterpretation of this report by other design team members can result in costly problems. You could lower that risk by having GeoEngineers confer with appropriate members of the design team after submitting the report. Also retain GeoEngineers to review pertinent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnical engineering or geologic report. Reduce that risk by having GeoEngineers participate in pre -bid and preconstruction. conferences, and by providing construction observation. Do NOT REDRAw THE EXPLORATION LOGS Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a File No, 11805-001 -01 Page B-2 GWENGINEER��r July 14, 2006 . i I geotechnical engineering or geologic report should never be redrawn for inclusion in architectural or other design drawings. Only photographic or electronic reproduction is acceptable, but recognize that separating logs from the report can elevate risk. GIVE CONTRACTORS A COMPLETE REPORT AND GUIDANCE Some owners and design professionals believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contractors the complete geotechnical engineering or geologic report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with GeoEngineers and/or to conduct additional study to obtain the specific types of information they need or prefer. A pre-b'd conference can also be valuable. Be sure contractors have sufficient time to perform additional study. Only then might an owner be in a position to give contractors the best information available, while requiring them to at least share the financial responsibilities stemming from unanticipated conditions. Further, a contingency for unanticipated conditions should be included in your project budget and schedule. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to on -site personnel and to adjacent properties. READ THESE PROVISIONS CLOSELY Some clients, design professionals and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments, claims and disputes. GeoEngineers includes these explanatory "limitations" provisions in our reports to help reduce such risks. Please confer with GeoEngineers if you are unclear how these "Report Limitations and Guidelines for Use" apply to your project or site. GEOTECHNICAL, GEOLOGIC AND ENVIRONMENTAL REPORTS SHOULD NOT BE INTERCHANGED The equipment, techniques and personnel used to perforin an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, a geotechnical engineering or geologic report does not usually relate any environmental findings, conclusions or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. BIOLOGICAL POLLUTANTS GeoEngineers' Scope of Work specifically excludes the investigation, detection, prevention, or assessment of the presence of biological pollutants in or around any structure. Accordingly, this report includes no interpretations, recommendations, findings, or conclusions for the purpose of detecting, preventing, assessing, or abating biological pollutants. The term "biological pollutants" includes, but is not limited to, molds, fungi, spores, bacteria, and viruses, and/or any of their byproducts. File No.] 1805-001-02 Page B-3 GWENGINEERird) July 14. 2006 I I GWENGINEERS�� . I I I I 11 I I I I I I I APPENDix C RoCKERIES I I APPENDIX C GENERAL ROCKERIES Rockery walls may be used in both cut and fill areas. In cut areas where dense native soils are exposed, rockery walls may be up to 10 feet high if the ground surface behind the wall is level, or up to 6 feet high for a 1.5H: IV backslope. In fill areas, we recommend limiting the wall height to 4 feet when retaining fill having a level backslope, or 4 feet for a 2H: IV backslope. A height of more than 4 feet of fill can be achieved using reinforced materials within the fill. Reinforced fills should be designed on a case by case basis by the geotechnical engineer. We recommend that rockery walls be founded on dense native soils or on structural fill placed to the recommended standard. In our opinion, when adequate foundation support and suitable materials are present such as those outlined above, rockery walls will provide a cost-effective earth retention system. Specific construction guidelines for rockery walls are presented in the following paragraphs. CONSTRUCTION GUIDELINES The primary purpose of a rockery is to protect the slope face from erosion and raveling while providing limited soil retention. The base of the rockery should be embedded at least one-half the thickness of the lowest course of rocks or 18 inches below the adjacent ground surface, whichever is greater. The rockery should be supported on firm, undisturbed medium dense or denser native soils or on compacted structural fill. The final rockery face should be constructed with a batter of between IH:5V and IH:6V. The rockery rocks should be tabular and rectangular. Rocks should be