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BMP C220: Storm Drain Inlet Protection <br />Purpose To prevent coarse sediment from entering drainage systems prior to <br />permanent stabilization of the disturbed area. <br />Conditions of Use Where storm drain inlets are to be made operational before permanent <br />stabilization of the disturbed drainage area. Protection should be provided <br />for all storm drain inlets downslope and within 500 feet of a disturbed or <br />construction area, unless the runoff that enters the catch basin will be <br />conveyed to a sediment pond or trap. Inlet protection may be used <br />anywhere to protect the drainage system. It is likely that the drainage <br />system will still require cleaning. <br />Table 4.9 lists several options for inlet protection. All of the methods for <br />storm drain inlet protection are prone to plugging and require a high <br />frequency of maintenance. Drainage areas should be limited to 1 acre or <br />less. Emergency overflows may be required where stormwater ponding <br />would cause a hazard. If an emergency overflow is provided, additional <br />end-of-pipe treatment may be required. <br />Table 4.9 <br />Storm Drain Inlet Protetion <br />Applicable for <br />Type of Inlet Emergency Pavedl Earthen <br />Protection Overflow Surfaces Conditions of Use <br />Dro Inlet Protection <br />Excavated drop inlet Yes, Earthen Applicable for heavy flows. Easy <br />protection temporary to maintain. Large area <br />flooding will Requirement: 30' X 30'/acre <br />occur <br />Block and gravel drop Yes Paved or Earthen Applicable for heavy concentrated <br />inlet protection flows. Will not pond. <br />Gravel and wire drop No Applicable for heavy concentrated <br />inlet protection flows. Will pond. Can withstand <br />traffic. <br />Catch basin filters Yes Paved or Earthen Fre uent maintenance re uired. <br />Curb Inlet Protection <br />Curb inlet protection Small capacity Paved Used for sturdy, more compact <br />with a wooden weir overflow installation. <br />Block and gravel curb Yes Paved Sturdy, but limited filtration. <br />inlet protection <br />Culvert Inlet Protection <br />Culvert inlet sediment 18 month expected life. <br />tra <br />4-82 Volume ll — Construction Stormwater Pollution Prevenfion February 2005 <br />