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t � <br /> Cooley Smiles Dental Clinic 17318.20 October 18,2017 <br /> Drainage Report Section II,Page 3 <br /> Minimum Requirement#7: Flow Control: Projects must provide flow control to reduce the impacts of <br /> stormwater runoff from hard surfaces and land cover conversions.The following circumstances require <br /> achievement of the standard flow control requirement for western Washington: <br /> i.) Projects in which the total of effective impervious surfaces is 10,000 square feet or more in <br /> a threshold discharge area, or <br /> ii.) Projects that convert 0.75 acres or more of vegetation to lawn or landscape, or <br /> iii.) Projects that through a combination of effective hard surfaces and converted vegetation <br /> areas cause a 0.15 cubic foot per second (cfs) increase or greater in the 100-year flow <br /> frequency from a threshold discharge area as estimated using the Western Washington <br /> Hydrology Model or other approved model and 15-minute time steps.The WWHM report <br /> for this project can be found in Section IV. <br /> The project requires flow control because the total of effective impervious surfaces is 10,000 sf or more <br /> in a threshold discharge area. See Section IV. <br /> Minimum Requirement#8:Wetlands Protection:This project site's stormwater does not discharge into <br /> a wetland and does not require wetland protection. <br /> Minimum Requirement#9: Operation and Maintenance:An operation and maintenance manual that is <br /> consistent with the provisions in Volume V of the SWMMWW is required for proposed Stormwater <br /> Treatment and Flow Control BMPs/facilities.The party (or parties) responsible for maintenance and <br /> operation shall be identified in the operation and maintenance manual. For private facilities approved <br /> by the City of Everett, a copy of the operation and maintenance manual shall be retained on-site or <br /> within reasonable access to the site, and shall be transferred with the property to the new owner. For <br /> public facilities, a copy of the operation and maintenance manual shall be retained in the appropriate <br /> department. A log of maintenance activity that indicates what actions were taken shall be kept and be <br /> available for inspection. See Section VIII. <br /> 250 4th Avenue South,Suite 200 <br /> Edmonds,WA 98020 <br /> ENGINEERING ph.425.778.8500 I f.425.778.5536 <br /> www.cgengineering.com <br />