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2010 SWMM MINIMUM REQUIREMENTS SUMMARY <br /> MR : MINIMUM REQUIREMENT <br /> SSP : STORMWATER SITE PLAN <br /> MR#1 PREPARATION OF STORMWATER SITE PLAN: <br /> Stormwater site plan follows the City of Everett 2010 Stormwater Management Manual & <br /> Public Work Policy # 2-11. <br /> MR#2 CONSTRUCTION OF STORMWATER POLLUTION PREVENTION <br /> PLAN (SWPPP): <br /> Refer to section IV for SWPPP. <br /> MR#3 SOURCE CONTROL OF POLLUTION: <br /> Onsite BMP's will be used to minimize the source pollutant sources that include <br /> parts/vehicle cleaning, spills/leaks of fuel and other liquids, replacement of liquids, outdoor <br /> storage of batteries/liquids/parts, and vehicle parking. <br /> MR#4 PRESERVATION OF NATURAL DRAINAGE SYSTEMS AND <br /> OUTFALLS: <br /> The developed site drainage will be discharged into the existing combined sewer system <br /> that drains to the west within a closed pipe system to follow its natural drainage path. <br /> MR#5 ONSITE STORMWATER MANAGEMENT: <br /> Per Minimum Requirement#5 (Section 2.2.5 of the SWMM), the following BMP's shall <br /> be applied to provide onsite stormwater management and must be considered in the <br /> following order: On-site infiltration areas, Raingardens and then Downspout dispersion. <br /> Infiltration/Bioretention is not recommended because the site contains soils that would not <br /> infiltrate well and the contributing impervious area is more than 2,000 SF. Downspout <br /> Dispersion is not feasible because the required vegetated flow path required by the BMP <br /> could not be met. Onsite stormwater management for the roof and driveway area will be <br /> provided by a Stormtank system that will outlet into the City's combined sewer system. <br /> MR#6 RUNOFF TREATMENT: Water quality is exempt per volume 1 section 2.2.6 of <br /> the City of Everett Stormwater Management Manual because the PGIS is less than the <br /> threshold area of 5,000 SF and also per Public Work Policy#2-11 as it falls in the combined <br /> sewer area. <br /> MR#7 FLOW CONTROL: Flow control for the roof and driveway area will be provided <br /> by a Stormtank system located beneath the proposed building. The Storm tank system will <br /> have ST-36 tanks for a total depth of 3-feet and a 1 ft stone storage around the storm tank. <br /> Storm tank will provide a total volume of 7,880 CF. The outlet from the stormtank will be <br /> connected to the combined sewer system that drains to the west. <br /> Insight Engineering Co. -Stormwater Site Plan 09/10/18 <br /> -5 - <br />