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Stormwater Site Plan
Yelm High School North Parking Lot Surfacing Improvements Project Stormwater Site Plan Site Location 1315 Yelm Avenue W Yelm, WA 98597 Prepared For: Yelm Community Schools 107 1st Street N Yelm, WA 98597 Report Prepared By: JSA Civil, LLC 111 Tumwater Boulevard SE, Suite C210 Tumwater, WA 98501 Contact: Charlie Severs, PE (360) 515-9600 charlie.severs@jsa-civil.com Date Prepared June 15, 2023 2 of 6 TABLE OF CONTENTS Stormwater Site Plan Cover Sheet ………………..…………………………………………………………………………………………………………………………1 Table of Contents …………………..………………………………………………………………………………………………………………2 Project Engineer’s Certification …..………………………..………………………………………………………………………………3 Section 1: Project Overview ………………….…….………….………………………………………………….…………………………4 Section 2: Site Conditions …………………………………..………..………………………..………………..………………………..…4 Existing Site Conditions …………………….……………….………………………………………..……………….……..…4-5 Soils Information …………………………………….…………………………………………………………………………………5 Section 3: Off-site Analysis Report …………………………..……………………….……….……………….……………..………….5 Section 4: Permanent Stormwater Control Plan ………………………………………….…….…………….…………..……….5 Summary Section ………………………………..…………………….……………………………….……..………………..……5 Performance Standards and Goals ……………………………..…………..……………………….………………….….5 Water Quality System …………………………….……………………..…………………..……………..…………..……5-6 Flow Control System ………………………………..……………..…………………………………….………..………………6 Section 5: Permits ………………………………………..…………………..……………….…………………..………….…………………6 Section 6: Construction Stormwater Pollution Prevention Plan ………………………..…………………………..………6 . Appendices Appendix 1: Design Calculations Appendix 2: Construction Stormwater Pollution Prevention Plan Appendix 3: Operations and Maintenance Manual Appendix 4: Geotechnical Memorandum 3 of 6 PROJECT ENGINEER’S CERTIFICATION The technical material and data contained in these documents were prepared under the supervision and direction of the undersigned, whose seal, as a professional engineer to practice as such, is affixed below. June 15, 2023 Charlie Severs, PE Date Principal 4 of 6 SECTION 1: PROJECT OVERVIEW Project Overview This Stormwater Site Plan was prepared for the proposed Yelm High School Parking Lot Expansion Project that is located at 1315 Yelm Avenue W. This report was prepared to comply with the minimum technical standards and requirements that are set forth in the most current version of the Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW). The proposed site improvements include the following: Site preparation, grading, and erosion control activities Upgrading the north parking lot from gravel surfacing to asphalt. Construction of on-site stormwater facilities The proposed project improvements will result in more than 5,000 ft2 of redeveloped impervious surface area. According to the SWMMWW, Minimum Requirements 1-9 need to be addressed. The following table summarizes how each requirement will be met. MINIMUM REQUIREMENT COMPLIANCE WITH MINIMUM REQUIREMENT #1 - Stormwater Site Plan The contents of this report and the enclosed plans are intended to satisfy this requirement. #2 - Construction SWPPP A Construction SWPPP has been prepared and is enclosed as an appendix. #3 - Source Control of Pollution If required, a Source Control Pollution Prevention Plan will be recorded against the property prior to certificate of occupancy. #4 - Drainage Path Preservation Preservation of the site’s previously established natural drainage paths will be maintained to the maximum extent practicable. #5 - Stormwater Management 100% on-site infiltration is proposed. The LID flow duration performance standard will be met for this project. #6 - Water Quality More than 5,000 ft2 of new/replaced impervious surface is proposed. A bioretention facility will be constructed. #7 - Flow Control More than 10,000 ft2 of new/replaced impervious surface is proposed. On-site retention facilities will be constructed. #8 - Wetlands Protection According to the Thurston County Geodata mapping center, there are no on-site #9 - Operation & Maintenance An Agreement to Maintain Stormwater facilities will be recorded against the property, if required. Table 1: Compliance with Minimum Technical Requirements SECTION 2: SITE CONDITIONS Existing Site Conditions The subject project threshold discharge area is approximately 0.65 acres in size and is located on the north side of Thurston County TPN 21724210500; the TPN is approximately 36.6 acres. The School District is currently under construction for the redevelopment of the soccer field and tennis courts. The 5 of 6 parking lot that serves the soccer field and tennis courts is a gravel parking lot that will be upgraded to asphalt surfacing. The proposed site improvements will disturb the entire project threshold discharge area. The project area’s land topography, generally, slopes in an east-to-west direction. According to FEMA mapping, the property is not in the floodplain. At the time of the project survey, there wasn’t any evidence to suggest that the site was or is being used as a solid waste dump site. Soils Information A geotechnical memorandum was finalized by Landau Associates on October 24, 2022. According to the geotechnical engineer’s findings, the in-situ soils are suitable for on-site infiltration. The engineer’s recommended long-term infiltration rate for the design of stormwater facilities is 6.8 inches/hour. Groundwater was not encountered in any of the excavated test pits down to a depth of 9’ below existing grade. More than 5’ of vertical separation will be provided between the bottom of the proposed bioretention facility and the groundwater depth. The geotechnical memorandum is enclosed as an appendix. SECTION 3: OFF-SITE ANALYSIS AND REPORT On-site generated stormwater runoff from the project area will be routed to an on-site bioretention facility. Off-site discharge is not proposed. Historic off-site drainage courses will not be altered. Consequently, downstream impacts are not anticipated. SECTION 4: PERMANENT STORMWATER CONTROL PLAN Summary Section The following tables identifies the different land-type designations and their respective areas for the on- site threshold discharge area. ON-SITE LAND TYPE DESIGNATIONS AREA (ACRES)% OF TOTAL AREA Threshold Discharge Area 0.65 100.0% Proposed Impervious Surface Area 0.45 69% Proposed Pervious Surface Area.0.20 31% Performance Standards and Goals Basic Treatment is required for the proposed site improvements. The LID and Flow Control minimum performance standards also need to be met. A bioretention facility is proposed. Enhanced Treatment will be provided. 100% infiltration is proposed. Thus, the Flow Control and LID flow duration standards will be met. Water Quality System According to Volume 1, Section 2.5.6, of the SWMMWW, Basic Treatment is required for the proposed project improvements. 0.45 acres of pollution-generating impervious surface area will require treatment. Clear Creek’s 2012 Western Washington Hydrologic Modeling (WWHM) software was used to verify that at least 91% of the influent runoff file from pollution-generating impervious surfaces pass through the bioretention facility. The bioretention facility will be lined with 18” of biofiltration soil 6 of 6 media. According to the completed model, 100% of the runoff file will infiltrate through the bioretention facility’s soil media. The WWHM water quality analysis is enclosed as an appendix. Flow Control System The on-site bioretention facility has been designed in accordance with the SWMMWW. WWHM software was used to size the facility. 