hard, sound, durable and free of weathered portions, seams, cracks and other defects. Based on the height of the cut and the slope behind the rockery, we recommend that the rockeries be constructed using rock weights from about 750 to 5,000 pounds (3- to 5-man rocks as defined by Associated Rockery Contractors). The rock density should not be less than 160 pcf. The lower 2 to 4 feet of the rockery should be constructed using 4- to 5 man-size rocks. Rock selection and placement should be accomplished to reduce the number and size of voids. In the exposed face of the wall, no openings greater than 6 inches in dimension in any direction should be permitted. Rock courses should be gradational in size from bottom to top with the largest rocks of uniform size being placed for the lowest two courses. The contact between rocks should slope downward to the back side of the rockery. Each course of rocks should be seated tightly and evenly on the course beneath. After seating each course of rock, voids between the rocks should be chinked on the back with quarry spalls to eliminate passage of backfill material. Backfill immediately behind the rockery should I consist of quarry spalls. The spalls should consist of well -graded 3/4- to 4-inch crushed rock and should be durable, uncontaminated by soil or other debris, and not readily susceptible to weathering. I The quarry spall fill should be at least 18 inches wide from the rockery and the face of the cut. The spalls should be placed and compacted in lifts to a level approximately 2 inches below the top of each course of rocks as they are placed, until the uppermost course is placed. Backfill material falling onto the bearing surface of one rock course must be removed before setting the next course. Rock placement should be such that each rock above the base course will be supported on two rocks in the next lower row. File No. 11805-001-02 Page C-1 GMENGINEER��r July 14, 2006 A perforated drainpipe should be embedded in the backfill at the base of the rockery. This drain should discharge to the storm drain system or daylight at a location that will not impact the adjacent road or other moisture -sensitive areas. A qualified contractor experienced in rockery construction should install rockeries. The construction should be monitored by a geotechnical engineer. File No.] 1805-001-02 Page C-2 GWENGINEER��r July 14, 2006 07/19/2007 13:14 FAX U--- _ — — — —_ — I GWENGINEER��r Ll I GEO.EVERETT (a 002 MEMORANDUM 2924 Colby Avenue, Everett Washington 90201, TELEPHONE: (425) 252-4565, FAX (425) 252-AM6 mm.geoengineers-com To- Davis Hargrave, Lance Mueller & Associ es tsLxe� FROM: Debra overbay, GeoF_ngineerS DATE, July 19, 2007 FILE: 11805-002-00 SUBJECT: Magic Toyota - Garage Bearing Pressure and Seismic Design This mernorandurn summarizes our discussions and recommendations for additional soil bearing pressure and seismic design for design of the Magic Toyota facility located at 21300 ffighway 99 in Edmonds, Washington. GeoEngineers provided a design report for the project dated July 14, 2006. Allowable Soil Bearing Pressure We understand that you are considering using higher bearing pressures for the garage to be constructed in the south site area. If higher soil bearing values are' desirable, it is possible to overexca:vate an additional thickness of the existing loose fill soils, where present, and replace them with compacted crushed rock. An allowable soil bearing value of 5,000 psf can be utilized provided a minimum 4-foot depth of crushed rock is placed and compacted beneath the footing. This bearing pressure can also be utilized where footings are founded on dense native soils, or on compacted crushed rock overlying these soils. The allowable bearing value applies to the total of dead and long-term live loads exclusive of the weight of the footing and any overlying backfill. An increase of one-third may be used when considering wind or seismic loading. All column and continuous footings should have minimum widths of 3 feet and 1-1/2 feet, respectively. The footings should be founded at least 18 inches below the lowest adjacent grade for frost protection. We estimate that the settlement of isolated column footings will be on the order of Y. to I inch, depending on the loading conditions. We recommend a representative from our firm observe footing excavations to confirm soil conditions are as anticipated. It will be possible to reduce the recommended 4-foot thickness of crushed rock if dense native soils are present- After the footing excavation is completed and the subgrade has been observed by a. geotechnical engineer, the base should be compacted to the extent practical using a high-energy vibratory compactor. Crushed rock backfill should be placed in the excavation in horizontal lifts which