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9 <br /> facilities prior to modification, bypassing of facilities during modification, and construction <br /> timing criteria as applicable. (SEPA Water Policies) <br /> 14. Pollutant source control for the fueling facilities shall be required in accordance with City <br /> standards. (SEPA Water Policies) <br /> 15. The design and construction of the SMI StormFilters shall meet the following criteria: <br /> i. The StormFilter must be preceded by a pretreatment wetvaultltank containing <br /> at least 30% of the 6-month, 24-hour storm runoff volume from the <br /> contributing, developed drainage area. <br /> ii. The StormFilter must treat at least the 6-month, 24-hour storm. <br /> iii. The StormFilter cartridges shall be designed with a maximum flow rate of 7.5 <br /> gpm per cartridge. Flows exceeding 7.5 gpm shall be bypassed around the <br /> system, but should generally pass through the pretreatment wetvault/tank. <br /> iv. The StormFilter media shall target dissolved pollutants and nutrients, in <br /> addition to total suspended solids. As more effective media become available <br /> in the future, the StormFilter shall be upgraded, during routine cartridge <br /> replacement, to utilize these improved media. <br /> v. The StormFilter shall be designed with a minimum of 2.3 feet of head <br /> differential between the inverts of the inlet and outlet of the filter. <br /> Downstream hydraulic calculations will be performed to demonstrate that <br /> downstream conditions will not reduce the hydraulic potential across the filter <br /> due to backwater effects. <br /> vi. Routine maintenance of the StormFilter is required. A detailed operation and <br /> maintenance plan for the system must be prepared for approval by the City. A <br /> certificate of system maintenance must be submitted to the City annually. <br /> vii. Maintenance and operation of the StormFilter on this site shall be adopted, in <br /> the future, to reflect the current knowledge regarding this emerging <br /> technology. <br /> viii. All other applicable, and non-conflicting criteria in the current edition of <br /> Semi's Product Design Manual shall be followed in the design, construction <br /> and maintenance of the SMI StormFilter on this site. <br /> ix. For StormFilters located downstream of detention systems, the SMI mass <br /> loading design procedure, with the following assumptions, shall be utilized: <br /> 1. TSS removal required = 80% <br /> 2. Vb=the volume of dead storage plus the 7-day average live storage <br /> volume from the routing of the 6 month, 24-hour storm through the <br /> detention system (if a 7-day routing is not available,us Vb=volume <br /> of dead storage) <br /> 3. Vr=the runoff volume from the mean annual storm(use precipitation <br /> volume of 0.48 inches) <br /> 4. Depth of water in basin, H = depth of Vb <br /> 5. Mean annual rainfall = 37 inches <br /> 6. Percent runoff capture =90% <br /> J 7. Event Mean Concentration (EMC) = 100mg/L <br /> EXHIBIT # <br /> PAGE OF (( <br />