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234 Edmonds - Geotech Storm Report_INVT_2018.pdfZipperGeo Geoprofessional Consultants Project No. 1948.01 January 30, 2018 Johnny Vong 2442 Market Street, #562 Seattle, Washington 98107 Subject: Stormwater Infiltration Feasibility Proposed Edmonds Apartments 23326 Highway 99 Edmonds, Washington Dear Mr. Vong: In accordance with your request and authorization, Zipper Geo Associates, LLC (ZGA) has completed our stormwater infiltration feasibility analysis for the proposed Edmonds Apartments project located at 23326 Highway 99 in Edmonds, Washington. Our services were complete in general accordance with our proposal (P17342) dated January 2, 2018. Written authorization to proceed with our evaluation was provided by you on January 2, 2018 through signature of our proposal. The observations and conclusions summarized herein are based in part upon subsurface soil and groundwater conditions observed in borings completed for this work. In the event that site conditions or proposed improvements change, it may be necessary to modify the conclusions presented in this report. This report is an instrument of service and has been prepared in general accordance with locally accepted geotechnical engineering practice. This report has been prepared for the exclusive use of you and your agents, for specific application to the subject property and stated purpose. PROJECT DESCRIPTION The project site consist of an undeveloped 1.37 acre property located at 23326 Highway 99 in Edmonds, Washington. The project will consist of developing the site with a new apartment building and related site improvements. The new building will include 5 levels of living space over two levels of parking. The lower levels of parking and a portion of the living spaces above will be buried to the west and daylight to the east. The lower level of parking is currently planned with a finished floor elevation of 408 feet. The project currently proposes to manage stormwater runoff through a buried stormwater detention vault located in the northeast portion of the property. The bottom of the vault is currently planned at elevation 402 feet, roughly 6 to 19 feet below existing site grades. Existing 19019 - 36" Avenue West, Suite E Lynnwood, Washington 98036 (425) 582-9928 Zipper Geo Associates, LLQ Edmonds Apartments — Infiltration Feasibility Project No. 1948.01 January 30, 2018 site features and the proposed plan view layout of proposed improvements are shown on the attached Figure 1, Site and Exploration Plan. PURPOSE AND SCOPE The purpose of our services was to conduct a stormwater infiltration feasibility analysis in the vicinity of the proposes stormwater vault. Our scope of services generally included characterizing subsurface soil and groundwater conditions in the vicinity of the vault and evaluating stormwater feasibility. SUBSURFACE SOIL AND GROUNDWATER CONDITIONS Mapped Geology We reviewed published geologic mapping of the site vicinity through the Washington State Department of Natural Resource's web -based mapping application Washington Geologic Information Portal (https://geologyportal.dnr.wa.gov/). The published mapping indicates the site is underlain by Vashon Till. The mapping describes Vashon Till as a nonsorted mixture of clay, silt, sand, pebbles, cobbles, and boulders, all in variable amounts. The mapping further describes the Till as " It typically is hard lodgement till and often is referred to as "hardpan." The "hardpan" is largely a result of compaction caused by the great weight of the overriding ice, hundreds of meters thick." Soil Conservation Service Hydrologic Soil Group Classification We reviewed Soil Conservation Service (SCS) mapping of the site vicinity through USDA NRCS's Web Soil Survey application (https://websoilsurveV.sc.egov.usda.gov/App/WebSoilSurvey.asp��). The mapping indicates the site is underlain by Alderwood-Urban Land Complex soils. Subsurface Soil Conditions To characterize subsurface soil conditions, we completed five geotechnical testing borings on the site. Boring B-5 was completed in the vicinity of the proposed stormwater detention vault. The locations of the borings are shown on the attached Figure 1, Site and Exploration Plan. Soil conditions observed in boring B-5 generally consisted of about 9 inches of topsoil underlain by dense, gray -brown, silty sand with trace gravel extending to about 5 feet below existing site grade (Weathered Till). Below the Weathered Till, the boring encountered dense, grading to very dense, silty sand with variable amounts of gravel (Till) extending to the completion depth of about 30 feet below existing site grade. The remaining borings (completed to depths ranging from about 20 to 40 feet below existing site grade) generally encountered similar soil conditions (Weathered Till over Till), although some borings encountered fill soils within the upper 10 feet of existing site grade. Soil conditions observed in the borings were generally consistent with the mapped geology described above. Logs of the borings are attached. 