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Rpt_Prelim Storm Civil Engineers ● Structural Engineers ● Landscape Architects ● Community Planners ● Land Surveyors Stormwater Report PREPARED FOR: Mr. Evan Mann Copper Ridge LLC PO Box 73790 Puyallup, WA 98373-0790 PROJECT: Crystal Springs Preliminary Plat Yelm, Washington 2210633.10 PREPARED BY: Quinten Foster Project Engineer REVIEWED BY: J. Matthew Weber, PE Principal DATE: October 2021 Stormwater Report PREPARED FOR: Mr. Evan Mann Copper Ridge LLC PO Box 73790 Puyallup, WA 98373-0790 PROJECT: Crystal Springs Preliminary Plat Yelm, Washington 2210633.10 PREPARED BY: Quinten Foster Project Engineer REVIEWED BY: J. Matthew Weber, PE Principal DATE: October 2021 I hereby state that this Stormwater Report for Crystal Springs Preliminary Plat has been prepared by me or under my supervision and meets the standard of care and expertise that is usual and customary in this community for professional engineers. I understand that City of Yelm does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. 10/06/2021 Stormwater Report Crystal Springs Preliminary Plat 2210633.10 Table of Contents Section Page 1.0 Project Overview ............................................................................................................................ 1 2.0 Summary of Minimum Requirements .......................................................................................... 1 2.1 MR 1 – Preparation of Stormwater Site Plans .................................................................... 1 2.2 MR 2 - Construction Stormwater Pollution Prevention ....................................................... 1 2.3 MR 3 – Source Control of Pollution ..................................................................................... 1 2.4 MR 4 – Preservation of Natural Drainage Systems and Outfalls ........................................ 1 2.5 MR 5 – Onsite Stormwater Control ..................................................................................... 1 2.6 MR 6 – Runoff Treatment ................................................................................................... 2 2.7 MR 7 – Flow Control ........................................................................................................... 2 2.8 MR 8 – Wetlands Protection ............................................................................................... 2 2.9 MR 9 – Basin/Watershed Planning ..................................................................................... 2 2.10 MR 10 – Operation and Maintenance ................................................................................. 2 3.0 Existing Conditions ....................................................................................................................... 2 4.0 Soils Reports .................................................................................................................................. 2 5.0 Wells ................................................................................................................................................ 2 6.0 Fuel Tanks ...................................................................................................................................... 3 7.0 Sub-Basin Description................................................................................................................... 3 8.0 Analysis of the 100-Year Flood ..................................................................................................... 3 9.0 Aesthetic Considerations for Facilities ....................................................................................... 3 10.0 Facility Sizing and Downstream Analysis ................................................................................... 3 10.1 Conveyance ........................................................................................................................ 3 10.2 Treatment ............................................................................................................................ 3 10.3 Flow Control ........................................................................................................................ 3 10.4 Roof Runoff ......................................................................................................................... 4 11.0 Covenants Dedications, Easements ............................................................................................ 4 12.0 Property Owners Association Articles of Incorporation ............................................................ 4 13.0 Conclusion ...................................................................................................................................... 4 Stormwater Report Crystal Springs Preliminary Plat 2210633.10 Appendices Appendix A Exhibits A-1 ............. Vicinity Map A-2 ............. NRCS Soil Map A-3 ............. Developed Basin Map A-4 ............. FEMA 100-Year Flood Plain Map Appendix B Conveyance Calculations B-1 ............. WWHM Report Appendix C Geotechnical Report Earth Solutions NW, LLC, October 6, 2021 Stormwater Report Crystal Springs Preliminary Plat 1 2210633.10 1.0 Project Overview The following hydrology report summarizes the storm drainage analysis and design for a 30-lot development located at 714 NW Crystal Springs Road in Yelm, Thurston County, Washington. The land is currently a 4.89-acre property. The project includes the addition of 30 residential lots for single-family homes, a new roadway and sidewalks, sewer, water services, and stormwater facilities to treat and dispose of the project's stormwater. The proposed roadway features and utilities will be extended from NW Crystal Springs Road, as well as connecting to Woodland Court SE. No offsite road improvements will be required, other than frontage improvements along the panhandle at NW Crystal Springs Road. The 4.89-acre site is located in Section 19, Township 17 North, Range 02 East, W. M. The Thurston County tax parcel number associated with the project is 22719210403. The increased stormwater runoff resulting from the addition of impervious area will be treated and retained in accordance with the most recent Washington State Department of Ecology (DOE) Stormwater Management Manual for Western Washington (SMMWW). 2.0 Summary of Minimum Requirements This project is subject to the SMMWW and is a new development that will add more than 10,000 square feet of impervious surfaces; therefore, all Minimum Requirements (MR) apply to this project. 2.1 MR 1 – Preparation of Stormwater Site Plans This report and the project plans represent the Stormwater Site Plan for this project and satisfy MR 1. 2.2 MR 2 - Construction Stormwater Pollution Prevention A Construction Stormwater Pollution Prevention Plan will be prepared with final engineering. 2.3 MR 3 – Source Control of Pollution Pollution source control will be provided for the site by separating roof runoff from pollution generating surfaces. The residential roads should be maintained and cleaned of debris, garbage, and sediment, as required. The Construction SWPPP, addressing MR 3, will be prepared with final engineering. 2.4 MR 4 – Preservation of Natural Drainage Systems and Outfalls The project proposes to infiltrate all stormwater runoff, so all runoff will be retained in the developed condition. There are no natural drainage systems or outfalls to preserve. 2.5 MR 5 – Onsite Stormwater Control This project will meet the Low Impact Development (LID) Performance Standard. The onsite soils have a high infiltration capacity, and all runoff will be retained onsite through treatment systems and infiltration facilities. The LID Performance Standard will be met by infiltrating all stormwater runoff from the site. Refer to Section 10.0 for facility sizing. Stormwater Report Crystal Springs Preliminary Plat 2 2210633.10 2.6 MR 6 – Runoff Treatment Over 5,000 square feet of pollution generating impervious surface (PGIS) will be added as part of these improvements; therefore, runoff treatment is required for this site. Stormwater from the roadways will be conveyed to stormwater treatment filters before being infiltrated. There are two distinct basins conveying stormwater to separate treatment systems and inf iltration trenches. Final treatment system sizing will be completed with final engineering. 2.7 MR 7 – Flow Control The project exceeds the thresholds for new development projects and must provide flow control . Proposed flow control is achieved with the use of infiltration trenches that will infiltrate 100 percent of runoff. Refer to Section 10.0 for facility sizing. 2.8 MR 8 – Wetlands Protection To our knowledge, no wetlands are located on or adjacent to the site. 2.9 MR 9 – Basin/Watershed Planning To our knowledge, no basin plans exist for the site. All of Yelm is within a critical aquifer recharge area. Treatment of stormwater prior to infiltration is proposed via media filter manholes. Final sizing of the treatment system will be done with final engineering. 2.10 MR 10 – Operation and Maintenance The stormwater system for the roadway improvements will be publicly owned and maintained. The City of Yelm shall be responsible for the operation and maintenance of the public stormwater facilities. An Operation and Maintenance Plan consisting of maintenance checklists for stormwater management will be prepared with final engineering. Operation and maintenance for drainage facilities constructed for each lot shall be the responsibility of the individual owners. 3.0 Existing Conditions The site is presently covered with grass and a few deciduous trees, along with an existing building on the south end of the site, with slopes ranging from 0 to 5 percent. Presently, it appears the site runs off to the south and down the current access road to NW Crystal Springs Road. 4.0 Soils Reports Site soils are identified by the Natural Resources Conservation Service (NRCS) Web Soil Survey as Spanaway gravelly sandy loam, a Type A soil. This soil is characterized as very deep, somewhat excessively drained. Earth Solutions NW conducted a site investigation to confirm subsurface soil conditions and establish a design infiltration rate. Soil test holes were dug in the vicinity of the proposed infiltration basins of the project and observations confirm that the soil types match the SCS soil description. A soil log map showing the location of the test holes is included in the geotechnical report. The report recommends a design infiltration rate of 20 inches per hour. Please see Appendix C for the complete Earth Solutions NW report. 5.0 Wells An existing well is present at the northern edge of the site. The well will be decommissioned according to City of Yelm and Washington Department of Health standards. Stormwater Report Crystal Springs Preliminary Plat 3 2210633.10 Each lot will be served by the City of Yelm STEP collection system. The holding tank will be maintained by the City and pumped on a regular basis. Domestic water will be provided by the City of Yelm water distribution system. 