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03 Geotech Letter15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 • (425) 449-4704 • FAX (425) 449-4711 Earth Solutions NW LLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services February 11, 2020 ES-6375.01 Bush, Roed & Hitchings, Inc. 2009 Minor Avenue East Seattle, Washington 98102 Attention: Mr. Ted Dimof Subject: Infiltration Evaluation Southwest 320th Street Plat Southwest 320th Street and 21st Avenue Southwest Federal Way, Washington Reference: King County King County Surface Water Design Manual (KCSWDM) April 24, 2016 Bush, Roed, & Hitchings Boundary & Topographic Survey December 3, 2018 R.W. Tabor et al. Geologic Map of the Tacoma Quadrangle, Washington, 2015 United States Department of Agriculture Natural Resources Conservation Service Online Web Soil Survey (WSS) resource Dear Mr. Dimof: As requested, Earth Solutions NW, LLC (ESNW) has prepared this infiltration evaluation letter for the subject site. Our scope of services included subsurface exploration, infiltration testing, engineering analysis, and preparation of this letter. Project Description The subject site is located along the south side of Southwest 320 th Street, approximately 120 feet west of the intersection with 21st Avenue Southwest, in Federal Way, Washington, as illustrated on the attached Vicinity Map (Plate 1). The site consists of two adjoined residential tax parcels (King County Parcel Nos. 132103-9002 and -9091) totaling approximately 2.0 acres of land area. The subject site is moderately overgrown with trees and brambles and has a remnant foundation and dilapidated shed along the southern border of the property. We understand a short plat has been proposed for the subject site and will include multiple single-family lots, a stormwater management facility, access roads, and related site improvements. Bush, Roed & Hitchings, Inc. ES-6375.01 February 11, 2020 Page 2 Earth Solutions NW, LLC If the design assumptions outlined in this section are incorrect or change, or if construction conditions differ from those encountered during our fieldwork, ESNW should be contacted to review the recommendations and conclusions provided in this letter. Subsurface Conditions As part of this infiltration evaluation, an ESNW representative observed, logged, and sampled four test pits excavated across the subject site using a mini-trackhoe and operator retained by our firm on January 17, 2020. The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). Please refer to the attached test pit logs for a more detailed description of subsurface conditions. Representative soil samples collected at the test pit locations were analyzed in accordance with both Unified Soil Classification System (USCS) and United States Department of Agriculture (USDA) methods and procedures. Topsoil was encountered in the upper approximate 6 to 18 inches of existing grades at the test pit locations, characterized by dark brown color, the presence of fine organic material, and small root intrusions. Fill was encountered at test pit locations TP-101 and TP-102 extending to depths of roughly six and one-half to eight feet below the existing ground surface (bgs). The fill was characterized primarily as loose dark brown silty sand with gravel (USCS: SM). Plastic, metal, rubber, and wood debris was observed in the fill. Where encountered, fill should be evaluated by ESNW at the time of construction to assess the suitability for use as structural fill and/or foundation support. Underlying the topsoil and fill, native soils consisted of a heavily weathered layer of loose to medium dense silty sand with gravel and sandy silt with gravel (USCS: SM and ML, respectively). Underlying the weathered layer, native soils consisted of poorly to well-graded gravel, poorly graded gravel with silt and sand, silty gravel, and poorly graded sand with gravel (USCS: GP, GW, GP-GW, GM, and SP, respectively). The native soils were generally encountered in a damp to moist condition and extended to the maximum exploration depth of nine feet bgs. Geologic Setting The referenced geologic map identifies Vashon till (Qgt) across the site with Vashon recessional outwash deposits (Qgo) mapped to the west of the subject site. As described on the geologic map, Vashon till is typically a compact diamict of subrounded to well-rounded clasts which were glacially transported and deposited. The diamict is readily comprised of sand, silt, gravel, pebbles, and cobbles. As described on the geologic map, recessional outwash consists primarily of moderately sorted to well sorted, stratified sand and gravel. Groundwater Groundwater seepage was not encountered at the test pit locations during our exploration on January 17, 2020. Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater flow rates are higher during the winter, spring, and early summer months. Bush, Roed & Hitchings, Inc. ES-6375.01 February 11, 2020 Page 3 Earth Solutions NW, LLC Infiltration Evaluation Our evaluation of the proposed infiltration facilities was completed in general accordance with applicable requirements and procedures of the referenced 2016 KCSWDM as adopted by the City of Federal Way. We understand an infiltration facility is proposed for the short plat. In-situ testing was completed in general accordance with the small-scale Pilot Infiltration Test (PIT) procedure, as outlined in the 2016 KCSWDM. To evaluate the infiltration capacity of soils, in-situ testing was completed at TP-103 and TP-104 at a depth of six feet bgs. Our testing program consisted of a soak period, steady state period, and falling head period. Due to the soil variability observed at the proposed design depth, two separate preliminary infiltration rates were calculated for the predominant soil types observed at the property (clean sand deposits and gravels). The table below summarizes the short-term (measured) rate at each test location, in units of inches per hour (iph). Test Pit Measured Rate (iph) Depth (feet) Soil Type TP-103 60 6 Poorly graded gravel with silt and sand (GP-GM) TP-104 24 6 Poorly graded sand (SP) Per the referenced 2016 KCSWDM, correction factors must be applied to the measured rates to account for testing methods, facility geometry, and influent control to prevent siltation. In our opinion, the following correction factors and calculated total correction factor should be applied to the measured field rates.  Test uncertainty (Ftesting) 0.5  Infiltration facility geometry (Fgeometry) 0.9  Long-term plugging of soils (Fplugging) 1.0 (gravels)  Long-term plugging of soils (Fplugging) 0.9 (medium sands) Application of the total correction factor to the measured rates are provided in the table below: Test Pit Design Rate (iph) TP-103 20 TP-104 10 From a geotechnical standpoint, infiltration is feasible within locations underlain by gravels and clean sand deposits. The upper silty sand and sandy silt deposits and fill identified at the property generally exhibit poor infiltration potential and should not be targeted for infiltration facilities. Minimum vertical separation between the bottoms of the proposed facilities and groundwater must be considered during design. We recommend provisions for overflow be incorporated into final designs, wherever practicable. Bush, Roed & Hitchings, Inc. February 11, 2020 ES-6375.01 Page4 Given the variability of the site soils infiltration potential, ESNW should be in correspondence with the facility designer to assist with applying appropriate rates to the targeted infiltrating soils at the proposed infiltration facility location and acknowledging depth to restrictive layers. Additionally, ESNW should be retained at the time of facility construction to confirm soils types and provide additional recommendations as needed. Limitations This letter has been prepared for the exclusive use of Bush, Roed, & Hitchings, Inc. and their representatives. A warranty is neither expressed nor implied. The recommendations and conclusions provided in this letter are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. Variations in the soil and groundwater conditions encountered at the test pit locations may exist and may not become evident until construction. ESNW should reevaluate the contents of this letter if variations are encountered. ESNW should be retained during construction to observe facility installation and to confirm soil types are as anticipated in this letter. Supplementary recommendations may be provided during construction, as necessary. We appreciate the opportunity to be of service to you and trust this letter meets your current needs. Should you have questions, or if additional information is required, please call. Sincerely, EARTH SOLUTIONS NW, LLC Kyler T. Kelly Senior Staff Geologist Attachments: Plate 1 -Vicinity Map Plate 2 -Test Pit Location Plan Test Pit Logs Grain Size Distribution Raymond A. Coglas, P.E. Principal Engineer Earth Solutions NW, LLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drwn.CAM Checked KTK Date Jan.2020 Date 01/29/2020 Proj.No.6375.01 Plate 1 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Vicinity Map S.W.320th Street Plat Federal Way,Washington Reference: King County,Washington OpenStreetMap.org NORTH NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. SITE Plate Proj.No. Date Checked By Drwn.ByEarthSolutionsNWLLCGeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCCAM KTK 01/29/2020 6375.01 2TestPitLocationPlan S.W.320thStreetPlatFederalWay,WashingtonNORTH 0 3 0 6 0 1 2 0 Sc ale in Feet1"=6 0 ' NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. NOTE:The graphics shown on this plate are not intended for design purposes or precise scale measurements,but only to illustrate the approximate test locations relative to the approximate locations of existing and /or proposed site features.The information illustrated is largely based on data provided by the client at the time of our study.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. LEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-6375.01,Jan.2020 Approximate Location of ESNW Test Pit,Proj.No. ES-6375,Oct.2018 Subject Site Proposed Infiltration Pond Existing Building TP-1 TP-101 TP-101 TP-102TP-103 TP-104 TP-3 TP-1 TP-2 TP-4 TP-5 TP-6 Remnant Concrete Foundation Dilapidated Shed S.W. 320TH STREET 21ST AVENUE S.W.350340 330320 350 340 330 320 336.5 331.5 331.0MC = 11.00% TPSL SM GM Dark brown TOPSOIL (Fill) -plastic and metal debris Dark brown silty SAND with gravel, loose, moist (Fill) -plastic and metal debris to 6.5' Brown silty GRAVEL with sand, medium dense to dense, moist Test pit terminated at 7.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. Bottom of test pit at 7.0 feet. 1.5 6.5 7.0 NOTES Depth of Topsoil & Sod 18": forest duff GROUND ELEVATION 338 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 1/17/20 COMPLETED 1/17/20 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-101 PROJECT NUMBER ES-6375.01 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375-1.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 338.0 331.0 TPSL SM Dark brown TOPSOIL (Fill) -contains gravel Brown silty SAND with gravel, medium dense, moist (Fill) -plastic, metal and wood debris to BOH -minor caving to BOH Test pit terminated at 8.0 feet below existing grade. No groundwater encountered during excavation. Caving observed from 3.0 feet to BOH. Bottom of test pit at 8.0 feet. 1.0 8.0 NOTES Surface Conditions: gravel fill GROUND ELEVATION 339 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 1/17/20 COMPLETED 1/17/20 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-102 PROJECT NUMBER ES-6375.01 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375-1.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 340.5 338.5 333.5 332.0 MC = 7.20% Fines = 5.70% MC = 7.30% Fines = 1.70% TPSL SM GP- GM GP Dark brown TOPSOIL, trace roots to 4.5' Brown silty SAND with gravel, loose, moist Brown poorly graded GRAVEL with silt and sand, medium dense, moist -minor caving to BOH -infiltration test at 6' [USDA Classification: extremely gravelly loamy coarse SAND] Gray poorly graded GRAVEL with sand, medium dense to dense, moist [USDA Classification: extremely gravelly coarse SAND] Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. Caving observed from 5.0 feet to BOH. Bottom of test pit at 9.0 feet. 0.5 2.5 7.5 9.0 NOTES Depth of Topsoil & Sod 6": forest duff GROUND ELEVATION 341 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 1/17/20 COMPLETED 1/17/20 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-103 PROJECT NUMBER ES-6375.01 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375-1.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 332.0 329.5 326.0 324.0 MC = 3.80% Fines = 1.70% MC = 7.20% Fines = 3.20% TPSL SM SP GP Dark brown TOPSOIL, trace roots to 5' Brown silty SAND with gravel, medium dense, moist Gray poorly graded SAND with gravel, medium dense, moist [USDA Classification: very gravelly SAND] -infiltration test at 6', increased gravel content -minor caving to BOH Gray poorly graded GRAVEL with sand, medium dense to dense, moist [USDA Classification: extremely gravelly coarse SAND] Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. Caving observed from 6.5 feet to BOH. Bottom of test pit at 9.0 feet. 1.0 3.5 7.0 9.0 NOTES Depth of Topsoil & Sod 12": forest duff GROUND ELEVATION 333 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 1/17/20 COMPLETED 1/17/20 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-104 PROJECT NUMBER ES-6375.01 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375-1.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 339.0 337.0 332.5 MC = 2.50% MC = 1.80% Fines = 2.50% MC = 2.00% TPSL SM GW Dark brown TOPSOIL -trace roots to 6' Tan silty SAND with gravel, medium dense, damp Tan well-graded GRAVEL with sand, dense, damp [USDA Classification: extremely gravelly coarse SAND] -slight caving from 3' to 6' Test pit terminated at 7.5 feet below existing grade. No groundwater encountered during excavation. Caving observed from 3.0 to 6.0 feet. Bottom of test pit at 7.5 feet. 1.0 3.0 7.5 NOTES Depth of Topsoil & Sod 6"- 12": forest duff GROUND ELEVATION 340 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 10/26/18 COMPLETED 10/26/18 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-1 