1901936 th Avenue West, Suite E Lynnwood, WA 98036 (425) 582-9928 Page 2 Zipper Geo Associates, LLQ Edmonds Apartments — Infiltration Feasibility Project No. 1948.01 January 30, 2018 Groundwater Conditions Groundwater was not encountered in any of the 5 borings completed. However, perched groundwater conditions can typically develop at the contact between the Weathered Till and Till soils. Perched groundwater typically consists of a thin layer of saturated soil that develops during wetter times of the year. Summary of Laboratory Testing For purposes of evaluating infiltration feasibility, a grain size analysis test was completed on a composite of samples S-4 through S-6 from boring B-5. These samples were obtained from approximately elevation 395 to 400 feet as representative of the infiltration receptor soils (assuming bottom of vault elevation of 402 feet). The grain size analysis on the composite sample indicated a fines content of about 33 percent at a moisture content of about 7 percent. A copy of the grain size analysis of the composite sample is attached. CONCLUSIONS Stormwater design in the City of Edmonds is regulated by the DOE's 2014 Stormwater Management Manual for Western Washington (2014 SWMM) and the City of Edmonds June 8, 2017 Stormwater Addendum. Appendix A of the June 2017 Edmonds Stormwater Addendum (ESA) outlines infeasibility criteria for various stormwater management BMPs. For infiltration systems, the ESA requires at least 1 foot of permeable soil from the bottom of the infiltration system to the seasonal high groundwater table or other impermeable layer. The 2014 SWMM defines permeable soil as "Soil materials with a sufficiently rapid infiltration rate so as to greatly reduce or eliminate surface and stormwater runoff. These soils are generally classified as SCS hydrologic soil types A and B." As indicated above, SCS mapping indicates the site is underlain by the Alderwood group of soils. The 2014 SWMM classifies the Alderwood group soils as hydrologic soil group C. The 2014 SWMM defines hydrologic soil group as: "Soils having low infiltration rates when thoroughly wetted and consist chiefly of soils with a layer that impedes downward movement of water and soils with moderately fine to fine textures. These soils have a low rate of water transmission (0.05-0.15 in/hr.)." Additionally, in many areas, the 2014 SWMM generally refers to hardpan or glacial till as an impermeable layer as related to stormwater infiltration. We agree with the DOE's classification of till as an impermeable soil as related to stormwater infiltration. Additionally, the till at this site is extremely dense and contains fines contents generally in excess of 30 percent further supporting the generally impermeable nature of it. As such, it is our opinion that stormwater infiltration at the currently proposed vault location and elevation is infeasible due to the impermeable nature of till 19019 36' Avenue West, Suite E Lynnwood, WA 98036 (425) 582-9928 Page 3 Zipper Geo Associates, LLQ Edmonds Apartments — Infiltration Feasibility Project No. 1948.01 January 30, 2018 soils at this site. Based on proposed site grades and soils encountered in other borings, it is further our opinion that stormwater infiltration at other locations on the site is infeasible. CLOSURE We hope this letter meets your current needs. If you have any questions or comments, please contact us at (425) 582-9928. Sincerely, Zipper Geo Associates, LLC Robert A. Ross, P.E. Principal Geotechnical Engineer Attachments: Figure 1, Site and Exploration Plan Boring Logs Lab Test Analysis Results 19019 36' Avenue West, Suite E Lynnwood, WA 98036 (425) 582-9928 Page 4 J.vl 20 LF 8" SEWER 0 0.5% LL- I L N 02-34'42" W 38.21 0 0.5111 SS I bl LF �'7EWE� SS ��42 ss � ss 14.85' V// - 111 32 LF 8 WR SS SS 3 LF I TORM SSMH ..... 6— SID 3. o SS 3 104S� 12" STORM @j4L '.93' RIM=425.43 �j 00' IELF �8SEWE��S@Ll 3% SS B 2 01 %\ SID IE=414.95 ADS J27.2' B-3 422 14.85' D 4301- &5. 