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Preliminary Stormwater Report
YELM AUTO RECYCLING P R E L I M I N A R Y D R A I N A G E R E P O R T J U N E 2 0 1 8 Table of Contents Part 1 – Project Site Analysis and Data Part 2 – Site Development Layout Part 3 – Offsite Analysis Report Part 4 – Applicable Minimum Requirements Part 5 – Permanent Stormwater Control Plan Part 6 – Source Control BMPs Part 7 – Construction SWPPP Part 8 – Special Reports and Studies Part 9 – Other Permits Part 10 – Operational and Maintenance Plan Part 11 – Bond Quantities and Financial Responsibility Part 12 – Grading and Drainage Plans ____________________________________________________ 18025 Drainage Report 1-1 Project Engineer Prepared by: RB Engineering, Inc. (RBE) PO Box 923 Chehalis, WA 98532 (360) 740-8919 Robertb@RBEngineers.com Contact: Robert W. Balmelli PE RBE Project: 17041 Prepared for: NPR Holdings LLC Ubaida Mufrej 3655 E. Marginal Ways Seattle, Washington 98134 ubaida@safariexports.com Reference: 2014 WSDOE Stormwater Manual Project Engineers Certification “I hereby certify that this Drainage and Erosion Control Plan for Yelm Auto Recycling has been prepared by me or under my supervision and meets minimum standards the Stormwater Management Manual for Western Washington and normal standards of engineering practice. I hereby acknowledge and agree that the jurisdiction does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities designed by me.” Project Engineers Stamp ____________________________________________________ 18025 Drainage Report 1-2 PART 1 – PROJECT SITE ANALYSIS AND DATA Permit Requested: Site Plan Review Other Permits Required: Building Permit Grading/Earthwork SEPA Review Agency Permit No.: Pending Site Address: 939 North Pacific Rd Yelm, Washington 98597 Section, Township, Range: Section 19 Township 17 Range 02E, W.M Total Site Area: 13.93 Acres Zoning: I - Industrial Project Overall Description The project is to include the development of an auto wrecking yard named, Yelm Auto Recycling, on lot 64300900200. Development will include the construction of 3 structures to be used for office space, storage and general shop/maintenance space. Construction will also include the development of onsite customer parking, graveled and paved vehicle storage yards, water, sewer, and power service, stormwater facilities, and frontage improvements along North Pacific Road. Proposed Flow Control Improvements The flow control facilities proposed for this project were designed and modeled using the latest edition of the Western Washington Hydrology Manual Continuous Simulation Program. The site will utilize the areas extremely well-draining soils to dispose of stormwater through infiltration. Stormwater will be conveyed to bioretention swales along the sites east/west boundaries. Test pits dug at the stormwater facilities proposed locations revealed infiltration rates in excess of 100 in/hr. For design purposed, stormwater facilities were modeled with a Ksat safety factor of 4 and an infiltration rate of 20. The soils report can be found in Part 8 of this document. Proposed Water Quality Improvements The water quality improvements for the project site runoff consist of the addition of a bioretention swales at the sites east/west boundaries. The swales will be constructed in include an 18-inch thick layer of WSDOE approved amended soils. Proposed Conveyance System The proposed conveyance systems will consist of Type I catch basins and conveyance pipe in various sizes to distribute stormwater to the proposed stormwater facilities. Proposed Discharge Location The project site will infiltrate all runoff at the proposed bioretention swale locations. ____________________________________________________ 18025 Drainage Report 1-3 Downstream Condition The site contains a ridge running SE to NW. The ridge effectively splits the site with stormwater naturally draining to the east/west boundaries. The proposed improvements will have no effect on the existing conditions as runoff will be contained on-site. Given the sites native well- draining soils it is likely that stormwater presently is infiltrated before leaving the site. Onsite Soils and Geology An on-site soils report was completed for this project site be Parnell Engineering, LLC. A copy of the report is included in Part 8 – Special Reports and Studies, of this document. The report stated that infiltration on-site is feasible with calculated infiltration rates exceeding 100 in/hr. The report recommends a design infiltration of 20 in/hr be used. Based upon this information the storm design concept of infiltration was selected. ____________________________________________________ 18025 Drainage Report 2-1 PART 2 – SITE DEVELOPMENT LAYOUT Project Topography The site topography is nearly level to gently sloping. Elevations range from a high of 338 ft. at the south-central portion of the site to a low of 328 ft. at the NE corner of the site. Land Use and Ground Cover Site vegetation consists of sparsely located conifer trees along with Scotts bloom, indigenous brush and field grass. The subject site is bounded by rural residential property to the north, undeveloped property to the east, Northern Pacific Road NW to the south, and a private drive- way to the