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20170370 Stormwater Site Plan 11202017Stormwater Site Plan �f SCJ ALLIANCE CONSULTING SERVICES TABLE OF CONTENTS Stormwater Site Plan CoverSheet ................................................................................................................................ ..............................1 Tableof Contents ...................................................................................................................... ..............................2 Project Engineer's Certification .............................................................................................. ..............................3 Section 1: Determination of Minimum Requirements ......................................................... ..............................4 Section 2: Project Overview ................................................................................................... ............................4 -5 Section 3: Existing Conditions Summary ................................................................................ ..............................5 Section 4: Off -site Analysis Report .......................................................................................... ..............................5 Section 5: Permanent Stormwater Control Plan ................................................................... ..............................6 SummarySection ................................................................................................................. ..............................6 WaterQuality Focilities .................................................................................................... ............................6 -7 FlowControl Focilities ........................................................................................................ ..............................7 Section 6: Construction Stormwater Pollution Prevention Plan ......................................... ..............................7 Section 7: Special Reports and Studies ................................................................................... ..............................7 Section8: Other Permits .......................................................................................................... ..............................7 Section 9: Declaration of Covenant for Privately Maintained Flow Control & Treatment Facilities ...........8 Appendices Appendix 1: Site Vicinity Map Appendix 2: Determination of Minimum Requirements Worksheet Appendix 3: Basin Map Exhibits Appendix 4: Design Calculations Appendix 5: Geotechnical Report Appendix 6: Construction Stormwater Pollution Prevention Plan Appendix 7: Stormwater Plan Sheets Yelm Community Schools Bypass Road 2 of 8 Stormwater Site Plan PROJECT ENGINEER'S CERTIFICATION "I hereby state that this Stormwater Site Plan / Construction SWPPP for the Yelm High School access road project has been prepared by me or under my supervision and meets the requirements of the Stormwater Management Manual for Western Washington and the standard of care and expertise which is usual and customary in this community for professional engineers. I understand that the City of Yelm does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me." Charlie Severs, PE 20 NOVEMBER 2017 Date M. r b � xl 16 [i i 52179 �S RFGIST�R�� o IV Yelm Community Schools Bypass Road 3 of 8 Stormwater Site Plan STORMWATER SITE PLAN The following report was prepared for the proposed Yelm High School Bypass Road in Yelm, Washington. This project was prepared to comply with the minimum technical standards and requirements that are set forth in the 2014 Stormwater Management Manual for Western Washington (SWMMWW). SECTION 1: DETERMINATION OF MINIMUM REQUIREMENTS The proposed Yelm High School Bypass Road project will result in more than 5,000 ft' of new impervious surface. In accordance with Volume 1, Section 2.4, of the SWMMWW, a Stormwater Site Plan is required for this project. As a result, Minimum Requirements 1 -9 will need to be addressed. The below table summarizes how each requirement will be met. MINIMUM REQUIREMENT COMPLIANCE WITH MINIMUM REQUIREMENT #1 - Stormwater Site Planning The contents of this report and all included appendices are intended to satisfy this requirement. A Construction SWPPP has been prepared and is enclosed herein as #2 - Construction SWPPP Appendix 6. #3 - Source Control of Pollution A Source Control Pollution Prevention Plan will be prepared and included with the O &M manual. #4 - Drainage Path Preservation Preservation of the site's previously established natural drainage paths will be maintained to the maximum extent practicable Stormwater management and BMP strategies for this project are #5 - On -site Stormwater Management described within this report and all included appendices. Basic treatment is required for this project. BMP T7.40 CAVFS1 will be #6 - Runoff Treatment installed adjacent to the proposed access road. #7 -Flow Control Flow control is required for this project. An infiltration pond will be constructed on -site. #8 - Wetlands Protection According to Thurston County's Geodata mapping, the project is not positioned in or adjacent to wetlands and /or wetland buffers. If required, a Stormwater Maintenance Agreement will be recorded #9 — Operations &Maintenance against the property prior to project completion. Table 1: Compliance with Minimum Technical Requirements SECTION 2: PROJECT OVERVIEW The proposed Yelm High School Bypass Roadway will be constructed on Thurston County Tax Parcel No. 21724240000. Specifically, the proposed site improvements / construction activities include the following: • Site preparation, grading, and erosion control activities • Construction of a 32' wide x 1,300' long road that connects Yelm High School to Tahoma Blvd. • Construction of on -site water quality and flow control facilities 1 Compost Amended Vegetated Filter Strip Yelm Community Schools Bypass Road 4 of 8 Stormwater Site Plan A site vicinity map of the proposed project location is enclosed herein as Appendix 1. Minimum Requirements 1 -9 are required for this project. A Minimum Requirements worksheet has been prepared and is enclosed herein as Appendix 2. SECTION 3: EXISTING CONDITIONS SUMMARY The 17.83 acre site consists primarily of overgrown brush and is undeveloped. There is a canopy of mature trees that are located at the northeast corner of the parcel. Construction activities will disturb approximately 15% of the total site area. The site, generally, slopes towards the center of parcel where a kettle has naturally formed. According to Thurston County's Geodata mapping center, there are no on- site wetlands and /or wetland buffers. Based on available historic photographs, a large portion of the site has remained undeveloped. Aerial photographs from 1990 & 2017 are provided. Below. �Y �, PROJECTLOCATION - AERIAL FROM 1990 t� Figure 1: 1990 and 2017 Existing Conditions Exhibits The subject property is located in FEMAZ Community Panel Number 53067C0353E. At the time of the project survey3, there wasn't any evidence to suggest that the site was or is being used as a solid waste dump, sump, and /or sanitary fill. SECTION 4: OFF -SITE ANALYSIS REPORT On -site generated stormwater runoff will be collected, treated, and routed to an infiltration pond that has been designed to retain and infiltrate 100% of the runoff. Historic drainage courses will not be altered. Consequently, downstream impacts are not anticipated. I Federal Emergency Management Agency 3 The field work for the project survey was completed by True Point Surveying, LLC in August 2017. Yelm Community Schools Bypass Road 5 of 8 Stormwater Site Plan +n_\I PROJECT LOCATION k `Rh AERIAL FROM 2017 f Figure 1: 1990 and 2017 Existing Conditions Exhibits The subject property is located in FEMAZ Community Panel Number 53067C0353E. At the time of the project survey3, there wasn't any evidence to suggest that the site was or is being used as a solid waste dump, sump, and /or sanitary fill. SECTION 4: OFF -SITE ANALYSIS REPORT On -site generated stormwater runoff will be collected, treated, and routed to an infiltration pond that has been designed to retain and infiltrate 100% of the runoff. Historic drainage courses will not be altered. Consequently, downstream impacts are not anticipated. I Federal Emergency Management Agency 3 The field work for the project survey was completed by True Point Surveying, LLC in August 2017. Yelm Community Schools Bypass Road 5 of 8 Stormwater Site Plan SECTION 5: PERMANENT STORMWATER CONTROL PLAN Summary Section The project consists of the one (1) drainage basin. Stormwater runoff from the project's drainage basin will be dispersed across CAVFS facilities for basic treatment and will be routed to an on -site retention pond for infiltration. A basin map exhibit that delineates the project's different land type designations has been prepared and is enclosed herein as Appendix 3. The following table identifies the different on- site land type designations and their respective areas for the project's drainage basin. DRAINAGE BASIN AREA (ACRES) % OF TOTAL AREA Existing Tributary Area 17.83 100.0% Existing Impervious Surface Area 0.00 0.0% Existing Forested Area 17.83 100.0% Proposed Impervious Surface Area 1.18 6.6% Proposed Roadway Area 0.98 5.5% Proposed Sidewalk Area 0.20 1.1% Proposed Landscaping Areas 0.47 2.6% Remaining Native Area 16.18 90.8% Table 2: Drainage Basin Land Type Designations Summary Table Water Quality Facilities According to Volume V, Section 7.4, of the SWMMWW, CAVFS can be used to meet basic runoff treatment and enhanced treatment objectives. They are a practical application in areas where there is space for roadside embankments, which is the case for this project. To meet basic treatment requirements 91% of the influent runoff file must pass through the soil profile of the CAVFS. The CAVFS facilities have been designed in accordance with BMP T7.40 — CAVFS. According to Volume V, Section 7.4, of the SWMMWW, a continuous runoff model must be used to calculate the size of the CAVFS facilities. The CAVFS will be constructed on both sides of the proposed bypass road and will be spaced at one - hundred (100) foot intervals (max.). As a result, only 1,650 ft2 of roadway area will be discharged to each CAVFS. MGS Flood software was used to calculate the size of each typical CAVFS facility. According to the runoff model, which is enclosed herein as Appendix 4, a five (5) foot wide by five (5) long CAVFS will need be constructed at each spillway4 to meet the basic runoff treatment requirements. 4 Each spillway will be spaced 100' O.C. along the proposed bypass road. Yelm Community Schools Bypass Road 6 of 8 Stormwater Site Plan Please refer to the stormwater plan sheets, enclosed herein as Appendix 7, to view the location, cross - sections, details, etc. of the proposed water quality facilities. Flow Control Facilities WWHM software was used to calculate the size of the proposed infiltration pond. The long -term design infiltration rate, as recommended by Insight Geologic, Inc., is 6.50 inches /hour. The proposed pond will be four (4) feet deep, which includes one (1) foot of freeboard /overflow storage, and will have 3:1 side slopes. According to the completed WWHM model, the minimum pond volume at the freeboard /overflow storage elevation needs to be 0.169 acre -feet. Additionally, the minimum bottom pond area needs to be 1,600 ft2. The WWHM report is enclosed herein as Appendix 4. Below are the WWHM sizing screenshots for the proposed infiltration pond. CEN0RI05 aciliy Name !` i � Faoliry Typa f0 OmINY OWIN3 Dosmctrnem cannn�con os��0 rrx�w,ememeawr.� emo FO�a I nomac.ne I rowNrrsa Feeny Dim.n.mnD oily Dimensions eun,swemn Dee I� FxMe[bmonlul 00 e0rx�lxi �.,j 1 n.�m<o.ynlN 0 N�� ussaosMM IGN AW Sa.slm•gM TE,AS swosMM W12 s astr MM SY GIC, INC. m aaa'r�nrnn.l — !{r-�{ a.airei 1 ' F---H F—°i ,Wmrl.a.�,w ®irN „ av�e.r amrn�7ixm rm� snow RO.a le Fo a 100 %INFILTRATION ro Is nnlsms.�q � eyx e "1T- TEeam al Oremw EEe+etion (n� 1. ��nnemon 1 J enas�e emn_ern��ro�«eraw,. =la Pa= nwc T. . �r� paonos Gl,�� rD �AD� __J X00 r�� lo rCla"aw �p� Jr�o� !aa ©enex ®o^^� J ®Spn.e..lm.e �w,wa.a srisaun ®� ■� N®®® OEM Rmsoamao ®EqRIN WE®® 013 nt ®��mm® 1 � rn W s • ,. loom. Del,uaom CEN0RI05 aciliy Name !` i � Faoliry Typa f0 OmINY OWIN3 Dosmctrnem cannn�con os��0 rrx�w,ememeawr.� emo FO�a I nomac.ne I rowNrrsa Feeny Dim.n.mnD oily Dimensions eun,swemn Dee I� FxMe[bmonlul 00 e0rx�lxi �.,j 1 n.�m<o.ynlN 0 N�� ussaosMM IGN AW Sa.slm•gM TE,AS swosMM W12 s astr MM SY GIC, INC. m aaa'r�nrnn.l — !{r-�{ a.airei 1 ' F---H F—°i ,Wmrl.a.�,w ®irN „ av�e.r amrn�7ixm rm� snow RO.a le Fo a 100 %INFILTRATION ro Is nnlsms.