81 - - - - - - - 428- SS - SS I I - - - - �g \ - - ll-� SS SD -SD SS- - - - - - - 426 - - - - - - - - - - - - - - --- - - - - - - - - - SD - -SD STORM AND SEWER A 420 424 so B-1 - - - - - - - - - - - - - - - - - - - -- 422------ ARE GRAPHIC ILLUSTR GARAGE CONTRACTOR TO VERII ENTRANCE ISDMH RIM 42t -418. 420— RCP W = 4 - - - - - - - - 171 AND DEPTH IN FIELD RCP N = 414.73 PARKING LEVEL L 7 18" PVC N. S. E. & Wl I Z CLE CHANNEI 41,384' 416 L -418 GARAGE FF: Ll ELEV.=418' 414- 6" R Pl ELEV.=408' 3" WATER ",I (DOMESTIC) - - - - - - D-7 -412 -416. 6. 6.83' 7?7\ 420- 474 -TO TA L AREA 6 72 sq. ft. f 11.54' 0 PVC & W B-4 NNEL 401.00' L5\ ISSS—MH Rim 104 -418 412 18" Pvc S ICTR CHANNEI = 40 STPRMWATER VATJ-LT--- L 511 2 RCP W = 06t CP S = - - ::: L- gin INSIDE ECEVATIDNS- - SS :�: :-- (3s- TOP= 407 -�ERSESS 12" PIPE OUT= 403' S- -410— BO \416- 402' B-5 I CR RIM = 12 = 404.721.0 112- - --T RCCP (E) = 404.62, 10,9 T-- CONTROL STRUCTURE RIM=405.38 RM) 11/0 IE IN/OUT=403.00 STO AULT TOP OF STAND PIPE=406.00 CC SS V 6.73' A E F 4441,'q -408 ,' >-�- I- '- 4v, 4�1 --Z 5.94' -S> A09 6 70' tg, 19 1 1�llpu a R a 14% LEGEND 1 BORRING NUMBER AND Edmonds Apartments APPROXIMATE LOCATION enH!EEM- 23326 Hwy 99 Edmonds, Washington 30 0 15 30 SITE AND EXPLORATION PLAN SCALE IN FEET DATE: JANUARY 2018 Job No. 1948.01 Zipper Geo Associates, LLC FIGURE REFERENCE CONCEPT UTILITY PLAN PREPARED BY PATRICK HARRON &ASSOCIATES, LLC., DATED JANUARY 15,2018 1901936th Ave. W.,Suite E 1 Lynnwood, WA, 98036 SHT.1 of I Boring Location: See Figure 1, Site and Exploration Plan Drilling CompanV-. Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 419' Drilling Method: Hollow Stem Auger Hammer TVpe: Auto B-1 Date Drilled: 1/16/2018 Drill Rig: D50 L2qaLd by TLW :E SOIL DESCRIPTION U) LU _j Z 0 > 0 E < . co U) Z3 2 0 0 PENETRATION RESISTANCE (blows/foot) U) 0 0 Fn 0) E Cn The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Hammer Weight and Drop: 20 40 60 7 inches of topsoil over loose, brown, moist, silty SAND, trace I I I I I I I I I I I I I gravel -,141 - 4 --------------------------------------------- Dense, moist, gray, silty SAND, some gravel (Weathered Till) — S-1 18" 0 37 -------------------------------------------- Medium, wet, light gray, silty SAND, some to trace gravel - 5 - (Weathered Till) S-2 13 -1 -1 -f-t-t -t-t- -t-t-t I -r t t-t t --- �t- rt-T- ------------------------------------------- Very dense, moist, light gray, silty SAND, some to trace gravel (Till) 20 S-5 = 3" at 21.0 feet possible cobbles -+�-�--4-4-4-44 44444++++- -+4-4-4-4- "I'll" I I t 441111 25 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits 50/6 50/6 50/3 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-1 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of Boring Location: See Figure 1, Site and Exploration Plan Top Elevation: 419' Date Drilled: 1/16/2018 1 SOIL DESCRIPTION 4�- :E The stratification lines represent the approximate boundaries 0- a) between soil types. The transition may be gradual. Refer to 0 report text and appendices for additional information. 25 ' I Very Dense, moist, light gray, SAND, with silt and gravel at 29.0 feet possible cobbles to boulders 30 - Boring completed at approximately 30 feet on 1/16/18. No groundwater observed ATD. 9911 40 45 50 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits Drilling CompanV-. Holocene Drilling Bore Hole Dia.: 7" Drilling Method: Hollow Stem Auger Hammer TVpe: Auto Drill Rig: D50 L2qaLd by TLW PENETRATION RESISTANCE (blows/foot) U) LU Q) Standard Penetration Test _j Z > 0 Hammer Weight and Drop: 0 E < Z3 0 . co U) 2 0 20 40 60 Fn S-6 50/ is 50/5 Cn 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-1 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 2 of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling CompanV-. Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 430' Drilling Method: Hollow Stem Auger Hammer TVpe: Auto B-2 Date Drilled: 1/16/2018 Drill Rig: D50 L2qaLd by TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) U) LU U) 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries _j Z 0 > 0 Hammer Weight and Drop: 0 E Cn between soil types. The transition may be gradual. Refer to E < Z3 report text and appendices for additional information. . co U) 2 0 Fn 0 0 20 40 60 inches of topsoil over medium dense, moist, brown, silty SAND , tr ace gravel (Possible Fill) 5 1 ------------------------------------------- Dense, damp, light brown, silty SAND, some gravel (Possible Fill) 1 loose and wet from 10.0 feet and 12.0 feet ------------------------------------------- Very dense, moist, light gray, gravelly SAND, with silt (Till) 15 20 25 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits S-1 7" S-2 181. S-3 1 18" S4 1 181. S-5 1 12" U -4� 4 4- 4- 4- 111 111 - -T-T---T-777777� -1 111411 - ------------ -- 25 44 8 50/6 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-2 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of 2 Boring Location: See Figure 1, Site and Exploration Plan Top Elevation: 430' Date Drilled: 1/16/2018 1 SOIL DESCRIPTION 4�- :E The stratification lines represent the approximate boundaries 0- a) between soil types. The transition may be gradual. Refer to 0 report text and appendices for additional information. 