6.0 Fuel Tanks No fuel tanks were observed at the project site. 7.0 Sub-Basin Description Site topography contributes zero acres of offsite storm runoff. There are two separate basins in the developed conditions. Each basin has an independent treatment and infiltration system. The impervious areas used for determining flow control and water treatment do not include individual lots. On-lot runoff will be collected and infiltrated in individual drywells. Refer to Appendix A-3 for the Developed Basin Map. Drywell sizing will be provided with final engineering. 8.0 Analysis of the 100-Year Flood Federal Emergency Management Agency (FEMA) mapping does not indicate flooding in the immediate area. Refer to the exhibit in Appendix A-4. 9.0 Aesthetic Considerations for Facilities The proposed stormwater infiltration facilities will be underground and have minimal impact to the aesthetics of the site. 10.0 Facility Sizing and Downstream Analysis The stormwater system was sized and analyzed using the latest edition of the Western Washington Hydrology Model (WWHM) continuous modeling software. As previously described, conservative infiltration rates of 20 inches per hour were used for the design calculations. 10.1 Conveyance Conveyance sizing will be completed with final engineering. 10.2 Treatment Basic treatment will be provided via media filter cartridge manholes /catch basins. Final sizing will be completed with final engineering 10.3 Flow Control Flow control will be provided by infiltration trenches. Each basin will have a single trench. Basin A will have a 4.0-foot deep trench with a bottom area of 1,240 square feet that will be constructed in the open space in Tract A. The trench will be 20 feet wide and 62 feet long. Basin B will have a 4.0-foot deep trench with a bottom area of 200 square feet that will be constructed on the south side of NW Crystal Springs Road. The trench will be 3 feet wide and 66 feet long. Stormwater Report Crystal Springs Preliminary Plat 4 2210633.10 Infiltration Basin Summary Basin Pervious Area (ac) Impervious Area (ac) Trench Dimensions (ft x ft) Percent Infiltrated A 0.34 1.21 20 x 62 100 B 0.14 0.19 3 x 66 100 The two infiltration basins were sized in accordance with the SMMWW and exceed the required storage volumes. 10.4 Roof Runoff Stormwater for the roof area of the homes will be infiltrated in individual drywells. The drywells will be sized in accordance with SMMWW Volume 3, Chapter 3, Section 3.1.1 - BMP T5.10A Downspout Full Infiltration System. Refer to Appendix B-1 for the roof downspout system detail. 11.0 Covenants Dedications, Easements The storm facilities for the right-of-way improvements shall be publicly owned and maintained. A maintenance agreement should be executed to ensure future maintenance of the facilities. The on-lot systems will be privately owned and maintained and therefore do not require covenants, dedications, or easements. 12.0 Property Owners Association Articles of Incorporation Not applicable. 13.0 Conclusion The proposed project involves site improvements associated with a 30-lot development. The project includes clearing, grading, erosion control, utility improvements, and stormwater management facilities. The site, as proposed, will meet the requirements of the most recent Department of Ecology Stormwater Management Manual for Western Washington (SMMWW). This report and associated plans have been prepared within the guidelines established by the City of Yelm for stormwater management. This analysis is based on data and records either supplied to or obtained by AHBL. These documents are referenced within the text of the analysis. The analysis has been prepared using procedures and practices within the standard accepted practices of the industry. AHBL, Inc. Quinten Foster Project Engineer QF/lsk October 2021 Q:\2021\2210633\WORDPROC\Reports\20211006 Rpt (Storm) 2210633.10.docx Stormwater Report Crystal Springs Preliminary Plat 2210633.10 Appendix A Exhibits A-1 .................... Vicinity Map A-2 .................... NRCS Soil Map A-3 .................... Developed Basin Map A-4 .................... FEMA 100-Year Flood Plain Map Civil EngineersStructural EngineersLandscape ArchitectsCommunity PlannersLand SurveyorsNeighborsCRYSTAL SPRINGSPRELIMINARY PLATCANALRD SECOATES AVE NW510WOODLAND CT SESITEVICINITY MAPSCALE: 1" = 660' (1/8 MILE) Soil Map—Thurston County Area, Washington (A-2) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/5/2021 Page 1 of 35199540519956051995805199600519962051996405199660519968051997005199720519974051997605199780519980051995405199560519958051996005199620519964051996605199680519970051997205199740519976051997805199800530070530090530110530130530150530170530190530210530230 530070 530090 530110 530130 530150 530170 530190 530210 530230 46° 57' 4'' N 122° 36' 17'' W46° 57' 4'' N122° 36' 9'' W46° 56' 55'' N 122° 36' 17'' W46° 56' 55'' N 122° 36' 9'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 35 70 140 210 Feet 0 10 20 40 60 Meters Map Scale: 1:766 if printed on B portrait (11" x 17") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Thurston County Area, Washington Survey Area Data: Version 15, Aug 31, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 18, 2020—Jul 20, 2020 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—Thurston County Area, Washington (A-2) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/5/2021 Page 2 of 3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 110 Spanaway gravelly sandy loam, 0 to 3 percent slopes 4.5 63.1% 111 Spanaway gravelly sandy loam, 3 to 15 percent slopes 2.6 36.9% Totals for Area of Interest 7.1 100.0% Soil Map—Thurston County Area, Washington A-2 Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/5/2021 Page 3 of 3 CRYSTAL SPRINGS STREET NW 2618TRACT A171216141113201991523612341078252124TRACT B5292722APN22719210404CITY OF YELM2830ssss sssssssssssssssssssss sssss(STORMFILTER)66LF 12" PERF CPEP(MAINTENANCE ACCESS)62LF 12" PERF. CPEP10' O.C.33 7337335334333336337 337 337 3373363373383 3 6 3 3 7 3 3 8 338337336337336 337 338 339 340 340 339 338 337 338339CRYSTAL SPRINGS ST NW WOODLAND CT SE ROAD AROAD BROAD CCB #13RIM: 331.98CB #14RIM: 331.98CB #15RIM: 332.05CB #16RIM: 333.46CB #9RIM: 336.28CB #10RIM: 336.28CB #8RIM: 337.56CB #7RIM: 336.04CB #6RIM: 336.04CB #17RIM: 335.44CB #11RIM: 336.02CB #12RIM: 336.11CO #1RIM: 336.23CO #2RIM: 336.93CO #3RIM: 336.77CB #5RIM: 338.28CB #2RIM: 335.60CB #1RIM: 335.60CB #3RIM: 335.61CB #4RIM: 335.66APN22719210403NGRAPHIC SCALE0801601" = 80 FEET40PROPOSED 200 SF X 4FTDEEP INFILTRATION TRENCHPROPOSED 1,240 SF X 4FTDEEP INFILTRATIONTRENCH12" CPEPSTORM PIPE (TYP)Civil EngineersStructural EngineersLandscape ArchitectsCommunity PlannersLand SurveyorsNeighborsCRYSTAL SPRINGSPRELIMINARY PLATBasin A (onsite)Basin B (road C) National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 10/5/2021 at 6:14 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 122°36'33"W 46°57'12"N 122°35'55"W 46°56'47"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 Stormwater Report Crystal Springs Preliminary Plat 2210633.10 Appendix B Conveyance Calculations B-1 .................... WWHM Report WWHM2012 PROJECT REPORT Infiltration 10/6/2021 1:15:41 PM Page 2 General Model Information Project Name:Infiltration Site Name: Site Address: City: Report Date:10/6/2021 Gage:Lake Lawrence Data Start:1955/10/01 Data End:2008/09/30 Timestep:15 Minute Precip Scale:0.857 Version Date:2019/09/13 Version:4.2.17 POC Thresholds Infiltration 10/6/2021 1:15:41 PM Page 3 Landuse Basin Data Predeveloped Land Use Infiltration 10/6/2021 1:15:41 PM Page 4 Mitigated Land Use onsite Bypass:No GroundWater:No Pervious Land Use acre C, Pasture, Flat 0.34171 Pervious Total 0.34171 Impervious Land Use acre ROADS FLAT 0.87734 DRIVEWAYS FLAT 0.09642 SIDEWALKS FLAT 0.23942 Impervious Total 1.21318 Basin Total 1.55489 Element Flows To: Surface Interflow Groundwater onsite onsite Infiltration 10/6/2021 1:15:41 PM Page 5 Routing Elements Predeveloped Routing Infiltration 10/6/2021 1:15:41 PM Page 6 Mitigated Routing onsite Bottom Length:62.00 ft. Bottom Width:20.00 ft. Trench bottom slope 1:0 To 1 Trench Left side slope 0:0 To 1 Trench right side slope 2:0 To 1 Material thickness of first layer:4 Pour Space of material for first layer:0.33 Material thickness of second layer:0 Pour Space of material for second layer:0 Material thickness of third layer:0 Pour Space of material for third layer:0 Infiltration On Infiltration rate:20 Infiltration safety factor:1 Total Volume Infiltrated (ac-ft.):236.313 Total Volume Through Riser (ac-ft.):0 Total Volume Through Facility (ac-ft.):236.313 Percent Infiltrated:100 Total Precip Applied to Facility:0 Total Evap From Facility:0 Discharge Structure Riser Height:4 ft. Riser Diameter:12 in. Element Flows To: Outlet 1 Outlet 2 Gravel Trench Bed Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.028 0.000 0.000 0.000 0.0444 0.028 0.000 0.000 0.574 0.0889 0.028 0.000 0.000 0.574 0.1333 0.028 0.001 0.000 0.574 0.1778 0.028 0.001 0.000 0.574 0.2222 0.028 0.002 0.000 0.574 0.2667 0.028 0.002 0.000 0.574 0.3111 0.028 0.002 0.000 0.574 0.3556 0.028 0.003 0.000 0.574 0.4000 0.028 0.003 0.000 0.574 0.4444 0.028 0.004 0.000 0.574 0.4889 0.028 0.004 0.000 0.574 0.5333 0.028 0.005 0.000 0.574 0.5778 0.028 0.005 0.000 0.574 0.6222 0.028 0.005 0.000 0.574 0.6667 0.028 0.006 0.000 0.574 0.7111 0.028 0.006 0.000 0.574 0.7556 0.028 0.007 0.000 0.574 0.8000 0.028 0.007 0.000 0.574 0.8444 0.028 0.007 0.000 0.574 0.8889 0.028 0.008 0.000 0.574 0.9333 0.028 0.008 0.000 0.574 0.9778 0.028 0.009 0.000 0.574 1.0222 0.028 0.009 0.000 0.574 Infiltration 10/6/2021 1:15:41 PM Page 7 1.0667 0.028 0.010 0.000 0.574 1.1111 0.028 0.010 0.000 0.574 1.1556 0.028 0.010 0.000 0.574 1.2000 0.028 0.011 0.000 0.574 1.2444 0.028 0.011 0.000 0.574 1.2889 0.028 0.012 0.000 0.574 1.3333 0.028 0.012 0.000 0.574 1.3778 0.028 0.012 0.000 0.574 1.4222 0.028 0.013 0.000 0.574 1.4667 0.028 0.013 0.000 0.574 1.5111 0.028 0.014 0.000 0.574 1.5556 0.028 0.014 0.000 0.574 1.6000 0.028 0.015 0.000 0.574 1.6444 0.028 0.015 0.000 0.574 1.6889 0.028 0.015 0.000 0.574 1.7333 0.028 0.016 0.000 0.574 1.7778 0.028 0.016 0.000 0.574 1.8222 0.028 0.017 0.000 0.574 1.8667 0.028 0.017 0.000 0.574 1.9111 0.028 0.018 0.000 0.574 1.9556 0.028 0.018 0.000 0.574 2.0000 0.028 0.018 0.000 0.574 2.0444 0.028 0.019 0.000 0.574 2.0889 0.028 0.019 0.000 0.574 2.1333 0.028 0.020 0.000 0.574 2.1778 0.028 0.020 0.000 0.574 2.2222 0.028 0.020 0.000 0.574 2.2667 0.028 0.021 0.000 0.574 2.3111 0.028 0.021 0.000 0.574 2.3556 0.028 0.022 0.000 0.574 2.4000 0.028 0.022 0.000 0.574 2.4444 0.028 0.023 0.000 0.574 2.4889 0.028 0.023 0.000 0.574 2.5333 0.028 0.023 0.000 0.574 2.5778 0.028 0.024 0.000 0.574 2.6222 0.028 0.024 0.000 0.574 2.6667 0.028 0.025 0.000 0.574 2.7111 0.028 0.025 0.000 0.574 2.7556 0.028 0.025 0.000 0.574 2.8000 