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New pipe outfalls can provide an opportunity for low-cost fish habitat <br />improvements. For example, an alcove of low -velocity water can be <br />created by constructing the pipe outfall and associated energy <br />dissipater back from the stream edge and digging a channel, over - <br />widened to the upstream side, from the outfall. Overwintering juvenile <br />and migrating adult salmonids may use the alcove as shelter during <br />high flows. Bank stabilization, bioengineering, and habitat features <br />may be required for disturbed areas. This work may require a HPA. <br />See Volume V for more information on outfall system design. <br />Maintenance • Inspect and repair as needed. <br />Standards . Add rock as needed to maintain the intended function. <br />• Clean energy dissipater if sediment builds up. <br />BMP C220: Storm Drain Inlet Protection <br />Purpose Storm drain inlet protection prevents coarse sediment from entering <br />drainage systems prior to permanent stabilization of the disturbed area. <br />Conditions of Use Use storm drain inlet protection at inlets that are operational before <br />permanent stabilization of the disturbed drainage area. Provide protection <br />for all storm drain inlets downslope and within 500 feet of a disturbed or <br />construction area, unless conveying runoff entering catch basins to a <br />sediment pond or trap. <br />Also consider inlet protection for lawn and yard drains on new home <br />construction. These small and numerous drains coupled with lack of <br />gutters in new home construction can add significant amounts of sediment <br />into the roof drain system. If possible delay installing lawn and yard drains <br />until just before landscaping or cap these drains to prevent sediment from <br />entering the system until completion of landscaping. Provide 18-inches of <br />sod around each finished lawn and yard drain. <br />Table 4.2.2 lists several options for inlet protection. All of the methods for <br />storm drain inlet protection tend to plug and require a high frequency of <br />maintenance. Limit drainage areas to one acre or less. Possibly provide <br />emergency overflows with additional end -of -pipe treatment where <br />stormwater ponding would cause a hazard. <br />• <br />Volume II — Construction Stormwater Pollution Prevention - August 2012 <br />4-79 <br />