west. Natural or Man-Made Drainage Patterns The site contains a ridge running SE to NW. The ridge effectively splits the site with stormwater naturally draining to the east/west boundaries. The proposed improvements will have no effect on the existing conditions as runoff will be contained on-site. Given the sites native well- draining soils it is likely that stormwater presently is infiltrated before leaving the site. Tributary and Discharge Points of Flow There are no tributary points of flow. The centralized ridge on-site prevents off-site flows from entering the project. Historical Drainage Problems RBE is not aware of any historical drainage problems for this site. Existing Utilities (Storm, Sewer, Water) The existing utilities available to site include power, water, sewer, storm. Erosion Potential The site has a slight erosion potential. As part of the development plans a detailed Erosion Control Plan and Storm Water Pollution Prevention Plan will be prepared and submitted with the final drainage report for use during site construction to minimize erosion and mitigate sedimentation within and off the site. Critical Areas Onsite The site does not contain any critical areas Existing Fuel Storage Tanks Review of the onsite parcels resulted in no evidence of existing fuel storage tanks above or below ground for this property. Groundwater Wells The property does not include any onsite ground water wells. ____________________________________________________ 18025 Drainage Report 2-2 Septic Systems There are no septic systems on-site. Aquifer Recharge Area The site is within the City of Yelm Aquifer Recharge Area. Wellhead Protection Area The site is not within any wellhead protection areas for public utilities. ____________________________________________________ 18025 Drainage Report 3-1 PART 3 – OFFSITE ANALYSIS REPORT RBE staff visually inspected the site and offsite surrounding areas. With all runoff being infiltrated an offsite analysis was deemed unnecessary. ____________________________________________________ 18025 Drainage Report 4-1 PART 4 – APPLICABLE MINIMUM REQUIREMENTS The minimum requirements for stormwater development and redevelopment sites are listed in Volume I of the 2012 SMMWW. Not all minimum requirements of this section apply to all projects. Determination of applicable minimum requirements is also based in part on Section 2.4 of the Manual. Applicable Criteria Areas Existing Site Impervious Coverage 0.00 AC New Plus Replaced Impervious Surface 12.44 AC Vegetation Area Converted to Lawn or Landscaped Area 0.75 AC Land Disturbing Area 13.19 AC ____________________________________________________ 18025 Drainage Report 4-2 ____________________________________________________ 18025 Drainage Report 4-3 Based on the thresholds given in Figures 2.4.1 and/or 2.4.2 of Volume I of the Manual, the proposed project must address or comment on Minimum Requirements #1 through #9. These requirements as they apply to the project are discussed in more detail below. Minimum Requirement (MR) #1 – Stormwater Site Plans: All projects meeting the thresholds of Section 2.4 of Volume I of the SMMWW shall prepare a Stormwater Site Plan for local government review. The proposed project will create over 5,000 square feet of impervious surfacing, and therefore a Stormwater Site Plan complying with minimum requirements #1 through #10 is required. MR #2 – Construction Storm Water Pollution Prevention Plan: The proposed project exceeds the thresholds of Section 2.5 and therefore a Construction Storm Water Pollution Prevention Plan is required for this project. A SWPPP will be created as a standalone document for this project and submitted with the final drainage report. MR #3 – Source Control of Pollution: All known, available and reasonable source control BMPs shall be applied to the project to limit pollutants coming in contact with stormwater. The BMPs for this project will be incorporated into the project’s Final Operation and Maintenance Plan. MR #4 – Preservation of Natural Drainage Systems/Outfalls: Proposed stormwater will be infiltrated on-site. There will be no effect to the sites natural drainage. ____________________________________________________ 18025 Drainage Report 4-4 MR #5 – On-Site Stormwater Management: The stormwater management plan was developed to meet the following project threshold, “New Development Inside the UGA on a Parcel of 5 Acres or Larger”. Projects triggering Minimum Requirements #1 through #9, must meet the requirements in Table 2.5.1. ____________________________________________________ 18025 Drainage Report 4-5 LID Performance Standard The project will utilize bioretention facilities to treat and infiltrate all runoff generated on-site. MR #7 – Flow Control: Thresholds When assessing a project against the following thresholds, consider only those impervious, hard, and pervious surfaces that are subject to this minimum requirement as determined in Section 2.4 of this chapter. The following circumstances require achievement of the standard flow control requirement for western Washington: Projects in which the total of effective impervious surfaces is 10,000 square feet or more in a threshold discharge area, or This project creates more than 10,000 square feet of effective impervious surface in its threshold discharge area. Projects that convert ¾ acres or more of vegetation to lawn or landscape, or convert 2.5 acres or more of native vegetation to pasture in a threshold discharge area, and from which there is a surface discharge in a natural or man-made conveyance system from the site, or This project does not exceed this criterion. Projects that through a combination of effective hard surfaces and converted vegetation areas cause a 0.10 cubic feet per second increase in the 100-year flow frequency from a threshold discharge area as estimated using the Western Washington Hydrology Model or other approved model and one-hour time steps (or a 0.15 cfs increase using 15-minute time steps). 2 This project exceeds the criterion. Standard Flow Control Requirement The LID Performance Standard will be met. Flow control will be provided via infiltration through the proposed bioretention facilities. MR #8 – Wetlands Protection: There are no wetlands within the proposed project limits. MR #9 – Operation & Maintenance: ____________________________________________________ 18025 Drainage Report 4-6 An operation and maintenance agreement and manual will be included in the final drainage report and functions as a standalone document for the developer and property owners. MR #10 – Agreements and Financial Guarantees: Facility agreements and financial guarantees when required will be reviewed by the applicant and executed at the appropriate time determined by the reviewing agency. Supplemental Requirement SR#1 – Basin/Watershed Planning: There are no basin or watershed requirements for this project area. Supplemental Requirement SR#2 – Offsite Analysis and Mitigation The offsite analysis for this project did not yield any mitigation for this project. Drainage Easements: No onsite easements are required or needed for this project’s drainage facilities. Drainage Facility Setbacks: Bioretention Swales 10’ from property line, 10’ from any structure. Adjustments: No adjustments have been requested for this project. Exceptions and Variances: No variances are requested at this time. ____________________________________________________ 18025 Drainage Report 5-1 PART 5 – PERMANENT STORMWATER CONTROL PLAN Existing Site Hydrology Existing site hydrology is based on our site investigation, field topographic survey, aerial topographic mapping and completed soils review for the subject project. The site consists of the basins outlined below. Pre-developed Basin (P#) Current Land Use: Vacant Lot Land Use Assumptions and Site Parameters Basin ID Land Use Cover Slope Acres Hydrologic Group Comments P1 Forested Flat 5.81 A P2 Forested Flat 4.22 A P3 Forested Flat 3.16 A Total 13.19 Developed Site Hydrology (D#) The developed site hydrology was modeled using the latest version of the WWHM Continuous Simulation model created by WSDOE. A complete summary for each sub-basin is included in the chart below. Because of the existing topography, the site was able to be graded and modeled as one basin. Basin D1 includes all the new impervious surfaces created by the development of the project. Basin Summary Proposed Land Use: Residential – Multi-Family Housing Land Use Assumptions and Site Parameters Basin ID Land Use Cover Slope Acres Hydrologic Group Comments D1 Parking Flat 1.14 A Gravel Flat 4.09 A Sidewalks Flat 0.00 A Roof Flat 0.09 A Lawn Flat 0.49 A D2 Parking Flat 0.81 A Gravel Flat 3.05 A Sidewalks Flat 0.04 A Roof Flat 0.06 A Lawn Flat 0.26 A ____________________________________________________ 18025 Drainage Report 5-2 D3 Parking Flat 0.00 A Gravel Flat 3.16 A Sidewalks Flat 0.00 A Roof Flat 0.00 A Lawn Flat 0.00 A Total 13.19 Flow Control System Design & Analysis The proposed storm water facilities were designed using the WWHM storm water model created by WSDOE. Flow and Water Quality Control Facilities Proposed: Basin Facility Type Comments D1 Bioretention Swale - 363’L X 3’W X 2.5’D Water Quality/Flow Control D2 Bioretention Swale - 465’L X 3’W X 2’D Water Quality/Flow Control D3 Bioretention Swale - 469’L X 3’W X 2’D Water Quality/Flow Control RBE conducted modeling of all basins using WWHM12 continuous simulation model. Listed below are narratives of each delineated drainage basin for this project. Basin Narratives Basin D1 Basin D1 encompasses the eastern half of the site and involves collecting, treating, and infiltrating all runoff generated within the basin by utilizing a 363-foot long by 3’ wide bioretention swale. Basin D2 Basin D3 encompasses the southwestern quarter of the site and involves collecting, treating, and infiltrating all runoff generated within the basin by utilizing a 465-foot long by 3-foot wide bioretention swale. Basin D3 Basin D3 encompasses the northwestern quarter of the site and involves collecting, treating, and infiltrating all runoff generated within the basin by utilizing a 400-foot long by 3-foot wide bioretention swale. ____________________________________________________ 18025 Drainage Report 5.1-1 PART 5.1 – FLOW CONTROL Flow Control System Design & Analysis The proposed stormwater facility was designed using the professional version of the WWHM stormwater model created for WSDOE. The proposed site development was modeled using WWHM that resulted in the following pond volumes listed below. The WWHM data output also outlines the control structure dimensions and elevations. See WWHM data output for that information. Flow Control Facility Proposed: Bioretention Swale D1 Bioretention Swale Design Summary Swale Stage Storage Elevation (ft)Detention Volume (ac-ft) Top of Swale 332.5 0.22 Design Water Surface 332.0 0.15 Bottom Live Storage 330.0 0 The proposed swale is approximately 363 feet long x 3 feet wide x 2.5 feet deep. The final dimensions will be detailed in the final construction drawings prepared after approval of the Site Plan Review. Flow Control Facility Proposed: Bioretention Swale D2 Bioretention Swale Design Summary Swale Stage Storage Elevation (ft)Detention Volume (ac-ft) Top of Swale 333.5 0.20 Design Water Surface 333.0 0.12 Bottom Live Storage 331.5 0 The proposed swale is approximately 465 feet long x 3 feet wide x 2 feet deep. The final dimensions will be detailed in the final construction drawings prepared after approval of the Site Plan Review. Flow Control Facility Proposed: Bioretention Swale D3 Bioretention Swale Design Summary Swale Stage Storage Elevation (ft)Detention Volume (ac-ft) Top of Swale 332.5 0.19 Design Water Surface 332.0 0.12 Bottom Live Storage 330.5 0 The proposed swale is approximately 469 feet long x 3 feet wide x 2 feet deep. The final dimensions will be detailed in the final construction drawings prepared after approval of the Site ____________________________________________________ 18025 Drainage Report 5.1-2 Plan Review. WWHM Data Output The following figures and WWHM modeling data output are included on the following pages of this section: WWHM Modeling Data Output WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Basin 1 Site Name: BASIN 1 Site Address: 939 Northern Pacific Rd City : Yelm Report Date: 6/6/2018 Gage : Lake Lawrence Data Start : 1955/10/01 00:00 Data End : 2008/09/30 00:00 Precip Scale: 0.86 Version Date: 2018/03/02 Version : 4.2.14 ___________________________________________________________________ Low Flow Threshold for POC 1 : 8 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Forest, Flat 5.81 Pervious Total 5.81 Impervious Land Use acre Impervious Total 0 Basin Total 5.81 ___________________________________________________________________ Element Flows To: ____________________________________________________ 18025 Drainage Report 5.1-3 Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Lawn, Flat .49 Pervious Total 0.49 Impervious Land Use acre ROOF TOPS FLAT 0.09 PARKING FLAT 5.23 Impervious Total 5.32 Basin Total 5.81 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 ___________________________________________________________________ Name : Bioretention 1 Bottom Length: 363.00 ft. Bottom Width: 3.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 0 Material type for second layer: GRAVEL Material thickness of third layer: 0 Material type for third layer: GRAVEL Infiltration On Infiltration rate: 20 Infiltration safety factor: 1 Wetted surface area On Total Volume Infiltrated (ac-ft.): 945.045 Total Volume Through Riser (ac-ft.): 0.044 Total Volume Through Facility (ac-ft.): 945.089 Percent Infiltrated: 100 Total Precip Applied to Facility: 14.211 Total Evap From Facility: 3.407 Underdrain not used Discharge Structure ____________________________________________________ 18025 Drainage Report 5.1-4 Riser Height: 2 ft. Riser Diameter: 24 in. Element Flows To: Outlet 1 Outlet 2 ___________________________________________________________________ Bioretention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.1025 0.0000 0.0000 0.0000 0.0440 0.1022 0.0005 0.0000 0.0000 0.0879 0.0999 0.0011 0.0000 0.0001 0.1319 0.0975 0.0017 0.0000 0.0003 0.1758 0.0952 0.0024 0.0000 0.0005 0.2198 0.0929 0.0031 0.0000 0.0010 0.2637 0.0906 0.0038 0.0000 0.0016 0.3077 0.0883 0.0046 0.0000 0.0024 0.3516 0.0860 0.0055 0.0000 0.0036 0.3956 0.0837 0.0063 0.0000 0.0050 0.4396 0.0814 0.0073 0.0000 0.0068 0.4835 0.0791 0.0082 0.0000 0.0090 0.5275 0.0768 0.0093 0.0000 0.0117 0.5714 0.0745 0.0103 0.0000 0.0149 0.6154 0.0722 0.0114 0.0000 0.0186 0.6593 0.0700 0.0126 0.0000 0.0230 0.7033 0.0677 0.0138 0.0000 0.0280 0.7473 0.0654 0.0150 0.0000 0.0337 0.7912 0.0631 0.0163 0.0000 0.0403 0.8352 0.0609 0.0177 0.0000 0.0477 0.8791 0.0586 0.0190 0.0000 0.0560 0.9231 0.0563 0.0205 0.0000 0.0653 0.9670 0.0541 0.0219 0.0000 0.0756 1.0110 0.0518 0.0235 0.0000 0.0871 1.0549 0.0496 0.0250 0.0000 0.0997 1.0989 0.0473 0.0267 0.0000 0.1136 1.1429 0.0451 0.0283 0.0000 0.1287 1.1868 0.0428 0.0300 0.0000 0.1453 1.2308 0.0406 0.0318 0.0000 0.1634 1.2747 0.0384 0.0336 0.0000 0.1829 1.3187 0.0361 0.0354 0.0000 0.2041 1.3626 0.0339 0.0373 0.0000 0.2270 1.4066 0.0317 0.0392 0.0000 0.2517 1.4505 0.0294 0.0412 0.0000 0.2782 1.4945 0.0272 0.0433 0.0000 0.3065 1.5000 0.0250 0.0435 0.0000 0.3065 Surface retention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 1.5000 0.1025 0.0435 0.0000 0.3114 0.0469 1.5440 0.1048 0.0481 0.0000 0.3114 0.0939 1.5879 0.1071 0.0527 0.0000 0.3202 0.1409 1.6319 0.1095 0.0575 0.0000 0.3291 0.1881 ____________________________________________________ 18025 Drainage Report 5.1-5 1.6758 0.1118 0.0623 0.0000 0.3380 0.2352 1.7198 0.1141 0.0673 0.0000 0.3468 0.2825 1.7637 0.1165 0.0724 0.0000 0.3557 0.3298 1.8077 