are 6 to 8 inches in loose thickness. Each lift should be uniformly compacted prior to placing subsequent lifts. We recommend that the crushed rock backfill be submitted to GeoEngineers for approval prior to using. Any 'p of the materials locally available that meet the Washington State Department of TrarAS ortation Standard Specifications for crushed surfacing would be suitable where placed above water. A clean, well -graded material may be appropriate in lower areas of the cxcavation if groundwater is present. It is critical that the structural fill underneath footings be prepared properly to limit differential settlements. We recommend that all footing excavations and fill placement be observed by a representative from our firm to verify that the procedures conform with the intent of our recominendations; and the plans and specifications. Discl.Aim5R: Any electronic form, facsimile or hard copy of the original document (�mail, text, table, and/or figure). If provided, and any attachments are only a copy of the original document The original document is stored by GaoEngineers, Inc. and will serve as the official document of record. 7�19/2007 13:14 FAX GEO EVERM Memorandum to Lance Mueller & Associates July 19, 2007 Page 2 Ia003 Seismic Design We understand that 2006 EBC is being utilized for design of the structures. The Site Class and spectral response accelerations provided in our July 2006 report are appropriate for seismic design using 2006 IBC. We trust this memorandum meets your immediate needs. Please call if you bave any questions or comments. I I I I I I I I I I I GEoENGINEERS MEMORANDUM Lr.eol) 2924 Colby Avenue, Everett, Washington 98201, TELEPHONE: (425) 252-4565, FAX: (425) 252-4586 www.geoengineers.com TO: Davis Hargrave, Lance Mueller & Associates FRom: Bob Metcalf� / Debra Overbay, GeoEngineers DATE: July 26, 2007 FILE: 11805-001-02 SUBJECT: Magic Toyota - Detention Vault Recommendations This memorandum summarizes our discussions and recommendations for design of the proposed underground detention vault at the Magic Toyota facility located at 21300 Highway 99 in Edmonds, Washington. GeoEngineers provided a design report for the project dated July 14, 2006. We understand that the project may include an underground detention vault to be located under the parking garage at the south end of the site. The vault measures approximately 45 feet long, by 20 feet wide and 7.5 feet deep. We understand that the vault will have about one foot of cover and the floor of the vault will be at about Elevation 346.9 feet. The area where the vault is located may have perched groundwater 5 to 6 feet above the bottom of the vault. Previous subsurface explorations at the site include borings drilled about 15 to 41.5 feet below the existing ground surface. Although borings were not drilled in the vault area, boring B-4 was drilled in the southern area of the property. Perched groundwater was observed in boring B-4 about 5 feet below the ground surface, which corresponds to about Elevation 351 feet. Allowable Soil Bearing Pressure In our opinion, the vault footings may be designed using an allowable soil bearing pressure of 3,000 psf provided that the vault is founded on medium dense to very dense glacial soils or on at least 2 feet of properly compacted structural fill overlying medium dense glacial soils. Some overexcavation. may be required below the vault, especially if loose or soft fill soils exist. We recommend that a representative from our firm evaluate the subgrade condition for the vault to determine whether adequate bearing soils are exposed or whether zones of unsuitable soils exist, which should be removed and replaced for adequate support. In addition, fill placement and compaction under the vault should be observed and tested where necessary. The contractor should be prepared to control groundwater in the excavation. Lateral Earth Pressures We understand that the vault will be designed with permanent wall drainage to prevent the build-up of hydrostatic pressures on the vault walls. We also understand that the wall drainage pipe will be located no higher than one foot above the floor of the vault. Vault retaining walls with permanent drainage that are not structurally restrained should be designed to resist lateral soil pressures equal to an equivalent fluid density of 35 pounds per cubic foot (pcf). If the tops of the walls will be structurally restrained, an equivalent fluid density of 55 pcf will be appropriate. Walls are assumed to be restrained if top movement during backfilling is less than H11000, where H is the wall height. The above soil pressures assume that drainage is provided behind the walls. For the drained condition, we recommend that backfill within 2 feet of the walls consist of free -draining sand and gravel containing less than 5 percent fines. We also recommend installing a 4-inch-diameter perforated drainpipe within the free- DiscLAiMER: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Memorandum to Lance Mueller & Associates July 26, 2007 Page 2 draining material at the base of the walls. The drainpipes should discharge into the storm water collection system. Each drainpipe should incorporate a cleanout at the upper end of the pipe run. If drainage is not provided behind the walls (undrained conditions), we recommend that the vault walls be designed for full hydrostatic pressures based on an equivalent fluid density of 85 pcf (triangular distribution). In addition, the vault floor should be designed to resist hydrostatic uplift pressures. A unit weight of 130 pef should be used for the compacted weight of the cover soil when computing uplift resistance. The vault should be designed with additional surcharge pressures resulting from adjacent foundation loads or traffic loads, if needed. Vault Backfill We recommend that the vault excavation be backfilled using suitable on -site soils, placed and compacted as structural fill. Wet and/or silty soils removed from the vault excavation should'not be used as structural fill against the vault walls unless they are properly moisture conditioned. The excavated soils, located above the observed groundwater seepage may be suitable for placement as structural fill. The on -site soils should be free of organics, debris, and other deleterious materials. Fill placed more than 2 feet below the garage subgrade should be compacted to at least 90 percent of the maximum dry density (MDD) per ASTM D 1557. Structural fill placed within 2 feet of the garage subgrade should be compacted to at least 95 percent of the MDD. We trust this memorandum meets your immediate needs. Please call if you have any questions or comments. I EXPIRES 4 / I I /- -/ File No. 11805-001-02 GEoENGINEERS �2 1 1 TEMPORARY EROSION AND SEDIMENTATION POND SIZING CALCULATIONS cot' t�� LEXPIRES 12-05—&l Edmonds Toyota 21300 Highway 99 Edmonds, Washington Prepared for: Lance Mueller & Associates 130 Lakeside Suite #250 Seattle, WA 98122 June 29, 2007 Our Job No. 12888 F C, �, 7, JUL 2 7 0 'TREET FILE BUILDING DEPT. CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES 18215 72ND AVENUE SOUTH KENT, WA 98032 (42-5) 251-6222 (425) 251-8782 FAx BRANCH OFFICES * OLYMPIA, WA + TAcow, WA + SACRAMENTO, CA TEMECULA, CA www.barghausen.com I 1.0 GENERAL INFORMATION 2.0 INPUT DATA SUMMARY TABLE OF CONTENTS APPENDIX EXHIBITS Vicinity Map Basin Map Isopluvial Map Temporary Erosion and Sedimentation Control Pond Sizing Calculations Soils Map Geotechnical Report Pages 1,2 3 12888.002.doc � I 1.0 GENERAL INFORMATION The proposed project site is located in a portion of the Northwest quarter of Section 29, Township 27 North, Range 4 East, Willamette Meridian, City of Edmonds, Snohomish County, Washington. More specifically, the site is located near the intersection of Aurora Avenue North and 212th Street. The project consists of a single -story car dealership building, as well as a two-story parking garage facility. The site will be approximately 90 percent impervious as well as having a stormwater conveyance system, water quality vault, detention vault, and an off -site conveyance system on the south side of the site. ONSITE AREAS TESC (to trap) = 1.59 acres Total Site Area = 1.59 acres The temporary erosion control plans and final grading plans will be designed in accordance with City of Edmonds standards. One sediment trap is being designed for this project. The trap is sized in accordance with the 1992 DOE standards. The following pages contain calculations for the sediment trap. The existing soils include Alderwood Gravelly Sandy Loam, which is considered a Type C classification. The temporary conditions during construction will be a graded condition and a higher curve number was selected according to soil type. Existing Condition Curve Numbers DOE Table 111- 1. 3 Gravel Roads and Parking Lots (C) 89 Open Spaces (50-75% grass) (C) 90 ImDervious Surfaces 98 Curve Numbers Under TESC Conditions Sto hed Default DOE Table IH-1.3 FNewly Graded Area (C) 91 N/A This project meets minimum Best Management Practices for erosion control, based on the 1992 Stormwater Management Manual for the Puget Sound Basin developed by the Department of Ecology by providing a temporary rock construction entrance, temporary V-ditches with rock check dams, silt fences around the perimeter of the site, and sediment traps These minimum Best Management Practices meet established criteria for providing erosion control methodology for a project site within the City of Edmonds. The curve numbers provided by StormShed are higher and, therefore, provide a more conservative estimate of on -site conditions than do closely related "Dirt Roads and Parking Lots" and "Fair Condition Open Spaces" shown on DOE Table 111- 1.3 in the Pond Sizing Exhibit. 