25 - Very dense, moist, light gray, silty SAND, trace to some gravel (Till) grades to with gravel 30 9911 at 39.0 feet possible cobbles to boulders 40. Boring completed at approximately 40 feet on 1/16/18. No groundwater observed ATD. 45 50 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits Drilling CompanV-. Holocene Drilling Bore Hole Dia.: 7" Drilling Method: Hollow Stem Auger Hammer TVpe: Auto Drill Rig: D50 L2qaLd by TLW PENETRATION RESISTANCE (blows/foot) U) LU Q) Standard Penetration Test _j Z > 0 Hammer Weight and Drop: 0 E < Z3 0 . co U) 2 0 20 40 60 Fn —INE0 T3;" Cn 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-2 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 2 of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling CompanV: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 427' Drilling Method: Hollow Stem Auger Hammer TVpe: Auto B-3 Date Drilled: 1/16/2018 Drill Rig: D50 L2qaLd by TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) U) LU U) 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries _j Z 0 > 0 Hammer Weight and Drop: 0 E Cn between soil types. The transition may be gradual. Refer to E < Z3 report text and appendices for additional information. . co U) 2 0 Fn 0 0 20 40 60 I I . I .0 - — 7 inches of topsoil over loose, moist, gray -brown, silty SAND, � I I I I I I I I I I I I trace gravel (Possible Fill) i 1 — --------------------------------------------- Dense, moist, gray, SAND, with gravel and silt (Weathered Till) Very dense, moist, light gray, silty SAND, some gravel (Till) S-1 O�7 S-2 1.5 A 0 T_- I -L T_TT__F_F_ I I LL� LILL 5 43 5 - 1 -1 -f-t-t -t-t- -t-t-t I -r t t-t t- A 20 - grades to with silt S-5 = 0 3 3 11/4 at 21.0 feet possible cobbles to boulders 4�4-4-4-4-44 44444++++- -+4-4--�--[- 111111111 111111111 1111111— I I 1 1 1441 11,1111 Itti "I -_ "'Ill"; 25 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-3 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of 2 Boring Location: See Figure 1, Site and Exploration Plan Top Elevation: 427' Date Drilled: 1/16/2018 1 SOIL DESCRIPTION 4�- :E The stratification lines represent the approximate boundaries 0- a) between soil types. The transition may be gradual. Refer to 0 report text and appendices for additional information. 25 ' I Very Dense, moist, light gray, silty SAND, some gravel (Till) 30 Boring completed at approximately 31 feet on 1/16/18. No groundwater observed ATD. 9911 40 45 50 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits Drilling CompanV-. Holocene Drilling Bore Hole Dia.: 7" Drilling Method: Hollow Stem Auger Hammer TVpe: Auto Drill Rig: D50 L2qaLd by TLW PENETRATION RESISTANCE (blows/foot) U) LU Q) Standard Penetration Test _j Z > 0 Hammer Weight and Drop: 0 E < Z3 0 . co U) 2 0 20 40 60 Fn 6-tj .6 S-7 = 0 1 #W 50/2 Cn 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-3 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 2 of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling CompanV: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 413' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-4 Date Drilled: 1/16/2018 Drill Rig: D50 L2qaLd by TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) U) LU U) 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries _j Z 0 > 0 Hammer Weight and Drop: 0 E Cn between soil types. The transition may be gradual. Refer to E < Z3 report text and appendices for additional information. . co U) 2 0 Fn 0 0 20 40 60 of topsoil over medium dense, moist, light brown to rinches b "', s' Ity SAND, trace gravel (Possible Fill) S-1 7" --------------------------------------------- 5 - Medium dense, moist, light gray -brown, silty SAND (Weathered Till) S-2 181. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Very dense, moist, light gray, silty SAND, with gravel (Till) 4 S-3 1 181, qgrades to with silt 1 S4 1 181. 