7702 RAINIER DR 2022-04-05 - Laserfiche WebLink

Introduction This report has been prepared at the request of Kymera Construction in support ofa2-lot short Plat fora site located on the west side of Rainer Drive Everett,Washington in the NW'/4 ofthe SW'/4 Section 7, Township 28 North,Range 06 East W.M. The site address is 7702 Rainer Drive,Everett WA.(Parcel #003936-001-005-00) (Refer to Site Location and Vicinity Map). This report addresses the drainage report contents and organization of MR 1 to MR 9 per DOE 2014 Stormwater Management Manual as adopted by the City of Everett. Specifically we have designed the drainage using the LID applications as outlined in Volume 1, Chapter 2, Table 2.5.1 of the DOE 2014 Stormwater Management Manual. Project Overview The project consists of construction of a 2-lot short plat on a 0.45 acre site.The existing lot currently has an existing home and shop.The majority of the site cover is lawn and some trees.The existing frontage consists of 12-feet of pavement and 6-ft gravel shoulders.Located at the rear of the site is a buffer area the will be contained and a native growth protection area and protected from further development. Once developed,the site will add a new single family home and driveway, with a total of 4,995 sf of new impervious area in the form of2,450 sf for the home,walkway and patio.The parking and driveway will account for the 1,770 sf.And the half street improvements make up the remaining 775 sf.The existing home and shop will remain. Since the proposed site improvements are 4,995 sf in size and are under the 5,000 sf threshold, per Volume 1, Figure 2.1, flow control and water quality are not required and Low Impact Development standards utilizing a dispersal trench will be used to address drainage runoff from the site improvements. Half street frontage improvements on Rainer Drive in the form of 18-feet of pavement,curb,gutters and 5-ft sidewalks will be required The soils logs dug for the site, showed the upper portion of the site had brown sandy loam with evidence of mottling at about 31 inches and the lower half of the site was dark silt loam with seepage noted at 25-inches both areas were not suitable for infiltration. Conditions of Approval Summary The City will issue the Conditions of approval once the project has been reviewed and approved. Kymera 2-Lot SP Full Drainage Report Revised:April 21,2018 Page 2