0.028 0.026 0.000 0.574 2.8444 0.028 0.026 0.000 0.574 2.8889 0.028 0.027 0.000 0.574 2.9333 0.028 0.027 0.000 0.574 2.9778 0.028 0.028 0.000 0.574 3.0222 0.028 0.028 0.000 0.574 3.0667 0.028 0.028 0.000 0.574 3.1111 0.028 0.029 0.000 0.574 3.1556 0.028 0.029 0.000 0.574 3.2000 0.028 0.030 0.000 0.574 3.2444 0.028 0.030 0.000 0.574 3.2889 0.028 0.030 0.000 0.574 3.3333 0.028 0.031 0.000 0.574 3.3778 0.028 0.031 0.000 0.574 3.4222 0.028 0.032 0.000 0.574 3.4667 0.028 0.032 0.000 0.574 3.5111 0.028 0.033 0.000 0.574 3.5556 0.028 0.033 0.000 0.574 3.6000 0.028 0.033 0.000 0.574 Infiltration 10/6/2021 1:15:41 PM Page 8 3.6444 0.028 0.034 0.000 0.574 3.6889 0.028 0.034 0.000 0.574 3.7333 0.028 0.035 0.000 0.574 3.7778 0.028 0.035 0.000 0.574 3.8222 0.028 0.035 0.000 0.574 3.8667 0.028 0.036 0.000 0.574 3.9111 0.028 0.036 0.000 0.574 3.9556 0.028 0.037 0.000 0.574 4.0000 0.028 0.037 0.000 0.574 Infiltration 10/6/2021 1:15:41 PM Page 9 Analysis Results POC 1 POC #1 was not reported because POC must exist in both scenarios and both scenarios must have been run. Infiltration 10/6/2021 1:15:41 PM Page 10 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. Infiltration 10/6/2021 1:15:41 PM Page 11 Appendix Predeveloped Schematic Infiltration 10/6/2021 1:15:43 PM Page 12 Mitigated Schematic Infiltration 10/6/2021 1:15:45 PM Page 13 Predeveloped UCI File Infiltration 10/6/2021 1:15:45 PM Page 14 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1955 10 01 END 2008 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Infiltration.wdm MESSU 25 MitInfiltration.MES 27 MitInfiltration.L61 28 MitInfiltration.L62 END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 13 IMPLND 1 IMPLND 5 IMPLND 8 RCHRES 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 13 C, Pasture, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 13 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 13 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 Infiltration 10/6/2021 1:15:45 PM Page 15 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 13 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 13 0 4.5 0.06 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 13 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 13 0.15 0.4 0.3 6 0.5 0.4 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 13 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 5 DRIVEWAYS/FLAT 1 1 1 27 0 8 SIDEWALKS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 5 0 0 1 0 0 0 8 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 5 0 0 4 0 0 0 1 9 8 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 5 0 0 0 0 0 8 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 Infiltration 10/6/2021 1:15:45 PM Page 16 5 400 0.01 0.1 0.1 8 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 5 0 0 8 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 5 0 0 8 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** onsite*** PERLND 13 0.3417 RCHRES 1 2 PERLND 13 0.3417 RCHRES 1 3 IMPLND 1 0.8773 RCHRES 1 5 IMPLND 5 0.0964 RCHRES 1 5 IMPLND 8 0.2394 RCHRES 1 5 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 onsite 2 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit Infiltration 10/6/2021 1:15:45 PM Page 17 * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 92 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.028466 0.000000 0.000000 0.000000 0.044444 0.028466 0.000418 0.000000 0.574074 0.088889 0.028466 0.000835 0.000000 0.574074 0.133333 0.028466 0.001253 0.000000 0.574074 0.177778 0.028466 0.001670 0.000000 0.574074 0.222222 0.028466 0.002088 0.000000 0.574074 0.266667 0.028466 0.002505 0.000000 0.574074 0.311111 0.028466 0.002923 0.000000 0.574074 0.355556 0.028466 0.003340 0.000000 0.574074 0.400000 0.028466 0.003758 0.000000 0.574074 0.444444 0.028466 0.004175 0.000000 0.574074 0.488889 0.028466 0.004593 0.000000 0.574074 0.533333 0.028466 0.005010 0.000000 0.574074 0.577778 0.028466 0.005428 0.000000 0.574074 0.622222 0.028466 0.005845 0.000000 0.574074 0.666667 0.028466 0.006263 0.000000 0.574074 0.711111 0.028466 0.006680 0.000000 0.574074 0.755556 0.028466 0.007098 0.000000 0.574074 0.800000 0.028466 0.007515 0.000000 0.574074 0.844444 0.028466 0.007933 0.000000 0.574074 0.888889 0.028466 0.008350 0.000000 0.574074 0.933333 0.028466 0.008768 0.000000 0.574074 0.977778 0.028466 0.009185 0.000000 0.574074 1.022222 0.028466 0.009603 0.000000 0.574074 1.066667 0.028466 0.010020 0.000000 0.574074 1.111111 0.028466 0.010438 0.000000 0.574074 1.155556 0.028466 0.010855 0.000000 0.574074 1.200000 0.028466 0.011273 0.000000 0.574074 1.244444 0.028466 0.011690 0.000000 0.574074 1.288889 0.028466 0.012108 0.000000 0.574074 1.333333 0.028466 0.012525 0.000000 0.574074 1.377778 0.028466 0.012943 0.000000 0.574074 1.422222 0.028466 0.013360 0.000000 0.574074 1.466667 0.028466 0.013778 0.000000 0.574074 1.511111 0.028466 0.014195 0.000000 0.574074 1.555556 0.028466 0.014613 0.000000 0.574074 1.600000 0.028466 0.015030 0.000000 0.574074 1.644444 0.028466 0.015448 0.000000 0.574074 1.688889 0.028466 0.015865 0.000000 0.574074 1.733333 0.028466 0.016283 0.000000 0.574074 1.777778 0.028466 0.016700 0.000000 0.574074 1.822222 0.028466 0.017118 0.000000 0.574074 1.866667 0.028466 0.017535 0.000000 0.574074 1.911111 0.028466 0.017953 0.000000 0.574074 1.955556 0.028466 0.018370 0.000000 0.574074 Infiltration 10/6/2021 1:15:45 PM Page 18 2.000000 0.028466 0.018788 0.000000 0.574074 2.044444 0.028466 0.019205 0.000000 0.574074 2.088889 0.028466 0.019623 0.000000 0.574074 2.133333 0.028466 0.020040 0.000000 0.574074 2.177778 0.028466 0.020458 0.000000 0.574074 2.222222 0.028466 0.020875 0.000000 0.574074 2.266667 0.028466 0.021293 0.000000 0.574074 2.311111 0.028466 0.021710 0.000000 0.574074 2.355556 0.028466 0.022128 0.000000 0.574074 2.400000 0.028466 0.022545 0.000000 0.574074 2.444444 0.028466 0.022963 0.000000 0.574074 2.488889 0.028466 0.023380 0.000000 0.574074 2.533333 0.028466 0.023798 0.000000 0.574074 2.577778 0.028466 0.024215 0.000000 0.574074 2.622222 0.028466 0.024633 0.000000 0.574074 2.666667 0.028466 0.025051 0.000000 0.574074 2.711111 0.028466 0.025468 0.000000 0.574074 2.755556 0.028466 0.025886 0.000000 0.574074 2.800000 0.028466 0.026303 0.000000 0.574074 2.844444 0.028466 0.026721 0.000000 0.574074 2.888889 0.028466 0.027138 0.000000 0.574074 2.933333 0.028466 0.027556 0.000000 0.574074 2.977778 0.028466 0.027973 0.000000 0.574074 3.022222 0.028466 0.028391 0.000000 0.574074 3.066667 0.028466 0.028808 0.000000 0.574074 3.111111 0.028466 0.029226 0.000000 0.574074 3.155556 0.028466 0.029643 0.000000 0.574074 3.200000 0.028466 0.030061 0.000000 0.574074 3.244444 0.028466 0.030478 0.000000 0.574074 3.288889 0.028466 0.030896 0.000000 0.574074 3.333333 0.028466 0.031313 0.000000 0.574074 3.377778 0.028466 0.031731 0.000000 0.574074 3.422222 0.028466 0.032148 0.000000 0.574074 3.466667 0.028466 0.032566 0.000000 0.574074 3.511111 0.028466 0.032983 0.000000 0.574074 3.555556 0.028466 0.033401 0.000000 0.574074 3.600000 0.028466 0.033818 0.000000 0.574074 3.644444 0.028466 0.034236 0.000000 0.574074 3.688889 0.028466 0.034653 0.000000 0.574074 3.733333 0.028466 0.035071 0.000000 0.574074 3.777778 0.028466 0.035488 0.000000 0.574074 3.822222 0.028466 0.035906 0.000000 0.574074 3.866667 0.028466 0.036323 0.000000 0.574074 3.911111 0.028466 0.036741 0.000000 0.574074 3.955556 0.028466 0.037158 0.000000 0.574074 4.000000 0.028466 0.037576 0.000000 0.574074 4.044444 0.028466 0.038841 0.099321 0.574074 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 0.857 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 0.857 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL Infiltration 10/6/2021 1:15:45 PM Page 19 END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 END MASS-LINK END RUN Infiltration 10/6/2021 1:15:45 PM Page 20 Predeveloped HSPF Message File Infiltration 10/6/2021 1:15:45 PM Page 21 Mitigated HSPF Message File Infiltration 10/6/2021 1:15:45 PM Page 22 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2021; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT INFILTRATION 10/5/2021 3:36:19 PM Page 2 General Model Information Project Name:INFILTRATION Site Name: Site Address: City: Report Date:10/5/2021 Gage:Lake Lawrence Data Start:1955/10/01 Data End:2008/09/30 Timestep:15 Minute Precip Scale:0.857 Version Date:2019/09/13 Version:4.2.17 POC Thresholds INFILTRATION 10/5/2021 3:36:19 PM Page 3 Landuse Basin Data Predeveloped Land Use INFILTRATION 10/5/2021 3:36:19 PM Page 4 Mitigated Land Use ROAD C Bypass:No GroundWater:No Pervious Land Use acre C, Pasture, Flat 0.14 Pervious Total 0.14 Impervious Land Use acre ROADS FLAT 0.19 Impervious Total 0.19 Basin Total 0.33 Element Flows To: Surface Interflow Groundwater ROAD C TRENCH ROAD C TRENCH INFILTRATION 10/5/2021 3:36:19 PM Page 5 Routing Elements Predeveloped Routing INFILTRATION 10/5/2021 3:36:19 PM Page 6 Mitigated Routing ROAD C TRENCH Bottom Length:66.00 ft. Bottom Width:3.00 ft. Trench bottom slope 1:0 To 1 Trench Left side slope 0:0 To 1 Trench right side slope 2:0 To 1 Material thickness of first layer:4 Pour Space of material for first layer:0.33 Material thickness of second layer:0 Pour Space of material for second layer:0 Material thickness of third layer:0 Pour Space of material for third layer:0 Infiltration On Infiltration rate:20 Infiltration safety factor:1 Total Volume Infiltrated (ac-ft.):42.325 Total Volume Through Riser (ac-ft.):0 Total Volume Through Facility (ac-ft.):42.326 Percent Infiltrated:100 Total Precip Applied to Facility:0 Total Evap From Facility:0 Discharge Structure Riser Height:4 ft. Riser Diameter:12 in. Element Flows To: Outlet 1 Outlet 2 Gravel Trench Bed Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.004 0.000 0.000 0.000 0.0444 0.004 0.000 0.000 0.091 0.0889 0.004 0.000 0.000 0.091 0.1333 0.004 0.000 0.000 0.091 0.1778 0.004 0.000 0.000 0.091 0.2222 0.004 0.000 0.000 0.091 0.2667 0.004 0.000 0.000 0.091 0.3111 0.004 0.000 0.000 0.091 0.3556 0.004 0.000 0.000 0.091 0.4000 0.004 0.000 0.000 0.091 0.4444 0.004 0.000 0.000 0.091 0.4889 0.004 0.000 0.000 0.091 0.5333 0.004 0.000 0.000 0.091 0.5778 0.004 0.000 0.000 0.091 0.6222 0.004 0.000 0.000 0.091 0.6667 0.004 0.001 0.000 0.091 0.7111 0.004 0.001 0.000 0.091 0.7556 0.004 0.001 0.000 0.091 0.8000 0.004 0.001 0.000 0.091 0.8444 0.004 0.001 0.000 0.091 0.8889 0.004 0.001 0.000 0.091 0.9333 0.004 0.001 0.000 0.091 0.9778 0.004 0.001 0.000 0.091 1.0222 0.004 0.001 0.000 0.091 INFILTRATION 10/5/2021 3:36:19 PM Page 7 1.0667 0.004 0.001 0.000 0.091 1.1111 0.004 0.001 0.000 0.091 1.1556 0.004 0.001 0.000 0.091 1.2000 0.004 0.001 0.000 0.091 1.2444 0.004 0.001 0.000 0.091 1.2889 0.004 0.001 0.000 0.091 1.3333 0.004 0.002 0.000 0.091 1.3778 0.004 0.002 0.000 0.091 1.4222 0.004 0.002 0.000 0.091 1.4667 0.004 0.002 0.000 0.091 1.5111 0.004 0.002 0.000 0.091 1.5556 0.004 0.002 0.000 0.091 1.6000 0.004 0.002 0.000 0.091 1.6444 0.004 0.002 0.000 0.091 1.6889 0.004 0.002 0.000 0.091 1.7333 0.004 0.002 0.000 0.091 