515 SE EVERETT MALL WAY BASE FILE 2016-01-01 MF Import

c �. 2. Treatment of stormwater runoff from paved areas must occur, per City standazds, prior to dischazge of the stormwater from the site •or to a stream or wetland. Stormwater veatment is required when 5,000 squue feet of new or redeveloped pavement results from the project. The options for stormwater treatment for this project are: a) a wetpond; b) a consuucted wetland; or c) a SMI StormFilter (see additiona] criteria below). SMI StormFilter: The City will allow the use of a Stormwater Management, Inc. (SMn StormFilter to meet the City's stormwater treatment standuds, provided the design and construction of the SMI StormFilter meet the following critcria: „- a) The StormFilter must be preceded by a pretreatment wetvault/tank containing at least 30% of the 6- month, 24-hour storm runoff volume from the contributing, developed drainage area. b) The StormFilter must treat at least the 6-month, 24-hour storm. c) The StormFilter shall be designed using a maximum flow rate of 7.5 gpm per cartridge. Flows exceeding the design flow shall be bypassed azound the system, but should generally pass through the pretreatment wetvaulUtank. d) The StormFilter media shall target dissolved pollutants and nutrients as well as total suspended solids. As more effective media become available in the future, the StormFilter shall be upgraded, during routine cartridge replacement, to utilize the improved media. e) The StormFilter shall be designed with a minimum of 2.3 feet of head differendal between the inverts of the inlet and outlet of the filter. Uownstream hydraulic calculations will be performed to demonsuate that downstream conditions will not reduce the hydraulic potential across the Filter due to backwater effects. � Routine maintenance of the StormFilter is required. A detuled operation and maintenance plan for the system must be prepared for approval by the City. A certificate of system maintenance must be submitted to the City annually. g) Maintenance and operation of the StormFilter on this site shall be adapted in the future, to reflect the current knowledge regarding this emerging !.echnology. h) All other applicable, and non-conflicting, criteria in the current edition of SMI's Product Design Manual shall be followed in the design, construction, and maintenance of the SMI StormFilter on this site. (SEPA Water Policies) Everett Mall Way is designated as a"Gateway" corridor in the City's General Plan. The General Plan states, "Because Everett wants to develop and promote an attractive image, all entry corridors into the City should be designated as "Gateways" and standazds should be applied to developments along such "Gateways" relating to building design, landscaping, signage, outdoor storage and other aesthetic