100% of the runoff file from the threshold discharge area will infiltrate on-site. Off-site discharge is not proposed. The WWHM LID and flow control analysis is enclosed as an appendix. SECTION 5: PERMITS Civil Plan Review approval will need to be secured from the City of Yelm. SECTION 6: CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN A Construction Stormwater Pollution Prevention Plan has been prepared and is enclosed as an appendix. APPENDIX 1 DESIGN CALCULATIONS WWHM2012 PROJECT REPORT YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 2 General Model Information Project Name:YELM HIGH SCHOOL Site Name: Site Address: City: Report Date:6/15/2023 Gage:Eaton Creek Data Start:1955/10/01 Data End:2011/09/30 Timestep:15 Minute Precip Scale:0.857 Version Date:2021/08/18 Version:4.2.18 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre A B, Forest, Flat 0.65 Pervious Total 0.65 Impervious Land Use acre Impervious Total 0 Basin Total 0.65 Element Flows To: Surface Interflow Groundwater YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre A B, Lawn, Flat 0.1 Pervious Total 0.1 Impervious Land Use acre PARKING FLAT 0.55 Impervious Total 0.55 Basin Total 0.65 Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 5 Routing Elements Predeveloped Routing YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 6 Mitigated Routing Bioretention 1 Bottom Length: 66.00 ft. Bottom Width: 1.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW Material thickness of second layer: 0 Material type for second layer: Sand Material thickness of third layer: 0 Material type for third layer: GRAVEL Infiltration On Infiltration rate:6.8 Infiltration safety factor:1 Wetted surface area On Total Volume Infiltrated (ac-ft.):88.264 Total Volume Through Riser (ac-ft.):0 Total Volume Through Facility (ac-ft.):88.264 Percent Infiltrated:100 Total Precip Applied to Facility:2.736 Total Evap From Facility:0.541 Underdrain not used Discharge Structure Riser Height:2 ft. Riser Diameter:12 in. Element Flows To: Outlet 1 Outlet 2 Bioretention Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.0172 0.0000 0.0000 0.0000 0.0495 0.0170 0.0000 0.0000 0.0000 0.0989 0.0164 0.0001 0.0000 0.0000 0.1484 0.0159 0.0001 0.0000 0.0000 0.1978 0.0153 0.0002 0.0000 0.0000 0.2473 0.0147 0.0003 0.0000 0.0001 0.2967 0.0142 0.0003 0.0000 0.0001 0.3462 0.0136 0.0004 0.0000 0.0002 0.3956 0.0131 0.0005 0.0000 0.0003 0.4451 0.0125 0.0006 0.0000 0.0004 0.4945 0.0120 0.0008 0.0000 0.0006 0.5440 0.0115 0.0009 0.0000 0.0008 0.5934 0.0109 0.0010 0.0000 0.0011 0.6429 0.0104 0.0012 0.0000 0.0014 0.6923 0.0099 0.0013 0.0000 0.0018 0.7418 0.0093 0.0015 0.0000 0.0023 0.7912 0.0088 0.0017 0.0000 0.0028 0.8407 0.0083 0.0019 0.0000 0.0035 0.8901 0.0078 0.0021 0.0000 0.0042 0.9396 0.0073 0.0023 0.0000 0.0051 0.9890 0.0068 0.0025 0.0000 0.0061 1.0385 0.0063 0.0028 0.0000 0.0072 1.0879 0.0058 0.0030 0.0000 0.0084 1.1374 0.0053 0.0033 0.0000 0.0098 1.1868 0.0048 0.0035 0.0000 0.0114 DIMENSIONS OF FACILITY 100% INFILTRATION OF RUNOFF FILE 1.5' OF BIORETENTION SOIL MEDIA BIORETENTION STORAGE DEPTH. AN ADDITIONAL 1' OF FREEBOARD STORAGE WILL BE PROVIDED YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 7 1.2363 0.0043 0.0038 0.0000 0.0131 1.2857 0.0038 0.0041 0.0000 0.0150 1.3352 0.0034 0.0044 0.0000 0.0172 1.3846 0.0029 0.0047 0.0000 0.0195 1.4341 0.0024 0.0050 0.0000 0.0220 1.4835 0.0020 0.0053 0.0000 0.0248 1.5000 0.0015 0.0055 0.0000 0.0608 Bioretention Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)To Amended(cfs)Infilt(cfs) 1.5000 0.017218 0.005454 0.0000 0.0023 0.0040 1.5495 0.017799 0.006320 0.0000 0.0023 0.0080 1.5989 0.018384 0.007215 0.0000 0.0024 0.0120 1.6484 0.018973 0.008139 0.0000 0.0025 0.0161 1.6978 0.019566 0.009091 0.0000 0.0026 0.0202 1.7473 0.020163 0.010074 0.0000 0.0027 0.0243 1.7967 0.020764 0.011086 0.0000 0.0027 0.0285 1.8462 0.021369 0.012127 0.0000 0.0028 0.0326 1.8956 0.021979 0.013199 0.0000 0.0029 0.0369 1.9451 0.022592 0.014301 0.0000 0.0030 0.0411 1.9945 0.023209 0.015434 0.0000 0.0030 0.0453 2.0440 0.023831 0.016597 0.0000 0.0031 0.0496 2.0934 0.024456 0.017791 0.0000 0.0032 0.0539 2.1429 0.025086 0.019016 0.0000 0.0033 0.0583 2.1923 0.025719 0.020272 0.0000 0.0033 0.0627 2.2418 0.026357 0.021559 0.0000 0.0034 0.0671 2.2912 0.026998 0.022879 0.0000 0.0035 0.0715 2.3407 0.027644 0.024230 0.0000 0.0036 0.0759 2.3901 0.028294 0.025613 0.0000 0.0037 0.0804 2.4396 0.028948 0.027028 0.0000 0.0037 0.0849 2.4890 0.029605 0.028476 0.0000 0.0038 0.0895 2.5385 0.030267 0.029956 0.0000 0.0039 0.0940 2.5879 0.030933 0.031469 0.0000 0.0040 0.0986 2.6374 0.031603 0.033016 0.0000 0.0040 0.1033 2.6868 0.032277 0.034595 0.0000 0.0041 0.1079 2.7363 0.032955 0.036208 0.0000 0.0042 0.1126 2.7857 0.033637 0.037854 0.0000 0.0043 0.1173 2.8352 0.034323 0.039535 0.0000 0.0043 0.1220 2.8846 0.035013 0.041249 0.0000 0.0044 0.1268 2.9341 0.035707 0.042998 0.0000 0.0045 0.1316 2.9835 0.036405 0.044781 0.0000 0.0046 0.1364 3.0330 0.037108 0.046598 0.0000 0.0046 0.1412 3.0824 0.037814 0.048451 0.0000 0.0047 0.1461 3.1319 0.038524 0.050338 0.0000 0.0048 0.1510 3.1813 0.039239 0.052261 0.0000 0.0049 0.1559 3.2308 0.039957 0.054219 0.0000 0.0049 0.1609 3.2802 0.040680 0.056213 0.0000 0.0050 0.1659 3.3297 0.041406 0.058242 0.0000 0.0051 0.1709 3.3791 0.042137 0.060308 0.0000 0.0052 0.1759 3.4286 0.042871 0.062410 0.0000 0.0052 0.1810 3.4780 0.043610 0.064548 0.0000 0.0053 0.1861 3.5275 0.044352 0.066723 0.0483 0.0053 0.1912 3.5769 0.045099 0.068935 0.2257 0.0053 0.1963 3.6264 0.045850 0.071183 0.4712 0.0053 0.2015 3.6758 0.046605 0.073469 0.7588 0.0053 0.2067 3.7253 0.047364 0.075793 1.0650 0.0053 0.2119 3.7747 0.048126 0.078154 1.3657 0.0053 0.2172 3.8242 0.048893 0.080553 1.6378 0.0053 0.2225 YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 8 3.8736 0.049664 0.082990 1.8629 0.0053 0.2278 3.9231 0.050439 0.085465 2.0318 0.0053 0.2331 3.9725 0.051218 0.087978 2.1504 0.0053 0.2385 4.0220 0.052001 0.090530 2.2755 0.0053 0.2439 4.0714 0.052789 0.093121 2.3809 0.0053 0.2493 4.1209 0.053580 0.095751 2.4818 0.0053 0.2548 4.1703 0.054375 0.098420 2.5787 0.0053 0.2603 4.2198 0.055174 0.101129 2.6721 0.0053 0.2658 4.2692 0.055977 0.103877 2.7624 0.0053 0.2713 4.3187 0.056785 0.106665 2.8498 0.0053 0.2769 4.3681 0.057596 0.109494 2.9346 0.0053 0.2825 4.4176 0.058412 0.112362 3.0170 0.0053 0.2881 4.4670 0.059231 0.115271 3.0973 0.0053 0.2918 4.5000 0.059780 0.117232 3.1755 0.0053 0.0000 YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 9 Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Bioretention 1 YELM HIGH SCHOOL 6/15/2023 11:45:22 AM Page 10 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.65 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.1 Total Impervious Area:0.55 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.000503 5 year 0.000862 10 year 0.00119 25 year 0.001734 50 year 0.002251 100 year 0.002884 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1956 0.004 0.000 1957 0.001 0.000 1958 0.001 0.000 1959 0.001 0.000 1960 0.001 0.000 1961 0.001 0.000 1962 0.000 0.000 1963 0.001 0.000 1964 0.001 0.000 1965 0.001 0.000 NO FLOW RELEASED OFF-SITE YELM HIGH SCHOOL 6/15/2023 11:45:48 AM Page 11 1966 0.001 0.000 1967 0.001 0.000 1968 0.001 0.000 1969 0.001 0.000 1970 0.001 0.000 1971 0.001 0.000 1972 0.011 0.000 1973 0.001 0.000 1974 0.001 0.000 1975 0.001 0.000 1976 0.001 0.000 1977 0.001 0.000 1978 0.001 0.000 1979 0.000 0.000 1980 0.001 0.000 1981 0.001 0.000 1982 0.001 0.000 1983 0.001 0.000 1984 0.001 0.000 1985 0.000 0.000 1986 0.001 0.000 1987 0.001 0.000 1988 0.000 0.000 1989 0.001 0.000 1990 0.000 0.000 1991 0.002 0.000 1992 0.001 0.000 1993 0.000 0.000 1994 0.000 0.000 1995 0.001 0.000 1996 0.001 0.000 1997 0.001 0.000 1998 0.001 0.000 1999 0.001 0.000 2000 0.000 0.000 2001 0.000 0.000 2002 0.000 0.000 2003 0.000 0.000 2004 0.000 0.000 2005 0.000 0.000 2006 0.000 0.000 2007 0.001 0.000 2008 0.000 0.000 2009 0.001 0.000 2010 0.001 0.000 2011 0.001 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0108 0.0000 2 0.0036 0.0000 3 0.0019 0.0000 4 0.0015 0.0000 5 0.0005 0.0000 6 0.0005 0.0000 7 0.0005 0.0000 8 0.0005 0.0000 YELM HIGH SCHOOL 6/15/2023 11:45:48 AM Page 12 9 0.0005 0.0000 10 0.0005 0.0000 11 0.0005 0.0000 12 0.0005 0.0000 13 0.0005 0.0000 14 0.0005 0.0000 15 0.0005 0.0000 16 0.0005 0.0000 17 0.0005 0.0000 18 0.0005 0.0000 19 0.0005 0.0000 20 0.0005 0.0000 21 0.0005 0.0000 22 0.0005 0.0000 23 0.0005 0.0000 24 0.0005 0.0000 25 0.0005 0.0000 26 0.0005 0.0000 27 0.0005 0.0000 28 0.0005 0.0000 29 0.0005 0.0000 30 0.0005 0.0000 31 0.0005 0.0000 32 0.0005 0.0000 33 0.0005 0.0000 34 0.0005 0.0000 35 0.0005 0.0000 36 0.0005 0.0000 37 0.0005 0.0000 38 