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tw <br /> PACIFIC groundwater GROUP <br /> W <br /> > ro <br /> O � <br /> 2 v <br /> cc <br /> Technical Memorandum o 0 <br /> 0- <br /> F- U w <br /> To: Thad Newport I City of Everett Engineering/Permit Services,425- 9 F W <br /> From: Janet Knox I Pacific Groundwater Group (PGG), 206-329-1893 ' E <br /> Re: Stormwater Site Plan and Drainage Report for Everett Steel Site $ 2 n o <br /> Date: August 21, 2019 E Ln z m <br /> v 0 <br /> E `C c ro 9 5 Z v d <br /> DRAINAGE REPORT EXECUTIVE SUMMARY o Q o o cc <br /> This drainage report summarizes the stormwater management plans for a cleanup project at the <br /> Everett Steel Scrapyard,including descriptions of how it will fulfill Minimum Requirements(MR) <br /> #1-5. The stormwater site plan for MR 1 is described entirely in this document, while the Storm- <br /> water Pollution Prevention Plan (SWPPP) for MR 2 is presented as a separate document (PGG <br /> 2019b). <br /> The site is predominantly flat with high infiltration capacity,and flow from or onto adjacent prop- <br /> erties is negligible. The cleanup will involve excavating contaminated soils and backfilling to <br /> grade, returning the site to its current drainage characteristics.No drainage system will be added <br /> to the site as infiltration is adequate to prevent stormwater runoff. <br /> MR 1 - STORMWATER SITE PLAN NARRATIVE <br /> PROJECT OVERVIEW <br /> This project is a soil excavation for environmental remediation at the Everett Steel Scrapyard site, <br /> as described in the Cleanup Action Plan(CAP) (PGG 2019a). The site is predominantly flat with <br /> high infiltration capacity, and flow from or onto adjacent properties is negligible. The excavation <br /> will be to a depth of 3 feet across most of the area,reaching 6 feet in a few sections. Excavation is <br /> planned for the late dry season when there will be only a very small chance of any precipitation <br /> and thus erosion control or ponding water. After the cleanup objectives have been achieved, the <br /> excavation will be backfilled to grade with gravel. As such, this project will have no long-term <br /> impacts on the drainage characteristics of the site. <br /> EXISTING CONDITIONS SUMMARY <br /> Total acreage: 2.97 1 .1 <br /> Disturbed acreage: 1.1 OCT - 1 2020 <br /> CITY OF EVERETT <br /> P 206.329.0141 F 206.329.6968 12377 Eastlake Avenue East I Seattle,Washington 98102 Aylvjacpices <br /> Water Resource &Environmental Consulting <br />