�q � eyx e "1T- TEeam al Oremw EEe+etion (n� 1. ��nnemon 1 J ®Spn.e..lm.e �w,wa.a srisaun ®� ■� N®®® OEM nt ®��mm® � s Please refer to the stormwater plan sheets, enclosed herein as Appendix 7, to view the location, cross - sections, details, etc. of the proposed infiltration pond. SECTION 6: CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN A Construction Stormwater Pollution Prevention Plan has been prepared and is enclosed herein as Appendix 6. SECTION 7: SPECIAL REPORTS & STUDIES A geotechnical report was prepared by Insight Geologic, Inc. and is enclosed herein as Appendix 5. SECTION 8: OTHER PERMITS A National Pollution Discharge Elimination System (NPDES) Notice of Intent (NOI) will be secured with the Department of Ecology before commencing with construction activities. A City of Yelm Civil Engineering Permit will also be applied for before starting construction activities. Yelm Community Schools Bypass Road 7 of 8 Stormwater Site Plan SECTION 9: DECLARATION OF COVENANT FOR FLOW CONTROL & WQ FACILITIES The proposed flow control and water quality facilities for the proposed bypass roadway project will be privately maintained. If required, an Agreement to Maintain Stormwater Facilities will be prepared and recorded against the property. An Operations and Maintenance Manual has been prepared and is enclosed herein as Appendix 6. END OF STORMWATER SITE PLAN Yelm Community Schools Bypass Road 8 of 8 Stormwater Site Plan APPENDIX 1 SITE VICINITY MAP -,*I► 1 _ �0 SC.J ALLIANCE CONSULTING SERVICES • N-h Yelm t'+r� 8q 3q M - -- Nlsgsally%nes OHl-0 1 JJ e F 5 I-t High School a n qb�° O� b PROJECT LOCATION M R`se - WiJP�e �ia"N =i 1FC1'snne ne.E c3 a s • i iiillttt�i�11 _ YELM HIGH SCHOOL �LG F PROJECT LOCATION u TAHOMA BOULEVARD SE 8730 Tallon Lane NE, Suite 200 • Lacey, WA 98516 • Office 360.352.1465 • Fax 360.352.1509 • scjalliance.com APPENDIX 2 DETERMINATION OF MINIMUM REQUIREMENTS Start Here Does the site have See Redevelopment 35% or more of Yes Minimum existing impervious 10 Requirements and coverage? Flow Chart No Does the project convert (Figure 2.4.2) 3/4 acres or more of Does the project vegetation to lawn or result in 5,000 landscaped areas, or square feet, or No convert 2.5 acres or more greater, of new plus of native vegetation to replaced hard pasture? surface area? Does the project Yes Yes No result in 2,000 square feet, or greater, of new plus replaced All Minimum hard surface area? Requirements apply to the new and replaced hard surfaces and converted Yes No vegetation areas. Minimum Requirements Does the project have 91 through 95 apply to land disturbing the new and replaced activities of 7,000 hard surfaces and the Yes square feet or greater? land disturbed. No Minimum Requirement 92 applies. Figure 2.4.1 — Flow Chart for Determining Requirements for New Development Volume I Minimum Technical Requirements December 2014 2 -5 APPENDIX 3 BASIN MAP EXHIBIT w 0 a a m IS MJVAIinos HWOH` i z E/. w Q w / Q w O Q Q w w LU Q w U w > z Q ZD z z 11 r� �z � o Uug6y O O Q w ' U (n CO Of W W w O �j U) U) U) W W z W W W �/ U U U U U Q Q Q Q Q o ti — 00 M M 00 co °? cy "I co ti o 0 0 — — - o i a APPENDIX 4 DESIGN CALCULATIONS MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.38 Program License Number: 200810007 Project Simulation Performed on: 10/26/2017 4:19 PM Report Generation Date: 10/26/2017 4:20 PM Input File Name: Yelm Community Schools Bypass Road Project Project Name: Analysis Title: Individual CAVFS Analysis Comments: PRECIPITATION INPUT Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 1 Full Period of Record Available used for Routing Precipitation Station : 95003205 Puget West 32 in_5min 10/01/1939 - 10/01/2097 Evaporation Station 951032 Puget West 32 in MAP Evaporation Scale Factor 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default * * * * * * * * ** Default HSPF Parameters Used (Not Modified by User) * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * ** WATERSHED DEFINITION * * * * * * * * * * * * * * * * * * * * * ** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.039 0.039 Area of Links that Include Precip /Evap (acres) 0.000 0.000 Total (acres) 0.039 0.039 ---------------- - - - - -- SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---- - - - - -- Subbasin : Subbasin 1 ------- Area(Acres) -- Till Forest 0.000 Till Pasture 0.000 Till Grass 0.000 Outwash Forest 0.039 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 Green Roof 0.000 User 2 0.000 Impervious 0.000 Subbasin Total 0.039 ---------------- - - - - -- SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---- - - - - -- Subbasin : Subbasin 1 ------- Area(Acres) -- Till Forest 0.000 Till Pasture 0.000 Till Grass 0.000 Outwash Forest 0.000 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 Green Roof 0.000 User 2 0.000 Impervious 0.039 CAVFS FACILITIES Subbasin Total Q-0-39-.-;' I WILL BE CONSTRUCTED EVERY 100' ALONG * * * * * * * * * * * * * * * * * * * * * * * ** LINK DATI THE PROPOSED BYPASS ROAD ---------------- - - - - -- SCENARIO: PRE (EACH SIDE) Number of Links: 0 * * * * * * * * * * * * * * * * * * * * * * * ** LINK DATA * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** ---------------- - - - - -- SCENARIO: POSTDEVELOPED Number of Links: 1 Link Name: New CAVFS Lnk1 Link Type: Compost Amended Vegetated Filter Strip (CAVFS) Downstream Link: None Compost Thickness (ft) : 0.670 Compost Porosity ( %) : 20.000 Compost Hydraulic Conductivity (in /hr) : 1.000 CAVFS Length (ft) : 5.000 CAVFS Width (ft) : 5.000 CAVFS Slope, Z (ft/ft) : 20.000 Gravel Spreader Width (ft) : 1.000 Gravel Hydraulic Conductivity (in /hr) : 2.000 Gravel Porosity ( %) : 30.000 Soil Infiltration Rate (in /hr) : 6.500 Precipitation and Evaporation NOT Applied to Surface of CAVFS * * * * * * * * * * * * * * * * * * * ** *FLOOD FREQUENCY AND DURATION STATISTICS * * * * * * * * * * * * * * * * * ** ---------------- - - - - -- SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ---------------- - - - - -- SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 * * * * * * * * ** *Groundwater Recharge Summary * * * * * * * * * * * ** Recharge is computed as input to Perind Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac -ft) Subbasin: Subbasin 1 7.244 Total: 7.244 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac -ft) ----------------------------------------------------------------------------------------------- Subbasin: Subbasin 1 0.000 Link: New CAVFS Lnk1 12.885 Total: 12.885 Total Predevelopment Recharge is Less than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.046 ac -ft /year, Post Developed: 0.082 ac -ft /year * * * * * * * * ** *Water Quality Facility Data * * * * * * * * * * * ** ---------------- - - - - -- SCENARIO: PREDEVELOPED Number of Links: 0 ---------------- - - - - -- SCENARIO: POSTDEVELOPED Number of Links: 1 MORE THAN 91 OF THE STORMWATER * * * * * * * * ** Link: New CAVFS Lnk1 PASSES THROUGH EACH CAVFS Infiltration /Filtration Statistics----------- - - - - -- - FACILITY Inflow Volume (ac -ft): 13.55 Inflow Volume Including PPT -Evap (ac -ft : 13.55 Total Runoff Infiltrated (ac -ft): 12.89, 5.070 Total Runoff Filtered (ac -ft): 0.00, 0.02 0 Primary Outflow To Downstream System (ac -ft): 0.67 Secondary Outflow To Downstream System (ac -ft): 0.00 WWHM20 PROJECT General Model Information Project Name: Infiltration Pond Site Name: Site Address: City: Report Date: 11/17/2017 Gage: Eaton Creek Data Start: 1955/10/01 Data End: 2011/09/30 Timestep: 15 Minute Precip Scale: 0.857 Version Date: 2017/04/14 Version: 4.2.13 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year Infiltration Pond 11/17/2017 1:37:09 PM Page 2 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Forest, Flat 1.65 Pervious Total 1.65 Impervious Land Use acre Impervious Total 0 Basin Total 1.65 Element Flows To: Surface Interflow Groundwater Infiltration Pond 11/17/2017 1:37:09 PM Page 3 Mitigated Land Use Basin 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Lawn, Flat 0.47 Pervious Total 0.47 Impervious Land Use acre ROADS FLAT 0.98 SIDEWALKS FLAT 0.2 Impervious Total 1.18 Basin Total 1.65 Element Flows To: Surface Trapezoidal Pond 1 Interflow Groundwater Trapezoidal Pond 1 Infiltration Pond 11/17/2017 1:37:09 PM Page 4 Mitigated Routing Trapezoidal Pond 1 Bottom Length: 40.00 ft. Area(ac.) Bottom Width: 40.00 ft. Discharge(cfs) Infilt(cfs) Depth: 4 ft. 0.036 Volume at riser head: 0.1689 acre -feet. 0.000 Infiltration On 0.0444 Infiltration rate: 6.5 0.001 Infiltration safety factor: 1 0.240 Total Volume Infiltrated (ac -ft.): 184.691 Total Volume Through Riser (ac -ft.): 0 Total Volume Through Facility (ac -ft.): 184.691 Percent Infiltrated: 100 Total Precip Applied to Facility: 0 Total Evap From Facility: 0 Side slope 1: 3 To 1 0.000 Side slope 2: 3 To 1 0.2222 Side slope 3: 3 To 1 0.008 Side slope 4: 3 To 1 0.240 Discharge Structure 0.039 Riser Height: 3 ft. 0.000 Riser Diameter: 100 in. 0.3111 Element Flows To: 0.012 Outlet 1 Outlet 2 0.240 Pond Hydraulic Table Stage(feet) Area(ac.) Volume(ac -ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.036 0.000 0.000 0.000 0.0444 0.037 0.001 0.000 0.240 0.0889 0.037 0.003 0.000 0.240 0.1333 0.038 0.005 0.000 0.240 0.1778 0.038 0.006 0.000 0.240 0.2222 0.039 0.008 0.000 0.240 0.2667 0.039 0.010 0.000 0.240 0.3111 0.040 0.012 0.000 0.240 0.3556 0.040 0.013 0.000 0.240 0.4000 0.041 0.015 0.000 0.240 0.4444 0.041 0.017 0.000 0.240 0.4889 0.042 0.019 0.000 0.240 0.5333 0.042 0.021 0.000 0.240 0.5778 0.043 0.023 0.000 0.240 0.6222 0.043 0.025 0.000 0.240 0.6667 0.044 0.027 0.000 0.240 0.7111 0.045 0.029 0.000 0.240 0.7556 0.045 0.031 0.000 0.240 0.8000 0.046 0.033 0.000 0.240 0.8444 0.046 0.035 0.000 0.240 0.8889 0.047 0.037 0.000 0.240 0.9333 0.047 0.039 0.000 0.240 0.9778 0.048 0.041 0.000 0.240 1.0222 0.048 0.043 0.000 0.240 1.0667 0.049 0.045 0.000 0.240 1.1111 0.050 0.048 0.000 0.240 1.1556 0.050 0.050 0.000 0.240 Infiltration Pond 11/17/2017 1:37:09 PM Page 6 1.2000 0.051 0.052 0.000 0.240 1.2444 0.051 0.054 0.000 0.240 1.2889 0.052 0.057 0.000 0.240 1.3333 0.052 0.059 0.000 0.240 1.3778 0.053 0.061 0.000 0.240 1.4222 0.054 0.064 0.000 0.240 1.4667 0.054 0.066 0.000 0.240 1.5111 0.055 0.069 0.000 0.240 1.5556 0.055 0.071 0.000 0.240 1.6000 0.056 0.074 0.000 0.240 1.6444 0.057 0.076 0.000 0.240 1.6889 0.057 0.079 0.000 0.240 1.7333 0.058 0.081 0.000 0.240 1.7778 0.058 0.084 0.000 0.240 1.8222 0.059 0.086 0.000 0.240 1.8667 0.060 0.089 0.000 0.240 1.9111 0.060 0.092 0.000 0.240 1.9556 0.061 0.095 0.000 0.240 2.0000 0.062 0.097 0.000 0.240 2.0444 0.062 0.100 0.000 0.240 2.0889 0.063 0.103 0.000 0.240 2.1333 0.064 0.106 0.000 0.240 2.1778 0.064 0.109 0.000 0.240 2.2222 0.065 0.111 0.000 0.240 2.2667 0.066 0.114 0.000 0.240 2.3111 0.066 0.117 0.000 0.240 2.3556 0.067 0.120 0.000 0.240 2.4000 0.067 0.123 0.000 0.240 2.4444 0.068 0.126 0.000 0.240 2.4889 0.069 0.129 0.000 0.240 2.5333 0.070 0.132 0.000 0.240 2.5778 0.070 0.136 0.000 0.240 2.6222 0.071 0.139 0.000 0.240 2.6667 0.072 0.142 0.000 0.240 2.7111 0.072 0.145 0.000 0.240 2.7556 0.073 0.148 0.000 0.240 2.8000 0.074 0.152 0.000 0.240 2.8444 0.074 0.155 0.000 0.240 2.8889 0.075 0.158 0.000 0.240 2.9333 0.076 0.162 0.000 0.240 2.9778 0.076 0.165 0.000 0.240 3.0222 0.077 0.168 0.293 0.240 3.0667 0.078 0.172 1.522 0.240 3.1111 0.079 0.175 3.275 0.240 3.1556 0.079 0.179 5.425 0.240 3.2000 0.080 0.183 7.907 0.240 3.2444 0.081 0.186 10.68 0.240 3.2889 0.081 0.190 13.72 0.240 3.3333 0.082 0.193 17.00 0.240 3.3778 0.083 0.197 20.51 0.240 3.4222 0.084 0.201 24.22 0.240 3.4667 0.084 0.205 28.14 0.240 3.5111 0.085 0.208 32.24 0.240 3.5556 0.086 0.212 36.53 0.240 3.6000 0.087 0.216 40.98 0.240 3.6444 0.087 0.220 45.60 0.240 3.6889 0.088 0.224 50.37 0.240 3.7333 0.089 0.228 55.28 0.240 Infiltration Pond 11/17/2017 1:37:09 PM Page 7 3.7778 0.090 0.232 60.34 0.240 3.8222 0.090 0.236 65.54 0.240 3.8667 0.091 0.240 70.86 0.240 3.9111 0.092 0.244 76.30 0.240 3.9556 0.093 0.248 81.87 0.240 4.0000 0.094 0.252 87.54 0.240 4.0444 0.094 0.256 93.32 0.240 Infiltration Pond 11/17/2017 1:37:09 PM Page 8 Analysis Results POC 1 0. ti J Im o1 T Cumulative Pro6a6ility T°' 0 00 —�= oo, --- i.-.. 0000 ob 1 r 5 uo zo D bo �U ao �D sus a oo 0001 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 1.65 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0.47 Total Impervious Area: 1.18 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.001278 5 year 0.002188 10 year 0.003021 25 year 0.004401 50 year 0.005715 100 year 0.00732 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 0.009 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 0.001 0.000 1963 0.001 0.000 1964 0.001 0.000 1965 0.001 0.000 Infiltration Pond 11/17/2017 1:37:09 PM Page 9 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 0.004 0.000 1972 0.028 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 0.001 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 0.001 0.000 1986 0.001 0.000 1987 0.001 0.000 1988 0.001 0.000 1989 0.001 0.000 1990 0.001 0.000 1991 0.005 0.000 1992 0.001 0.000 1993 0.001 0.000 1994 0.001 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 0.001 0.000 2001 0.001 0.000 2002 0.000 0.000 2003 0.001 0.000 2004 0.001 0.000 2005 0.000 0.000 2006 0.001 0.000 2007 0.001 0.000 2008 0.001 0.000 2009 0.001 0.000 2010 0.001 0.000 2011 0.001 0.000 Ranked Annual Peaks Ranked Annual Rank 1 2 3 4 6 8 Peaks for Predeveloped and Predeveloped Mitigated 0.0275 0.0000 0.0092 0.0000 0.0047 0.0000 0.0037 0.0000 0.0013 0.0000 0.0013 0.0000 0.0013 0.0000 0.0013 0.0000 Mitigated. POC #1 Infiltration Pond 11/17/2017 1:37:45 PM Page 10 9 0.0013 0.0000 10 0.0013 0.0000 11 0.0013 0.0000 12 0.0013 0.0000 13 0.0013 0.0000 14 0.0013 0.0000 15 0.0013 0.0000 16 0.0013 0.0000 17 0.0013 0.0000 18 0.0013 0.0000 19 0.0013 0.0000 20 0.0013 0.0000 21 0.0013 0.0000 22 0.0013 0.0000 23 0.0013 0.0000 24 0.0013 0.0000 25 0.0013 0.0000 26 0.0013 0.0000 27 0.0013 0.0000 28 0.0013 0.0000 29 0.0013 0.0000 30 0.0013 0.0000 31 0.0013 0.0000 32 0.0013 0.0000 33 0.0013 0.0000 34 0.0013 0.0000 35 0.0013 0.0000 36 0.0013 0.0000 37 0.0013 0.0000 38 0.0013 0.0000 39 0.0013 0.0000 40 0.0013 0.0000 41 0.0013 0.0000 42 0.0013 0.0000 43 0.0013 0.0000 44 0.0012 0.0000 45 0.0012 0.0000 46 0.0012 0.0000 47 0.0012 0.0000 48 0.0012 0.0000 49 0.0011 0.0000 50 0.0010 0.0000 51 0.0010 0.0000 52 0.0010 0.0000 53 0.0008 0.0000 54 0.0006 0.0000 55 0.0005 0.0000 56 0.0004 0.0000 Infiltration Pond 11/17/2017 1:37:45 PM Page 11 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass /Fail 0.0006 4194 0 0 Pass 0.0007 3613 0 0 Pass 0.0007 3108 0 0 Pass 0.0008 2647 0 0 Pass 0.0008 2233 0 0 Pass 0.0009 1879 0 0 Pass 0.0009 1609 0 0 Pass 0.0010 1356 0 0 Pass 0.0010 1159 0 0 Pass 0.0011 922 0 0 Pass 0.0012 667 0 0 Pass 0.0012 456 0 0 Pass 0.0013 268 0 0 Pass 0.0013 116 0 0 Pass 0.0014 22 0 0 Pass 0.0014 21 0 0 Pass 0.0015 21 0 0 Pass 0.0015 20 0 0 Pass 0.0016 19 0 0 Pass 0.0016 19 0 0 Pass 0.0017 18 0 0 Pass 0.0017 18 0 0 Pass 0.0018 18 0 0 Pass 0.0018 17 0 0 Pass 0.0019 16 0 0 Pass 0.0019 16 0 0 Pass 0.0020 16 0 0 Pass 0.0020 14 0 0 Pass 0.0021 13 0 0 Pass 0.0021 12 0 0 Pass 0.0022 12 0 0 Pass 0.0022 12 0 0 Pass 0.0023 11 0 0 Pass 0.0023 11 0 0 Pass 0.0024 11 0 0 Pass 0.0024 11 0 0 Pass 0.0025 10 0 0 Pass 0.0025 10 0 0 Pass 0.0026 10 0 0 Pass 0.0026 10 0 0 Pass 0.0027 10 0 0 Pass 0.0027 10 0 0 Pass 0.0028 9 0 0 Pass 0.0028 9 0 0 Pass 0.0029 9 0 0 Pass 0.0029 9 0 0 Pass 0.0030 9 0 0 Pass 0.0030 9 0 0 Pass 0.0031 9 0 0 Pass 0.0032 9 0 0 Pass 0.0032 9 0 0 Pass 0.0033 9 0 0 Pass 0.0033 9 0 0 Pass Infiltration Pond 11/17/2017 1:37:45 PM Page 12 0.0034 8 0 0 Pass 0.0034 8 0 0 Pass 0.0035 8 0 0 Pass 0.0035 8 0 0 Pass 0.0036 7 0 0 Pass 0.0036 7 0 0 Pass 0.0037 7 0 0 Pass 0.0037 6 0 0 Pass 0.0038 6 0 0 Pass 0.0038 6 0 0 Pass 0.0039 6 0 0 Pass 0.0039 6 0 0 Pass 0.0040 6 0 0 Pass 0.0040 6 0 0 Pass 0.0041 6 0 0 Pass 0.0041 6 0 0 Pass 0.0042 6 0 0 Pass 0.0042 6 0 0 Pass 0.0043 6 0 0 Pass 0.0043 6 0 0 Pass 0.0044 6 0 0 Pass 0.0044 6 0 0 Pass 0.0045 6 0 0 Pass 0.0045 6 0 0 Pass 0.0046 6 0 0 Pass 0.0046 5 0 0 Pass 0.0047 5 0 0 Pass 0.0047 4 0 0 Pass 0.0048 4 0 0 Pass 0.0048 4 0 0 Pass 0.0049 4 0 0 Pass 0.0049 4 0 0 Pass 0.0050 4 0 0 Pass 0.0050 4 0 0 Pass 0.0051 4 0 0 Pass 0.0052 4 0 0 Pass 0.0052 4 0 0 Pass 0.0053 4 0 0 Pass 0.0053 4 0 0 Pass 0.0054 4 0 0 Pass 0.0054 4 0 0 Pass 0.0055 4 0 0 Pass 0.0055 4 0 0 Pass 0.0056 4 0 0 Pass 0.0056 4 0 0 Pass 0.0057 4 0 0 Pass 0.0057 4 0 0 Pass Infiltration Pond 11/17/2017 1:37:45 PM Page 13 Water Quality Water Quality BMP Flow On -line facility volume: On -line facility target flow: Adjusted for 15 min: Off -line facility target flow: Adjusted for 15 min: ind Volume for POC #1 0 acre -feet 0 cfs. 0 cfs. 0 cfs. 0 cfs. Infiltration Pond 11/17/2017 1:37:45 PM Page 14 LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Waterfluality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac -ft) Infiltration Infiltrated Treated (ac -ft) (ac -ft) Credit Trapezoidal Pond 1 POC ❑ 168.14 ❑ 99.96 Total Volume Infiltrated 168.14 0.00 fl.flfl 99.96 0.00 0% No Treat. Credit Duration Compliance with LID Analysis Standard 8% of2 -yrto 50% of Result = 2 yr Passed Infiltration Pond 11/17/2017 1:37:45 PM Page 15 Appendix Predeveloped Schematic in Infiltration Pond 11/17/2017 1:37:50 PM Page 17 Mitigated Schematic Infiltration Pond 11/17/2017 1:37:50 PM Page 18 MENNEN mom 91MEMEN 01. INEEMEN mr7MONEENE MENEEMEN ONEENEEN MENEEMEN MENEEMEN MENEEMEN MENEEMEN Infiltration Pond 11/17/2017 1:37:50 PM Page 18 Predeveloped UC/ File RUN GLOBAL WWHM4 model simulation START 1955 10 01 END RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 END GLOBAL 2011 09 30 FILES <File> <Un #> END FILES OPN SEQUENCE UNIT SYSTEM 1 < ---- - - - - -- - File Name---- ------------------------ - - > * ** * ** INGRP INDELT 00:15 PERLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY -INFO1 # - # < ---------- Title ----------- > * * *TRAN PIVL DIG1 FIL1 1 Basin 1 MAX END DISPLY -INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN * ** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD * ** END OPCODE PARM # # K * ** END PARM END GENER PERLND GEN -INFO PYR DIG2 FIL2 YRND 1 2 30 9 <PLS > < ------- Name ------- >NBLKS Unit - systems Printer * ** # - # User t- series Engl Metr * ** in out * ** 1 A /B, Forest, 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 * ** 1 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 * * * * * * * ** 1 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT -INFO Infiltration Pond 11/17/2017 1:37:50 PM Page 19 PWAT -PARM1 <PLS > PWATER variable monthly parameter value flags * ** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT * ** 1 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 1 0 5 2 400 0.05 0.3 END PWAT -PARM2 PWAT -PARM3 <PLS > PWATER input info: Part 3 # - # * * *PETMAX PETMIN INFEXP 1 0 0 2 END PWAT -PARM3 PWAT -PARM4 <PLS > PWATER input info: Part 4 # - # CEPSC UZSN NSUR 1 0.2 0.5 0.35 END PWAT -PARM4 AGWRC 0.996 * ** INFILD DEEPFR BASETP AGWETP 2 0 0 0 * ** INTFW IRC LZETP * ** 0 0.7 0.7 PWAT - STATEI <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 1 0 0 0 0 3 1 END PWAT - STATEI END PERLND IMPLND GEN -INFO <PLS > < ------- Name ------- > Unit - systems Printer * ** # - # User t- series Engl Metr * ** in out * ** END GEN -INFO * ** Section IWATER * ** ACTIVITY <PLS > * * * * * * * * * * * ** Active Sections * * * * * * * * * * * * * * * * * * * * * * * * * * * ** # - # ATMP SNOW IWAT SLD IWG IQAL * ** END ACTIVITY PRINT -INFO <ILS > * * * * * * ** Print -flags * * * * * * ** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL * * * * * * * ** END PRINT -INFO IWAT -PARM1 <PLS > IWATER variable monthly parameter value flags * ** # - # CSNO RTOP VRS VNN RTLI * ** END IWAT -PARM1 IWAT -PARM2 <PLS > IWATER input info: Part 2 * ** # - # * ** LSUR SLSUR NSUR RETSC END IWAT -PARM2 IWAT -PARM3 <PLS > IWATER input info: Part 3 * ** # - # * * *PETMAX PETMIN END IWAT -PARM3 IWAT - STATEI <PLS > * ** Initial conditions at start of simulation # - # * ** RETS SURS END IWAT - STATEI GWVS 0 Infiltration Pond 11/17/2017 1:37:50 PM Page 20 hW11 =1010M0111 SCHEMATIC <- Source -> < -- Area - -> <- Target -> MBLK * ** <Name> # <- factor -> <Name> # Tbl# * ** Basin 1 * ** PERLND 1 1.65 COPY 501 12 PERLND 1 1.65 COPY 501 13 * * * ** *Routing * * * * ** END SCHEMATIC NETWORK <- Volume -> < -Grp> <- Member - > < -- Mult- - >Tran <- Target vols> < -Grp> <- Member -> * ** <Name> # <Name> # # <- factor - >strg <Name> # # <Name> # # * ** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <- 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 * ** END GEN -INFO * ** Section RCHRES * ** ACTIVITY <PLS > * * * * * * * * * * * ** Active Sections * * * * * * * * * * * * * * * * * * * * * * * * * * * ** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG * ** END ACTIVITY PRINT -INFO <PLS > * * * * * * * * * * * * * * * ** Print -flags * * * * * * * * * * * * * * * * * ** PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR * * * * * * * ** END PRINT -INFO HYDR -PARM1 RCHRES Flags for each HYDR Section * ** # - # VC Al A2 A3 ODFVFG for each * ** ODGTFG for each FUNCT for each FG FG FG FG possible exit * ** possible exit possible exit * * * * * * * * * * * * * * * ** END HYDR -PARM1 HYDR -PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 * ** < ------ >< -------- ><--------><-------- > <-------- > <-------- > <--- - - - - -> * ** 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 <------ > <--- - - - - -> <--- > <--- > <--- > <--- > < - - -> * ** <--- > <--- > <--- > <--- > < - - -> END HYDR -INIT END RCHRES SPEC - ACTIONS END SPEC - ACTIONS FTABLES 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 Infiltration Pond 11/17/2017 1:37:50 PM Page 21 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 * ** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS -LINK < Volume> < -Grp> <- Member - > < -- Mult - -> <Target> < -Grp> <- Member - > * ** <Name> <Name> # # <- factor -> <Name> <Name> # # * ** MASS -LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS -LINK 12 MASS -LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS -LINK 13 END MASS -LINK END RUN Infiltration Pond 11/17/2017 1:37:50 PM Page 22 Mitigated UC/ File RUN GLOBAL WWHM4 model simulation START 1955 10 01 END RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 END GLOBAL 2011 09 30 FILES <File> <Un #> END FILES OPN SEQUENCE UNIT SYSTEM 1 < ---- - - - - -- - File Name---- ------------------------ - - > * ** * ** INGRP INDELT 00:15 PERLND 7 IMPLND 1 IMPLND 8 RCHRES 1 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY -INFO1 # - # < ---------- Title ----------- > * * *TRAN PIVL DIG1 FIL1 1 Trapezoidal Pond 1 MAX END DISPLY -INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN * ** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD * ** END OPCODE PARM # # K * ** END PARM END GENER PERLND GEN -INFO PYR DIG2 FIL2 YRND 1 2 30 9 <PLS > < ------- Name ------- >NBLKS Unit - systems Printer * ** # - # User t- series Engl Metr * ** in out * ** 7 A /B, Lawn, 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 * ** 7 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT -INFO <PLS > * * * * * * * * * * * * * * * ** Print -flags * * * * * * * * * * * * * * * * * * * * * * * * * * * ** PIVL PYR Infiltration Pond 11/17/2017 1:37:50 PM Page 23 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC * * * * * * * ** 7 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 * ** 7 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 7 0 5 0.8 400 0.05 0.3 0.996 END PWAT -PARM2 PWAT -PARM3 <PLS > PWATER input info: Part 3 * ** # - # * * *PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 7 0 0 2 2 0 0 0 END PWAT -PARM3 PWAT -PARM4 <PLS > PWATER input info: Part 4 * ** # - # CEPSC UZSN NSUR INTFW IRC LZETP * ** 7 0.1 0.5 0.25 0 0.7 0.25 END PWAT -PARM4 PWAT- STATEI <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 7 0 0 0 0 3 1 0 END PWAT- STATEI 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 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 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 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 8 0 0 0 0 0 END IWAT -PARM1 IWAT -PARM2 <PLS > IWATER input info: Part 2 * ** # - # * ** LSUR SLSUR NSUR RETSC Infiltration Pond 11/17/2017 1:37:50 PM Page 24 1 400 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 8 0 0 END IWAT -PARM3 IWAT - STATEI <PLS > * ** Initial conditions at start of simulation # - # * ** RETS SURS 1 0 0 8 0 0 END IWAT - STATEI END IMPLND SCHEMATIC <- Source -> < -- Area - -> <- Target -> MBLK * ** <Name> # <- factor -> <Name> # Tbl# * ** Basin 1 * ** PERLND 7 0.47 RCHRES 1 2 PERLND 7 0.47 RCHRES 1 3 IMPLND 1 0.98 RCHRES 1 5 IMPLND 8 0.2 RCHRES 1 5 * * * ** *Routing * * * * ** PERLND 7 0.47 COPY 1 12 IMPLND 1 0.98 COPY 1 15 IMPLND 8 0.2 COPY 1 15 PERLND 7 0.47 COPY 1 13 RCHRES 1 1 COPY 501 17 END SCHEMATIC NETWORK <- Volume -> < -Grp> <- Member - > < -- Mult- - >Tran <- Target vols> < -Grp> <- Member -> * ** <Name> # <Name> # # <- factor - >strg <Name> # # <Name> # # * ** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <- 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 Trapezoidal Pond -005 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 Infiltration Pond 11/17/2017 1:37:50 PM Page 25 RCHRES Flags for each HYDR Section * ** # - # VC Al 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 SPEC - ACTIONS END SPEC - ACTIONS FTABLES FTABLE 1 91 5 Depth Area Volume Outflowl Outflow2 Velocity Travel Time * ** (ft) (acres) (acre -ft) (cfs) (cfs) (ft /sec) (Minutes) * ** 0.000000 0.036731 0.000000 0.000000 0.000000 0.044444 0.037222 0.001643 0.000000 0.240741 0.088889 0.037717 0.003309 0.000000 0.240741 0.133333 0.038215 0.004996 0.000000 0.240741 0.177778 0.038716 0.006706 0.000000 0.240741 0.222222 0.039220 0.008438 0.000000 0.240741 0.266667 0.039728 0.010192 0.000000 0.240741 0.311111 0.040239 0.011969 0.000000 0.240741 0.355556 0.040753 0.013769 0.000000 0.240741 0.400000 0.041271 0.015592 0.000000 0.240741 0.444444 0.041792 0.017437 0.000000 0.240741 0.488889 0.042316 0.019307 0.000000 0.240741 0.533333 0.042843 0.021199 0.000000 0.240741 0.577778 0.043374 0.023115 0.000000 0.240741 0.622222 0.043907 0.025054 0.000000 0.240741 0.666667 0.044444 0.027018 0.000000 0.240741 0.711111 0.044985 0.029005 0.000000 0.240741 0.755556 0.045528 0.031017 0.000000 0.240741 0.800000 0.046075 0.033052 0.000000 0.240741 0.844444 0.046625 0.035112 0.000000 0.240741 0.888889 0.047179 0.037197 0.000000 0.240741 0.933333 0.047736 0.039306 0.000000 0.240741 0.977778 0.048295 0.041440 0.000000 0.240741 1.022222 0.048859 0.043599 0.000000 0.240741 1.066667 0.049425 0.045783 0.000000 0.240741 1.111111 0.049995 0.047992 0.000000 0.240741 1.155556 0.050568 0.050227 0.000000 0.240741 1.200000 0.051144 0.052487 0.000000 0.240741 1.244444 0.051724 0.054773 0.000000 0.240741 1.288889 0.052306 0.057085 0.000000 0.240741 1.333333 0.052893 0.059423 0.000000 0.240741 1.377778 0.053482 0.061787 0.000000 0.240741 1.422222 0.054074 0.064177 0.000000 0.240741 1.466667 0.054670 0.066593 0.000000 0.240741 1.511111 0.055269 0.069037 0.000000 0.240741 1.555556 0.055872 0.071506 0.000000 0.240741 1.600000 0.056478 0.074003 0.000000 0.240741 1.644444 0.057086 0.076527 0.000000 0.240741 1.688889 0.057699 0.079077 0.000000 0.240741 1.733333 0.058314 0.081655 0.000000 0.240741 1.777778 0.058933 0.084261 0.000000 0.240741 1.822222 0.059555 0.086894 0.000000 0.240741 Infiltration Pond 11/17/2017 1:37:50 PM Page 26 1.866667 0.060180 1.911111 0.060808 1.955556 0.061440 2.000000 0.062075 2.044444 0.062714 2.088889 0.063355 2.133333 0.064000 2.177778 0.064648 2.222222 0.065299 2.266667 0.065954 2.311111 0.066612 2.355556 0.067273 2.400000 0.067938 2.444444 0.068605 2.488889 0.069276 2.533333 0.069950 2.577778 0.070628 2.622222 0.071309 2.666667 0.071993 2.711111 0.072680 2.755556 0.073370 2.800000 0.074064 2.844444 0.074761 2.888889 0.075462 2.933333 0.076165 2.977778 0.076872 3.022222 0.077582 3.066667 0.078296 3.111111 0.079012 3.155556 0.079732 3.200000 0.080455 3.244444 0.081182 3.288889 0.081912 3.333333 0.082645 3.377778 0.083381 3.422222 0.084120 3.466667 0.084863 3.511111 0.085609 3.555556 0.086359 3.600000 0.087111 3.644444 0.087867 3.688889 0.088626 3.733333 0.089388 3.777778 0.090154 3.822222 0.090923 3.866667 0.091695 3.911111 0.092471 3.955556 0.093249 4.000000 0.094031 END FTABLE 1 END FTABLES 0.089555 0.092243 0.094960 0.097705 0.100478 0.103279 0.106110 0.108968 0.111856 0.114773 0.117719 0.120694 0.123699 0.126733 0.129797 0.132891 0.136015 0.139169 0.142354 0.145568 0.148814 0.152090 0.155398 0.158736 0.162105 0.165506 0.168939 0.172403 0.175898 0.179426 0.182986 0.186578 0.190202 0.193859 0.197548 0.201270 0.205026 0.208814 0.212635 0.216490 0.220379 0.224301 0.228257 0.232246 0.236270 0.240329 0.244421 0.248548 0.252710 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.000000 0.240741 0.293178 0.240741 1.522913 0.240741 3.275884 0.240741 5.425181 0.240741 7.907404 0.240741 10.68237 0.240741 13.72155 0.240741 17.00325 0.240741 20.51018 0.240741 24.22800 0.240741 28.14451 0.240741 32.24909 0.240741 36.53225 0.240741 40.98543 0.240741 45.60073 0.240741 50.37080 0.240741 55.28868 0.240741 60.34776 0.240741 65.54166 0.240741 70.86418 0.240741 76.30929 0.240741 81.87105 0.240741 87.54358 0.240741 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 * ** RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR O 1 1 1 WDM 1001 FLOW ENGL REPL RCHRES 1 HYDR O 2 1 1 WDM 1002 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1003 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL Infiltration Pond 11/17/2017 1:37:50 PM Page 27 COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS -LINK <Volume> < -Grp> <- Member - > < -- Mult - -> <Target> <Name> <Name> # # <- factor -> <Name> MASS -LINK 2 PERLND PWATER SURO 0.083333 RCHRES END MASS -LINK 2 MASS -LINK 3 PERLND PWATER IFWO 0.083333 RCHRES END MASS -LINK 3 MASS -LINK 5 IMPLND IWATER SURO 0.083333 RCHRES END MASS -LINK 5 MASS -LINK 12 PERLND PWATER SURO 0.083333 COPY END MASS -LINK 12 MASS -LINK 13 PERLND PWATER IFWO 0.083333 COPY END MASS -LINK 13 MASS -LINK 15 IMPLND IWATER SURO 0.083333 COPY END MASS -LINK 15 MASS -LINK 17 RCHRES OFLOW OVOL 1 COPY END MASS -LINK 17 END MASS -LINK END RUN < -Grp> <- Member - > * ** <Name> # # * ** INFLOW IVOL INFLOW IVOL INFLOW IVOL IN�I�I111�uh/G \�I INPUT MEAN INPUT MEAN IN�I�I111�uh/G \�I Infiltration Pond 11/17/2017 1:37:50 PM Page 28 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 -2017; 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 Infiltration Pond 11/17/2017 1:37:50 PM Page 31 APPENDIX 5 GEOTECHNICAL REPORT INSIGHT GEOLOGIC, INC. August 29, 2017 J. W. Morrissette & Associates 1700 Cooper Point Road SW Suite B -2 Olympia, Washington 98502 Attention: Scott Severs Report Geotechnical and Groundwater Evaluation Proposed Yelm High School Bypass Road Yelm, Washington Project No. 847 - 004 -01 INTRODUCTION Insight Geologic, Inc. is pleased to provide our report for the evaluation of subsurface conditions at the location of the proposed Yelm High School Bypass Road in Yelm, Washington. The location of the site is shown relative to surrounding physical features in the Vicinity Map, Figure 1. The road will connect Tahoma Boulevard SE on the south and Yelm High School on the north to reduce traffic on Yelm Boulevard. The proposed roadway alignment crosses a low swale that could be impacted by high groundwater during winter months and may impact stormwater infiltration. Currently, the property for the roadway is not developed and is vegetated with grass and brush. Our services were performed in general accordance with our proposal dated May 1, 2017 and authorized on July 17, 2017. SCOPE OF SERVICES The purpose of our services was to provide geotechnical properties of the site soils for the road as well as evaluating winter high ground water levels. The specific tasks performed are outlined as follows. 1. Provide for the location of subsurface utilities at the site. We proposed using the One Call utility location system for this task. 2. Explored the subsurface soil conditions at the site by advancing five (5) exploratory test pits along the proposed alignment. The test pits were excavated using a backhoe and extended to 6 feet below ground surface (bgs). 3. Log the soils encountered in the test pits in general accordance with the Unified Soil Classification System (ASTM D2487). Detailed logs of the borings were completed in the field. 4. Collect representative soil samples from the test pits for laboratory analyses. 1015 EAST 4TH AVENUE, OLYMPIA, WASHINGTON 98506 PHONE: 360.754.2128 FAx:360.754.9299 Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 5. Install one (1) monitoring well with piezometer for groundwater monitoring in the low area of the project site. The well consisted of 1 -inch diameter casing and screen, and extended to the depth of 9 feet bgs. The piezometer was completed inside the locking steel monument. 6. Prepare a final written report for the project presenting our conclusions and recommendations for site grading, retaining walls, pavement design, estimated design infiltration rates for stormwater, along with our supporting field and laboratory information. FINDINGS Surface Conditions The project site is situated at an elevation between 342 and 326 feet above mean sea level (MSL) and is currently undeveloped. The site is bounded by Yelm High School to the north, Tahoma Boulevard SE to the south, and undeveloped parcels to the east and west. The northern portion of the site is relatively level with a moderate slope between the northern third and central third of the site. The southern portion of the site gently slopes north to the central portion of the site. The property is covered in grasses, scotch broom, and blackberry bushes, with scattered groves of pine trees, and the northern third of the site is wooded. An existing well house is located on the western edge of the subject property. Geology Based on our review of available published geologic maps, Vashon age glacial outwash deposits underlie the project site and surrounding area. This material is described as continental glacial outwash gravels. This material was deposited by outwash rivers during the waning stages of the most recent glacial period in the Puget Sound and is not glacially consolidated. Subsurface Explorations We explored subsurface conditions at the site on August 3 and 4, 2017 by advancing one boring and excavating five test pits in the locations as shown on the Site Plan, Figure 2 and Table 1, below. The exploratory borings were completed by Standard Environmental Probe using a Geoprobe 5410 direct push drill rig. The test pits were excavated using a track - mounted excavator. A geologist from Insight Geologic monitored the explorations and maintained a log of the conditions encountered. The boring was completed at the depth of 12 feet bgs and the test pits were completed at the depth of 6 feet bgs. The soils were visually classified in general accordance with the system described in ASTM D2487- 06. A key to our exploration logs and the explorations are contained in Attachment A. Table 1. Exploration Location Stationing Exploration Name Approximate Station Location TP -1 Approximately 100 feet west of station 10 +80 TP -2 7 +00 TP -3 8 +60 TP -4 13 +00 TP -5 15 +40 MW -1 Approximately 120 feet west of station 10 +90 FILE • 847-004-01 I I T GE0L0GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 The monitoring well installed in the boring consists of 1 -inch diameter casing and screen to the depth of 9 feet bgs. The well was installed with a tamper resistant steel cover, flush with the surrounding grade. The monitoring well construction details are included in Attachment A. Soil Conditions Surface conditions encountered within the explorations were consistent across the site, with one exception. Soils within test pits TP -1 to TP -4 and MW -1 generally consisted of dark brown to brown fine to coarse gravel with sand and cobbles (GP) in a dry to moist and loose to medium dense condition. Soils within test pit TP -5 consisted of brown fine to medium sand with occasional gravel (SP) in a dry to moist and loose to medium dense condition. The soils encountered are consistent with Spanaway gravelly sandy loam and Nisqually loamy fine sand, which is mapped for the majority of the site. These soils are generally formed from glacial outwash and generally have restrictive layers occurring greater than 7 feet below grade. Percolation is high, with rates between 1.98 and 5.95 inches per hour, according to the U.S. Department of Agriculture Soil Survey. Surficial site soils are identified in Attachment B. Groundwater Conditions Groundwater was not encountered in any of the explorations completed at the site. No evidence of seasonal high groundwater was encountered within the explorations. Laboratory Testing We selected six soil samples for gradation analyses in general accordance with ASTM D422 to define soil class and obtain parameters for stormwater infiltration calculations. Our laboratory test results are provided in Attachment C. "TORMWATER INFILTRATION We completed a stormwater infiltration rate evaluation in general accordance with the Washington State Department of Ecology Stormwater Manual for Western Washington (SMWW) as adopted by the City of Yelm. For the purposes of this evaluation, we selected Method 2, "ASTM Gradation Testing at Full Scale Infiltration Facilities" to estimate the long -term design infiltration rates at the site. Method 2 is based on the Dio results of the ASTM grain -size distribution analyses to estimate long -term design infiltration rates. The Method 2 values are listed in Table 3.8 of Volume III of the SMWW. To better identify infiltration rates for soils having Dio values which lie between the values listed in the table, we have plotted those values graphically and calculated a best -fit line to the data. The equation for the best fit line is y = 23.3x — 0.5, where "y" is the infiltration rate in inches per hour and "x" is the Dio value as determined by the ASTM gradation testing. By substituting our Dio sample values for "x" in the equation, we are able to calculate design infiltration rates (Fdesign) for each analyzed sample. Based on our analyses, we estimate that long -term design infiltration rates (Fdesign) for the infiltration pond area is 6.5 inches per hour, based on the lowest rate found at the infiltration pond location. The results of our stormwater infiltration evaluation are presented in Table 2. FILE • 847-004-01 I I T C8E ®L ®GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 Table 2. Design Infiltration Rates — Simple Method Exploration Name Unit Depth Range (feet) Dio Value Design Infiltration Rate (inches per hour) TP -1 GP 2.0-6.0 0.85 19.3 TP -2 GP 1.0-6.0 0.65 14.6 TP-3 GP 0.0-1.0 1.1 20 TP-3 GP 1.0-6.0 1.0 20 TP-5 SP 2.0-6.0 0.2 4.2 MW -1 GP 10.0-12.0 0.3 6.5 CONCLUSIONS AND RECOMMENDATIONS General Based on the results of our review, subsurface explorations and engineering analyses, it is our opinion that the proposed roadway is feasible from a geotechnical standpoint. The soils encountered in our explorations are typically in a loose condition near ground surface. To limit the potential for structure settlement, we recommend that shallow foundations and slabs -on -grade be established on a minimum 1 -foot thick layer of structural fill. Depending on final grading plans and the time of year earthwork is performed; it could be practical to reuse the on -site soils as structural fill under the foundations /slabs. Stormwater infiltration at the site is feasible. We have provided a design infiltration rate of 6.5 inches per hour for the proposed stormwater infiltration system. Winter high groundwater monitoring will be conducted between December 2017 and March 2018, with a data - logging pressure transducer maintaining a record of the site groundwater levels within the monitoring well. Following completion of the study, we will prepare a report regarding site suitability for stormwater infiltration including our groundwater monitoring data and final long -term infiltration rate with any additional recommendations, as appropriate. Earthwork General We anticipate that site development earthwork will include clearing and stripping of existing vegetation, preparing subgrades, excavating for utility trenches, and placing and compacting structural fill. We expect that the majority of site grading can be accomplished with conventional earth moving equipment in proper working order. Our explorations did not encounter appreciable amounts of debris or unsuitable soils associated with past site development. Still, it is possible that concrete slabs, abandoned utility lines or other development features could be encountered during construction. The contractor should be prepared to deal with these conditions. FILE • . 847-004-01 4 I I T GE0L0GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 Clearing and Stripping Clearing and stripping should consist of removing surface and subsurface deleterious materials including sod /topsoil, trees, brush, debris and other unsuitable loose /soft or organic materials. Stripping and clearing should extend at least 5 feet beyond all structures and areas to receive structural fill. We estimate that a stripping depth of about 0.5 feet will be required to remove the surficial organic layer encountered in our explorations. Deeper stripping depths may be required if additional unsuitable soils are exposed during stripping operations. We recommend that trees be removed by overturning so that the majority of roots are also removed. Depressions created by tree or stump removal should be backfilled with structural fill and properly compacted. Subgrade Preparation After stripping and excavating to the proposed subgrade elevation, and before placing structural fill, the exposed subgrade should be thoroughly compacted to a firm and unyielding condition. The exposed subgrade should then be proof - rolled using loaded, rubber -tired heavy equipment. We recommend that Insight Geologic be retained to observe the proof - rolling prior to placement of structural fill or foundation concrete. Areas of limited access that cannot be proof - rolled can be evaluated using a steel probe rod. If soft or otherwise unsuitable areas are revealed during proof - rolling or probing, that cannot be compacted to a stable and uniformly firm condition, we generally recommend that: 1) the subgrade soils be scarified (e.g., with a ripper or farmer's disc), aerated and recompacted; or 2) the unsuitable soils be overexcavated and replaced with structural fill. Temporary Excavations and Groundwater Handling Excavations deeper than 4 feet should be shored or laid back at a stable slope if workers are required to enter. Shoring and temporary slope inclinations must conform to the provisions of Title 296 Washington Administrative Code (WAC), Part N, "Excavation, Trenching and Shoring." Regardless of the soil type encountered in the excavation, shoring, trench boxes or sloped sidewalls were required under the Washington Industrial Safety and Health Act (WISHA). The contract documents should specify that the contractor is responsible for selecting excavation and dewatering methods, monitoring the excavations for safety and providing shoring, as required, to protect personnel and structures. In general, temporary cut slopes should be inclined no steeper than about 1.5H:1V (horizontal: vertical). This guideline assumes that all surface loads are kept at a minimum distance of at least one - half the depth of the cut away from the top of the slope, and that significant seepage is not present on the slope face. Flatter cut slopes were necessary where significant seepage occurs or if large voids are created during excavation. Some sloughing and raveling of cut slopes should be expected. Temporary covering with heavy plastic sheeting should be used to protect slopes during periods of wet weather. We anticipate that if perched groundwater is encountered during construction can be handled adequately with sumps, pumps, and /or diversion ditches. Groundwater handling needs will generally be lower during the late summer and early fall months. We recommend that the contractor performing FILE • 847-004-01 AIM T C8E ®L®GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 the work be made responsible for controlling and collecting groundwater encountered during construction. Permanent Slopes We anticipate that permanent slopes will be utilized for the proposed project in the area of the stormwater pond and possibly in the area where the roadway is expected to cross the steeper slope near the northern portion of the site. Where permanent slopes are necessary, we recommend the slopes be constructed at a maximum inclination of 2HAV. Where 2H:1V permanent slopes are not feasible, protective facings and /or retaining structures should be considered. To achieve uniform compaction, we recommend that fill slopes be overbuilt and subsequently cut back to expose well- compacted fill. Fill placement on slopes should be benched into the slope face and include keyways. The configuration of the bench and keyway depends on the equipment being used. Bench excavations should be level and extend into the slope face. We recommend that a vertical cut of about 3 feet be maintained for benched excavations. Keyways should be about 1 -1/2 times the width of the equipment used for grading or compaction. Erosion Control We anticipate that erosion control measures such as silt fences, straw bales and sand bags will generally be adequate during development. Temporary erosion control should be provided during construction activities and until permanent erosion control measures are functional. Surface water runoff should be properly contained and channeled using drainage ditches, berms, swales, and tightlines, and should not discharge onto sloped areas. Any disturbed sloped areas should be protected with a temporary covering until new vegetation can take effect. Jute or coconut fiber matting, excelsior matting or clear plastic sheeting is suitable for this purpose. Graded or disturbed slopes should be tracked in -place with the equipment running perpendicular to the slope contours so that the track marks provide a texture to help resist erosion. Ultimately, erosion control measures should be in accordance with local regulations and should be clearly described on project plans. Wet Weather Earthwork Some of the near surface soils contain up to near 5 percent fines. While this soil is generally considered to be well drained, significant rainfall may increase the moisture content of this soil more than a few percent above the optimum moisture content, increasing the likelihood that the soil will become unstable and it may become difficult or impossible to meet the required compaction criteria. Disturbance of near surface soils should be expected if earthwork is completed during periods of wet weather. The wet weather season in this area generally begins in October and continues through May. However, periods of wet weather may occur during any month of the year. If wet weather earthwork is unavoidable, we recommend that: • The ground surface is sloped so that surface water is collected and directed away from the work area to an approved collection /dispersion point. • Earthwork activities not take place during periods of heavy precipitation. FILE • • I I T C8E ®L ®GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 • Slopes with exposed soil be covered with plastic sheeting or otherwise protected from erosion. • Measures are taken to prevent on -site soil and soil stockpiles from becoming wet or unstable. Sealing the surficial soil by rolling with a smooth -drum roller prior to periods of precipitation should reduce the extent that the soil becomes wet or unstable. • Construction traffic is restricted to specific areas of the site, preferably areas that are surfaced with materials not susceptible to wet weather disturbance. • A minimum 1 -foot thick layer of 4- to 6 -inch quarry spalls is used in high traffic areas of the site to protect the subgrade soil from disturbance. • Contingencies are included in the project schedule and budget to allow for the above elements. Structural Fill Materials General Material used for structural fill should be free of debris, organic material and rock fragments larger than 3 inches. The workability of material for use as structural fill will depend on the gradation and moisture content of the soil. As the amount of fines increases, soil becomes increasingly more sensitive to small changes in moisture content and adequate compaction becomes more difficult or impossible to achieve. On -Site Soil We anticipate that the majority of the on -site soils encountered during construction will consist of gravels with sand located at or near the surface of the site. It is our opinion that this material is a suitable source for structural fill during a significant portion of the year. However, we anticipate that screening will be needed to remove oversize clasts prior to placement. On -site materials used as structural fill should be free of roots, organic matter and other deleterious materials and particles larger than 3 inches in diameter. Select Granular Fill Select granular fill should consist of imported, well - graded sand and gravel or crushed rock with a maximum particle size of 3 inches and less than 5 percent passing a U.S. Standard No. 200 sieve based on the minus % -inch fraction. Organic matter, debris or other deleterious material should not be present. In our experience, "gravel borrow" as described in Section 9- 03.14(1) of the 2008 WSDOT Standard Specifications is typically a suitable source for select granular fill during periods of wet weather, provided that the percent passing a U.S. Standard No. 200 sieve is less than 5 percent based on the minus % -inch fraction. Structural Fill Placement and Compaction General Structural fill should be placed on an approved subgrade that consists of uniformly firm and unyielding inorganic native soils or compacted structural fill. Structural fill should be compacted at a moisture content near optimum. The optimum moisture content varies with the soil gradation and should be evaluated during construction. FILE • 847-004-01 AIM T C8E ®L®GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 Structural fill should be placed in uniform, horizontal lifts and uniformly densified with vibratory compaction equipment. The maximum lift thickness will vary depending on the material and compaction equipment used, but should generally not exceed the loose thicknesses provided on Table 3. Structural fill materials should be compacted in accordance with the compaction criteria provided in Table 4. Table 3. Recommended Uncompacted Lift Thickness Table 4. Recommended Compaction Criteria in Structural Fill Zones Percent Maximum Dry Density Determined by Fill Type ASTM Test Method D 1557 at ±3% of Optimum Moisture 0 to 2 Feet Below > 2 Feet Below pipe Zone Su bg rade Su bg rade Imported or On -site Granular, 95 95 ----- Maximum Particle Size < 1 -1/4 -inch Imported or On -site Granular, N/A (Proof -roll) N/A (Proof -roll) ----- Maximum Particle Size >1 -1/4 -inch Trench Back-fill' 95 92 90 Note: 'Trench backfill above the pipe zone in nonstructural areas should be compacted to at least 85 percent. Conventional Retaining Walls General We do not anticipate that retaining walls would be utilized for the proposed project. If permanent slopes are necessary, the following sections provide general guidelines for retaining wall design on this site. We should be contacted during the design phase to review retaining wall plans and provide supplemental recommendations, if needed. Drainage Positive drainage is imperative behind any retaining structure. This can be accomplished by using a zone of free - draining material behind the wall with perforated pipes to collect water seepage. The drainage material should consist of coarse sand and gravel containing less than 5 percent fines based FILE No. 847 - 004 -01 0 I I T C8E ®L ®GIC, VNC. Recommended Uncompacted Fill Thickness Compaction (inches) Equipment Granular Materials Maximum Particle Size Granular Materials Maximum Particle Size > 1 Mi < 1 1/2 inch 1 1/2 inch Hand Tools (Plate Compactors 4-8 Not Recommended and Jumping Jacks) Rubber -tire Equipment 10-12 6-8 Light Roller 10-12 8-10 Heavy Roller 12-18 12-16 Hoe Pack Equipment 18-24 12-16 Note: The above table is intended to serve as a guideline and should not be included in the project specifications. Table 4. Recommended Compaction Criteria in Structural Fill Zones Percent Maximum Dry Density Determined by Fill Type ASTM Test Method D 1557 at ±3% of Optimum Moisture 0 to 2 Feet Below > 2 Feet Below pipe Zone Su bg rade Su bg rade Imported or On -site Granular, 95 95 ----- Maximum Particle Size < 1 -1/4 -inch Imported or On -site Granular, N/A (Proof -roll) N/A (Proof -roll) ----- Maximum Particle Size >1 -1/4 -inch Trench Back-fill' 95 92 90 Note: 'Trench backfill above the pipe zone in nonstructural areas should be compacted to at least 85 percent. Conventional Retaining Walls General We do not anticipate that retaining walls would be utilized for the proposed project. If permanent slopes are necessary, the following sections provide general guidelines for retaining wall design on this site. We should be contacted during the design phase to review retaining wall plans and provide supplemental recommendations, if needed. Drainage Positive drainage is imperative behind any retaining structure. This can be accomplished by using a zone of free - draining material behind the wall with perforated pipes to collect water seepage. The drainage material should consist of coarse sand and gravel containing less than 5 percent fines based FILE No. 847 - 004 -01 0 I I T C8E ®L ®GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 on the fraction of material passing the % -inch sieve. The wall drainage zone should extend horizontally at least 12 inches from the back of the wall. If a stacked block wall is constructed, we recommend that a barrier such as a non -woven geotextile filter fabric be placed against the back of the wall to prevent loss of the drainage material through the wall joints. A perforated smooth - walled rigid PVC pipe, having a minimum diameter of 4 inches, should be placed at the bottom of the drainage zone along the entire length of the wall. Drainpipes should discharge to a tightline leading to an appropriate collection and disposal system. An adequate number of cleanouts should be incorporated into the design of the drains in order to provide access for regular maintenance. Roof downspouts, perimeter drains or other types of drainage systems should not be connected to retaining wall drain systems. Design Parameters We recommend an active lateral earth pressure of 31 pcf (equivalent fluid density) for a level backfill condition. This assumes that the top of the wall is not structurally restrained and is free to rotate. For restrained walls that are fixed against rotation (at -rest condition), an equivalent fluid density of 45 pcf can be used for the level backfill condition. For seismic conditions, we recommend a uniform lateral pressure of 14H psf (where H is the height of the wall) be added to the lateral pressures. This seismic pressure assumes a peak ground acceleration of 0.32 g. Note that if the retaining system is designed as a braced system but is expected to yield a small amount during a seismic event, the active earth pressure condition may be assumed and combined with the seismic surcharge. The recommended earth pressure values do not include the effects of surcharges from surface loads or structures. If vehicles were operated within one -half the height of the wall, a traffic surcharge should be added to the wall pressure. The traffic surcharge can be approximated by the equivalent weight of an additional 2 feet of backfill behind the wall. Other surcharge loads, such as construction equipment, staging areas and stockpiled fill, should be considered on a case -by -case basis. Pavement Design Recommendations We recommend a pavement section for the bypass roadway to consist of the following minimum compacted thicknesses placed on a properly prepared subgrade: 8 inches of gravel base, 2 inches of crushed surfacing top course, (CSTC), and 3 inches of commercial asphalt concrete pavement. Alternatively, the pavement section may consist of 6 inches of asphalt- treated base and 3 inches of commercial asphalt concrete. It should be realized that asphaltic pavements are not maintenance free. Our recommended pavement section represents our minimum recommendation for an average level of performance during a 20- year design life; therefore, an average level of maintenance will likely be required. A 20 -year pavement life typically assumes that an overlay will be placed after about 12 years. Thicker asphalt, base and subbase courses would offer better long -term performance, but would cost more initially. Conversely, thinner courses would be more susceptible to "alligator" cracking and other failure modes. As such, pavement design can be considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and higher maintenance costs. FILE • . 847-004-01 • I I T GE0L0GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 The native subgrade soils are anticipated to consist mostly of gravels and sand with cobbles. Based on our experience with similar soil types, our analysis is based on a California Bearing Ratio (CBR) value of 15 percent. These values assume the upper foot of subgrade soils will be compacted to a minimum of 95 percent of the modified proctor maximum dry density. We recommend the following regarding asphalt pavement materials and pavement construction • Subgrade Preparation: Upper 12 inches of pavement subgrade should be proof - rolled and inspected for deflection. Areas showing more than 'h -inch deflection during proof rolling should be over excavated and replaced with gravel base. • Subbase Course: We recommend that the subbase conform to Section 9- 03.10, Gravel Base, of the 2016 WSDOTiAPWA Standard Specifications for Road, Bridge and Municipal Construction (Standard Specifications). The Gravel Base shall be placed and compacted in accordance with Section 4 -02 of the Standard Specifications. • Base Course: We recommend that the crushed aggregate base course conform to Section 9- 03.9(3), Crushed Surfacing Top Course, (CSTC) of the WSDOT Standard Specifications. The CSTC shall be placed and compacted in accordance with Section 4 -04 of the Standard Specifications. • Asphalt Concrete: We recommend that the asphalt concrete be Commercial Asphalt conforming to Sections 9 -02 and 9 -03 of the Standard Specifications. We also recommend that the Commercial Asphalt be placed and compacted in accordance with Section 5 -04 of the Standard Specifications. Compaction: All base material should be compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D1557. We recommend that asphalt be compacted to a minimum of 92 percent of the Rice (theoretical maximum) density or 96 percent of Marshall (maximum laboratory) density. DUGUMENT REVIEW AND CONSTRUCTION OBSERVATION We recommend that we be retained to review the portions of the plans and specifications that pertain to earthwork construction and stormwater infiltration. We recommend that monitoring, testing and consultation be performed during construction to confirm that the conditions encountered are consistent with our explorations and our stated design assumptions. Insight Geologic would be pleased to provide these services upon request. REFERENCES International Code Council, "International Building Code ", 2015. Seismic Compression of As- compacted Fill Soils with Variable Levels of Fines Content and Fines Plasticity, Department of Civil and Environmental Engineering, University of California, Los Angeles, July 2004. Washington State Department of Transportation ( WSDOT), Standard Specifications for Road, Bridge and Municipal Construction Manual, 2016. FILE • 847-004-01 I I T GE0L0GIC, VNC. Yelm High School Bypass Road Geotechnical and Groundwater Evaluation Report August 29, 2017 LIMITATIONS We have prepared this geotechnical and groundwater evaluation report for the exclusive use of J. W. Morrissette & Associates and their authorized agents for the proposed Yelm High School Bypass Road project to be located adjacent to Tahoma Boulevard SE in Yelm, Washington. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions, expressed or implied, should be understood. Please refer to Attachment D titled "Report Limitations and Guidelines for Use" for additional information pertaining to use of this report. We appreciate the opportunity to be of service to you on this project. Please contact us if you have questions or require additional information. Respectfully Submitted, INSIGHT GEOLOGIC, INC. William E. Halbert, L.E.G., L.HG. Principal Attachments FILE No. 847 - 004 -01 11 FIGURES INS T GE ®L ®GIC, VNC. MCKENNA, WASHINGTON 7.5 MINUTE QUADRANGLE Year1990 SCALE: 1: 24000 YELM HIGH SCHOOL BYPASS ROAD INSIGHT GEOLOGIC, INC, YELM, WASHINGTON Figure 1 Vicinity Map • _� 334 pring l I I. Yelm ' 7717'. q Flume Ho ` stir - .J �• ` AthletjC.. -- Fi sis fV a •..� • ' ass. . •1. - J I// r,;�� • 12 ( /J 24 _� 24 r ?, ••� • - 1' I - - Ic aids { J•�r• tirt5 L° C� 111111 �" _ I� : I ] 9 GaH Caurse rk Solberg Lake x'g12 • • t 375 I seat 2 6.� i MCKENNA, WASHINGTON 7.5 MINUTE QUADRANGLE Year1990 SCALE: 1: 24000 YELM HIGH SCHOOL BYPASS ROAD INSIGHT GEOLOGIC, INC, YELM, WASHINGTON Figure 1 Vicinity Map YELM, HIGH SCHOOL wow- 1 nk() 1Y151 u I LIMN KX: KI 17 �r 1IIN- 2172 4240191 TAHOMA Bl�l,+' SOURCE: JWM &A LEGEND: MW -1 APPROXIMATE MONITORING WELL LOCATION ATP -1 APPROXIMATE TEST PIT LOCATION APPROXIMATE PROJECT BOUNDARY SCALE: 1" = 200 YELM HIGH SCHOOL BYPASS ROAD YELM, WASHINGTON Figure G INSIGHT GEOLOGIC, INC. Site Plan ATTACHMENT A EXPLORATION LOGS INS T GE ®L ®GIC, VNC. SOIL CLASSIFICATION CHART MAJOR DIVISIONS SYMBOLS GROUP NAME CC CEMENT CONCRETE AC El GW WELL- GRADED GRAVEL, CRUSHED ROCK/ QUARRY SPALLS GRAVEL CLEAN TOPSOIL /SOD /DUFF COMPACTION TEST FINE TO COARSE GRAVEL PP POCKET PENETROMETER AND GRAVEL SA SIEVE ANALYSIS DS DIRECT SHEAR GP POORLY GRADED GRAVEL TX TRIAXIAL COMPRESSION GRAVELLY <5 % FINES UC UNCONFINED COMPRESSION MC MOISTURE CONTENT SOILS VS VANE SHEAR MORE THAN 50% COARSE OF COARSE GRAVEL GM SILTY GRAVEL GRAINED FRACTION WITH FINES GC CLAYEY GRAVEL SOILS RETAINED ON NO. 4SIEVE 12% FINES SW WELL- GRADED SAND, SAND CLEAN FINE TO COARSE SAND MORE THAN 5o% RETAINED ON AND SAND NO. 200 SIEVE SANDY 5% FINES SP POORLY GRADED SAND SOILS MORE THAN 50% OF COARSE SAND SM SILTY SAND FRACTION WITH FINES PASSING NO.4 SIEVE >12 %FINES Sc CLAYEY SAND SILTS ML SILT AND INORGANIC CL CLAY FINE CLAYS GRAINED ORGANIC SILT, SOILS LIQUID LIMIT LESS THAN 50 ORGANIC OL ORGANIC CLAY SILT OF HIGH PLASTICITY, SILTS MH MORE THAN 50% AND INORGANIC ELASTIC SILT CH CLAY OF HIGH PLASTICITY, PASSING NO. 200 SIEVE CLAYS FAT CLAY LIQUID LIMIT �� i ORGANIC CLAY, 50ORMORE ORGANIC �'�� CH ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT 70 60 k 50 W O Z 40 U 1= 30 cn Q a 20 10 0 10 20 30 40 50 60 70 80 90 100 LIQUID LIMIT SOIL MOISTURE MODIFIERS: DRY - ABSENCE OF MOISTURE, DUSTY, DRY TO THE TOUCH MOIST - DAMP, BUT NO VISIBLE WATER WET - VISIBLE FREE WATER OR SATURATED, USUALLY SOIL IS OBTAINED BELOW WATER TABLE INSIGHT GEOLOGIC, INC. ADDITIONAL MATERIAL SYMBOLS SYMBOLS TYPICAL DESCRIPTION CC CEMENT CONCRETE AC ASPHALT CONCRETE CA CHEMICAL ANALYSIS CR CRUSHED ROCK/ QUARRY SPALLS PM PERMEABILITY OR TS TOPSOIL /SOD /DUFF GROUNDWATER EXPLORATION SYMBOLS MEASURED GROUNDWATER LEVEL IN EXPLORATION, WELL, OR PIEZOMETER i GROUNDWATER OBSERVED AT TIME OF EXPLORATION PERCHED WATER OBSERVED AT TIME OF EXPLORATION MEASURED FREE PRODUCT IN WELL OR PIEZOMETER STRATIGRAPHIC CONTACT APPROXIMATE CONTACT BETWEEN SOIL STRATA OR GEOLOGIC UNIT - -- APPROXIMATE LOCATION OF SOIL STRATA CHANGE WITHIN GEOLOGIC SOIL UNIT APPROXIMATE GRADUAL CHANGE BETWEEN SOIL STRATA OR GEOLOGIC SOIL UNIT APPROXIMATE GRADUAL CHANGE OF SOIL STRATA WITHIN GEOLOGIC SOIL UNIT LABORATORY/ FIELD TEST CLASSIFICATIONS %F PERECENT FINES MD MOISTURE CONTENT AND DRY DENSITY AL ATTERBERG LIMITS OC ORGANIC COMPOUND CA CHEMICAL ANALYSIS PM PERMEABILITY OR CP LABORATORY HYDRAULIC CONDUCTIVITY COMPACTION TEST PP POCKET PENETROMETER CS CONSOLIDATION TEST SA SIEVE ANALYSIS DS DIRECT SHEAR TX TRIAXIAL COMPRESSION HA HYDROMETER ANALYSIS UC UNCONFINED COMPRESSION MC MOISTURE CONTENT VS VANE SHEAR SAMPLER SYMBOLS 2.4 INCH I.D. SPLIT BARREL ® SHELBY TUBE DIRECT -PUSH ® PISTON STANDARD PENETRATION TEST ® BULK OR GRAB SHEEN CLASSIFICATIONS NS NOVISIBLESHEEN SS SLIGHT SHEEN MS MODERATE SHEEN HS HEAVY SHEEN NT NOT TESTED Key to Exploration Logs MW -1 =F -° C2 REMARKSAND w w Sao N LITHOLOGY SOIL DESCRIPTION LABORATORY WELL TEST RESULTS CONSTRUCTION 0 1 2 3 4 5 6 ' 8 9 10 11 12 13 14 15L 1 2 3 4 48/18 48/24 24/36 24/40 Dark brown fine to coarse gravel with fine to medium sand, loose, dry Grades to light brown fine to coarse gravel with cobbles and fine to coarse sand, loose, dry Grades to medium dense, moist 0) M U > a Q U p m o 0 > III IIII IIII IIII IIII IIII Groundwater not encounterted I LEGEND: PROJECT NO.: 847 - 004 -01 DATE: AUGUST 4, 2017 TOTAL DEPTH: 12 FEET DOE WELL NO.: BJM -535 DRILLING CONTRACTOR: STD ENV PROBE DRILLING EQUIPMENT: GEOPROBE 5410 LOGGED BY: AND YELM HIGH SCHOOL BYPASS ROAD YELM, WASHINGTON INSIGHT GEDLflGIC, INC. Exploration Log MW -1 TR -1 DEPTH REMARKS AND (FT) U.S.C.S. LITHOLOGY SOIL DESCRIPTION LABORATORY TEST RESULTS 0 1 2 .3 4 5 � (D Brown fine to coarse gravel with fine to medium sand and cobbles, trace organics, loose, dry Grades to brown fine to coarse gravel with fine to coarse sand, silt and cobbles, loose, dry Grades to light brown fine to coarse gravel and cobbles, loose, moist 6 7 8 9 10 Groundwater not encountered LEGEND: PROJECT NO.: 847 - 004 -01 DATE: AUGUST 3, 2017 TOTAL DEPTH: 6 FEET DRILLING EQUIPMENT: EXCAVATOR LOGGED BY: ANDREW JOHNSON YELM HIGH SCHOOL BYPASS ROAD YELM, WASHINGTON INSIGHT GEOLoric, INC. Exploration Log TP -1 TR -2 DEPTH REMARKS AND (FT) U.S.C.S. LITHOLOGY SOIL DESCRIPTION LABORATORY TEST RESULTS 0 1 2 .3 4 5 � Dark brown fine to coarse gravel with fine to coarse sand, trace organics, loose, dry Grades to light brown fine to coarse gravel with medium to coarse sand and cobbles, loose, dry 6 7 8 9 10 Groundwater not encountered LEGEND: PROJECT NO.: 847 - 004 -01 DATE: AUGUST 3, 2017 TOTAL DEPTH: 6 FEET DRILLING EQUIPMENT: EXCAVATOR LOGGED BY: ANDREW JOHNSON YELM HIGH SCHOOL BYPASS ROAD YELM, WASHINGTON INSIGHT GEOLoric, INC. Exploration Log TP -2 TR -3 DEPTH REMARKS AND (FT) U.S.C.S. LITHOLOGY SOIL DESCRIPTION LABORATORY TEST RESULTS 0 1 2 .3 4 5 � Dark brown fine to coarse gravel with cobbles, trace sand and organics, loose, dry Grades to light brown fine to coarse gravel with cobbles and medium sand, medium dense, dry 6 7 8 9 10 Groundwater not encountered LEGEND: PROJECT NO.: 847 - 004 -01 DATE: AUGUST 3, 2017 TOTAL DEPTH: 6 FEET DRILLING EQUIPMENT: EXCAVATOR LOGGED BY: ANDREW JOHNSON YELM HIGH SCHOOL BYPASS ROAD YELM, WASHINGTON INSIGHT GEOLoric, INC. Exploration Log TP -3 TR -4 DEPTH REMARKS AND (FT) U.S.C.S. LITHOLOGY SOIL DESCRIPTION LABORATORY TEST RESULTS 0 1 2 .3 4 5 � Dark brown fine to coarse gravel with fine to medium sand and cobbles, trace organics, loose, dry Grades to light brown fine to coarse gravel with fine to coarse sand, medium dense, dry 6 7 8 9 10 Groundwater not encountered LEGEND: PROJECT NO.: 847 - 004 -01 DATE: AUGUST 3, 2017 TOTAL DEPTH: 6 FEET DRILLING EQUIPMENT: EXCAVATOR LOGGED BY: ANDREW JOHNSON YELM HIGH SCHOOL BYPASS ROAD YELM, WASHINGTON INSIGHT GEOLoric, INC. Exploration Log TP -4 TP -5 DEPTH REMARKS AND (FT) U.S.C.S. LITHOLOGY SOIL DESCRIPTION LABORATORY TEST RESULTS 0 Dark brown fine to medium sand, occasional gravel, loose, dry 1 Grades to brown fine to medium sand, loose, moist 2 .3 � U) 4 5 6 Groundwater not encountered 7 8 9 10 LEGEND: PROJECT NO.: 847 - 004 -01 DATE: AUGUST 3, 2017 TOTAL DEPTH: 6 FEET DRILLING EQUIPMENT: EXCAVATOR LOGGED BY: ANDREW JOHNSON INSIGHT GEOLoric, INC. YELM HIGH SCHOOL BYPASS ROAD YELM, WASHINGTON Exploration Log TP -5 ATTACHMENT B WEB SOIL SURVEY INS T GE ®L ®GIC, VNC. z a 0196615 M ..ST L£ aZZT K u� C O g y C6 . N O d N i Q m w p O O 7 U cn c = .2 .9 cn_ _2 E CU H m n } a cn R a M „b£ L£ aZZT 0196615 co z a OSS66L9 06b661S WtffiL5 OLE6615 WffiLS 05Z6615 0616615 0556615 06b6615 OEbtnLS OLE6615 Ol£6615 OSZ66LS 0616615 0 a) c s ns d m Q m a C o o L O U U cn C L .2 .9 L 0 E CL } U6 O U) Z 0 a 0 LL Z Ca C 0 Z W W J a a5 m n m E N `m O Q 7 O T m U) E O U N L T m i Q O N O V L H m 'p L N CU U ° Q -0 C U U a) U N E O p C U C6 N Q C6 n ca U UB � E C U) E cu N 3 U o O) N p m a; 0 cu c6 O- p C U Cu L m = a) y -0 > L O O a) C > L � w6 ° L o -o -o n :2 T L LO U6 O cu co E E n a m o c6 E 0) Q j, � .O U) a) y E 0) E a) U _ O-0 Q'n p N y a) C 75 W E .0 O N U- co O O N N � a) r O � N a T m (D o > U) ro U) = N ) Q �n O a) O � U m O N Z d V U) > i N 3 O a0 U d� �d 3 N w 0 t6 O Zv O a) a5 U L d m ° N 0 U) 1 3 o n U Z U O ° (6 r rn p C_ o o a) ° a)-0 W �� ° O En N �y)E co d U) o c n 2 — o .cn p LO a) N Un C7 U) V) f6 � O m N to 0 M> O .L-� n a) O N a7 ° � � y cLn d C7 CL ` a Z Q m a)CD � o Q)_ � � � a °m_ E W U m) Co d O N 0 N Q L p L .Q C � o n `n U n a) m m o ¢ aT ) m a) U N L aU ) :5 o a) =01 U) p n �O Q p_E O U a '15 p U) U) u p T Ln a) N N 2i m 7 U U O p L - C C U J n N ) L Q) U6 a) m 2 - m w - L L a) o n � ° H O L Q) a5 Z N L Q O C OU n f0 (p N to y (p a5 a) m p N O L J� C O T L a) a) a3 U N O] (6 � N O N O] E - O a1 a) ° O-0 > C O C Q> N U) 7 a) a5 O .L.-� L i U 3 a5 .O C U Q N U .-- (6 C m Q O� Q M L C E > E E _ cA � N E � ° U .� ° w � � ° `o � w n as O ° o c U) o o a) aa)) m -7— C N 0 a) > ¢ n O N O m cfl o E- 01 Co a) U ;6 j L p U) L n .2 a) U Q> U) (n a) — � E = O O � N .a) U E Q) a) a E p m p cn�U N O N L U n=oQ co .L--� L H o O 7 u) co O LP cA— a3 O 0— L E L H LO) ._ w U- co O O N N � a) r O � N a T m (D o > U) ro U) = N ) Q �n O a) O � U m O N Z d V U) > i N 3 O a0 U d� �d 3 N w 0 t6 O Zv N 0 U) o LL U r m co d >, C c 2 y O L d ¢ U) J m E a1 ° a O O a .Q C T m U U6 tD CY p (a p U) U) a) > L O f1 U) y N U) O (B R a) �C U J ¢ C ai m LL O 3 O F m O a a U) CL ° N U) CL Q V @ R) N �G (6 d LL O ?� O d U) , _6 M > -� > = 'o LL s L9 ` O a) m U C c D O Y U m . C > a C a) a) > O Y O a] U ¢ U) U) U) C a O `O m m a7 U O U c5 c7 J 6 J f a it U) U) U) C _ U) U) U) d C a 0 � i4 u CL 9 0 x o 0 <�4c00 > +X 0.0► oa a U) U- co O O N N � a) r O � N a T m (D o > U) ro U) = N ) Q �n O a) O � U m O N Z d V U) > i N 3 O a0 U d� �d 3 N w 0 t6 O Zv U) (A a T m O O L U) no 0 a� c U) R T C 7 0 U c 0 L a a5 A� W A� W J CL m 2 0 0 o a M N LCJ O Ln N co LP CO O O 70 a a 1 a 't O aD N a a C i O v 's y R R i O (D a M a) y - c T O a N O — 3 O E y R C 6 y = Z C a) T U N Q O w C a T > CL O C y i y M O t CL R c 4 y p n m H O Q Q E R R y R O R D w z (n U) o a m E T � o = R a7 m a` CL `o f0 � w ti O r N r +R+ H ATTACHMENT C LABORATORY ANALYSES RESULTS INS T GE ®L ®GIC, VNC. Gradation Analysis Summary Data Job Name: Yelm High School Bypass Road Sample Location: MW -1 Job Number: 847 - 004 -01 Sample Name: MW -1 10.0' -12.0' Date Tested: 8/7/17 Depth: 10 - 12 Feet Tested By: Jessica Christensen Moisture Content ( %) 2.5% LL -- PL -- PI - - D10 0.30 D30 4.80 D60 18.00 D90 32.00 Cc 4.27 Cu 60.00 ASTM Classification Group Name: Poorly Graded Gravel with Sand Symbol: GP INSIGHT GEOLOGIC, INC. Percent Percent by Sieve Size Passing Size Fraction Weight 3.0 in. (75.0) 100.0 Coarse Gravel 36.8 1.5 in. (37.5) 100.0 Fine Gravel 33.4 3/4 in. (19.0) 63.2 3/8 in. (9.5 -mm) 38.0 Coarse Sand 7.0 No. 4 (4.75 -mm) 29.8 Medium Sand 10.1 No. 10 (2.00 -mm) 22.8 Fine Sand 8.7 No. 20 (.850 -mm) 17.8 No. 40 (.425 -mm) 12.7 Fines 4.0 No. 60 (.250 -mm) 8.8 Total 100.0 No. 100 (.150 -mm) 6.3 No. 200 (.075 -mm) 4.0 LL -- PL -- PI - - D10 0.30 D30 4.80 D60 18.00 D90 32.00 Cc 4.27 Cu 60.00 ASTM Classification Group Name: Poorly Graded Gravel with Sand Symbol: GP INSIGHT GEOLOGIC, INC. Gradation Analysis Summary Data Job Name: Yelm High School Bypass Road Sample Location: TP -1 Job Number: 847 - 004 -01 Sample Name: TP -1 2.0' -6.0' Date Tested: 8/7/17 Depth: 2 - 6 Feet Tested By: Jessica Christensen Moisture Content ( %) 2.8% LL -- PL -- PI - - D10 0.85 D30 15.00 D6o 46.00 D90 67.00 Cc 5.75 Cu 54.12 ASTM Classification Group Name: Poorly Graded Gravel Symbol: GP INSIGHT GEOLOGIC, INC. Percent Percent by Sieve Size Passing Size Fraction Weight 3.0 in. (75.0) 100.0 Coarse Gravel 62.2 1.5 in. (37.5) 45.0 Fine Gravel 22.4 3/4 in. (19.0) 37.8 3/8 in. (9.5 -mm) 20.8 Coarse Sand 2.1 No. 4 (4.75 -mm) 15.4 Medium Sand 7.1 No. 10 (2.00 -mm) 13.2 Fine Sand 5.2 No. 20 (.850 -mm) 10.2 No. 40 (.425 -mm) 6.1 Fines 0.9 No. 60 (.250 -mm) 3.0 Total 100.0 No. 100 (.150 -mm) 1.6 No. 200 (.075 -mm) 0.9 LL -- PL -- PI - - D10 0.85 D30 15.00 D6o 46.00 D90 67.00 Cc 5.75 Cu 54.12 ASTM Classification Group Name: Poorly Graded Gravel Symbol: GP INSIGHT GEOLOGIC, INC. Gradation Analysis Summary Data Job Name: Yelm High School Bypass Road Sample Location: TP -2 Job Number: 847 - 004 -01 Sample Name: TP -2 1.0' -6.0' Date Tested: 8/7/17 Depth: 1 - 6 Feet Tested By: Jessica Christensen Moisture Content ( %) 2.4% LL -- PL -- PI - - D10 0.65 Dap 8.00 D60 18.00 D90 53.00 Cc 5.47 Cu 27.69 ASTM Classification Group Name: Poorly Graded Gravel with Sand Symbol: GP INSIGHT GEOLOGIC, INC. Percent Percent by Sieve Size Passing Size Fraction Weight 3.0 in. (75.0) 100.0 Coarse Gravel 35.9 1.5 in. (37.5) 81.6 Fine Gravel 42.0 3/4 in. (19.0) 64.1 3/8 in. (9.5 -mm) 34.3 Coarse Sand 5.9 No. 4 (4.75 -mm) 22.1 Medium Sand 10.8 No. 10 (2.00 -mm) 16.2 Fine Sand 4.6 No. 20 (.850 -mm) 12.4 No. 40 (.425 -mm) 5.3 Fines 0.8 No. 60 (.250 -mm) 2.2 Total 100.0 No. 100 (.150 -mm) 1.3 No. 200 (.075 -mm) 0.8 LL -- PL -- PI - - D10 0.65 Dap 8.00 D60 18.00 D90 53.00 Cc 5.47 Cu 27.69 ASTM Classification Group Name: Poorly Graded Gravel with Sand Symbol: GP INSIGHT GEOLOGIC, INC. Gradation Analysis Summary Data Job Name: Yelm High School Bypass Road Sample Location: TP -3 Job Number: 847 - 004 -01 Sample Name: TP -3 0.0' -1.0' Date Tested: 8/7/17 Depth: 0 - 1 Feet Tested By: Jessica Christensen Moisture Content ( %) 3.2% LL -- PL -- PI - - D10 1.10 D30 40.00 D60 54.00 D90 69.00 Cc 26.94 Cu 49.09 ASTM Classification Group Name: Poorly Graded Gravel Symbol: GP INSIGHT GEOLOGIC, INC. Percent Percent by Sieve Size Passing Size Fraction Weight 3.0 in. (75.0) 100.0 Coarse Gravel 78.2 1.5 in. (37.5) 23.0 Fine Gravel 9.4 3/4 in. (19.0) 21.8 3/8 in. (9.5 -mm) 15.9 Coarse Sand 1.6 No. 4 (4.75 -mm) 12.5 Medium Sand 4.9 No. 10 (2.00 -mm) 10.9 Fine Sand 4.7 No. 20 (.850 -mm) 9.3 No. 40 (.425 -mm) 5.9 Fines 1.2 No. 60 (.250 -mm) 3.2 Total 100.0 No. 100 (.150 -mm) 2.1 No. 200 (.075 -mm) 1.2 LL -- PL -- PI - - D10 1.10 D30 40.00 D60 54.00 D90 69.00 Cc 26.94 Cu 49.09 ASTM Classification Group Name: Poorly Graded Gravel Symbol: GP INSIGHT GEOLOGIC, INC. Gradation Analysis Summary Data Job Name: Yelm High School Bypass Road Sample Location: TP -3 Job Number: 847 - 004 -01 Sample Name: TP -3 1.0' -6.0' Date Tested: 8/7/17 Depth: 1 - 6 Feet Tested By: Jessica Christensen LL -- PL -- PI - - D10 1.00 D30 14.00 D6o 27.00 D90 45.00 Cc 7.26 Cu 27.00 ASTM Classification Group Name: Poorly Graded Gravel with Sand Symbol: GP INSIGHT GEOLOGIC, INC. Moisture Content ( %) 2.4% Percent Percent by Sieve Size Passing Size Fraction Weight 3.0 in. (75.0) 100.0 Coarse Gravel 59.2 1.5 in. (37.5) 83.9 Fine Gravel 24.6 3/4 in. (19.0) 40.8 3/8 in. (9.5 -mm) 25.4 Coarse Sand 4.3 No. 4 (4.75 -mm) 16.2 Medium Sand 7.8 No. 10 (2.00 -mm) 11.9 Fine Sand 3.5 No. 20 (.850 -mm) 9.4 No. 40 (.425 -mm) 4.1 Fines 0.6 No. 60 (.250 -mm) 1.6 Total 100.0 No. 100 (.150 -mm) 0.9 No. 200 (.075 -mm) 0.6 LL -- PL -- PI - - D10 1.00 D30 14.00 D6o 27.00 D90 45.00 Cc 7.26 Cu 27.00 ASTM Classification Group Name: Poorly Graded Gravel with Sand Symbol: GP INSIGHT GEOLOGIC, INC. Gradation Analysis Summary Data Job Name: Yelm High School Bypass Road Sample Location: TP -5 Job Number: 847 - 004 -01 Sample Name: TP -5 2.0' -6.0' Date Tested: 8/7/17 Depth: 2 - 6 Feet Tested By: Jessica Christensen Moisture Content ( %) Percent Sieve Size Passing 7.3% Percent by Size Fraction Weight 3.0 in. (75.0) 100.0 Coarse Gravel 0.0 1.5 in. (37.5) 100.0 Fine Gravel 0.1 3/4 in. (19.0) 100.0 3/8 in. (9.5 -mm) 100.0 Coarse Sand 0.5 No. 4 (4.75 -mm) 99.9 Medium Sand 44.1 No. 10 (2.00 -mm) 99.4 Fine Sand 52.3 No. 20 (.850 -mm) 97.5 No. 40 (.425 -mm) 55.3 Fines 3.0 No. 60 (.250 -mm) 16.5 Total 100.0 No. 100 (.150 -mm) 6.0 No. 200 (.075 -mm) 3.0 LL -- PL -- PI - - D10 0.20 D30 0.31 D60 0.47 D90 0.61 Cc 1.02 Cu 2.35 ASTM Classification Group Name: Poorly Graded Sand Symbol: SP INSIGHT GEOLOGIC, INC. 0 z C/) Q Q z Q to = m N C) � O Cl) rr In- V Cl) f_n o g o w �+ N � � � � M� W Q H r J O • I O O O O J 70 o U m O ^ Cl) L M ' R v a_ H ° O 1 � _ T J O LU O O z � O O w �• N *k ' N M in O +; H R - Q CO ON N ME 0 w N Cl w Of CO *k c N Of ' I a) o W O z � J O N W M Q H w co _ Ln O O O O O N W J U > m z �I O L ♦I O 0 I J O O uj O C7 O O O O O O O O O O O O O OO I- O LO V Cl) N z C7 tn z jgBiaM Aq Buissed }u93a9d ATTACHMENT D REPORT LIMITATIONS AND GUIDELINES FOR USE INS T GE ®L ®GIC, VNC. ATTACHMENT D REPORT LIMITATIONS AND GUIDELINES FOR USE' This attachment provides information to help you manage your risks with respect to the use of this report. GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES, PERSONS AND PROJECTS This report has been prepared for the exclusive use of J. W. Morrissette & Associates (Client) and their authorized agents. This report may be made available to regulatory agencies for review. This report is not intended for use by others, and the information contained herein is not applicable to other sites. Insight Geologic Inc. structures our services to meet the specific needs of our clients. For example, a geotechnical or geologic study conducted for a civil engineer or architect may not fulfill the needs of a construction contractor or even another civil engineer or architect that are involved in the same project. 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LIMITATIONS APPENDIX 6 CONSTRUCTION SWPPP Construction SWPPP �f SCJ ALLIANCE CONSULTING SERVICES TABLE OF CONTENTS Construction Stormwater Pollution Prevention Plan CoverSheet ................................................................................................................................ ..............................1 Tableof Contents ........................................................................................................................ ..............................2 Construction Stormwater Pollution Prevention Elements .................................................. ..............................3 Objective of the Stormwater Pollution Prevention Plon ............................................... ..............................3 Summaryof the Elements ................................................................................................. ..............................3 Element #1 — Mork Clearing Limits ................................................................................ ............................3 -4 Element #2 — Establish Construction Access ................................................................... ..............................4 Element #3 — Control Flow Rates ..................................................................................... ..............................4 Element #4 — Instoll Sediment Controls .......................................................................... ..............................4 Element#5 — Stabilize Soils ............................................................................................. ............................4 -5 Element#6 — Protect Slopes ............................................................................................. ..............................5 Element #7 — Protect Drain Inlets ..................................................................................... ..............................5 Element #8 — Stabilize Channels and Outlets ................................................................ ............................5 -6 Element#9 — Control Pollutonts ....................................................................................... ..............................6 Element #10 — Control Dewotering .................................................................................. ..............................6 Element#11 — Maintain BMPs ....................................................................................... ............................6 -7 Element #12 — Manage the Project .................................................................................... ..............................7 Element #13 — Protection Low Impact Development BMPs .......................................... ..............................8 ProjectDescription ................................................................................................................... ..............................8 Location............................................................................................................................... ..............................8 Project Overview ....................................... ............................... Existing Site Conditions ................................... ............................... Existing Drainage System ......................... ............................... Existing Topography and Vegetation .... ............................... AdjacentAreas ................................................. ............................... CriticalAreas .................................................... ............................... Soils................................................................... ............................... Erosion Problem Areas .................................... ............................... Construction Phasing ....................................... ............................... Construction Schedule ..................................... ............................... Engineering Calculations ............................. ............................... SitePlan ......................................................... ............................... References.................................................... ............................... ......................................... ............................... 8 ......................................... ............................... 8 ......................................... ............................... 8 ......................................... ............................... 9 ......................................... ............................... 9 ......................................... ............................... 9 ......................................... ............................... 9 ......................................... ............................... 9 ......................................... ............................... 9 ......................................... ............................... 9 ...........................10 ...........................10 ...........................10 Yelm Community Schools Bypass Road 2 of 10 Construction SWPPP CONSTRUCTION STORMWATER POLLUTION PREVENTION ELEMENTS Objective of Stormwater Pollution Prevention Plan 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 Volume 2 of the 2005 Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW). The SWMMWW 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 Summary of Elements The BMPs listed in this report, or their equivalent, are required. Any revisions by the Contractor to the BMPs listed in the SWPPP shall be approved by the Engineer in writing. Thus, if the Contractor does not require a BMP or needs to modify a BMP, the Contractor shall document the reason(s) and present the documentation to the Engineer for approval. Element #1- Mark Clearing Limits 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. Yelm Community Schools Bypass Road 3 of 10 Construction SWPPP • 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 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 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 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 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 Yelm Community Schools Bypass Road 4 of 10 Construction SWPPP (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 Element #6 - Protecting Slopes 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 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 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. Yelm Community Schools Bypass Road 5 of 10 Construction SWPPP BMP C202: Channel Lining BMP C209: Outlet Protection Element #9 - Control Pollutants 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 Engineer and /or the City of Centralia Element #10 - Control Dewatering All foundation, vault, and trench dewatering activities shall be routed to a sediment pond for basic filtering /treatment. 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 All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repairs shall be completed in accordance with the practices, procedures, and materials for each respective BMP. Sediment Control BMPs shall be inspected weekly or after a runoff - producing storm event during the dry season and daily during the wet season. Yelm Community Schools Bypass Road 6 of 10 Construction SWPPP All temporary erosion and Sediment Control BMPs shall be removed within thirty (30) days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on -site. Disturbed soil areas resulting from removal of BMPs or vegetation shall be permanently stabilized. Element #12 - Manage the Project Phasing of Construction - the project shall be phased where feasible in order to prevent, to the maximum extent practicable, the transport of sediment from the site during construction. Revegetation of exposed areas and maintenance of said vegetation shall be an integral part of the clearing activities for each phase. • Seasonal Work Limitations - from October 01 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt -laden runoff will be prevented from leaving the construction site. The following activities are exempt for the seasonal clearing and grading limitations: 1. Routine maintenance and necessary repair of erosion and sediment control BMPs. Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to the soil. Activities where there is 100% infiltration of surface runoff within the site in approved and installed erosion and sediment control facilities. • Inspection and Monitoring - all BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. The Certified Professional in Erosion and Sediment Control for this project is shall be on -site or on -call at all times during construction. The role of the Certified Professional in Erosion and Sediment Control is to identify problems or failures of erosion control measures in the field and to promptly initiate corrective measures. The Certified Professional in Erosion and Sediment Control shall be compensated by the Contractor. Sampling and analysis of discharged stormwater from the construction site may be necessary to ensure compliance with the standards. Whenever inspection and /or monitoring reveals that the BMPs identified in the Construction SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, the Construction SWPPP shall be modified, as appropriate, in a timely manner. • Maintenance of the Construction SWPPP - the Construction SWPPP shall be retained on -site or within reasonable access to the site. The Construction SWPPP shall be modified whenever there is a significant change in the design, construction, operation, and /or maintenance of any BMP. Yelm Community Schools Bypass Road 7 of 10 Construction SWPPP Element #13 — Protect Low Impact Development BMPs Protect all CAVFS facilities and the infiltration pond BMPs from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the CAVFS facilities and /or infiltration 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 PROJECT DESCRIPTION Location The proposed residential development site is located on Thurston County tax parcel numbers: 79300000300, 79300001401, and 79300001400, in the City of Tumwater, Washington. Project Overview The proposed Yelm High School Bypass Roadway will be constructed on Thurston County Tax Parcel No. 21724240000. Specifically, the proposed site improvements / construction activities include the following: • Site preparation, grading, and erosion control activities • Construction of a 32' wide x 1,300' long road that connect Yelm High School to Tahoma Boulevard • Construction of on -site water quality and flow control facilities EXISTING SITE CONDITIONS Existing Drainage System The site has not been developed. Stormwater runoff infiltrates on -site. Yelm Community Schools Bypass Road 8 of 10 Construction SWPPP Existing Topography & Vegetation The site consists primarily of overgrown brush and is undeveloped. There's a canopy of mature trees that are located at the northeast corner of the parcel. There is approximately ten (10) feet of topographic relief across the site. ADJACENT AREAS West Yelm Avenue is positioned to the north and the site is bound by Tahoma Boulevard SE to the south. CRITICAL AREAS There are no on -site critical areas. SOILS The on -site soil types are Nisqually loamy fine sand and Spanaway stony sandy loam. EROSION PROBLEM AREAS Potential on -site erosion control problems are not anticipated for this project. CONSTRUCTION PHASING This project will be completed in one (1) phase. CONSTRUCTION SCHEDULE Anticipated construction activities and sequences are shown in the following table. CONSTRUCTION ACTIVITY ANTICIPATED DATE OF COMPLETION Contractor Notice to Proceed 03/01/2018 Install Erosion Control Facilities 03/01/2018 Begin Site Rough Grading 03/05/2018 Begin Installing Site Infrastructure 04/15/2018 Stabilize Site 07/15/2019 Project Substantial Completion 08/01/2019 Table 1: Construction Schedule Yelm Community Schools Bypass Road 9 of 10 Construction SWPPP ENGINEERING CALCULATIONS Refer to this project's Stormwater Site Plan for stormwater design calculations. SITE PLAN TESC plans are enclosed in the Stormwater Site Plan REFERENCES Volume II of the 2014 Department of Ecology Stormwater Management Manual for Western Washington. END OF CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN Yelm Community Schools Bypass Road 10 of 10 Construction SWPPP APPENDIX 7 STORMWATER PLAN SHEETS