0.0005 0.0000 39 0.0005 0.0000 40 0.0005 0.0000 41 0.0005 0.0000 42 0.0005 0.0000 43 0.0005 0.0000 44 0.0005 0.0000 45 0.0005 0.0000 46 0.0005 0.0000 47 0.0005 0.0000 48 0.0005 0.0000 49 0.0004 0.0000 50 0.0004 0.0000 51 0.0004 0.0000 52 0.0004 0.0000 53 0.0003 0.0000 54 0.0002 0.0000 55 0.0002 0.0000 56 0.0002 0.0000 YELM HIGH SCHOOL 6/15/2023 11:45:48 AM Page 13 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0003 4210 0 0 Pass 0.0003 3639 0 0 Pass 0.0003 3132 0 0 Pass 0.0003 2647 0 0 Pass 0.0003 2244 0 0 Pass 0.0004 1888 0 0 Pass 0.0004 1621 0 0 Pass 0.0004 1366 0 0 Pass 0.0004 1163 0 0 Pass 0.0004 929 0 0 Pass 0.0005 674 0 0 Pass 0.0005 468 0 0 Pass 0.0005 272 0 0 Pass 0.0005 116 0 0 Pass 0.0005 22 0 0 Pass 0.0006 21 0 0 Pass 0.0006 21 0 0 Pass 0.0006 20 0 0 Pass 0.0006 19 0 0 Pass 0.0006 19 0 0 Pass 0.0007 18 0 0 Pass 0.0007 18 0 0 Pass 0.0007 18 0 0 Pass 0.0007 17 0 0 Pass 0.0007 16 0 0 Pass 0.0008 16 0 0 Pass 0.0008 16 0 0 Pass 0.0008 14 0 0 Pass 0.0008 13 0 0 Pass 0.0008 12 0 0 Pass 0.0009 12 0 0 Pass 0.0009 12 0 0 Pass 0.0009 12 0 0 Pass 0.0009 11 0 0 Pass 0.0009 11 0 0 Pass 0.0010 11 0 0 Pass 0.0010 10 0 0 Pass 0.0010 10 0 0 Pass 0.0010 10 0 0 Pass 0.0010 10 0 0 Pass 0.0011 10 0 0 Pass 0.0011 10 0 0 Pass 0.0011 9 0 0 Pass 0.0011 9 0 0 Pass 0.0011 9 0 0 Pass 0.0012 9 0 0 Pass 0.0012 9 0 0 Pass 0.0012 9 0 0 Pass 0.0012 9 0 0 Pass 0.0012 9 0 0 Pass 0.0013 9 0 0 Pass 0.0013 9 0 0 Pass 0.0013 9 0 0 Pass YELM HIGH SCHOOL 6/15/2023 11:45:48 AM Page 14 0.0013 8 0 0 Pass 0.0013 8 0 0 Pass 0.0014 8 0 0 Pass 0.0014 8 0 0 Pass 0.0014 7 0 0 Pass 0.0014 7 0 0 Pass 0.0014 7 0 0 Pass 0.0015 6 0 0 Pass 0.0015 6 0 0 Pass 0.0015 6 0 0 Pass 0.0015 6 0 0 Pass 0.0015 6 0 0 Pass 0.0016 6 0 0 Pass 0.0016 6 0 0 Pass 0.0016 6 0 0 Pass 0.0016 6 0 0 Pass 0.0016 6 0 0 Pass 0.0017 6 0 0 Pass 0.0017 6 0 0 Pass 0.0017 6 0 0 Pass 0.0017 6 0 0 Pass 0.0017 6 0 0 Pass 0.0018 6 0 0 Pass 0.0018 6 0 0 Pass 0.0018 6 0 0 Pass 0.0018 5 0 0 Pass 0.0018 5 0 0 Pass 0.0019 4 0 0 Pass 0.0019 4 0 0 Pass 0.0019 4 0 0 Pass 0.0019 4 0 0 Pass 0.0019 4 0 0 Pass 0.0020 4 0 0 Pass 0.0020 4 0 0 Pass 0.0020 4 0 0 Pass 0.0020 4 0 0 Pass 0.0020 4 0 0 Pass 0.0021 4 0 0 Pass 0.0021 4 0 0 Pass 0.0021 4 0 0 Pass 0.0021 4 0 0 Pass 0.0022 4 0 0 Pass 0.0022 4 0 0 Pass 0.0022 4 0 0 Pass 0.0022 4 0 0 Pass 0.0022 4 0 0 Pass 0.0023 4 0 0 Pass YELM HIGH SCHOOL 6/15/2023 11:45:48 AM Page 15 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. YELM HIGH SCHOOL 6/15/2023 11:45:48 AM Page 16 LID Report YELM HIGH SCHOOL 6/15/2023 11:45:55 AM Page 17 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. YELM HIGH SCHOOL 6/15/2023 11:45:55 AM Page 18 Appendix Predeveloped Schematic YELM HIGH SCHOOL 6/15/2023 11:45:57 AM Page 19 Mitigated Schematic YELM HIGH SCHOOL 6/15/2023 11:45:58 AM Page 20 Predeveloped UCI File YELM HIGH SCHOOL 6/15/2023 11:45:58 AM Page 21 Mitigated UCI File YELM HIGH SCHOOL 6/15/2023 11:45:58 AM Page 22 Predeveloped HSPF Message File YELM HIGH SCHOOL 6/15/2023 11:45:58 AM Page 23 Mitigated HSPF Message File YELM HIGH SCHOOL 6/15/2023 11:45:58 AM Page 24 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. 2005-2023; 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 APPENDIX 2 CONSTRUCTION SWPPP Construction Stormwater General Permit (CSWGP) Stormwater Pollution Prevention Plan (SWPPP) for Yelm High School North Parking Lot Surfacing Improvements Project Prepared for: Department of Ecology Southwest Region Permittee / Owner Developer Operator / Contractor Yelm Community Schools Yelm Community Schools T.B.D. 1315 Yelm Avenue W Yelm, WA 98597 Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number T.B.D.T.B.D.T.B.D. SWPPP Prepared By Name Organization Contact Phone Number Charlie Severs, PE JSA Civil, LLC (360) 515-9600 SWPPP Preparation Date June 15, 2023 Project Construction Dates Activity / Phase Start Date End Date Site Development 07/15/2023 08/30/2023 List of Acronyms and Abbreviations Acronym / Abbreviation Explanation 303(d)Section of the Clean Water Act pertaining to Impaired Waterbodies BFO Bellingham Field Office of the Department of Ecology BMP(s)Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead CO2 Carbon Dioxide CRO Central Regional Office of the Department of Ecology CSWGP Construction Stormwater General Permit CWA Clean Water Act DMR Discharge Monitoring Report DO Dissolved Oxygen Ecology Washington State Department of Ecology EPA United States Environmental Protection Agency ERO Eastern Regional Office of the Department of Ecology ERTS Environmental Report Tracking System ESC Erosion and Sediment Control GULD General Use Level Designation NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Units NWRO Northwest Regional Office of the Department of Ecology pH Power of Hydrogen RCW Revised Code of Washington SPCC Spill Prevention, Control, and Countermeasure su Standard Units SWMMEW Stormwater Management Manual for Eastern Washington SWMMWW Stormwater Management Manual for Western Washington SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control SWRO Southwest Regional Office of the Department of Ecology TMDL Total Maximum Daily Load VFO Vancouver Field Office of the Department of Ecology WAC Washington Administrative Code WSDOT Washington Department of Transportation WWHM Western Washington Hydrology Model Project Information (1.0) Project/Site Name: Yelm High School North Parking Lot Surfacing Improvements Project Street/Location: 1315 Yelm Avenue W City: Yelm State: WA Zip code: 98597 Subdivision: N/A Receiving waterbody: Thompson Creek Existing Conditions (1.1) Total acreage (including support activities such as off-site equipment staging yards, material storage areas, borrow areas). Total acreage: 0.65 acres Disturbed acreage: 0.65 acres Existing structures: N/A Landscape topography: Flat to moderate Drainage patterns: Stormwater runoff, generally, sheet flows in an east-to-west direction Existing Vegetation: Non-native maintained grass/turf.. Proposed Construction Activities / Project Narrative (1.2) The proposed construction activities will take place at 1315 Yelm Avenue W. On-site stormwater facilities will be constructed to retain and infiltrate 100% of on-site generated stormwater runoff. There are no known groundwater and/or soil contaminants on the site. Construction Stormwater Best Management Practices (BMPs) (2.0) The purpose of a Construction Stormwater Pollution Prevention Plan (SWPPP) is to describe the potential for pollution problems during the duration of a construction project. The SWPPP also explains and illustrates the measures that may need to be taken on the construction site to control said problems. The SWPPP is a guideline for the Contractor to follow during the construction process to prevent erosion and migration of sediments. Erosion control measures are not limited to those that are identified in this SWPPP or on the temporary erosion and sediment control plans. Construction Best Management Practices (BMPs) shall be installed as necessary to meet the Department of Ecology’s guidelines for construction stormwater pollution prevention and the requirements that are set forth in the National Pollutant Discharge Elimination System (NPDES) Permit. This SWPPP was prepared in accordance to the established guidelines and BMPs that are set forth in the 2019 Department of Ecology Stormwater Management Manual for Eastern Washington (SWMMEW). The SWMMEW describes the twelve (12) elements of construction stormwater pollution prevention. The twelve (12) elements include the following: Element 1 – Mark Clearing Limits Element 2 – Establish Construction Access Element 3 – Control Flow Rates Element 4 – Install Sediment Controls Element 5 – Stabilize Soils Element 6 – Protect Slopes Element 7 – Protect Drain Inlets Element 8 – Stabilize Channels and Outlets Element 9 – Control Pollutants Element 10 – Control Dewatering Element 11 – Maintain BMPs Element 12 – Manage the Project Element 13 – Protection of Low Impact Development BMPs The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e. hand-written notes and deletions). Update the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design. The 13 Elements (2.1) Element 1: Preserve Vegetation / Mark Clearing Limits (2.1.1) Prior to beginning land disturbing activities, which include site clearing and grading, the Contractor shall mark the clearing limits (including trees) that are to be preserved within the construction zone. High-visibility fences shall be installed/erected as shown on the temporary erosion and sediment control plan and in accordance with the landscaping plan. The following BMPs are applicable for this project. If the following BMPs are not shown on the construction plan set, the Engineer reserves the right to direct the Contractor to install, construct, and/or implement said BMPs. BMP C101: Preserving Natural Vegetation BMP C103: High-Visibility Plastic or Metal Fence with Backup Support BMP C104: Stake and Wire Fence Element 2: Establish Construction Access (2.1.2) A stabilized construction entrance shall be constructed to minimize the tracking of sediment onto any public road. The stabilized construction entrance shall be constructed per the TESC plans and details and in accordance with the requirements of BMP C105. BMP C105: Stabilized Construction Entrance Element 3: Control Flow Rates (2.1.3) Properties and waterways downstream from the development site shall be protected from erosion due to increases in the volume, velocity, and/or peak flow rates of stormwater runoff from the project site. The following BMPs are applicable for this project. If the following BMPs are not shown on the construction plan set, the Engineer reserves the right to direct the Contractor to install, construct, and/or implement said BMPs. BMP C240: Sediment Trap BMP C241: Temporary Sediment Pond Element 4: Install Sediment Controls (2.1.4) Prior to leaving a construction site or prior to discharging into an infiltration facility, stormwater runoff must pass through a sediment pond or some other appropriate BMP for removal of sediments. Silt fencing and straw bale barriers shall be constructed as shown on the temporary and erosion sediment control plans. The following BMPs are applicable for this project. If the following BMPs are not shown on the construction plan set, the Engineer reserves the right to direct the Contractor to install, construct, and/or implement said BMPs. BMP C230: Straw Bale Barrier BMP C231: Brush Barrier BMP C232: Gravel Filter Berm BMP C233: Silt Fence BMP C234: Vegetated Filter Strip BMP C235: Straw Wattles BMP C240: Sediment Trap BMP C241: Temporary Sediment Pond BMP C251: Construction Stormwater Filtration Element 5: Stabilize Soils (2.1.5) All exposed and unworked soils shall be stabilized by application of effective BMPs, which protect the soil from the erosive forces of raindrop impact, flowing water, and from wind erosion. From October 01 through April 30 of each calendar year, no soils shall remain exposed and unworked form more than two (2) days. From May 01 to September 30 of each calendar year, no soils shall remain exposed and unworked for more than seven (7) days. This condition applies to all on-site soils, whether at final grade or not. In areas where the on-site soils will remain unworked for more than the aforementioned time duration limits or have reached final grade, seeding and mulching shall be installed in accordance with BMP C120 and C121. Sod shall be installed in accordance with BMP C124 for disturbed areas that require immediate vegetative cover. Dust control shall be used as needed to prevent wind transport of dust from disturbed soil surfaces and in accordance with BMP C140. If the following BMPs are not shown on the construction plan set, the Engineer reserves the right to direct the Contractor to install, construct, and/or implement said BMPs. BMP C120: Temporary and Permanent Seeding BMP C121: Mulching BMP C123: Plastic Covering BMP C124: Sodding BMP C125: Topsoiling BMP C140: Dust Control West of the Cascade Mountains Crest Season Dates Number of Days Soils Can be Left Exposed During the Dry Season May 1 – September 30 7 days During the Wet Season October 1 – April 30 2 days East of the Cascade Mountains Crest, except the Central Basin* Season Dates Number of Days Soils Can be Left Exposed During the Dry Season July 1 – September 30 10 days During the Wet Season October 1 – June 30 5 days The Central Basin*, East of the Cascade Mountain Crest Season Dates Number of Days Soils Can be Left Exposed During the Dry Season July 1 – September 30 30 days During the Wet Season October 1 – June 30 15 days *Note: The Central Basin is defined as the portions of Eastern Washington with mean annual precipitation of less than 12 inches. Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Element 6: Protect Slopes (2.1.6) Slopes shall be constructed in such a manner that will minimize erosion. This shall include, but is not limited to: placing excavated material on the uphill side of trenches, collecting drainage at the top of slopes, etc. If the following BMPs are not shown on the construction plan set, the Engineer reserves the right to direct the Contractor to install, construct, and/or implement said BMPs. BMP C200: Interceptor Dike and Swale BMP C205: Subsurface Drains BMP C206: Level Spreader BMP C207: Check Dams Element 7: Protect Drain Inlets (2.1.7) All storm drain catch basins/inlets that are in use during construction, as well as all existing structures within the project limits, shall be protected so that stormwater runoff shall not enter any conveyance system without first being filtered or treated to remove sediment from sediment laden runoff. Install storm drain inlet protection devices as shown on the erosion and sediment control plans and in accordance with BMP C220. BMP C220: Storm Drain Inlet Protection Element 8: Stabilize Channels and Outlets (2.1.8) All temporary on-site conveyance channels shall be constructed and stabilized to prevent erosion. Stabilization that is adequate to prevent erosion of outlets and drainage channels shall be provided. If the following BMPs are not shown on the construction plan set, the Engineer reserves the right to direct the Contractor to install, construct, and/or implement said BMPs. BMP C202: Channel Lining BMP C209: Outlet Protection Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all conveyance systems. Element 9: Control Pollutants (2.1.9) All pollutants, including waste materials and demolition of debris, that are generated or brought on-site during construction activities shall be handled and disposed of in a manner that does not cause contamination of stormwater. Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic system drawdown, solvent and degreasing cleaning operations, fuel tank drawdown and removal, and other activities which may result in discharge or spillage of pollutants to the ground or into stormwater runoff must be conducted using spill prevention measures. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Emergency repairs may be performed on-site using temporary plastic placed beneath and, if raining, over the vehicle. Application of agricultural chemicals, including fertilizers and pesticides, shall be conducted in a manner and at application rates that will not result in loss of chemical(s) to stormwater runoff. Manufacturers’ recommendations shall be followed for application rates and procedures. The following Source Control BMPs will be prepared/implemented by the Contractor for this project. A Spill Prevention Plan Maintenance of storm drainage facilities Street sweeping at an interval that’s prescribed by the authority having jurisdiction Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete must not be dumped on-site, except in designated concrete washout areas with appropriate BMPs installed. Element 10: Control Dewatering (2.1.10) Clean, non-turbid dewatered water, as determined by the Certified Professional in Erosion and Sediment Control, can be discharged to systems tributary to state surface waters, provided the dewatering flow does not cause erosion or flooding to receiving waters. Highly turbid or otherwise contaminated dewatered water that’s from construction equipment operation, clamshell digging, concrete tremie pour, or work inside a cofferdam, shall be handled separately from stormwater at the site. Some disposal options, depending on site constraints, may include: Transport off-site in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute State waters On-site treatment using chemical treatment or other suitable treatment technologies Sanitary sewer discharge with local sewer district’s approval if there is no other option Element 11: Maintain BMPs (2.1.11) All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. Element 12: Manage the Project (2.1.12) The project will be managed based on the following principles: Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map. Sampling station(s) are located in accordance with applicable requirements of the CSWGP. Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Table 6 – BMP Implementation Schedule Phase of Construction Project Stormwater BMPs Date Wet/Dry Season [Insert construction activity] [Insert BMP][MM/DD/YYYY][Insert Season] Phase of Construction Project Stormwater BMPs Date Wet/Dry Season [Insert construction activity] [Insert BMP][MM/DD/YYYY][Insert Season] Element 13: Protect Low Impact Development (LID) BMPs (2.1.13) Protect all biofiltration swale and detention pond BMPs from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the biofiltration swale and/or detention pond. Restore BMPs to their fully functioning condition if they accumulate sediment during construction. Restoring the BMP must include removal of sediment and any sediment-laden swale and/or pond soils, and replacing the removed soils with soils meeting the design specification. Prevent compacting the biofiltration soil and detention pond BMPs by excluding construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. Keep all heavy equipment off existing soils under LID facilities that have been excavated to final grade to retain the infiltration rate of the soils. BMP C102: Buffer Zone BMP C103: High Visibility Fence BMP C200: Interceptor Dike and Swale BMP C201: Grass-Lined Channels BMP C207: Check Dams BMP C208: Triangular Silt Dike BMP C231: Brush Barrier BMP C233: Silt Fence BMP C234: Vegetated Strip Pollution Prevention Team (3.0) Table 7 – Team Information Title Name(s)Phone Number Certified Erosion and Sediment Control Lead (CESCL) Resident Engineer Emergency Ecology Contact Emergency Permittee/ Owner Contact Non-Emergency Owner Contact Monitoring Personnel Ecology Regional Office Southwest Regional Office (360) 742-9751 Monitoring and Sampling Requirements (4.0) Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: A record of the implementation of the SWPPP and other permit requirements Site inspections Stormwater sampling data The site log book must be maintained on-site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. Complete the following paragraph for sites that discharge to impaired waterbodies for fine sediment, turbidity, phosphorus, or pH: Site Inspection (4.1) Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with the applicable requirements of the CSWGP. Stormwater Quality Sampling (4.2) Turbidity Sampling (4.2.1) Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Table 8 – Turbidity Sampling Method Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size) Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the discharge’s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: 1. Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Region’s Environmental Report Tracking System (ERTS) within 24 hours. https://www.ecology.wa.gov/About-us/Get-involved/Report-an-environmental-issue Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, Yakima): (509) 575-2490 Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400 Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: Turbidity is 25 NTU (or lower). Transparency is 33 cm (or greater). Compliance with the water quality limit for turbidity is achieved. o 1 - 5 NTU over background turbidity, if background is less than 50 NTU o 1% - 10% over background turbidity, if background is 50 NTU or greater The discharge stops or is eliminated. pH Sampling (4.2.2) pH monitoring is required for “Significant concrete work” (i.e. greater than 1000 cubic yards poured concrete or recycled concrete over the life of the project).The use of engineered soils (soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (CO2) sparging (liquid or dry ice). 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Method for sampling pH: Table 8 – pH Sampling Method pH meter pH test kit Wide range pH indicator paper Reporting and Record Keeping (6.0) Record Keeping (6.1) Site Log Book (6.1.1) A site log book will be maintained for all on-site construction activities and will include: A record of the implementation of the SWPPP and other permit requirements Site inspections Sample logs Records Retention (6.1.2) Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.C of the CSWGP. Permit documentation to be retained on-site: CSWGP Permit Coverage Letter SWPPP Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. Updating the SWPPP (6.1.3) The SWPPP will be modified if: Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. Reporting (6.2) Discharge Monitoring Reports (6.2.1) Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period the DMR will be submitted as required, reporting “No Discharge”. The DMR due date is fifteen (15) days following the end of each calendar month. DMRs will be reported online through Ecology’s WQWebDMR System. https://www.ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Water-quality- permits-guidance/WQWebPortal-guidance Notification of Noncompliance (6.2.2) If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. Central Region at (509) 575-2490 for Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, or Yakima County Eastern Region at (509) 329-3400 for Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, or Whitman County Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Southwest Region at (360) 407-6300 for Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, or Wahkiakum Include the following information: 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. APPENDIX 3 OPERATIONS AND MAINTENANCE MANUAL Operations & Maintenance Manual Yelm High School North Parking Lot Surfacing Improvements Project 1315 Yelm Avenue W Yelm, WA 98597 TABLE OF CONTENTS Stormwater Facility Maintenance Program Cover Sheet …………………………………………..………………………………………………………………………………………………1 Table of Contents ………………….………………………………………………………………………………………………………………2 Estimate of Annual Maintenance Costs ……………….………………………………………………….……………………………3 Maintenance Plan Schedule …………………..………..……………………………………………………………………………………4 Location of Operations and Maintenance Manual ………………..……………..………………………………………………5 Written Description of Facilities …………………….………………………………………………………………………………………6 Required Recordkeeping and Reports ……………….……………………………………………………………………………………7 Maintenance Activity Log ………………………………………………………………………………………………………………………8 Maintenance Program …………………………………………………………………………………..……………………………………9 ESTIMATE OF ANNUAL MAINTENANCE COSTS ITEM #DESCRIPTION QTY.UNIT COST / UNIT ANNUAL COST Stormwater Piping1. pipe jetting & CB Cleaning 1 LS $500 $500 Bioretention Facility2. maintenance 1 LS $1,500 $1,500 Subtotal $2,000 Contingency @ 25%$500 Total $2,500 MAINTENANCE PLAN SCHEDULE On-site drainage facilities, which include stormwater piping and catch basins, will require routine maintenance. The following pages contain maintenance needs for most of the components that are a part of this project’s drainage system, as well as for some components that the project may not have. The checklist should be completed for all system components in accordance with the following schedule: M. Monthly from October through April A. Annually, once in late summer (preferably September) S. Storm-based, after any major storm event (use 1-inch in 24-hours as a guideline) Using copies of these pages, check off the problems investigated each time an inspection was performed. Add comments on problems found and actions taken. Some items do not need to be looked at every time an inspection is done. Use the suggested frequency as a guideline for the inspection. The following governing jurisdictions may be called for technical assistance. CONTACT PHONE NUMBER Department of Ecology Stormwater Division (360) 407-6438 LOCATION OF OPERATIONS AND MAINTENANCE MANUAL This manual will be kept 1315 Yelm Avenue W, Yelm, WA 98597. This manual shall be made available to the authority having jurisdiction personnel upon request. WRITTEN DESCRIPTION OF FACILITIES The construction of water quality and flow control facilities were required for this project. The on-site stormwater facilities were designed from the technical guidance that is provided in the 2019 Department of Ecology Stormwater Management Manual for Western Washington. The on-site stormwater facilities were designed to reduce pollutant loads and concentrations in stormwater runoff as well as to mitigate, to the maximum extent practicable, the impacts of increased stormwater runoff volumes and flow rates to receiving waters. The project was graded in such a manner so as to maintain, to the maximum extent practicable, the existing landform. The on-site water quality facilities were designed to treat the minimum water quality flow rate and treatment volume from pollution generating impervious surface runoff. This project’s stormwater facilities include stormwater conveyance piping and catch basins. REQUIRED RECORDKEEPING AND REPORTS If required, the Owner shall submit an annual report to the authority having jurisdiction by August 31st of each calendar year which will include, at a minimum, the following: Name, address, and telephone number of the person(s) responsible for plan implementation and the person(s) completing the report. Time period covered by the report. A chronological summary of activities conducted to implement the program(s) required by the Operations & Maintenance Plan. This information shall be logged in the logbook with any additional comments/narrative. For any activities that are completed by paid parties, include a copy of the invoice for services. An outline of planned activities for the next year. MAINTENANCE ACTIVITY LOG Maintenance ActivityMaintenance Activity LogYelm High School North Parking Lot Surfacing Improvements ProjectDate MAINTENANCE PROGRAM Inspection Period __________________________________________ Number of Sheets Attached __________________________________________ Date Inspected __________________________________________ Name of Inspector __________________________________________ Inspector’s Signature __________________________________________ APPENDIX 4 GEOTECHNICAL REPORT Draft Technical Memorandum 500 Columbia St NW, Ste 110 • Olympia, WA 98501 • 360.791.3178 TO: FROM: DATE: RE: Robert Droll, President, RWD Landscape Architects Chad McMullen, PE, and Lance Levine, PE October 24, 2022 Summary of Geotechnical Engineering Services Yelm High School Soccer Field Conversion and Tennis Courts Reconstruction Yelm, Washington RWD Project No. 22041 Landau Project No. 1444018.010.011 Introduction This memorandum summarizes the results of geotechnical engineering services provided by Landau Associates, Inc. (Landau) in support of the Yelm High School Soccer Field Conversion and Tennis Courts Reconstruction project, located at 1315 West Yelm Avenue in Yelm, Washington (site; Figure 1). Services were provided in accordance with the scope outlined in Landau’s proposal, dated September 27, 2022. This memorandum has been prepared with information provided by RWD Landscape Architects (RWD, project landscape architect) and Yelm Community Schools (YCS, project owner) and with data collected during Landau’s geotechnical field exploration and laboratory testing programs. Project Understanding YCS proposes to resurface a grass-covered soccer field and rebuild six tennis courts in the northwest corner of the site. The soccer field will be resurfaced with synthetic turf. RWD retained Landau to complete a limited field investigation and develop infiltration recommendations for onsite stormwater infiltration. Site Conditions The total area of the existing soccer field and tennis courts measures approximately 370 feet (ft) by 400 ft. An asphalt-paved walkway wraps around the perimeter of the soccer field. The field and courts are generally flat and level. Topography to the west of the site slopes gently downward; a privately developed parcel east of the site is elevated 1 to 2 ft above the existing soccer field. Terrain to the north and south is flat and level. Relevant site features are shown on Figure 2. Geologic Setting Geologic information for the site and the surrounding area was obtained from the Washington Geologic Information Portal (DNR, accessed October 13, 2022). Surficial deposits at the site are mapped as Fraser- age continental glacial outwash gravels (Qgog), a unit that consists of predominantly sandy gravels and gravelly sand with cobbles and boulders. This material was deposited during the last glacial recession and has not been glacially overridden. DRAFT Landau Associates Summary of Geotechnical Engineering Services Soccer Field Conversion and Tennis Courts Reconstruction 2 October 24, 2022 A layer of topsoil was observed in Landau’s October 2022 explorations. The topsoil consisted of silty sand and compost overlying glacial soils; YCS staff stated that the topsoil was placed to help establish grass turf. Other soil conditions encountered in Landau’s explorations were consistent with the mapped geology for the site. Subsurface Explorations On October 5, 2022, YCS excavated four test pits (TP-1 through TP-4) 8.0 to 9.0 ft below ground surface (bgs). The approximate locations of the explorations are shown on Figure 2. Landau personnel coordinated and monitored the field explorations, collected representative soil samples, and maintained detailed logs of the subsurface soil and groundwater conditions observed. Subsurface conditions were described using the soil classification system shown on Figure 3, in general accordance with ASTM International (ASTM) standard D2488, Standard Practice for Description and Identification of Soils (Visual-Manual Procedures). Summary logs of the explorations are presented on Figures 4 through 7. Soil samples were transported to Landau’s geotechnical laboratory for further examination and testing. Natural moisture content determinations were performed on select soil samples in accordance with ASTM standard test method D2216, Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass. The natural moisture content is shown as “W = xx” (i.e., percentage of dry weight) in the “Test Data” column on Figures 4 through 7. Grain size analyses were performed on select soil samples in accordance with ASTM standard test method D6913, Standard Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis. Samples selected for grain size analysis are designated with a “GS” in the “Test Data” column on Figures 4 through 7. Results of the grain size analyses are presented on Figure 8. Soil Conditions The soils observed in Landau’s October 2022 explorations were categorized into two units: • Topsoil: Topsoil was observed in all four test pits and consisted of grass turf over fine to medium sand with silt. The silty sand was mixed with compost to promote turf growth. The topsoil was in a loose, damp condition and extended 0.5 ft bgs. • Recessional Outwash: Recessional outwash was observed beneath the topsoil in all four test pits and consisted of sandy gravel with cobbles, of gravelly sand with cobbles, of gravelly sand with silt, and of fine to medium sand. Occasional boulders were observed in test pit TP-1. These variable soil gradations are typical of a sediment-choked, high-energy, braided river channel downstream of a receding glacier. The recessional outwash extended to the maximum depth explored. Groundwater Conditions Groundwater was not observed in Landau's October 2022 explorations, though soils were generally damp during test pit excavation. No seeps or pockets of moist or wet soil were observed. Mottling or other indicators of a seasonal high groundwater table were not observed. DRAFT Landau Associates Summary of Geotechnical Engineering Services Soccer Field Conversion and Tennis Courts Reconstruction 3 October 24, 2022 The groundwater conditions reported herein are for the specific date and locations indicated and may not be representative of other locations and/or times. Groundwater conditions will vary depending on local subsurface conditions, weather conditions, and other factors. Groundwater levels are expected to fluctuate seasonally, with maximum groundwater levels occurring during late winter and early spring. Conclusions and Recommendations Based on the subsurface conditions observed in Landau’s explorations, site soils are suitable for stormwater infiltration. Infiltration Rate Assessment The site is underlain by soils that will allow for moderate to rapid infiltration. Groundwater was not observed within the depths explored, and it is unlikely that infiltrated stormwater would mound above the groundwater table. Design infiltration rates were estimated using the results of Landau’s geotechnical laboratory tests (Figure 8) and the soil grain size method in the Washington State Department of Ecology’s 2019 Stormwater Management Manual for Western Washington (hereafter, 2019 SWMMWW). Correction factors were applied to account for site variability and the number of locations tested (CFv = 0.5), the test method (CFt = 0.4), and biofouling and siltation effects (CFm = 0.9). Landau used the simplified method to calculate design infiltration rates of 2.9 to 20 inches per hour, as shown in Table 1. (The 2019 SWMMWW limits infiltration rates to 20 inches per hour.) Table 1. Design Factored Infiltration Rates Exploration Designation Depth Range (ft bgs) Design Infiltration Rate (in/hr) TP-1 0.5–4.5 6.8 4.5–8 20(a) TP-2 0.5–1.5 6.8 1.5–8 20(a) TP-3 0.5–8 2.9 TP-4 0.5–1.5 2.9 1.5–5 15 5–8 20(a) (a) Maximum rate of 20 inches per hour. bgs = below ground surface ft = foot/feet in/hr = inches per hour DRAFT Landau Associates Summary of Geotechnical Engineering Services Soccer Field Conversion and Tennis Courts Reconstruction 4 October 24, 2022 Use of This Technical Memorandum Landau Associates has prepared this technical memorandum for the exclusive use of RWD Landscape Architects and Yelm Community Schools for specific application to the Yelm High School Soccer Field Conversion and Tennis Courts Reconstruction project in Yelm, Washington. No other party is entitled to rely on the information, conclusions, and recommendations included in this document without the express written consent of Landau Associates. Reuse of the information, conclusions, and recommendations provided herein for extensions of the project or for any other project, without review and authorization by Landau Associates, shall be at the user’s sole risk. Landau Associates warrants that, within the limitations of scope, schedule, and budget, its services have been provided in a manner consistent with that level of skill and care ordinarily exercised by members of the profession currently practicing in the same locality, under similar conditions as this project. Landau Associates makes no other warranty, either express or implied. Closing We trust that this memorandum provides you with the information needed to proceed with the project. If you have questions or comments, please contact Lance Levine at 360.628.5109 or at llevine@landauinc.com. LANDAU ASSOCIATES, INC. Chad McMullen, PE Senior Engineer Lance Levine, PE Senior Engineer CTM/LGL/SRW/mcs [\\OLYMPIA1\PROJECTS\1444\018.010\R\YHS SOCCER FIELD CONVERSION AND TENNIS COURTS RECONSTRUCTION DRAFT TECHNICAL MEMORANDUM 10.24.2022.DOCX] Attachments: Figure 1. Vicinity Map Figure 2. Site Exploration and Location Plan Figure 3. Soil Classification System and Key Figures 4–7. Logs of Test Pits TP-1 through TP-4 Figure 8. Grain Size Distribution DRAFT Landau Associates Summary of Geotechnical Engineering Services Soccer Field Conversion and Tennis Courts Reconstruction 5 October 24, 2022 References ASTM. 2017. Annual Book of ASTM Standards. In: Soil and Rock (I). West Conshohocken, PA: ASTM International. DNR. Washington Geologic Information Portal. Washington State Department of Natural Resources. Accessed October 13, 2022. Available online at: https://geologyportal.dnr.wa.gov/. Ecology. 2019. Stormwater Management Manual for Western Washington. Publication No. 19-10-021. Washington State Department of Ecology. July. Data Source: Esri. Yelm High School Soccer Field Conversion and Tennis Courts Reconstruction Yelm, Washington Vicinity Map Figure 1 0 0.5 1 Miles G:\Projects\1444\018\010\011\YelmHSSoccerField\YelmHSSoccerField.aprx 10/15/2022!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! !!! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! !!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! !!!!!!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! !!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! !!!!!!!!!!!! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! !!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!!!!!!!!!!!!!!!!! !!!!!!! ! ! ! !!!!!!!!!!!!!!!!!! ! ! ! ! ! ! ! ! ! ! !!!!!!! ! ! ! ! ! !!!!!!!!! !!!!!!!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! !!!!!!!!!!!!!!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!!!!!!!!!!!!!! ! ! ! ! ! !!!!!!!!!!!!! Bradshaw Rd SE LoisPl SES W M ck e nzi e Ave W e st R d S E OrdwayDr SE Cu llens RdSEVancilRdSEGeorge Rd SE 105th Way SE Co ates R d S E Mo s m a n A v e SW Crystal Springs St NWBurnett Rd SEMudR u n R d S E 3rd St NEMillRdSE93rd Ave SE Killion Rd SE109th Ave SEAnderson L n SE 104th Ave S E 2ndStSECanal R dSE 5 6 th Q uar ter Ma st er R d 89th Ave SE Clark Rd SESE 4thStMountainView RdSERhoton Rd SECull enRd S E Railway Rd S E1st St N Berry Valley Rd S E JoyceCt S E Fox H i l l R d SE 94th Ave SE Longmire St S E 1 66thB riga d e R d Rathbun Rd SEMcnieceDr SE86th Ln SE88th Ave SE 6 0thSig n alBattalionRd510 510 507 507 Yelm ! ! ! ! ! Everett Olympia Seattle Spokane Project Location !Project Location DRAFT Source: Google Maps 2022 Legend 0 120 240 Scale in Feet Note 1. Black and white reproduction of this color original may reduce its effectiveness and lead to incorrect interpretation. Landau Associates | Y:\CAD\1444\018.010\1444018.010.dwg | 10/12/2022 9:50 AM | caduser Yelm High School Soccer Field Conversion and Tennis Courts Reconstruction Yelm, Washington Site Exploration and Location Plan Figure 2 Approximate Test Pit Location and DesignationTP-1 TP-1 TP-2 TP-3 TP-4 93RD AVENUE SOUTHEAST DRAFT 3 Yelm High School Soccer FieldConversion and TennisCourts ReconstructionYelm, WashingtonCOARSE-GRAINED SOIL(More than 50% of coarse fraction retained on No. 4 sieve)(More than 50% of material islarger than No. 200 sieve size)SAND WITH FINES (Appreciable amount of fines) HIGHLY ORGANIC SOIL (Liquid limit greater than 50) SILT AND CLAY RK DB Rock (See Rock Classification) (Liquid limit less than 50) SILT AND CLAY Wood, lumber, wood chips GRAPHIC SYMBOL Construction debris, garbage PAVEMENT ROCK WOOD DEBRIS OTHER MATERIALS TYPICAL DESCRIPTIONS LETTER SYMBOL WD > 30% and < > 15% and < > 5% and < < > _ _ _ _ Primary Constituent: Secondary Constituents: Additional Constituents: Notes: 1. USCS letter symbols correspond to symbols used by the Unified Soil Classification System and ASTM classification methods. Dual letter symbols (e.g., SP-SM for sand or gravel) indicate soil with an estimated 5-15% fines. Multiple letter symbols (e.g., ML/CL) indicate borderline or multiple soil classifications. 2. Soil descriptions are based on the general approach presented in the Standard Practice for Description and Identification of Soils (Visual-Manual Procedure), outlined in ASTM D 2488. Where laboratory index testing has been conducted, soil classifications are based on the Standard Test Method for Classification of Soils for Engineering Purposes, as outlined in ASTM D 2487. 3. Soil description terminology is based on visual estimates (in the absence of laboratory test data) of the percentages of each soil type and is defined as follows: 4. Soil density or consistency descriptions are based on judgement using a combination of sampler penetration blow counts, drilling or excavating conditions, field tests, and laboratory tests, as appropriate. 50% - "GRAVEL," "SAND," "SILT," "CLAY," etc. 50% - "very gravelly," "very sandy," "very silty," etc. 30% - "gravelly," "sandy," "silty," etc. 15% - "with gravel," "with sand," "with silt," etc. 5% - "with trace gravel," "with trace sand," "with trace silt," etc., or not noted. SAMPLER TYPE & METHOD Recovery Depth Interval Sampler Graphic (variable) Code Description a b c d e f g h i 1 2 3 4 5 6 3.25-in OD, 2.42-in ID Split Spoon 2.00-in OD, 1.50-in ID Split Spoon Shelby Tube Grab Sample Single-Tube Core Barrel Double-Tube Core Barrel 2.50-in OD, 2.00-in ID WSDOT 3.00-in OD, 2.37-in ID Mod. Calif. Other - See text if applicable 300-lb Hammer, 30-inch Drop 140-lb Hammer, 30-inch Drop Pushed Sample Vibrocore (Rotosonic/Geoprobe) Other - See text if applicable Piston Extraction 1 Graphic Approximate water level at time after drilling/excavation/well AC or PC CLEAN SAND FINE-GRAINED SOILPT OH CH Well-graded gravel; gravel/sand mixture(s); little or no fines MH OL CL ML SC Field and Lab Test Data Soil Classification System SM SP(Little or no fines)(More than 50% of material is smaller than No. 200 sieve size)Silty gravel; gravel/sand/silt mixture(s) Silty sand; sand/silt mixture(s) Clayey sand; sand/clay mixture(s) Inorganic silt and very fine sand; rock flour; silty or clayey finesand or clayey silt with slight plasticity Inorganic clay of low to medium plasticity; gravelly clay; sandyclay; silty clay; lean clay Organic silt; organic, silty clay of low plasticity Inorganic silt; micaceous or diatomaceous fine sand Inorganic clay of high plasticity; fat clay Organic clay of medium to high plasticity; organic silt MAJOR DIVISIONS Pocket Penetrometer, tsf Torvane, tsf Photoionization Detector VOC screening, ppm Moisture Content, % Dry Density, pcf Material smaller than No. 200 sieve, % Grain Size - See separate figure for data Atterberg Limits - See separate figure for data Other Geotechnical Testing Chemical Analysis PP = 1.0 TV = 0.5 PID = 100 W = 10 D = 120 -200 = 60 GS AL GT CA Groundwater Code SW GC SAMPLE NUMBER & INTERVAL TYPICAL DESCRIPTIONS (2)(3) Asphalt concrete pavement or Portland cement pavement USCS LETTER SYMBOL(1) Approximate water level at time of drilling (ATD) Clayey gravel; gravel/sand/clay mixture(s) GRAPHIC SYMBOL Drilling and Sampling Key Description GM GP GW Poorly graded gravel; gravel/sand mixture(s); little or no fines Well-graded sand; gravelly sand; little or no fines Poorly graded sand; gravelly sand; little or no fines Peat; humus; swamp soil with high organic content CLEAN GRAVELGRAVEL AND GRAVELLY SOIL Sample Depth Interval Portion of Sample Retained for Archive or Analysis Sample Identification Number (Appreciable amount of fines) GRAVEL WITH FINES (Little or no fines) (More than 50% of coarse fraction passed through No. 4 sieve) SAND AND SANDY SOIL Soil Classification System and Key Figure DRAFTPoint located atTest Pit Completed 10/05/22 Total Depth of Test Pit = 8.0 ft. S-1 S-2 d d SP- SM SP GP W = 14 GS 2 inches of grass turf above 4 inches of fine to medium SAND with silt (loose, damp) (TOPSOIL) Dark brown, cobbly, very gravelly, fine to coarse SAND with trace organics (medium dense, damp) (RECESSIONAL OUTWASH) -- occasional small, rounded boulders measuring up to 16 inches Light brown, sandy, fine to coarse GRAVEL with cobbles and boulders (medium dense to dense, damp) -- soil caving; excavation terminated at 8.0 feet 0 2 4 6 8 10 12 Ground Elevation (ft): Excavation Method: CTMLogged By: Rubber-tired Backhoe Not Measured Excavated By:Yelm Community Schools Groundwater Not Encountered GROUNDWATER Elevation (ft)Notes:1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. TP-1 Sample Number& IntervalSampler TypeTest DataGraphic SymbolUSCS SymbolSAMPLE DATA SOIL PROFILE Depth (ft)Yelm High School Soccer FieldConversion and TennisCourts ReconstructionYelm, Washington Figure1444018.01 10/21/22 \\OLYMPIA1\PROJECTS\1444\018.010\T\1444018.010.GPJ SINGLE TEST PIT LOG4Log of Test Pit TP-1 DRAFTPoint located atTest Pit Completed 10/05/22 Total Depth of Test Pit = 8.0 ft. S-1 S-2 d d SP- SM SP GP W = 6 GS 2 inches of grass turf above 4 inches of fine to medium SAND with silt (loose, damp) (TOPSOIL) Dark brown, cobbly, very gravelly, fine to coarse SAND with trace organics (medium dense, damp) (RECESSIONAL OUTWASH) Light brown, sandy, fine to coarse GRAVEL with cobbles (medium dense to dense, damp) -- soil raveling and caving; excavation terminated at 8.0 feet 0 2 4 6 8 10 12 Ground Elevation (ft): Excavation Method: CTMLogged By: Rubber-tired Backhoe Not Measured Excavated By:Yelm Community Schools Groundwater Not Encountered GROUNDWATER Elevation (ft)Notes:1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. TP-2 Sample Number& IntervalSampler TypeTest DataGraphic SymbolUSCS SymbolSAMPLE DATA SOIL PROFILE Depth (ft)Yelm High School Soccer FieldConversion and TennisCourts ReconstructionYelm, Washington Figure1444018.01 10/21/22 \\OLYMPIA1\PROJECTS\1444\018.010\T\1444018.010.GPJ SINGLE TEST PIT LOG5Log of Test Pit TP-2 DRAFTPoint located atTest Pit Completed 10/05/22 Total Depth of Test Pit = 9.0 ft. S-1 S-2 d d SP- SM GP- GM SW- SM GP W = 16 GS 2 inches of grass turf above 4 inches of fine to medium SAND with silt (loose, damp) (TOPSOIL) Dark brown, sandy, fine to coarse GRAVEL with silt, cobbles, and trace organics (medium dense, damp) (RECESSIONAL OUTWASH) Light brown, gravelly, fine to coarse SAND with silt (loose to medium dense, damp) -- grades to with cobbles Light brown, cobbly, sandy, fine to coarse GRAVEL (medium dense to dense, damp) 0 2 4 6 8 10 12 Ground Elevation (ft): Excavation Method: CTMLogged By: Rubber-tired Backhoe Not Measured Excavated By:Yelm Community Schools Groundwater Not Encountered GROUNDWATER Elevation (ft)Notes:1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. TP-3 Sample Number& IntervalSampler TypeTest DataGraphic SymbolUSCS SymbolSAMPLE DATA SOIL PROFILE Depth (ft)Yelm High School Soccer FieldConversion and TennisCourts ReconstructionYelm, Washington Figure1444018.01 10/21/22 \\OLYMPIA1\PROJECTS\1444\018.010\T\1444018.010.GPJ SINGLE TEST PIT LOG6Log of Test Pit TP-3 DRAFTPoint located atTest Pit Completed 10/05/22 Total Depth of Test Pit = 8.0 ft. S-1 S-2 d d SP- SM GP- GM SP GP W = 8 GS 2 inches of grass turf above 4 inches of fine to medium SAND with silt (loose, damp) (TOPSOIL) Dark brown, sandy, fine to coarse GRAVEL with silt and trace organics (medium dense, damp) (RECESSIONAL OUTWASH) Light brown, fine to medium SAND (loose to medium dense, damp) -- grades to very gravelly, with cobbles, and dense Light brown, sandy, fine to coarse GRAVEL (dense, damp) 0 2 4 6 8 10 12 Ground Elevation (ft): Excavation Method: CTMLogged By: Rubber-tired Backhoe Not Measured Excavated By:Yelm Community Schools Groundwater Not Encountered GROUNDWATER Elevation (ft)Notes:1. Stratigraphic contacts are based on field interpretations and are approximate. 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols. TP-4 Sample Number& IntervalSampler TypeTest DataGraphic SymbolUSCS SymbolSAMPLE DATA SOIL PROFILE Depth (ft)Yelm High School Soccer FieldConversion and TennisCourts ReconstructionYelm, Washington Figure1444018.01 10/21/22 \\OLYMPIA1\PROJECTS\1444\018.010\T\1444018.010.GPJ SINGLE TEST PIT LOG7Log of Test Pit TP-4 DRAFT0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110100 6 Soil Description 60126 1001.5 163 Fine U.S. Sieve Numbers 3/8 140 200 Depth (ft) Natural Moisture (%)Symbol U.S. Sieve Opening in Inches 14 Silt or ClayGravel Unified Soil Classification Grain Size in MillimetersPercent Finer by Weight4 10 303/4 3 20 Sand Hydrometer MediumCoarseCobbles 4 Exploration Number 408 Sample Number Coarse 1/2 50 Fine SP GP SW-SM SP S-1 S-2 S-1 S-1 Very gravelly, fine to coarse SAND Sandy, fine to coarse GRAVEL Gravelly, well-graded SAND with silt Fine to medium SAND 14 6 16 8 1.5 3.0 3.0 2.0 TP-1 TP-2 TP-3 TP-4 Yelm High School Soccer FieldConversion and TennisCourts ReconstructionYelm, Washington Figure 1444018.01 10/12/22 \\OLYMPIA1\PROJECTS\1444\018.010\T\1444018.010.GPJ GRAIN SIZE FIGURE 8Grain Size Distribution