20 - grades to silty I S-5 1 91. Boring completed at approximately 21 feet on 1/16/18. No groundwater observed ATD. I 25 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits 17 23 56 74 50/3 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-4 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling CompanV: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 412' Drilling Method: Hollow Stem Auger Hammer TVpe: Auto B-5 Date Drilled: 1/16/2018 Drill Rig: D50 L2qaLd by TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) U) LU U) 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries _j Z 0 > 0 Hammer Weight and Drop: 0 E Cn between soil types. The transition may be gradual. Refer to E < Z3 report text and appendices for additional information. . co U) 2 0 Fn 0 0 20 40 60 9" of topsoil over dense, light gray -brown, silty SAND, trace I I I I I I I I I I I I I gravel (Weathered Till) -,141- 4 S-1 18" _1__7qj_T_7 T 7-TT-- 45 �7LL ILL 5 ---------------------------------------------- A Dense, wet, light gray, silty SAND, trace gravel (Till) S-2 101. 35 at 6.0 feet possible trace cobbles grades to very dense and moist 10. grades to with gravel S-3 181, S-4 T 15 1 is-5 1 8" grades to some gravel I S-6 1 7" 20 1 1 S-7 1 8" at 21.0 feet possible cobbles to boulders S-8 :: T 25 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits 0 50/6 TTTT--TT77r T-T- U �AL50/4 L�1-4 t -1 -4 - 4 4 -F-+++++- -++ A k 111/4 �AkIO16 44-4-4-4-44- � I i � � i i i i � i � � 1; 1; 1, �AL 50/4 t t - I I I %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-5 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of Boring Location: See Figure 1, Site and Exploration Plan Top Elevation: 412' Date Drilled: 1/16/2018 1 SOIL DESCRIPTION 4�- :E The stratification lines represent the approximate boundaries 0- a) between soil types. The transition may be gradual. Refer to 0 report text and appendices for additional information. 25 ' I Very dense, moist, light gray, silty SAND, some gravel grades to with silt 30 - L— Boring completed at approximately 30 feet on 1/16/18. 9911 40 45 50 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample clean sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits Drilling CompanV-. Holocene Drilling Bore Hole Dia.: 7" Drilling Method: Hollow Stem Auger Hammer TVpe: Auto Drill Rig: D50 L2qaLd by TLW PENETRATION RESISTANCE (blows/foot) U) LU Q) Standard Penetration Test _j Z > 0 Hammer Weight and Drop: 0 E < Z3 0 . co U) 2 0 20 40 60 Fn 6-9 .6 10 1 4" #W 50/3 Cn 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i E) —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948-01 Zipper Geo Associates BORING B-5 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 2 of 2 GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 X: (9 w 70 00 W 60 w z LL 50 z w W 40 w (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS oarse Fine 0a 'Se I edium Fine it Clay BOULDERS COBBLES LGRAVEL SEA N D FINE G �INED Comments: Exploratio Sample Depth (feet) Moisture (%) Fines (%) D scription B-2 t S2 5 ft. 7.7 41.2 Silty SAND, some gravel Project No. 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 X: (9 W 70 00 W 60 W z LL 50 z W W 40 W (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS oarse Fine 0a 'Se I edium Fine it Clay BOULDERS COBBLES LGRAVEL SEA N D FINE G �INED Comments: Exploratio Sample Depth (feet) Moisture (%) Fines (%) D scription B-2 t S4 15 ft. 5.2 14.5 Gravelly SAND, with silt Project No. 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 X: (9 W 70 00 W 60 W z LL 50 z W W 40 W (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS oarse Fine 0a 'Se I edium Fine it Clay BOULDERS COBBLES LGRAVEL SEA N D FINE G �INED Comments: Exploratio Sample Depth (feet) Moisture (%) Fines (%) D scription B-3 t S2 5 ft. 7.7 24.0 Silty SAND, with gravel Project No. 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 X: (9 W 70 00 W 60 W z LL 50 z W W 40 W (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS oarse Fine 0a 'Se I edium Fine it Clay BOULDERS COBBLES LGRAVEL SEA N D FINE G �INED Comments: Exploratio Sample Depth (feet) Moisture (%) Fines (%) D scription B-4 t S3 loft. 7.9 31.7 Silty SAND, with gravel Project No. 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 X: (9 W 70 00 W 60 W z LL 50 z W W 40 W (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS oarse Fine 0a 'Se I edium Fine it Clay BOULDERS COBBLES LGRAVEL SEA N D FINE G �INED Comments: Exploratio Sample Depth (feet) Moisture (%) Fines (%) D scription B-5 t S4-S6 12.5 to 17.5 ft. 6.6 33.4 Silty SAND, with gravel Project No. 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments