Erosion and Sediment Control Tip #24


 

Inlet protection at stormwater manholes (drop inlets):

One place on an active construction site that you definitely want to keep coarse particle sediment out of is the stormwater sewer manhole inlet.  Sediment in a storm sewer creates headaches. The Inlet Protection at these locations can be “built” or “bought”.  Built inlet protection as the term implies is constructed with conventional building materials and can be made from a silt fence like installation, straw wattles, sand bags, etc.  I’m not sure of how many “bought” or manufactured inlet protection devices there are for a manhole inlet, but one that you see a lot on construction sites is the domed inlet protection device by Silt Saver.  While this is not an endorsement of the product, I just want to make sure that everyone understands that there are still Do’s and Don’ts associated even with a simple and effective device like the domed inlet protection by Silt Saver. This device not only is effective if properly used but can  be re-used.  I reached out to Dave Goff of Silt Saver for some pointers and here are his thoughts:

 Do choose the correct frame based on the inlet size and shape.

  • Do select the correct filter based on the amount of water that can be safely impounded:
    • 2 Stage: To capture sediment and release stormwater
    • High Flow:  To avoid flooding roadways
  • Do ensure placement on a rigid surface or that the soil around the inlet is compacted
  • Do fill the rock bags completely with clean #57 stone preferably to ensure sufficient seal and ballast
  • Do reuse the frame to save money

Thanks Dave.

 

FYI – My Tips are also available as a Blog for those of you who Blog:

https://alsoilandwaterblog.blogspot.com/

 Clear Water Alabama 2022 will be near the Alabama Coast in the Fall.  Be on the lookout for a “Save The Date”.

 

Perry L Oakes, PE

Erosion and Sediment Control Program Coordinator

AL Soil and Water Conservation Committee

Desk (334) 887-4547

Cell (334) 703-6365

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