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CITY OF EVERETT STORMWATER MANAGEMENT MANUAL <br /> 3. Clean energy dissipater if sedimcnt builds up. i <br /> 3.3.11 BMP C220: Storm Drain Inlet Protection <br /> Purpose is[o prevent coarse sediment from cntering drainage systems prior to pertnanent stabiliution of <br /> thc disturbed arca. <br /> Conditions of Use <br /> For use where sto[m dcain inle�s are to be made operational before permanent stabilization o(the <br /> dishubed drainage area. Protection should be provided for all srortn draiu inlcts downslape and wi�hin <br /> 500 feet of a disturbed or construction aeea,unlcss the cunoff that enters the catch basin will be canveycd <br /> to a sediment pond or trap. Inlet protection may be used anywhere to protect the drainage system. It is <br /> likely that the drainage system will sNll require cleaning. <br /> Table 3.9 lists several options for inlet proteceon. All of the methods for stortn drain inlet protection are <br /> prone to plugging and requirc a high frequency of maintenance. Drainage azeas should be limited to <br /> 1 acre or Icss. Emergency overtlows may be required where stortnwater panding would cause a hazard. <br /> If an emcrgency overtlow is provided,addilional end-of-pipe treatment may be rcquired. <br /> Table 3.9 Storm Draln Inlet Protection <br /> Appllaable for <br /> Emargeney PavedlEaRhen <br /> Type of Inlet Protection Overflow Sutfreas Condltions of Use <br /> Drop Inlel Protection <br /> Excavated drop inlet Yes,temporary Earthen Applicable for heavy flows. Easy <br /> protection flooding will to maintain. Large area <br /> occur Requirement:30 x 30-feeVacre <br /> Block and gravel drop inlet Yes Paved or Applica6le for heavy concentrated <br /> protection Earthen Bows. Will not pond. <br /> Gravel and wire drop inlel No Applicable for heavy concentrated <br /> prntection flows. Will pond.Can withstand <br /> traffic. <br /> Catch basin filters Yes Paved or Frequenl maintenanca required. <br /> Earfhen <br /> Curb Inlel Protection , <br /> Curb inlel protection wilh a Small capaclly Paved Used for sturdy,more compact <br /> wooden weir overilow installalion. <br /> Block and gravel curb inlet Yes Paved Sturdy,bul limiled filtration. <br /> protection <br /> Culvert Inlet Proleclion <br /> Culvert inlel sediment trap 1B monlh expecled liFc. <br /> Design and Insfaflation Speci/ications <br /> I. Excavated Drop In(et Protec[ion—An excavatcd impoundment around thc stortn drain. Sediment <br /> settles out of the stortnwater prior to entering the sromi drain. <br /> a. Depth I to 2 fcet as measured from the crest of the inlet sttucture <br /> b. Side slopes of excavation no stecper than 2:1 <br /> Volume ll—Construction Sformwater Pollution Preventron <br /> 3•49 <br />