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i <br /> Stormwater Management Report Everett,WA <br /> I <br /> V. Analysis and Design of Required Runoff Control <br /> (Treatment and Stream Bank Erosion Control) BMPs <br /> The proposed improvements will consist of less than 5,000 sf of new impervious surface; <br /> therefore Stream Bank Erosion Control should not be required. However, due to the 4,382 <br /> sf of new impervious surface additional water quality volume is required. <br /> StormShed, as shown in Exhibit E, was used to calculate the required additional wet-pond <br /> volume. An area of 35,257 sf(0.81 ac) and a 6-month, 24-hour rainfall of 0.99 inches <br /> were used in this calculation. The precipitation is as noted in the Everett Stormwater <br /> Management Manual table 1-5.4. Using StormShed, we determined that an additional <br /> 2,305 cf of water quality volume is required. <br /> The existing water quality pond volume is 1,465 cf. The proposed wet-pond volume is <br /> approximately 4,025 cf, which gives an increase of approximately 2,560 cf. This increase <br /> • <br /> exceeds the required volume calculated above. <br /> See Exhibit C for Area Calculations <br /> See Exhibit D for Pond Calculations <br /> See Exhibit E for StormShed Calculations <br /> ' VI. Analysis and Design of Required Source Control BMPs <br /> The proposed development does not fit into any categories list in Table 1-4.1 and 1-4.2 in <br /> the City of Everett Stormwater Management Manual, dated January 1997. Based on these <br /> requirements, no source control should be required and therefore is not proposed. <br /> VII. Special Reports and Studies <br /> The project site does not include any environmentally sensitive areas, therefore no special <br /> reports or studies are required. <br /> lVlll. Other Permits <br /> The total disturbed area is less than an acre (Approx. 22,150 SF or 0.51 ac); therefore a <br /> NPDES permit is not required. In addition to the grading permit, this project will include <br /> permits to cover the tenant improvement to the existing building. <br /> IX. Miscellaneous Forms and Worksheets <br /> No other forms or worksheets are relevant the proposed project. <br /> X. Maintenance and Operation Requirements <br /> 1 PACLAND Job# 50183001 Page 4 <br />