0.1188 0.0776 0.0000 0.3646 0.3772 1.8516 0.1212 0.0828 0.0000 0.3734 0.4246 1.8956 0.1235 0.0882 0.0000 0.3823 0.4721 1.9396 0.1259 0.0937 0.0000 0.3911 0.5196 1.9835 0.1282 0.0993 0.0000 0.4000 0.5673 2.0275 0.1306 0.1050 0.0000 0.4089 0.6150 2.0714 0.1330 0.1108 0.0000 0.4177 0.6627 2.1154 0.1353 0.1167 0.0000 0.4266 0.7105 2.1593 0.1377 0.1227 0.0000 0.4355 0.7584 2.2033 0.1401 0.1288 0.0000 0.4443 0.8064 2.2473 0.1425 0.1350 0.0000 0.4532 0.8544 2.2912 0.1448 0.1413 0.0000 0.4621 0.9025 2.3352 0.1472 0.1477 0.0000 0.4709 0.9506 2.3791 0.1496 0.1542 0.0000 0.4798 0.9988 2.4231 0.1520 0.1609 0.0000 0.4887 1.0471 2.4670 0.1544 0.1676 0.0000 0.4975 1.0954 2.5110 0.1568 0.1744 0.0000 0.5064 1.1438 2.5549 0.1592 0.1814 0.0000 0.5152 1.1923 2.5989 0.1616 0.1884 0.0000 0.5241 1.2408 2.6429 0.1640 0.1956 0.0000 0.5330 1.2894 2.6868 0.1664 0.2028 0.0000 0.5418 1.3381 2.7308 0.1688 0.2102 0.0000 0.5507 1.3868 2.7747 0.1712 0.2177 0.0000 0.5596 1.4356 2.8187 0.1737 0.2253 0.0000 0.5684 1.4844 2.8626 0.1761 0.2330 0.0000 0.5773 1.5333 2.9066 0.1785 0.2407 0.0000 0.5862 1.5823 2.9505 0.1809 0.2486 0.0000 0.5950 1.6314 2.9945 0.1834 0.2567 0.0000 0.6039 1.6805 3.0385 0.1858 0.2648 0.0000 0.6128 1.7296 3.0824 0.1882 0.2730 0.0000 0.6216 1.7789 3.1264 0.1907 0.2813 0.0000 0.6305 1.8282 3.1703 0.1931 0.2898 0.0000 0.6394 1.8776 3.2143 0.1956 0.2983 0.0000 0.6482 1.9270 3.2582 0.1980 0.3069 0.0000 0.6571 1.9765 3.3022 0.2005 0.3157 0.0000 0.6659 2.0260 3.3462 0.2029 0.3246 0.0000 0.6748 2.0757 3.3901 0.2054 0.3335 0.0000 0.6837 2.1253 3.4341 0.2079 0.3426 0.0000 0.6925 2.1751 3.4780 0.2103 0.3518 0.0000 0.7014 2.2249 3.5220 0.2128 0.3611 0.0692 0.7103 2.2748 3.5659 0.2153 0.3705 0.3591 0.7191 2.3247 3.6099 0.2178 0.3800 0.7719 0.7280 2.3748 3.6538 0.2202 0.3897 1.2766 0.7369 2.4248 3.6978 0.2227 0.3994 1.8560 0.7457 2.4750 3.7418 0.2252 0.4093 2.4970 0.7546 2.5252 3.7857 0.2277 0.4192 3.1878 0.7635 2.5754 3.8297 0.2302 0.4293 3.9171 0.7723 2.6258 3.8736 0.2327 0.4394 4.6731 0.7812 2.6762 3.9176 0.2352 0.4497 5.4440 0.7900 2.7266 3.9615 0.2377 0.4601 6.2177 0.7989 2.7708 4.0000 0.2399 0.4693 6.9822 0.8067 1.5333 ___________________________________________________________________ ____________________________________________________ 18025 Drainage Report 5.1-6 Name : Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Bioretention 1 ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS POC #1 was not reported because POC must exist in both scenarios and both scenarios must have been run.Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ 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. 2005-2018; All Rights Reserved. ____________________________________________________ 18025 Drainage Report 5.1-7 WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Basin 2 Site Name: BASIN 2 Site Address: 939 Northern Pacific Rd City : Yelm WA Report Date: 6/6/2018 Gage : Lake Lawrence Data Start : 1955/10/01 00:00 Data End : 2008/09/30 00:00 Precip Scale: 0.86 Version Date: 2018/03/02 Version : 4.2.14 ___________________________________________________________________ Low Flow Threshold for POC 1 : 8 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Forest, Flat 4.22 Pervious Total 4.22 Impervious Land Use acre Impervious Total 0 Basin Total 4.22 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Bypass: No ____________________________________________________ 18025 Drainage Report 5.1-8 GroundWater: No Pervious Land Use acre A B, Lawn, Flat .26 Pervious Total 0.26 Impervious Land Use acre ROOF TOPS FLAT 0.06 SIDEWALKS FLAT 0.04 PARKING FLAT 3.86 Impervious Total 3.96 Basin Total 4.22 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 ___________________________________________________________________ Name : Bioretention 1 Bottom Length: 465.00 ft. Bottom Width: 3.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 0 Material type for second layer: Sand Material thickness of third layer: 0 Material type for third layer: GRAVEL Infiltration On Infiltration rate: 20 Infiltration safety factor: 1 Wetted surface area On Total Volume Infiltrated (ac-ft.): 705.783 Total Volume Through Riser (ac-ft.): 0 Total Volume Through Facility (ac-ft.): 705.783 Percent Infiltrated: 100 Total Precip Applied to Facility: 14.438 Total Evap From Facility: 4.104 Underdrain not used Discharge Structure Riser Height: 1.5 ft. Riser Diameter: 18 in. Element Flows To: Outlet 1 Outlet 2 ___________________________________________________________________ ____________________________________________________ 18025 Drainage Report 5.1-9 Bioretention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.1306 0.0000 0.0000 0.0000 0.0385 0.1280 0.0006 0.0000 0.0000 0.0769 0.1254 0.0012 0.0000 0.0001 0.1154 0.1229 0.0019 0.0000 0.0002 0.1538 0.1203 0.0026 0.0000 0.0005 0.1923 0.1177 0.0034 0.0000 0.0009 0.2308 0.1152 0.0042 0.0000 0.0014 0.2692 0.1126 0.0050 0.0000 0.0021 0.3077 0.1101 0.0059 0.0000 0.0031 0.3462 0.1075 0.0068 0.0000 0.0044 0.3846 0.1050 0.0078 0.0000 0.0059 0.4231 0.1024 0.0088 0.0000 0.0078 0.4615 0.0999 0.0099 0.0000 0.0100 0.5000 0.0973 0.0110 0.0000 0.0127 0.5385 0.0948 0.0122 0.0000 0.0159 0.5769 0.0922 0.0134 0.0000 0.0196 0.6154 0.0897 0.0146 0.0000 0.0238 0.6538 0.0872 0.0159 0.0000 0.0286 0.6923 0.0846 0.0172 0.0000 0.0341 0.7308 0.0821 0.0186 0.0000 0.0402 0.7692 0.0796 0.0200 0.0000 0.0472 0.8077 0.0770 0.0215 0.0000 0.0549 0.8462 0.0745 0.0230 0.0000 0.0635 0.8846 0.0720 0.0246 0.0000 0.0729 0.9231 0.0695 0.0262 0.0000 0.0834 0.9615 0.0670 0.0278 0.0000 0.0948 1.0000 0.0645 0.0295 0.0000 0.1074 1.0385 0.0620 0.0312 0.0000 0.1210 1.0769 0.0594 0.0330 0.0000 0.1359 1.1154 0.0569 0.0348 0.0000 0.1520 1.1538 0.0544 0.0367 0.0000 0.1694 1.1923 0.0519 0.0386 0.0000 0.1881 1.2308 0.0494 0.0406 0.0000 0.2084 1.2692 0.0469 0.0426 0.0000 0.2301 1.3077 0.0445 0.0446 0.0000 0.2533 1.3462 0.0420 0.0467 0.0000 0.2782 1.3846 0.0395 0.0489 0.0000 0.3048 1.4231 0.0370 0.0511 0.0000 0.3331 1.4615 0.0345 0.0533 0.0000 0.3633 1.5000 0.0320 0.0556 0.0000 0.3633 Surface retention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 1.5000 0.1306 0.0556 0.0000 0.3974 0.0519 1.5385 0.1332 0.0606 0.0000 0.3974 0.1039 1.5769 0.1357 0.0658 0.0000 0.4074 0.1560 1.6154 0.1383 0.0711 0.0000 0.4173 0.2081 1.6538 0.1409 0.0764 0.0000 0.4272 0.2602 1.6923 0.1435 0.0819 0.0000 0.4372 0.3124 1.7308 0.1461 0.0875 0.0000 0.4471 0.3647 1.7692 0.1487 0.0931 0.0000 0.4571 0.4170 1.8077 0.1513 0.0989 0.0000 0.4670 0.4693 ____________________________________________________ 18025 Drainage Report 5.1-10 1.8462 0.1538 0.1048 0.0000 0.4769 0.5217 1.8846 0.1564 0.1107 0.0000 0.4869 0.5741 1.9231 0.1590 0.1168 0.0000 0.4968 0.6266 1.9615 0.1617 0.1230 0.0000 0.5067 0.6792 2.0000 0.1643 0.1292 0.0000 0.5167 0.7318 2.0385 0.1669 0.1356 0.0000 0.5266 0.7844 2.0769 0.1695 0.1421 0.0000 0.5365 0.8371 2.1154 0.1721 0.1487 0.0000 0.5465 0.8898 2.1538 0.1747 0.1553 0.0000 0.5564 0.9426 2.1923 0.1773 0.1621 0.0000 0.5663 0.9954 2.2308 0.1799 0.1690 0.0000 0.5763 1.0483 2.2692 0.1826 0.1759 0.0000 0.5862 1.1013 2.3077 0.1852 0.1830 0.0000 0.5962 1.1542 2.3462 0.1878 0.1902 0.0000 0.6061 1.2073 2.3846 0.1904 0.1975 0.0000 0.6160 1.2604 2.4231 0.1931 0.2048 0.0000 0.6260 1.3135 2.4615 0.1957 0.2123 0.0000 0.6359 1.3667 2.5000 0.1983 0.2199 0.0000 0.6458 1.4199 2.5385 0.2010 0.2276 0.0000 0.6558 1.4732 2.5769 0.2036 0.2353 0.0000 0.6657 1.5265 2.6154 0.2063 0.2432 0.0000 0.6756 1.5799 2.6538 0.2089 0.2512 0.0000 0.6856 1.6333 2.6923 0.2116 0.2593 0.0000 0.6955 1.6868 2.7308 0.2142 0.2675 0.0000 0.7054 1.7403 2.7692 0.2169 0.2758 0.0000 0.7154 1.7939 2.8077 0.2195 0.2842 0.0000 0.7253 1.8475 2.8462 0.2222 0.2927 0.0000 0.7353 1.9012 2.8846 0.2249 0.3013 0.0000 0.7452 1.9549 2.9231 0.2275 0.3100 0.0000 0.7551 2.0087 2.9615 0.2302 0.3188 0.0000 0.7651 2.0625 3.0000 0.2329 0.3277 0.0000 0.7750 2.1164 3.0385 0.2355 0.3367 0.1200 0.7849 2.1703 3.0769 0.2382 0.3458 0.3391 0.7949 2.2243 3.1154 0.2409 0.3550 0.6219 0.8048 2.2783 3.1538 0.2436 0.3643 0.9542 0.8147 2.3323 3.1923 0.2462 0.3737 1.3261 0.8247 2.3865 3.2308 0.2489 0.3833 1.7286 0.8346 2.4406 3.2692 0.2516 0.3929 2.1526 0.8446 2.4948 3.3077 0.2543 0.4026 2.5891 0.8545 2.5491 3.3462 0.2570 0.4124 3.0289 0.8644 2.6034 3.3846 0.2597 0.4224 3.4625 0.8744 2.6578 3.4231 0.2624 0.4324 3.8809 0.8843 2.7122 3.4615 0.2651 0.4426 4.2756 0.8942 2.7667 3.5000 0.2678 0.4528 4.6391 0.9042 2.7667 3.5000 0.2678 0.4528 4.9654 0.9042 0.0000 ___________________________________________________________________ Name : Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Bioretention 1 ___________________________________________________________________ ____________________________________________________ 18025 Drainage Report 5.1-11 ___________________________________________________________________ ANALYSIS RESULTS POC #1 was not reported because POC must exist in both scenarios and both scenarios must have been run.Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ 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. 2005-2018; All Rights Reserved. ____________________________________________________ 18025 Drainage Report 5.1-12 WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Basin 3 Site Name: BASIN 3 Site Address: 939 Northern Pacific Rd City : Yelm WA Report Date: 6/6/2018 Gage : Lake Lawrence Data Start : 1955/10/01 00:00 Data End : 2008/09/30 00:00 Precip Scale: 0.86 Version Date: 2018/03/02 Version : 4.2.14 ___________________________________________________________________ Low Flow Threshold for POC 1 : 8 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Forest, Flat 3.16 Pervious Total 3.16 Impervious Land Use acre Impervious Total 0 Basin Total 3.16 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Bypass: No ____________________________________________________ 18025 Drainage Report 5.1-13 GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre PARKING FLAT 3.16 Impervious Total 3.16 Basin Total 3.16 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 ___________________________________________________________________ Name : Bioretention 1 Bottom Length: 469.00 ft. Bottom Width: 3.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 0 Material type for second layer: Sand Material thickness of third layer: 0 Material type for third layer: GRAVEL Infiltration On Infiltration rate: 20 Infiltration safety factor: 1 Wetted surface area On Total Volume Infiltrated (ac-ft.): 563.52 Total Volume Through Riser (ac-ft.): 0 Total Volume Through Facility (ac-ft.): 563.52 Percent Infiltrated: 100 Total Precip Applied to Facility: 12.798 Total Evap From Facility: 3.998 Underdrain not used Discharge Structure Riser Height: 1.5 ft. Riser Diameter: 18 in. Element Flows To: Outlet 1 Outlet 2 ___________________________________________________________________ Bioretention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) ____________________________________________________ 18025 Drainage Report 5.1-14 0.0000 0.1317 0.0000 0.0000 0.0000 0.0385 0.1291 0.0006 0.0000 0.0000 0.0769 0.1265 0.0012 0.0000 0.0001 0.1154 0.1239 0.0019 0.0000 0.0002 0.1538 0.1213 0.0026 0.0000 0.0005 0.1923 0.1187 0.0034 0.0000 0.0009 0.2308 0.1161 0.0042 0.0000 0.0014 0.2692 0.1136 0.0051 0.0000 0.0022 0.3077 0.1110 0.0060 0.0000 0.0031 0.3462 0.1084 0.0069 0.0000 0.0044 0.3846 0.1058 0.0079 0.0000 0.0059 0.4231 0.1033 0.0089 0.0000 0.0078 0.4615 0.1007 0.0100 0.0000 0.0101 0.5000 0.0981 0.0111 0.0000 0.0128 0.5385 0.0956 0.0123 0.0000 0.0160 0.5769 0.0930 0.0135 0.0000 0.0197 0.6154 0.0905 0.0147 0.0000 0.0240 0.6538 0.0879 0.0160 0.0000 0.0288 0.6923 0.0854 0.0174 0.0000 0.0344 0.7308 0.0828 0.0188 0.0000 0.0406 0.7692 0.0803 0.0202 0.0000 0.0476 0.8077 0.0777 0.0217 0.0000 0.0554 0.8462 0.0752 0.0232 0.0000 0.0640 0.8846 0.0726 0.0248 0.0000 0.0736 0.9231 0.0701 0.0264 0.0000 0.0841 0.9615 0.0675 0.0281 0.0000 0.0956 1.0000 0.0650 0.0298 0.0000 0.1083 1.0385 0.0625 0.0315 0.0000 0.1220 1.0769 0.0600 0.0333 0.0000 0.1370 1.1154 0.0574 0.0351 0.0000 0.1532 1.1538 0.0549 0.0370 0.0000 0.1708 1.1923 0.0524 0.0390 0.0000 0.1897 1.2308 0.0499 0.0409 0.0000 0.2101 1.2692 0.0473 0.0430 0.0000 0.2320 1.3077 0.0448 0.0450 0.0000 0.2555 1.3462 0.0423 0.0471 0.0000 0.2806 1.3846 0.0398 0.0493 0.0000 0.3074 1.4231 0.0373 0.0515 0.0000 0.3360 1.4615 0.0348 0.0537 0.0000 0.3663 1.5000 0.0323 0.0560 0.0000 0.3663 Surface retention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 1.5000 0.1317 0.0560 0.0000 0.4009 0.0524 1.5385 0.1343 0.0611 0.0000 0.4009 0.1048 1.5769 0.1369 0.0664 0.0000 0.4109 0.1573 1.6154 0.1395 0.0717 0.0000 0.4209 0.2098 1.6538 0.1421 0.0771 0.0000 0.4309 0.2624 1.6923 0.1447 0.0826 0.0000 0.4409 0.3150 1.7308 0.1473 0.0882 0.0000 0.4510 0.3677 1.7692 0.1499 0.0939 0.0000 0.4610 0.4204 1.8077 0.1525 0.0997 0.0000 0.4710 0.4732 1.8462 0.1551 0.1057 0.0000 0.4810 0.5260 1.8846 0.1578 0.1117 0.0000 0.4910 0.5788 1.9231 0.1604 0.1178 0.0000 0.5011 0.6318 ____________________________________________________ 18025 Drainage Report 5.1-15 1.9615 0.1630 0.1240 0.0000 0.5111 0.6847 2.0000 0.1656 0.1303 0.0000 0.5211 0.7377 2.0385 0.1683 0.1368 0.0000 0.5311 0.7908 2.0769 0.1709 0.1433 0.0000 0.5412 0.8439 2.1154 0.1735 0.1499 0.0000 0.5512 0.8971 2.1538 0.1762 0.1566 0.0000 0.5612 0.9503 2.1923 0.1788 0.1635 0.0000 0.5712 1.0036 2.2308 0.1814 0.1704 0.0000 0.5812 1.0569 2.2692 0.1841 0.1774 0.0000 0.5913 1.1102 2.3077 0.1867 0.1845 0.0000 0.6013 1.1636 2.3462 0.1894 0.1918 0.0000 0.6113 1.2171 2.3846 0.1920 0.1991 0.0000 0.6213 1.2706 2.4231 0.1947 0.2066 0.0000 0.6313 1.3242 2.4615 0.1973 0.2141 0.0000 0.6414 1.3778 2.5000 0.2000 0.2217 0.0000 0.6514 1.4314 2.5385 0.2027 0.2295 0.0000 0.6614 1.4851 2.5769 0.2053 0.2373 0.0000 0.6714 1.5389 2.6154 0.2080 0.2453 0.0000 0.6815 1.5927 2.6538 0.2107 0.2533 0.0000 0.6915 1.6466 2.6923 0.2133 0.2615 0.0000 0.7015 1.7005 2.7308 0.2160 0.2697 0.0000 0.7115 1.7544 2.7692 0.2187 0.2781 0.0000 0.7215 1.8084 2.8077 0.2214 0.2866 0.0000 0.7316 1.8625 2.8462 0.2240 0.2951 0.0000 0.7416 1.9166 2.8846 0.2267 0.3038 0.0000 0.7516 1.9707 2.9231 0.2294 0.3126 0.0000 0.7616 2.0249 2.9615 0.2321 0.3214 0.0000 0.7716 2.0792 3.0000 0.2348 0.3304 0.0000 0.7817 2.1335 3.0385 0.2375 0.3395 0.1200 0.7917 2.1878 3.0769 0.2402 0.3487 0.3391 0.8017 2.2422 3.1154 0.2429 0.3580 0.6219 0.8117 2.2967 3.1538 0.2456 0.3674 0.9542 0.8218 2.3512 3.1923 0.2483 0.3769 1.3261 0.8318 2.4057 3.2308 0.2510 0.3865 1.7286 0.8418 2.4603 3.2692 0.2537 0.3962 2.1526 0.8518 2.5149 3.3077 0.2564 0.4060 2.5891 0.8618 2.5696 3.3462 0.2591 0.4159 3.0289 0.8719 2.6244 3.3846 0.2618 0.4259 3.4625 0.8819 2.6792 3.4231 0.2645 0.4360 3.8809 0.8919 2.7340 3.4615 0.2673 0.4462 4.2756 0.9019 2.7889 3.5000 0.2700 0.4566 4.6391 0.9119 2.7889 3.5000 0.2700 0.4566 4.9654 0.9119 0.0000 ___________________________________________________________________ Name : Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Bioretention 1 ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS ____________________________________________________ 18025 Drainage Report 5.1-16 POC #1 was not reported because POC must exist in both scenarios and both scenarios must have been run.Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ 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. 2005-2018; All Rights Reserved. ____________________________________________________ 18025 Drainage Report 5.2-1 PART 5.2 – WATER QUALITY DESIGN Water Quality System Design & Analysis The drainage basins delineated for this project will have openly exposed pollution generating impervious surfaces. These tributary areas will be treated using the following treatment technologies listed under the associated drainage basins. Determine the Receiving Waters/Pollutants of concern based on Offsite Analyses Pollutants of Concern Step 2: Oil Control Facility This project will be required to provide oil control facility based on the analysis below. Oil Control Determination Chart ADT 100 Vehicles or Greater per 1000 SF Building Area Yes or No Site Subject to Petroleum Storage or Transfer Greater than 1500 Gallons per year.Yes or No Site have Parking, Storage or maintenance of 25 or more vehicles over 25 Tons gross weight. (Trucks, Buses, Trains, Heavy Equipment) Yes or No Road Intersection with measured ADT of 25000 vehicles or more on main roadway and 15000 vehicles or more on intersection roadway. Yes or No Step 3: Is Infiltration Practicable for pollutant removal? No Step 4: Phosphorus Control Required Oil Control Determination Chart Local Government Require Phosphorus control Yes or No ____________________________________________________ 18025 Drainage Report 5.2-2 Step 5: Enhanced Treatment Required Oil Control Determination Chart Site discharge directly to fresh waters or conveyance systems tributary to fresh waters?Yes or No Site uses infiltration strictly for flow control and the discharge is within 1.4 mile of fresh water designate for aquatic life?Yes or No Site an industrial project site?Yes or No Site a commercial project site?Yes or No Site a multi-family residential project site Yes or No UGA – Fully controlled and partially controlled limited access highways with AADT 15000 or greater No UGA - All other roads with and AADT of 7500 or greater.No Outside UGA - Roads with and AADT of 15,000 or greater unless discharging to a Strahler order Stream or large No Outside UGA - Road with an AADT of 30,000 or greater if discharging to a 4th Strahler order stream or larger.No Step 6: Select Basic/Enhanced Treatment Facility Based on the above determination the following Enhanced treatment requirements will be provided for this facility. Selected Treatment BMP’s Basin D1 Water Quality Facility: BMP T7.30 – Bioretention Swale – Enhanced Water Quality Facility: BMP T11.11 – Coalescing Plate Oil Water Separator RBE has selected these treatment methods for water quality control for the new PGIS associated with the project. Below is the summary of results from the WWHM water quality model. Bio-Retention Swale D1 – (See WWHM Data Output in Part 5.1 for Model Data) Basin D2 Water Quality Facility: BMP T7.30 – Bioretention Swale – Enhanced Water Quality Facility: BMP T11.11 – Coalescing Plate Oil Water Separator RBE has selected this treatment method for water quality control for the new PGIS associated with the project. Below is the summary of results from the WWHM water quality model. Bio-Retention Swale D2 – (See WWHM Data Output in Part 5.1 for Model Data) ____________________________________________________ 18025 Drainage Report 5.2-3 Basin D3 Water Quality Facility: BMP T7.30 – Bioretention Swale - Enhanced RBE has selected this treatment method for water quality control for the new PGIS associated with the project. Below is the summary of results from the WWHM water quality model. Bio-Retention Swale D3 – (See WWHM Data Output in Part 5.1 for Model Data) ____________________________________________________ 18025 Drainage Report 5.3-1 PART 5.3 – CONVEYANCE SYSTEM DESIGN Pipe Conveyance Design All onsite storm conveyance systems will be sized to accommodate the 25-year storm flows. All proposed onsite storm drain pipe will vary from 8 to 24 inches in diameter and the minimum slope shall not be less than 0.5%. Final conveyance pipe type and sizes will be provided in the final drainage report. ____________________________________________________ 18025 Drainage Report 6-1 PART 6 – SOURCE CONTROL BMPS The following permanent source control BMPs will be utilized for this project and will be included in the final Operation and Maintenance Manual submitted prior to final project acceptance by the County. Landscape and Lawn Vegetation Management ____________________________________________________ 18025 Drainage Report 7-1 PART 7 – CONSTRUCTION SWPPP A stand-alone SWPPP will be prepared for this project and submitted with the final drainage report. ____________________________________________________ 18025 Drainage Report 8-1 PART 8 – SPECIAL REPORTS AND STUDIES 1. Soils Report – Parnell Engineering, LLC ____________________________________________________ 18025 Drainage Report 9-1 PART 9 – OTHER PERMITS The following is a list of regulatory permits needed for this project and copies are attached if available. SEPA Review – Pending Determination Grading and Drainage – Pending Final Drainage and Grading Plans Building Permits – Pending Design and Permitting ____________________________________________________ 18025 Drainage Report 10-1 PART 10 – OPERATION AND MAINTENANCE MANUAL A final Operation and Maintenance Manual will be prepared during the final design of the drainage plan. It will follow the WSDOE guidelines. ____________________________________________________ 18025 Drainage Report 11-1 PART 11 – BOND QUANTITIES/FINANCIAL RESPONSIBILITY Facility agreements and financial guarantees when required will be reviewed by the applicant and executed at the appropriate time determined by the reviewing agency. ____________________________________________________ 18025 Drainage Report 12-1 PART 12 – GRADING AND DRAINAGE PLANS The half size drawing of the site civil grading and drainage plans are included on the following pages.