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1. PROJECT OVERVIEW <br /> This document is intended to provide engineering information necessary to support the <br /> building permit application to the City of Everett for the addition proposed on this lot. The <br /> site is located,.at 620 Waverly Ave, Everett, WA 98203; refer to Figure 1 for a vicinity map. <br /> This project will take access from the existing roadway to the east (Waverly Ave). The <br /> parcel area is approximately 0.14 acres. The existing site, in the area of disturbance <br /> consists of lawn. The slope of the site in the area of disturbance is mild and averages <br /> approximately 4 percent down to the southwest. The new addition will be located <br /> approximately 5 feet from the southern property line and 105 feet from the western <br /> property line. <br /> Figures 2 & 3 are provided to show the existing and developed basins and runoff <br /> conditions for this site. The runoff in the existing conditions sheet flows gradually over <br /> vegetated surfaces to the southwest toward the south property line. <br /> The drainage design has been laid out per the DOE 2019 Stormwater Management <br /> Manual for Western Washington (SWMMWW), as well as Chapter 4 of the City of <br /> Everett's current Design and Construction Standards and Specifications for Development <br /> (COE DCSSD) manual. This project is located within the 'Combined Sewer Area' of the <br /> City of Everett and has thus been designed to meet the requirements stated in Section 6- <br /> 10.1 of the COE DCSSD. This project proposes to construct approximately 388 sf of <br /> impervious surfaces on site. Due to the size of this project, Minimum Requirements 1-5 <br /> apply to all of the new plus replaced impervious surfaces, as well as any converted <br /> pervious surfaces. Also, because the project site is located within the combined sewer <br /> area of the City and is proposing more than 200 sf of impervious surfaces, Minimum <br /> Requirement #7 (Flow Control) also applies. Stormwater management will be met using <br /> an engineered underground detention system. There will not be any pollution-generating <br /> impervious surfaces proposed for this project. Thus, runoff treatment is not required. <br /> Lalone Addition 20-0902 <br /> October 2020 Page 3 <br />