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1 <br /> EXECUTIVE SUMMARY <br /> ' The project site comprises 0.64 acre of an existing gas station, car wash, and convenience store site that <br /> will be redeveloped into the same use without the car wash. This project will comply with all Nine <br /> Minimum Requirements of the City of Everett Stormwater Management Manual. <br /> Minimum Requirements Nos. 1 through 5 are all complied with; this document hereby meets the <br /> requirements of a Stormwater Site Plan and a Construction Stormwater Pollution Plan is provided in <br /> ' Section 6.0 of this Stormwater Site Plan. <br /> This is a commercial gas station and convenience store project; therefore, source control of pollution is <br /> required. The under canopy fueling slab will be isolated and equipped with an oil/water separator with an <br /> ' emergency gate valve in the event of spills. During construction several Flow Control BMPs will be <br /> utilized, including sediment traps, silt fence, temporary V-ditches, rock check dams, clearing limits will be <br /> marked, a rock construction entrance will be installed, dust control requirements will be followed during <br /> ' the drier summer months of construction, and mulching, seeding, and sodding of disturbed areas will be <br /> followed with this project. <br /> This project falls within a combined sewer area and will discharge to the same downstream drainage <br /> ' course it does under existing conditions. The on-site soils are not conducive for infiltration; therefore, a <br /> biofifter cell with overflow to address low-impact design requirements is proposed. <br /> ' In addition to the initial Five Minimum Requirements, the remaining Minimum Requirements 6 through 9 <br /> are followed with this project. Water quality is not required for this project based on the current City <br /> standards because the site falls within a combined storm and sewer service area. Flow control is not <br /> provided because the proposed development does not increase the amount of impervious area on the <br /> ' site. An Operations and Maintenance Manual has been prepared and is included in Section 9.0 of this <br /> report. <br /> ' The downstream drainage course from this project site is the public combined sewer and storm system <br /> located in the alley to the north of the site. The public combined sewer conveyance system continues <br /> east for over one-quarter mile. There were no problems discovered in the downstream drainage course. <br /> Please refer to the off-site analysis in this report for further description of the downstream drainage <br /> ' course. <br /> There is no upstream basin contributing to the developed areas on site as the surrounding areas on the <br /> north and east sides of the site drain to away from the site and the contributing areas from the west and <br /> ' south are fully improved streets containing a public collection and conveyance drainage system. <br /> The Rational Method was utilized in sizing the conveyance elements on this project site which is a <br /> conservative methodology. All runoff was conveyed without surcharging any manholes. Please refer to <br /> the later sections of this report for the conveyance sizing. <br /> 1 <br /> 1 <br /> ' 16580.007.doc <br />