10521 19TH AVE SE 2022-05-23 - Laserfiche WebLink

PUBLIC WORKS • Off -site Analysis Report: The Upstream Analysis on page 4 of the Drainage Report indicates that lawn and landscaped areas to the east of the site sheet flow toward the site. The proposed designs do not appear to address these off -site flows, nor account for them in the sizing of BMPs. Please delineate the contributing drainage area and account for all contributing drainage areas in the BMP sizing models. • Permanent Stormwater Control Plan: Include a new section of the Drainage Report under Minimum Requirement #1 titled "Permanent Stormwater Control Plan" and provide all of the information required per Section 3.1.5, Volume I of the SWMM in this section. • Special Reports and Studies: 1. The soils report and any other special reports or studies conducted to prepare the SSP should be included as an appendix to the Drainage Report. • Other Permits: 1. Include a list of other necessary permits and approvals as required, if those permits or approvals include conditions that affect the drainage plan, or contain more restrictive drainage -related requirements. If no other permits and approvals are required, state that in this section. • MR #3 — Pollution Prevention: As noted by the City in their July 7, 2017 letter to WEI, stormwater runoff from the dumpster area must be controlled and diverted from the storm drainage system. The revised plans include pre-treatment via a floatable material separator and gas trap and conveyance of the pre-treated runoff to the detention system via the storm drainage system. This does not comply with the requirements of the SWMM, which requires (Volume IV): Cover dumpsters, or keep them under cover such as a lean-to, to prevent the entry of stormwater. Replace or repair leaking garbage dumpsters. ■ Drain dumpsters and/or dumpster pads to sanitary sewer. Keep dumpster lids closed. Install waterproof liners. • MR #5 - On -Site Stormwater Management: BMP T5.13 Post Construction Soil Quality and Depth — Incorporate the guidelines for Option 4 from Building Soil; Guidelines and Resources for Implementing Soil Quality and Depth BMP T5.13 http://www.soilsforsalmon.ora/pdf/Soil BMP Manual.0 These guidelines should replace the guidelines in Appendix IV of the Drainage Report. Page 3 of 6