7702 RAINIER DR 2022-04-05 - Laserfiche WebLink

Minimum Requirement #5 On-Site Stormwater Management As discussed above, stormwater will be managed through the use of On-Site Stormwater Management Requirements" using "Low Impact Development Performance Standards" specifically using List 2 of the DOE 2014 Stormwater Management Manual,Volume 1, Chapter 2,Table 2.5.1, and BMP T5.13 to address stormwater runoff. Under Minimum Requirement 5, the site requires the use of various on-site stormwater management BMPs provided they are not infeasible according to criteria set forth in this manual. Volume I,Chapter 2 sets forth the selection process for these BMPs. Volume III, Chapter 3 contains specific information for the following on-site stormwater management BMPs and the following BMP's were reviewed and analyzed for use: TABLE 2.5.1 LIST#2 BMP FEASIBILITY Lawn and landscaped areas: 1. Post-Construction Soil Quality and Depth in accordance with BMP T5.13 in Volume V, Chapter 5 of this manual (Will be used) Roofs: 1. Full Dispersion in accordance with BMP T5.30 in Volume V,Chapter 5 of this manual, or,for single- family residential roofs and commercial roofs determined by City of Everett to have similar runoff pollution characteristics to single-family residential roofs, Downspout Full Infiltration Systems in accordance with BMP T5.l OA in Volume III, Chapter 3 of this manual(Not feasible due to soils logs at the rear of the site which show a dark silt loam with seepage noted at 25 inches and is not suitable for infiltration) 2. Bioretention in accordance with Volume V, Chapter 7 of this manual. (Not feasible due to soils logs at the rear of the site which show a dark silt loam with seepage noted at 25 inches and is not suitable for infiltration) 3. For single-family residential roofs and commercial roofs determined by City of Everett to have similar runoff pollution characteristics to single-family residential roofs, Downspout Dispersion Systems in accordance with BMP T5.10B in Volume III, Chapter 3 of this manual. (A dispersal trench will be used) 4. For single-family residential roofs and commercial roofs determined by City of Everett to have similar runoff pollution characteristics to single-family residential roofs, perforated Stub-out Connections in accordance with BMP T5.10C in Volume III,Chapter 3 of this manual. (N/A) Other Hard Surfaces: 1. Full Dispersion in accordance with BMP T5.30 in Volume V,Chapter 5 of this manual.(Not feasible due to site constraints and evidence of mottling at 28 to 30-inches). 2. Permeable pavement in accordance with BMP T5.15 in Volume V,Chapter 5 of this manual. NOTE: This is not a requirement to pave these surfaces. Where pavement is proposed,it must be permeable to the extent feasible unless full dispersion is employed. (Will be used). Kymera 2-Lot SP Full Drainage Report Revised:April 21,2018 Page 10