1.7778 0.004 0.002 0.000 0.091 1.8222 0.004 0.002 0.000 0.091 1.8667 0.004 0.002 0.000 0.091 1.9111 0.004 0.002 0.000 0.091 1.9556 0.004 0.002 0.000 0.091 2.0000 0.004 0.003 0.000 0.091 2.0444 0.004 0.003 0.000 0.091 2.0889 0.004 0.003 0.000 0.091 2.1333 0.004 0.003 0.000 0.091 2.1778 0.004 0.003 0.000 0.091 2.2222 0.004 0.003 0.000 0.091 2.2667 0.004 0.003 0.000 0.091 2.3111 0.004 0.003 0.000 0.091 2.3556 0.004 0.003 0.000 0.091 2.4000 0.004 0.003 0.000 0.091 2.4444 0.004 0.003 0.000 0.091 2.4889 0.004 0.003 0.000 0.091 2.5333 0.004 0.003 0.000 0.091 2.5778 0.004 0.003 0.000 0.091 2.6222 0.004 0.003 0.000 0.091 2.6667 0.004 0.004 0.000 0.091 2.7111 0.004 0.004 0.000 0.091 2.7556 0.004 0.004 0.000 0.091 2.8000 0.004 0.004 0.000 0.091 2.8444 0.004 0.004 0.000 0.091 2.8889 0.004 0.004 0.000 0.091 2.9333 0.004 0.004 0.000 0.091 2.9778 0.004 0.004 0.000 0.091 3.0222 0.004 0.004 0.000 0.091 3.0667 0.004 0.004 0.000 0.091 3.1111 0.004 0.004 0.000 0.091 3.1556 0.004 0.004 0.000 0.091 3.2000 0.004 0.004 0.000 0.091 3.2444 0.004 0.004 0.000 0.091 3.2889 0.004 0.004 0.000 0.091 3.3333 0.004 0.005 0.000 0.091 3.3778 0.004 0.005 0.000 0.091 3.4222 0.004 0.005 0.000 0.091 3.4667 0.004 0.005 0.000 0.091 3.5111 0.004 0.005 0.000 0.091 3.5556 0.004 0.005 0.000 0.091 3.6000 0.004 0.005 0.000 0.091 INFILTRATION 10/5/2021 3:36:19 PM Page 8 3.6444 0.004 0.005 0.000 0.091 3.6889 0.004 0.005 0.000 0.091 3.7333 0.004 0.005 0.000 0.091 3.7778 0.004 0.005 0.000 0.091 3.8222 0.004 0.005 0.000 0.091 3.8667 0.004 0.005 0.000 0.091 3.9111 0.004 0.005 0.000 0.091 3.9556 0.004 0.005 0.000 0.091 4.0000 0.004 0.006 0.000 0.091 INFILTRATION 10/5/2021 3:36:19 PM Page 9 Analysis Results POC 1 POC #1 was not reported because POC must exist in both scenarios and both scenarios must have been run. INFILTRATION 10/5/2021 3:36:19 PM Page 10 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. INFILTRATION 10/5/2021 3:36:19 PM Page 11 Appendix Predeveloped Schematic INFILTRATION 10/5/2021 3:36:20 PM Page 12 Mitigated Schematic INFILTRATION 10/5/2021 3:36:21 PM Page 13 Predeveloped UCI File INFILTRATION 10/5/2021 3:36:21 PM Page 14 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1955 10 01 END 2008 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 INFILTRATION.wdm MESSU 25 MitINFILTRATION.MES 27 MitINFILTRATION.L61 28 MitINFILTRATION.L62 END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 13 IMPLND 1 RCHRES 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 13 C, Pasture, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 13 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 13 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** INFILTRATION 10/5/2021 3:36:21 PM Page 15 13 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 13 0 4.5 0.06 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 13 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 13 0.15 0.4 0.3 6 0.5 0.4 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 13 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation INFILTRATION 10/5/2021 3:36:21 PM Page 16 # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** ROAD C*** PERLND 13 0.14 RCHRES 1 2 PERLND 13 0.14 RCHRES 1 3 IMPLND 1 0.19 RCHRES 1 5 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 ROAD C TRENCH 2 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES INFILTRATION 10/5/2021 3:36:21 PM Page 17 SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 92 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.004545 0.000000 0.000000 0.000000 0.044444 0.004545 0.000067 0.000000 0.091667 0.088889 0.004545 0.000133 0.000000 0.091667 0.133333 0.004545 0.000200 0.000000 0.091667 0.177778 0.004545 0.000267 0.000000 0.091667 0.222222 0.004545 0.000333 0.000000 0.091667 0.266667 0.004545 0.000400 0.000000 0.091667 0.311111 0.004545 0.000467 0.000000 0.091667 0.355556 0.004545 0.000533 0.000000 0.091667 0.400000 0.004545 0.000600 0.000000 0.091667 0.444444 0.004545 0.000667 0.000000 0.091667 0.488889 0.004545 0.000733 0.000000 0.091667 0.533333 0.004545 0.000800 0.000000 0.091667 0.577778 0.004545 0.000867 0.000000 0.091667 0.622222 0.004545 0.000933 0.000000 0.091667 0.666667 0.004545 0.001000 0.000000 0.091667 0.711111 0.004545 0.001067 0.000000 0.091667 0.755556 0.004545 0.001133 0.000000 0.091667 0.800000 0.004545 0.001200 0.000000 0.091667 0.844444 0.004545 0.001267 0.000000 0.091667 0.888889 0.004545 0.001333 0.000000 0.091667 0.933333 0.004545 0.001400 0.000000 0.091667 0.977778 0.004545 0.001467 0.000000 0.091667 1.022222 0.004545 0.001533 0.000000 0.091667 1.066667 0.004545 0.001600 0.000000 0.091667 1.111111 0.004545 0.001667 0.000000 0.091667 1.155556 0.004545 0.001733 0.000000 0.091667 1.200000 0.004545 0.001800 0.000000 0.091667 1.244444 0.004545 0.001867 0.000000 0.091667 1.288889 0.004545 0.001933 0.000000 0.091667 1.333333 0.004545 0.002000 0.000000 0.091667 1.377778 0.004545 0.002067 0.000000 0.091667 1.422222 0.004545 0.002133 0.000000 0.091667 1.466667 0.004545 0.002200 0.000000 0.091667 1.511111 0.004545 0.002267 0.000000 0.091667 1.555556 0.004545 0.002333 0.000000 0.091667 1.600000 0.004545 0.002400 0.000000 0.091667 1.644444 0.004545 0.002467 0.000000 0.091667 1.688889 0.004545 0.002533 0.000000 0.091667 1.733333 0.004545 0.002600 0.000000 0.091667 1.777778 0.004545 0.002667 0.000000 0.091667 1.822222 0.004545 0.002733 0.000000 0.091667 1.866667 0.004545 0.002800 0.000000 0.091667 1.911111 0.004545 0.002867 0.000000 0.091667 1.955556 0.004545 0.002933 0.000000 0.091667 2.000000 0.004545 0.003000 0.000000 0.091667 2.044444 0.004545 0.003067 0.000000 0.091667 2.088889 0.004545 0.003133 0.000000 0.091667 2.133333 0.004545 0.003200 0.000000 0.091667 2.177778 0.004545 0.003267 0.000000 0.091667 2.222222 0.004545 0.003333 0.000000 0.091667 2.266667 0.004545 0.003400 0.000000 0.091667 2.311111 0.004545 0.003467 0.000000 0.091667 2.355556 0.004545 0.003533 0.000000 0.091667 2.400000 0.004545 0.003600 0.000000 0.091667 2.444444 0.004545 0.003667 0.000000 0.091667 2.488889 0.004545 0.003733 0.000000 0.091667 2.533333 0.004545 0.003800 0.000000 0.091667 2.577778 0.004545 0.003867 0.000000 0.091667 2.622222 0.004545 0.003933 0.000000 0.091667 2.666667 0.004545 0.004000 0.000000 0.091667 2.711111 0.004545 0.004067 0.000000 0.091667 2.755556 0.004545 0.004133 0.000000 0.091667 INFILTRATION 10/5/2021 3:36:21 PM Page 18 2.800000 0.004545 0.004200 0.000000 0.091667 2.844444 0.004545 0.004267 0.000000 0.091667 2.888889 0.004545 0.004333 0.000000 0.091667 2.933333 0.004545 0.004400 0.000000 0.091667 2.977778 0.004545 0.004467 0.000000 0.091667 3.022222 0.004545 0.004533 0.000000 0.091667 3.066667 0.004545 0.004600 0.000000 0.091667 3.111111 0.004545 0.004667 0.000000 0.091667 3.155556 0.004545 0.004733 0.000000 0.091667 3.200000 0.004545 0.004800 0.000000 0.091667 3.244444 0.004545 0.004867 0.000000 0.091667 3.288889 0.004545 0.004933 0.000000 0.091667 3.333333 0.004545 0.005000 0.000000 0.091667 3.377778 0.004545 0.005067 0.000000 0.091667 3.422222 0.004545 0.005133 0.000000 0.091667 3.466667 0.004545 0.005200 0.000000 0.091667 3.511111 0.004545 0.005267 0.000000 0.091667 3.555556 0.004545 0.005333 0.000000 0.091667 3.600000 0.004545 0.005400 0.000000 0.091667 3.644444 0.004545 0.005467 0.000000 0.091667 3.688889 0.004545 0.005533 0.000000 0.091667 3.733333 0.004545 0.005600 0.000000 0.091667 3.777778 0.004545 0.005667 0.000000 0.091667 3.822222 0.004545 0.005733 0.000000 0.091667 3.866667 0.004545 0.005800 0.000000 0.091667 3.911111 0.004545 0.005867 0.000000 0.091667 3.955556 0.004545 0.005933 0.000000 0.091667 4.000000 0.004545 0.006000 0.000000 0.091667 4.044444 0.004545 0.006202 0.099321 0.091667 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 0.857 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 0.857 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 END MASS-LINK END RUN INFILTRATION 10/5/2021 3:36:21 PM Page 19 Predeveloped HSPF Message File INFILTRATION 10/5/2021 3:36:21 PM Page 20 Mitigated HSPF Message File INFILTRATION 10/5/2021 3:36:21 PM Page 21 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2021; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Stormwater Report Crystal Springs Preliminary Plat 2210633.10 Appendix C Geotechnical Report Earth Solutions NW, LLC, October 6, 2021 EarthSolutionsNWLLC EarthSolutions NW LLC 15365 N.E.90th Street,Suite 100 Redmond,WA 98052 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com Geotechnical Engineering Construction Observation/Testing Environmental Services GEOTECHNICAL ENGINEERING STUDY CRYSTAL SPRINGS 714 CRYSTAL SPRINGS STREET NORTHWEST YELM,WASHINGTON ES-8113 PREPARED FOR COPPER RIDGE, LLC October 6, 2021 _________________________ Scott S. Riegel, L.G., L.E.G. Senior Project Manager ________________________ Kyle R. Campbell, P.E. Principal Engineer GEOTECHNICAL ENGINEERING STUDY CRYSTAL SPRINGS 714 CRYSTAL SPRINGS STREET NORTHWEST YELM, WASHINGTON ES-8113 Earth Solutions NW, LLC 15365 Northeast 90th Street, Suite 100 Redmond, Washington 98052 Phone: 425-449-4704 | Fax: 425-449-4711 www.earthsolutionsnw.com 10/06/2021 Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Understand the Geotechnical-Engineering Services Provided for this Report Geotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities. The culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions. Geotechnical-Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific Times Geotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Likewise, geotechnical-engineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical- engineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project. Do not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project or purpose; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, the reliability of a geotechnical-engineering report can be affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis after the passage of time – if any is required at all – could prevent major problems. Read this Report in Full Costly problems have occurred because those relying on a geotechnical- engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full. You Need to Inform Your Geotechnical Engineer About Change Your geotechnical engineer considered unique, project-specific factors when developing the scope of study behind this report and developing the confirmation-dependent recommendations the report conveys. Typical changes that could erode the reliability of this report include those that affect: • the site’s size or shape; • the elevation, configuration, location, orientation, function or weight of the proposed structure and the desired performance criteria; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project or site changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing is performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed. This Report’s Recommendations Are Confirmation-Dependent The recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions exposed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be Misinterpreted Other design professionals’ misinterpretation of geotechnical- engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to: • confer with other design-team members; • help develop specifications; • review pertinent elements of other design professionals’ plans and specifications; and • be available whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction- phase observations. Give Constructors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually provide environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not obtained your own environmental information about the project site, ask your geotechnical consultant for a recommendation on how to find environmental risk-management guidance. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, the engineer’s services were not designed, conducted, or intended to prevent migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists. Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation. Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org October 6, 2021 ES-8113 Copper Ridge, LLC P.O. Box 73790 Puyallup, Washington 98373 Attention: Mr. Evan Mann Dear Mr. Mann: Earth Solutions NW, LLC (ESNW) is pleased to present this report supporting the planned residential development for Yelm, Washington. In our opinion, the proposed residential development is feasible from a geotechnical standpoint. Based on the conditions observed during our fieldwork, the subject site is underlain primarily by recessional outwash deposits that are suitable for infiltration. The proposed structures can be supported on conventional spread and continuous foundations bearing on competent native soil, recompacted native soil, or new structural fill placed directly on competent native soil. In general, competent native soil suitable for support of foundations will likely be encountered at depths of about two to four feet below the existing ground surface (bgs). Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of soils to the specifications of structural fill, or overexcavation and replacement with suitable structural fill, will likely be necessary. This report provides recommendations for foundation subgrade preparation, foundation and retaining wall design parameters, drainage, infiltration recommendations, the suitability of the on- site soils for use as structural fill, and other geotechnical recommendations. The opportunity to be of service to you is appreciated. If you have any questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Scott S. Riegel, L.G., L.E.G. Senior Project Manager 15365 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 Earth Solutions NW, LLC Table of Contents ES-8113 PAGE INTRODUCTION ................................................................................. 1 General..................................................................................... 1 Project Description ................................................................. 1 SITE CONDITIONS ............................................................................. 2 Surface ..................................................................................... 2 Subsurface .............................................................................. 2 Topsoil and Fill ............................................................. 2 Native Soil ..................................................................... 3 Geologic Setting ........................................................... 3 Groundwater ................................................................. 3 Geologically Hazardous Areas .............................................. 3 DISCUSSION AND RECOMMENDATIONS ....................................... 3 General..................................................................................... 3 Site Preparation and Earthwork ............................................. 4 Temporary Erosion Control ......................................... 4 In-Situ Soils .................................................................. 4 Wet Season Grading .................................................... 4 Structural Fill ................................................................ 4 Excavations and Slopes .............................................. 5 Foundations ............................................................................ 5 Seismic Design Considerations ............................................ 6 Slab-on-Grade Floors ............................................................. 7 Retaining Walls ....................................................................... 7 Drainage................................................................................... 8 Infiltration Evaluation ................................................... 8 Test Method .................................................................. 8 Test Results .................................................................. 9 Soil Types and Site Variability .................................... 9 Restrictive Layer .......................................................... 9 Summary and Recommendations............................... 9 Utility Support and Trench Backfill ....................................... 10 Pavement Sections ................................................................. 10 LIMITATIONS ...................................................................................... 11 Additional Services ................................................................. 11 Earth Solutions NW, LLC Table of Contents Cont’d ES-8113 GRAPHICS Plate 1 Vicinity Map Plate 2 Test Pit Location Plan Plate 3 Retaining Wall Drainage Detail Plate 4 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Test Pit Logs Appendix B Laboratory Test Results Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY CRYSTAL SPRINGS 714 CRYSTAL SPRINGS STREET NORTHWEST YELM, WASHINGTON ES-8113 INTRODUCTION General This report was prepared for the proposed residential development to be constructed at 714 Crystal Springs Street Northwest in Yelm, Washington. The purpose of this study was to provide geotechnical recommendations for the proposed development. Our scope of services for completing this geotechnical engineering study included the following:  Observing, logging, and sampling test pits for purposes of characterizing site soil and groundwater conditions;  Laboratory testing of soil samples collected at the test pit locations;  Engineering analyses and recommendations for the proposed development, and;  Preparation of this report. The following documents and resources were reviewed as part of our report preparation:  Geologic Map of the Centralia Quadrangle, Washington, 1987;  Conceptual Site Plan, undated;  Web Soil Survey (WSS) online resource, maintained by the Natural Resources Conservation Service under the United States Department of Agriculture, and;  Yelm Municipal Code Title 18.21: Critical Areas and Resource Lands. Project Description Based on review of the referenced plans, the subject site will be redeveloped with up to 30 single- family residences and associated improvements. Grading plans were not available at the time this report was prepared; however, given the low topographic relief on this site, we anticipate grading may include cuts and fills of up to about five feet with deeper excavations required to install underground utilities. Copper Ridge, LLC ES-8113 October 6, 2021 Page 2 Earth Solutions NW, LLC At the time this report was prepared, specific building load values were not available; however, we anticipate the proposed residential structures will consist of relatively lightly loaded wood framing supported on conventional foundations. Based on our experience with similar developments, we estimate wall loads on the order of 1 to 2 kips per linear foot and slab-on-grade loading of 150 pounds per square foot (psf). The feasibility of infiltrating runoff into native soils is being investigated as part of the project plans. If the above design assumptions are incorrect or change, ESNW should be contacted to review the recommendations in this report. ESNW should review the final design to verify the geotechnical recommendations provided in this report have been incorporated into the plans. SITE CONDITIONS Surface The subject site is located east of Crystal Springs Street Northwest in Yelm, Washington, as illustrated on the Vicinity Map (Plate 1). The site consists of a single tax parcel (Thurston County Parcel Number 22719210403) currently developed with a single-family residence, barn, detached garage, and associated improvements. The majority of the subject site is lightly to moderately vegetated with tall grass, and sparse trees and general landscaping around existing buildings. Topography is relatively level, with less than about five feet of total elevation change across the site. Subsurface A representative of ESNW observed, logged, and sampled six test pits, excavated at accessible locations within the proposed development area, on August 31, 2021, using a trackhoe and operator provided by the client. The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). Please refer to the test pit logs provided in Appendix A for a more detailed description of subsurface conditions. Representative soil samples collected at the test pit locations were analyzed in general accordance with Unified Soil Classification System (USCS) and United States Department of Agriculture (USDA) methods and procedures. Topsoil and Fill Topsoil was observed extending to depths of approximately 6 to 12 inches below existing grades. The topsoil thickness is variable and vegetation roots often extend below the topsoil zone into the underlying weathered native soil. The topsoil was characterized by dark brown color and fine organic material. Topsoil is not suitable for use as structural fill nor should it be mixed with material to be used as structural fill. Topsoil or otherwise unsuitable material can be used in landscape areas if desired. Fill was not encountered within the test pits; however, fill is likely present near the existing structures to some degree. If fill is encountered during construction, ESNW should be consulted to verify the suitability for support of the proposed structures and/or reuse as structural fill. Copper Ridge, LLC ES-8113 October 6, 2021 Page 3 Earth Solutions NW, LLC Native Soil Underlying the topsoil, native soils consisted primarily of medium dense to dense poorly and well- graded gravel with variable sand (USCS: GP and GW respectively). The native soils were generally encountered in a damp to moist condition and extended to the maximum exploration depth of 13 feet below ground surface (bgs). We encountered scattered large cobbles and small boulders at the test pit locations. Geologic Setting The referenced geologic map resource identifies recessional outwash, specifically Vashon drift gravel (Qdvg), across the site and surrounding areas. The referenced WSS resource identifies Spanaway gravelly sandy loam (Map Unit Symbols: 110 and 111) across the site and surrounding areas. Spanaway gravelly loam was formed in outwash plains. Based on our field observations, native soils on site are generally consistent with the geologic setting outlined in this section. Groundwater Groundwater was not encountered, at the time of our exploration (August 31, 2021). 