PROJECT NUMBER ES-6375 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 344.0 342.0 337.0 MC = 8.20% Fines = 50.40% MC = 3.10% TPSL ML GP Dark brown TOPSOIL -trace roots to 6.5' Tan sandy SILT with gravel, medium dense, damp [USDA Classification: gravelly LOAM] Tan poorly graded GRAVEL with sand, dense, damp -slight caving to 7' Test pit terminated at 8.0 feet below existing grade. No groundwater encountered during excavation. Caving observed from 5.0 to 7.0 feet. Bottom of test pit at 8.0 feet. 1.0 3.0 8.0 NOTES Depth of Topsoil & Sod 6"- 12": forest duff GROUND ELEVATION 345 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 10/26/18 COMPLETED 10/26/18 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-2 PROJECT NUMBER ES-6375 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 344.0 343.0 338.0 MC = 2.10% MC = 1.80% Fines = 1.70% TPSL SM SP Dark brown TOPSOIL -trace roots to 6' Brown silty SAND with gravel, loose to medium dense, moist Tan poorly graded SAND with gravel, dense, damp -slight caving to BOH [USDA Classification: very gravelly coarse SAND] Test pit terminated at 7.0 feet below existing grade. No groundwater encountered during excavation. Caving observed from 5.0 feet to BOH. Bottom of test pit at 7.0 feet. 1.0 2.0 7.0 NOTES Depth of Topsoil & Sod 6"- 12": forest duff GROUND ELEVATION 345 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 10/26/18 COMPLETED 10/26/18 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-3 PROJECT NUMBER ES-6375 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 349.0 346.0 342.5 MC = 4.60% MC = 10.20% TPSL SM SP Dark brown TOPSOIL (Fill) -trace roots to BOH Brown silty SAND with gravel, loose to medium dense, moist (Fill) -plastic and ceramic debris to 4' -becomes medium dense to dense Tan poorly graded SAND with gravel, dense, damp Test pit terminated at 7.5 feet below existing grade. No groundwater encountered during excavation. No caving observed. Bottom of test pit at 7.5 feet. 1.0 4.0 7.5 NOTES Depth of Topsoil & Sod 6"- 12": brambles GROUND ELEVATION 350 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 10/26/18 COMPLETED 10/26/18 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-4 PROJECT NUMBER ES-6375 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 349.5 348.0 343.0 MC = 3.30% MC = 4.50% TPSL SM GP Dark brown TOPSOIL, trace roots to 5' Tan silty SAND with gravel, medium dense, moist Tan poorly graded GRAVEL with sand, dense, damp Test pit terminated at 7.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. Bottom of test pit at 7.0 feet. 0.5 2.0 7.0 NOTES Depth of Topsoil & Sod 6": forest duff GROUND ELEVATION 350 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 10/26/18 COMPLETED 10/26/18 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-5 PROJECT NUMBER ES-6375 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 344.0 343.0 336.0MC = 2.20% Fines = 4.10% TPSL SM GP Dark brown TOPSOIL -trace roots to BOH Tan silty SAND with gravel, loose to medium dense, moist Tan poorly graded GRAVEL with sand, medium dense to dense, damp [USDA Classification: extremely gravelly coarse SAND] Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. Bottom of test pit at 9.0 feet. 1.0 2.0 9.0 NOTES Depth of Topsoil & Sod 12": forest duff GROUND ELEVATION 345 ft LOGGED BY KTK EXCAVATION METHOD AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 10/26/18 COMPLETED 10/26/18 DEPTH(ft)0 5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP-6 PROJECT NUMBER ES-6375 PROJECT NAME S.W. 320th Street Plat GENERAL BH / TP / WELL 6375.GPJ GINT US.GDT 2/12/20Earth Solutions NW 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 %Silt %ClayD100 D30 1.619 2.289 0.492 1.407 3 100 TP-103 TP-103 TP-104 TP-104 24 406 60 10.501 13.229 3.26 10.86 1.5 8 14 Cc Cu 5.7 1.7 1.7 3.2 COBBLES GRAVELPERCENT FINER BY WEIGHTSAND GRAIN SIZE IN MILLIMETERS 6.0ft. 9.0ft. 6.0ft. 9.0ft. coarse D90 fine Specimen Identification PL PI Classification Specimen Identification TP-103 TP-103 TP-104 TP-104 3/4 3/8 6.0ft. 9.0ft. 6.0ft. 9.0ft. LL 1 2006 10 501/2 HYDROMETERU.S. SIEVE OPENING IN INCHES 14034 U.S. SIEVE NUMBERS 37.5 37.5 37.5 37.5 26.834 30.361 27.536 18.697 D60 D10 0.31 0.578 0.276 0.247 USDA: Gray Extremely Gravelly Loamy Coarse Sand. USCS: GP-GM with Sand. USDA: Gray Extremely Gravelly Coarse Sand. USCS: GP with Sand. USDA: Gray Very Gravelly Sand. USCS: SP with Gravel. USDA: Gray Extremely Gravelly Coarse Sand. USCS: GP with Sand. 33.89 22.90 11.79 44.04 0.81 0.69 0.27 0.74 GRAIN SIZE DISTRIBUTION coarse SILT OR CLAYfinemedium 16 3020 PROJECT NUMBER ES-6375.01 PROJECT NAME S.W. 320th Street Plat GRAIN SIZE USDA WITH D90 ES-6375.01 S.W. 320TH STREET PLAT.GPJ GINT US LAB.GDT 1/21/20Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711