12888.002.doc The computer model utilized to size the temporary sediment trap was the StormShed program developed by Ingenious Systems, Inc., which utilizes the Santa Barbara Urban Hydrograph with a Type IA rainfall distribution. The temporary erosion control phase of this development should create a condition where no runoff leaves the developed portions of the site except where it is discharged from the sediment ponds. The entire site shall have no untreated runoff nor allow sediment -laden water to leave the site at any point. Groundwater, if encountered in the utility trenches, will be allowed to be pumped into the sediment trap. Baker tanks will not be used to collect groundwater. A high seasonal groundwater table is known to exist in this area. Exfiltration of groundwater into shallow excavations may occur during the wet seasonal months. Infiltration of runoff during the dry seasonal conditions will occur in the same shallow excavations. The actual quantities are anticipated to be small to negligible when compared to the surface water runoff inflow and discharge quantities. No impact on the treatment and removal of sediments is anticipated given the high groundwater tables. Runoff values prepared by the Soil Conservation Service, i.e., CN numbers, include provisions for shallow soils and high groundwater conditions. Final water quality runoff volume inflows will not be affected by the known groundwater conditions. It is anticipated that the introduction of fine silt clay particles into the sedimentation and erosion control ponds produce clogging of the pond bottom soil layers. This resulting clogging will, during the dryer seasonal conditions, inhibit the infiltration of runoff waters into the surrounding subsoils and will ultimately provide some protection to the groundwater from runoff pollutants. Construction sequencing provides for the logical installation of sedimentation, erosion control, and other features that may lend to site stabilization and dewatering of the subsoils during the early stages of site development. The proposal includes the utilization of the final stormwater quality treatment areas for sediment trap construction when possible. This minimizes excavation activities, allows for the stabilization of surfaces, and control of the erosion and sedimentation process by construction sequences. Site grading proposed will allow for the construction of final storm drainage facilities. This grading will include positive slopes for drainage to the interim treatment facilities, removal of stockpiles, and contouring for roadway base materials after utility installations. -2- 12888.002.doc 2.0 INPUT DATA SUMMARY Sizing Sediment Traps: To Sediment Trap*t 1.59 acres for both pre -developed and graded condition Pre -developed CN 88.7 0.47 acre CN = 86 Soil Type C 0. 11 acre CN = 98 Soil Type C 1.01 acres CN = 89 Soil Type C Graded CN 91 1.59 acres CN = 91 Soil Type C 2-year Precipitation = 1.5 inches ONS-ITE AREAS TESC (to trap) = 1.59 acres Total Site Area = 1.59 acres 11 Area tributary to sediment trap does not include the entire 4.18-acre site. 12888.002.doc I Appended on: 15:01:14 Friday, June 29, 2007 Pretesc Event Summary IPeak Q (c7fs) IPeak T (hrs) jHyd Vol (ac7ft) 1 0.0695 8.00 0.03727 FT Y—P —El 7A 1 0.2062 8.00 0.0825 7�� 0.3686 8.00 0. 1346 0.7296 8.00 0.2494 Record Id: Pretesc IDesign Method 71 SBUH infall type EIA jHyd Intv 10. 7 g Factor 484.007 1 7[Abstraction Coeff .20 IPervious Area 0.47 ac 7 IPervious CN 86.00 --][D—C CN 89.88 IPervious TC 2.76 min DC T 1=5.16 min I Pervious CN Cale I Description Area ub cn I Open spaces, lawns,parks (>75% grass) =1 0.47--ac —]F-86.00 I Pervious Composited CN (AMC 2) Pervious TC Cale Description I TT D nse grasses: 0.24 12.76 min Pervious TC I[_ 2.76 min Directly Connected CN Cale Description 11 SubArea IF —Sub cn Impervious swfaces (pavements, roofs, etc) 0.11 ac Gravel Roads & Parking Lots 1.01 ac DC Composited CN (AMC 2) !F-89.88 Directly Connected TC Cale Description i FS 170 mooth Surfaces.: 0.011 �[3 ��10.0110 !E�] Wp� IShallow I Paved and gravel areas (n--0.012) 75.00 ft 1.50% 0.0120 0.38 min F- Directly Connected TC 1[5.16min Licensed to: Barghausen Engineers � I 11 I Appended on: 10:07: 10 Friday, June 29, 2007 tesc Event Summary lPeak Q (cfs�) lPeak T (h:r:s])IHyd Vol 0.0880 ]1 0.04707 0.2230 8.00 11 0.09687 0.3779 11 8.00 ]1 0.1522 IF-1.5-7-070 0.7119 �[ 8.00 11 0.2710 Record Id: tesc Licensed to: Barghausen Engineers 1651 AM I Sw "j. 7, L - M 7 i -Y -lit t t5, RO RR, Rl I IL,,_-F -'BOTH a .[L"ST PLI p L 1. 2ND -�U - mg� STS. 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