Erosion and Sediment Control Tip #50

 

Alabama’s new 2022 Blue Book contains some changes related to silt fences.  One change is that the silt fence should be designed for dewatering and potential overtopping. The silt fence at full capacity should dewater in 4 to 12 hours. An overflow should be included that conveys the peak discharge for the design event.  While there can be several methods to meet these requirements, one is shown in the picture by inserting an overflow and dewatering board at the lowest point in the fence.

 

Also, remember that a silt fence should pond the runoff water from its small watershed for the design storm event.

 

Perry L Oakes, PE

Erosion and Sediment Control Program Coordinator

AL Soil and Water Conservation Committee

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