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 wetter, winter, spring, and early summer months. Geologically Hazardous Areas As part of this report, the subject property was evaluated for the presence of geologically hazardous areas in general accordance with the applicable Yelm municipal code. Based on our investigation, the site does not lie within or is immediately adjacent to geologically hazardous areas. DISCUSSION AND RECOMMENDATIONS General In our opinion, the proposed residential structures can be supported on conventional spread and continuous foundations bearing on undisturbed competent native soil, recompacted native soil or new structural fill placed directly on competent native soil. Competent soils suitable for support of foundations are anticipated to be exposed at depths of about two to four feet below existing grades across the majority of the site. Slab-on-grade floors should be supported on competent native soil, re-compacted native soil, or new structural fill. Organic material exposed at subgrade elevations must be removed below design elevation and grades restored with structural fill. Where loose, organic or other unsuitable materials are encountered at or below the footing subgrade elevation, the material should be removed and replaced with structural fill, as necessary. Copper Ridge, LLC ES-8113 October 6, 2021 Page 4 Earth Solutions NW, LLC This study has been prepared for the exclusive use of Copper Ridge, LLC and their representatives. No warranty, expressed or implied, is made. This study has been prepared in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. Site Preparation and Earthwork Site preparation activities will consist of installing temporary erosion control measures and performing clearing and site stripping. Grading activities will likely consist of cuts and fills on the order five feet with the deeper cuts associated with stormwater facilities and utility excavations. Temporary Erosion Control Temporary construction entrances and drive lanes, consisting of at least six inches of quarry spalls, should be considered in order to minimize off-site soil tracking and to provide a temporary road surface. Temporary slopes and stockpiles should be covered when not in use. Silt fencing should be installed along the margins of the property. Temporary infiltration swales and galleries can be considered for control of stormwater. Erosion control measures should conform to the applicable Washington State Department of Ecology and City of Yelm/Thurston County standards. In-Situ Soils The majority of the soils encountered during our subsurface exploration have a low to moderate sensitivity to moisture and were generally in a damp to moist condition at the time of the exploration on August 2021. Soils encountered during site excavations that are excessively over the optimum moisture content will require aeration or treatment prior to placement and compaction. Conversely, soils that are substantially below the optimum moisture content will require moisture conditioning through the addition of water prior to use as structural fill. An ESNW representative should determine the suitability of in-situ soils for use as structural fill at the time of construction. Wet Season Grading If grading takes place during the wet season surface water could collect and degrade site soils if not property controlled. The contractor should establish temporary drainage control measures, such as swales and ponds, prior to extended wet weather. ESNW should be consulted during construction to provide temporary drainage control recommendations. Structural Fill Structural fill is defined as compacted soil placed in foundation, slab-on-grade, and roadway areas. Fills placed to construct permanent slopes and throughout retaining wall and utility trench backfill areas are considered structural fill as well. Soils placed in structural areas should be placed in loose lifts of 12 inches or less and compacted to a relative compaction of 95 percent, based on the laboratory maximum dry density as determined by the Modified Proctor Method (ASTM D1557). More stringent compaction specifications may be required for utility trench backfill zones depending on the responsible utility district or jurisdiction. Copper Ridge, LLC ES-8113 October 6, 2021 Page 5 Earth Solutions NW, LLC Excavations and Slopes The Federal Occupation Safety and Health Administration (OSHA) and the Washington Industrial Safety and Health Act (WISHA) provide soil classification in terms of temporary slope inclinations. Soils that exhibit a high compressive strength are allowed steeper temporary slope inclinations than are soils that exhibit lower strength characteristics. Based on the soil conditions encountered at the test pit locations, site soils are classified as Type C by OSHA. New fill should also be considered Type C soil. Temporary slopes over four feet in height in Type C soils must be sloped no steeper than (1.5H:1V). Steeper temporary slopes may be feasible and should be evaluated by ESNW during construction. Where encountered, the presence of groundwater seepage may cause caving of temporary slopes. ESNW should observe site excavations to confirm soil types and allowable slope inclinations. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations, particularly utility trench excavations. Permanent slopes should be planted with vegetation to enhance stability and to minimize erosion and should maintain a gradient of 2H:1V or flatter. An ESNW representative should observe temporary and permanent slopes to confirm the slope inclinations are suitable for the exposed soil conditions. Supplementary recommendations with respect to excavations and slopes may be provided as conditions warrant. Foundations The proposed residential structures can be supported on conventional spread and continuous footings bearing on undisturbed competent native soil, recompacted native soil, or new structural fill placed directly on competent native soil. Based on the soil conditions encountered at the test sites, competent soils suitable for support of foundations are anticipated to be exposed at depths of about two to four feet below existing grades across the majority of the site. Where loose or unsuitable soil conditions are observed at foundation subgrade elevations, compaction of the soils to the specifications of structural fill, or overexcavation and replacement with granular structural fill will be necessary. Organic material exposed at foundation subgrade elevations must be removed and grades restored with structural fill. Provided the structures will be supported as described above, the following parameters can be used for design of the new foundations:  Allowable soil bearing capacity 2,500 psf  Passive earth pressure 300 pcf (equivalent fluid)  Coefficient of friction 0.40 A one-third increase in the allowable soil bearing capacity can be assumed for short-term wind and seismic loading conditions. Copper Ridge, LLC ES-8113 October 6, 2021 Page 6 Earth Solutions NW, LLC With structural loading as expected, total settlement in the range of 1.0 inch is anticipated, with differential settlement of about 0.5 inch. The majority of the settlements should occur during construction, as dead loads are applied. Seismic Design Considerations The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic design, specifically with respect to earthquake loads. Based on the soil conditions encountered at the test pit locations, the parameters and values provided below are recommended for seismic design per the 2018 IBC. Parameter Value Site Class D* Mapped short period spectral response acceleration, S S (g) 1.291 Mapped 1-second period spectral response acceleration, S 1 (g) 0.466 Short period site coefficient, Fa 1 Long period site coefficient, Fv 1.88† Adjusted short period spectral response acceleration, S MS (g) 1.291 Adjusted 1-second period spectral response acceleration, S M1 (g) 0.876† Design short period spectral response acceleration, S DS (g) 0.861 Design 1-second period spectral response acceleration, S D1 (g) 0.584† * Assumes medium dense native soil conditions, encountered to a maximum depth of 13 feet bgs during the August 2021 field exploration, remain medium dense or better to at least 100 feet bgs. † Values assume Fv may be determined using linear interpolation per Table 11.4-2 in ASCE 7-16. As indicated in the table footnote, several of the seismic design values provided above are dependent on the assumption that site-specific ground motion analysis (per Section 11.4.8 of ASCE 7-16) will not be required for the subject project. ESNW recommends the validity of this assumption be confirmed at the earliest available opportunity during the planning and early design stages of the project. Further discussion between the project structural engineer, the project owner, and ESNW may be prudent to determine the possible impacts to the structural design due to increased earthquake load requirements under the 2018 IBC. ESNW can provide additional consulting services to aid with design efforts, including supplementary geotechnical and geophysical investigation, upon request. Copper Ridge, LLC ES-8113 October 6, 2021 Page 7 Earth Solutions NW, LLC Liquefaction is a phenomenon where saturated or loose soil suddenly loses internal strength and behaves as a fluid. This behavior is in response to increased pore water pressures resulting from an earthquake or another intense ground shaking. In our opinion, site susceptibility to liquefaction may be considered low. The depth of the local groundwater table and the gradation and relatively dense characteristics of the native soil were the primary bases for this opinion. Slab-on-Grade Floors Slab-on-grade floors for the proposed residential structures should be supported on a firm and unyielding subgrade. Unstable or yielding areas of the subgrade should be recompacted, or overexcavated and replaced with suitable structural fill, prior to construction of the slab. A capillary break consisting of a minimum of four inches of free-draining crushed rock or gravel should be placed below the slab. The free-draining material should have a fines content of 5 percent or less (percent passing the Number 200 sieve, based on the minus three-quarter-inch fraction). In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. If a vapor barrier is to be utilized, it should be a material specifically designed for use as a vapor barrier and should be installed in accordance with the specifications of the manufacturer. Retaining Walls Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters can be used for retaining wall design:  Active earth pressure (unrestrained condition) 35 pcf  At-rest earth pressure (restrained condition) 55 pcf  Traffic surcharge (passenger vehicles) 70 psf (rectangular distribution)  Passive earth pressure 300 pcf  Coefficient of friction 0.40  Seismic surcharge 8H* * Where H equals the retained height. Additional surcharge loading from adjacent foundations, sloped backfill, retaining walls, or other loads should be included in the retaining wall design. Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design. Copper Ridge, LLC ES-8113 October 6, 2021 Page 8 Earth Solutions NW, LLC Retaining walls should be backfilled with at least 18 inches of free-draining material or suitable sheet drainage that extends along the height of the wall. The upper one foot of the wall backfill can consist of a less permeable soil, if desired. A perforated drain pipe should be placed along the base of the wall and connected to an approved discharge location. A typical retaining wall drainage detail is provided on Plate 3. Drainage Based on our field observations, the native soils generally consisted of well-drained, poorly to well-graded gravels with slightly variable sand contents. Because of the generally well-drained nature of the native gravels, significant groundwater is not anticipated to be encountered within shallow site excavations. ESNW should be consulted during preliminary grading to identify areas of seepage (if present) and provide recommendations to reduce the potential for instability related to seepage effects. Finish grades must be designed to direct surface drain water away from structures and slopes. The grade adjacent to buildings should be sloped away from the buildings at a gradient of at least 2 percent for a horizontal distance of at least 10 feet or more as setbacks allow. Water must not be allowed to pond adjacent to structures or slopes. Based on our field observations, it may be feasible to eliminate foundation drains, provided clean, well-drained deposits are exposed at footing subgrade elevation. However, confirmation should be provided by ESNW at the time of construction. A typical foundation drain detail is provided on Plate 4. Infiltration Evaluation We conducted in-situ pilot infiltration tests (PITs) at the two areas proposed for infiltration within the overall development. The PITs were completed at test pit locations TP-1 and TP-4 within native soils about 8 to 10 feet below existing grades. As indicated in the Subsurface section of this report, native soils encountered during our fieldwork were characterized primarily as Spanaway gravels with variable sand content. Based upon the results of USDA textural analyses performed on representative soil samples, native soils may also be classified chiefly as extremely gravelly coarse sand. Irrespective of gravel content, fines contents within the native gravels were generally less than one percent. Test Method The bottom of each PIT area was set at the approximate design facility bottom as recommended in the Method 1 Field Test Methods section of Appendix III-A. Water was metered into each PIT area using a pump fed hose to develop a constant head of about one foot. The hydraulic head was maintained until the water truck was emptied (3,800-gallon capacity), and measurements of flow for each test area was monitored by our field staff. Upon completion of the constant head soaking period, the water source was removed and each test area was allowed to drain. Upon drained conditions, the test pits were advanced to the limits of the excavator to determine soil stratigraphy and check for groundwater. Copper Ridge, LLC ES-8113 October 6, 2021 Page 9 Earth Solutions NW, LLC Test Results Our testing yielded measured (unfactored) infiltration rates of between 90 and 180 inches per hour (iph). The correction factors below were applied to the measured rates. Correction Factor Value Test Method 0.5 Geometry 0.9* Plugging 0.9 * This value is estimated based on typical pond geometry and uses information collected during the testing. The total correction factor applied to the measured infiltration rates was 0.4. The resulting long- term (design) infiltration rate is 36 iph. These rates were calculated using the lowest measured infiltration rate. Soil Types and Site Variability We conducted USDA textural analyses of representative soil samples collected at the PIT areas. On this basis, the majority of the native soil within the proposed areas consist of extremely gravelly coarse sand. The samples collected at the tested locations indicated consistent soil types across the site, with low variability. Restrictive Layer On this site, the restrictive layer is groundwater, as the alluvial sand and gravel persisted to the maximum exploration depth at each location. The groundwater was not identified on this site at the test pit locations during our fieldwork. Summary and Recommendations From a geotechnical standpoint, it is our opinion that the native gravels are suitable for infiltration. The low soil variability consisting of a consistent thick layer of sand and gravel and low fines contents within the gravels are the basis of this conclusion. Based on the results of our PIT program, a long-term infiltration rate of 36 iph may be used for the current infiltration trench design that will expose coarse gravel soils. Successful performance of the infiltration systems requires that the base of the facility (receptor soils) exposed sandy soils similar to those encountered at the test depth. The minimum vertical separation and corresponding trench base elevations detailed in the referenced groundwater summary should be incorporated into facility designs. ESNW should review final designs to confirm the recommendations provided in this letter report are incorporated. ESNW should be retained to observe construction of the infiltration facility areas during grading to confirm conditions are as anticipated. This site is identified as a highly susceptible critical aquifer recharge area per YMC section 18.21.070 and will require performance standards within this section to be met as part of the project design. Copper Ridge, LLC ES-8113 October 6, 2021 Page 10 Earth Solutions NW, LLC Utility Support and Trench Backfill In our opinion, the soils observed at the test pit locations are generally suitable for support of utilities. The native soils observed at the test pit locations are likely suitable for use as structural backfill in the utility trench excavations. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable requirements of presiding jurisdiction. Native sands and gravels used as backfill should be appropriately moisture conditioned through the addition of water to mitigate the settlement potential. Native soils proposed for use as utility trench backfill should contain aggregate of six inches in diameter or less. Caving of the trench sidewalls should be expected and will require temporary shoring to ensure safety is maintained during utility installation. Pavement Sections The performance of site pavements is largely related to the condition of the underlying subgrade. To ensure adequate pavement performance, the subgrade should be in a firm and unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement areas should be compacted to the specifications detailed in the Site Preparation and Earthwork section of this report. It is possible that soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading activities. Areas of unsuitable or yielding subgrade conditions may require remedial measures such as overexcavation and replacement with structural fill or thicker crushed rock sections prior to pavement. For relatively lightly loaded pavements subjected to automobiles and occasional truck traffic, the following sections can be considered for preliminary design:  Two inches of hot mix asphalt (HMA) placed over four inches of CRB, or;  Two inches of HMA placed over three inches of asphalt treated base (ATB). Heavier traffic areas generally require thicker pavement sections depending on site usage, pavement life expectancy, and site traffic. For preliminary design purposes, the following pavement sections for occasional truck traffic areas can be considered:  Three inches of HMA placed over six inches of crushed rock base (CRB), or;  Three inches of HMA placed over four-and-one-half inches of ATB. The HMA, CRB and ATB materials should conform to WSDOT specifications. Thurston County/City of Yelm minimum pavement requirements may supersede our recommendations and may require thicker pavement sections. Copper Ridge, LLC ES-8113 October 6, 2021 Page 11 Earth Solutions NW, LLC LIMITATIONS The recommendations and conclusions provided in this geotechnical engineering study 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. A warranty is not expressed or implied. Variations in the soil and groundwater conditions observed at the test pit locations may exist and may not become evident until construction. ESNW should reevaluate the conclusions in this geotechnical engineering study if variations are encountered. Additional Services ESNW should have an opportunity to review the final design with respect to the geotechnical recommendations provided in this report. ESNW should also be retained to provide testing and consultation services during construction. Drwn.MRS Checked SKH Date Sept.2021 Date 09/20/2021 Proj.No.8113 Plate 1 Earth Solutions NWLLC Geotechnical Engineering,Construction EarthSolutionsNWLLC EarthSolutions NW LLC Observation/Testing and Environmental Services Vicinity Map Crystal Springs Yelm,Washington Reference: Thurston 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. Yelm SITE Plate Proj.No. Date Checked By Drwn.ByEarthSolutionsNWLLCGeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCMRS SKH 09/20/2021 8113 2TestPitLocationPlan CrystalSpringsYelm,WashingtonLEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-8113,Aug.2021 Subject Site Existing Building NORTH 0 75 150 Sc ale in Feet1"=150' 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. TP-1 95TH C OURT S.E.W OODLANDCOURT S.E.TP-1 TP-2 TP-3 TP-4 TP-5 TP-6 330 334 330 334 N.W.RHOTONROADN.W.CRYSTALSPRINGSSTREET Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drwn.CAM Checked SSR Date Oct.2021 Date 10/06/2021 Proj.No.8113 Plate 3 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC NOTES: Free-draining Backfill should consist of soil having less than 5 percent fines. Percent passing No.4 sieve should be 25 to 75 percent. Sheet Drain may be feasible in lieu of Free-draining Backfill,per ESNW recommendations. Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1-inch Drain Rock. LEGEND: Free-draining Structural Backfill 1-inch Drain Rock 18"Min. Structural Fill Perforated Rigid Drain Pipe (Surround in Drain Rock) SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAW ING Retaining Wall Drainage Detail Crystal Springs Yelm,Washington Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drwn.CAM Checked SSR Date Oct.2021 Date 10/06/2021 Proj.No.8113 Plate 4 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Slope Perforated Rigid Drain Pipe (Surround in Drain Rock) 18"Min. NOTES: Do NOT tie roof downspouts to Footing Drain. Surface Seal to consist of 12"of less permeable,suitable soil.Slope away from building. LEGEND: Surface Seal:native soil or other low-permeability material. 1-inch Drain Rock SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAW ING Footing Drain Detail Crystal Springs Yelm,Washington Earth Solutions NW, LLC Appendix A Subsurface Exploration Test Pit Logs ES-8113 The subsurface conditions at the site were explored by excavating six test pits at the approximate locations illustrated on Plate 2 of this report. The test pit logs are provided in this Appendix. The subsurface exploration was completed on August 31, 2021 to a maximum depth of 13 feet below existing grades. Logs of the explorations observed by ESNW are presented in Appendix A. The final logs represent the interpretations of the field logs and the results of laboratory analyses. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. GRAVEL AND GRAVELLY SOILS CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES WELL-GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES POORLY-GRADED SANDS, GRAVELLY SAND, LITTLE OR NO FINES SILTY SANDS, SAND - SILT MIXTURES CLAYEY SANDS, SAND - CLAY MIXTURES INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SILTY SOILS INORGANIC CLAYS OF HIGH PLASTICITY SILTS AND CLAYS MORE THAN 50% OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE MORE THAN 50% OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE MORE THAN 50% OF COARSE FRACTION PASSING ON NO. 4 SIEVE MORE THAN 50% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE SOIL CLASSIFICATION CHART (APPRECIABLE AMOUNT OF FINES) (APPRECIABLE AMOUNT OF FINES) (LITTLE OR NO FINES) FINE GRAINED SOILS SAND AND SANDY SOILS SILTS AND CLAYS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS LETTERGRAPH SYMBOLSMAJOR DIVISIONS COARSE GRAINED SOILS TYPICAL DESCRIPTIONS WELL-GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLE OR NO FINES POORLY-GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLE OR NO FINES SILTY GRAVELS, GRAVEL - SAND - SILT MIXTURES CLEAN GRAVELS GRAVELS WITH FINES CLEAN SANDS (LITTLE OR NO FINES) SANDS WITH FINES LIQUID LIMIT LESS THAN 50 LIQUID LIMIT GREATER THAN 50 HIGHLY ORGANIC SOILS DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Earth Solutions NW LLC GB MC = 2.5% MC = 2.3% Fines = 1.2% MC = 3.8% Fines = 0.3% TPSL GP GP Dark brown TOPSOIL, abundant roots Brown poorly graded GRAVEL with sand, medium dense, damp -abundant cobbles and small boulders present throughout -minor caving to BOH [USDA Classification: extremely gravelly coarse SAND] -infiltration test Brown poorly graded GRAVEL, dense, damp [USDA Classification: extremely gravelly coarse SAND] Test pit terminated at 13.0 feet below existing grade. No groundwater encountered during excavation. Caving observed from 5.0 to 13.0 feet. 1.0 11.5 13.0 NOTES Depth of Topsoil & Sod 12": field grass LOGGED BY SKH EXCAVATION METHOD EXCAVATION CONTRACTOR Client Provided CHECKED BY SSR DATE STARTED 8/31/21 COMPLETED 8/31/21 GROUND WATER LEVEL: GROUND ELEVATION +-334 LONGITUDE -122.60337 LATITUDE 46.95015 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-1 PROJECT NUMBER ES-8113 PROJECT NAME Crystal Springs GENERAL BH / TP / WELL - 8113.GPJ - GRAPHICS TEMPLATE.GDT - 10/6/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG MC = 3.6% MC = 9.3% Fines = 0.9% MC = 3.0% Fines = 0.4% TPSL GP Dark brown TOPSOIL, abundant roots Brown poorly graded GRAVEL with sand, medium dense, damp -abundant cobbles and small boulders present throughout -minor caving from 3.5' to BOH -becomes moist [USDA Classification: extremely gravelly coarse SAND] -becomes damp [USDA Classification: extremely gravelly coarse SAND] Test pit terminated at 11.5 feet below existing grade. No groundwater encountered during excavation. Caving observed from 3.5 feet to BOH. 1.0 11.5 NOTES Depth of Topsoil & Sod 12": field grass LOGGED BY SKH EXCAVATION METHOD EXCAVATION CONTRACTOR Client Provided CHECKED BY SSR DATE STARTED 8/31/21 COMPLETED 8/31/21 GROUND WATER LEVEL: GROUND ELEVATION +-334 LONGITUDE -122.60344 LATITUDE 46.95049 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-2 PROJECT NUMBER ES-8113 PROJECT NAME Crystal Springs GENERAL BH / TP / WELL - 8113.GPJ - GRAPHICS TEMPLATE.GDT - 10/6/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG MC = 1.4% Fines = 0.4% MC = 1.8% Fines = 0.4% TPSL GW GW Dark brown TOPSOIL, abundant roots Brown well-graded GRAVEL with sand, medium dense, damp [USDA Classification: extremely gravelly coarse SAND] -abundant cobbles and small boulders present throughout -becomes very dense -minor caving from 8' to BOH Brown well-graded GRAVEL, dense, damp [USDA Classification: extremely gravelly coarse SAND] Test pit terminated at 11.0 feet below existing grade. No groundwater encountered during excavation. Caving observed from 8.0 feet to BOH. 1.0 9.0 11.0 NOTES Depth of Topsoil & Sod 12": field grass LOGGED BY SKH EXCAVATION METHOD EXCAVATION CONTRACTOR Client Provided CHECKED BY SSR DATE STARTED 8/31/21 COMPLETED 8/31/21 GROUND WATER LEVEL: GROUND ELEVATION +-333 LONGITUDE -122.60414 LATITUDE 46.95036 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-3 PROJECT NUMBER ES-8113 PROJECT NAME Crystal Springs GENERAL BH / TP / WELL - 8113.GPJ - GRAPHICS TEMPLATE.GDT - 10/6/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG MC = 1.8% MC = 2.1% Fines = 0.7% MC = 3.5% Fines = 0.4% TPSL GW GP Dark brown TOPSOIL, abundant roots Brown well-graded GRAVEL with sand, medium dense, damp -abundant cobbles and small boulders present throughout -minor caving from 4' to BOH -infiltration test [USDA Classification: extremely gravelly coarse SAND] Brown poorly graded GRAVEL with sand, medium dense, damp [USDA Classification: extremely gravelly coarse SAND] Test pit terminated at 11.0 feet below existing grade. No groundwater encountered during excavation. Caving observed from 4.0 feet to BOH. 1.0 9.5 11.0 NOTES Depth of Topsoil & Sod 12": field grass LOGGED BY SKH EXCAVATION METHOD EXCAVATION CONTRACTOR Client Provided CHECKED BY SSR DATE STARTED 8/31/21 COMPLETED 8/31/21 GROUND WATER LEVEL: GROUND ELEVATION +-331 LONGITUDE -122.60413 LATITUDE 46.95006 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-4 PROJECT NUMBER ES-8113 PROJECT NAME Crystal Springs GENERAL BH / TP / WELL - 8113.GPJ - GRAPHICS TEMPLATE.GDT - 10/6/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG MC = 2.4% MC = 1.7% Fines = 0.1% MC = 2.8% TPSL GP Dark brown TOPSOIL, abundant fine roots Brown poorly graded GRAVEL with sand, dense, damp -abundant cobbles and small boulders present throughout -minor caving from 4' to 6' -minor mottling -major caving from 6' to BOH [USDA Classification: extremely gravelly coarse SAND] Test pit terminated at 10.5 feet below existing grade. No groundwater encountered during excavation. Caving observed from 4.0 feet to BOH. 0.5 10.5 NOTES Depth of Topsoil & Sod 6": field grass LOGGED BY SKH EXCAVATION METHOD EXCAVATION CONTRACTOR Client Provided CHECKED BY SSR DATE STARTED 8/31/21 COMPLETED 8/31/21 GROUND WATER LEVEL: GROUND ELEVATION +-332 LONGITUDE -122.60331 LATITUDE 46.9495 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-5 PROJECT NUMBER ES-8113 PROJECT NAME Crystal Springs GENERAL BH / TP / WELL - 8113.GPJ - GRAPHICS TEMPLATE.GDT - 10/6/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG GB MC = 2.1% MC = 2.9% Fines = 0.7% MC = 3.8% TPSL GP Dark brown TOPSOIL, abundant fine roots Brown poorly graded GRAVEL with sand, medium dense, damp -abundant cobbles and small boulders present throughout -minor caving from 4.5' to BOH [USDA Classification: extremely gravelly coarse SAND] -becomes moist Test pit terminated at 12.5 feet below existing grade. No groundwater encountered during excavation. Caving observed from 4.5 feet to BOH. 1.0 12.5 NOTES Depth of Topsoil & Sod 12": field grass LOGGED BY SKH EXCAVATION METHOD EXCAVATION CONTRACTOR Client Provided CHECKED BY SSR DATE STARTED 8/31/21 COMPLETED 8/31/21 GROUND WATER LEVEL: GROUND ELEVATION +-331 LONGITUDE -122.60438 LATITUDE 46.94935 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-6 PROJECT NUMBER ES-8113 PROJECT NAME Crystal Springs GENERAL BH / TP / WELL - 8113.GPJ - GRAPHICS TEMPLATE.GDT - 10/6/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG Earth Solutions NW, LLC Appendix B Laboratory Test Results ES-8113 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 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER 304 1.2 0.3 0.9 0.4 0.4 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Brown Extremely Gravelly Coarse Sand. USCS: GP with Sand. USDA: Brown Extremely Gravelly Coarse Sand. USCS: GP. USDA: Brown Extremely Gravelly Coarse Sand. USCS: GP with Sand. USDA: Brown Extremely Gravelly Coarse Sand. USCS: GP with Sand. USDA: Brown Extremely Gravelly Coarse Sand. USCS: GW with Sand. 6 60 PERCENT FINER BY WEIGHTD10 6.934 12.226 10.116 11.877 7.12 14.952 25.97 27.313 26.824 18.742 GRAIN SIZE DISTRIBUTION 100 18.27 15.34 33.69 22.41 15.61 LL TP-01 TP-01 TP-02 TP-02 TP-03 0.818 1.693 0.811 1.197 1.2 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 37.5 75 75 75 37.5 %Silt 3.93 3.40 4.62 4.39 2.25 TP-01 TP-01 TP-02 TP-02 TP-03 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 7.0ft. 13.0ft. 8.0ft. 11.5ft. 2.0ft. 7.00ft. 13.00ft. 8.00ft. 11.50ft. 2.00ft. PL PROJECT NUMBER ES-8113 PROJECT NAME Crystal Springs GRAIN SIZE USDA ES-8113 CRYSTAL SPRINGS.GPJ GINT US LAB.GDT 9/9/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 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 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER 304 0.4 0.7 0.4 0.1 0.7 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Brown Extremely Gravelly Coarse Sand. USCS: GW. USDA: Brown Extremely Gravelly Coarse Sand. USCS: GW with Sand. USDA: Brown Extremely Gravelly Coarse Sand. USCS: GP with Sand. USDA: Brown Extremely Gravelly Coarse Sand. USCS: GP. USDA: Brown Extremely Gravelly Coarse Sand. USCS: GP. 6 60 PERCENT FINER BY WEIGHTD10 16.792 7.591 9.26 10.206 15.784 24.998 18.42 21.805 22.982 28.324 GRAIN SIZE DISTRIBUTION 100 5.16 16.56 24.81 4.27 10.23 LL TP-03 TP-04 TP-04 TP-05 TP-06 4.849 1.112 0.879 5.383 2.768 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 37.5 37.5 37.5 75 75 %Silt 2.33 2.81 4.47 0.84 3.18 TP-03 TP-04 TP-04 TP-05 TP-06 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 11.0ft. 8.0ft. 11.0ft. 7.0ft. 7.0ft. 11.00ft. 8.00ft. 11.00ft. 7.00ft. 7.00ft. PL PROJECT NUMBER ES-8113 PROJECT NAME Crystal Springs GRAIN SIZE USDA ES-8113 CRYSTAL SPRINGS.GPJ GINT US LAB.GDT 9/9/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 Earth Solutions NW, LLC Report Distribution ES-8113 EMAIL ONLY Copper Ridge, LLC P.O. Box 73790 Puyallup, Washington 98373 Attention: Mr. Evan Mann