Using Skimmers in Sediment Basins and Post-construction Stormwater Ponds to Improve Water Quality
Date & Time
Tuesday, September 27, 2022, 1:30 PM - 2:00 PM
Brian Free

The Construction General Permit (CGP) requires permittees to control stormwater volume and velocity while minimizing sediment discharges from their site. The CGP also states, “When discharging from basins and impoundments, permittees are required to utilize outlet structures that withdraw water from the surface.” Floating surface drains, commonly referred to as skimmers meet this requirement and are an important component in sediment basins for reducing sediment discharge and slowing peak flows from construction sites. The skimmer floats on the surface of the sediment basin as it fills and drains, releasing the cleanest water in the basin instead of draining from the bottom and releasing the dirtiest water as conventional outlets do. The skimmer drains the basin slowly over several days and at a constant rate to maximize settling. University research shows that incorporating skimmers into properly designed sediment basins can reduce suspended sediment discharges upward of 95% when compared to traditional basin designs utilizing bottom drains or perforated risers. Skimmers help improve water quality and achieve regulatory compliance in sediment basins during construction as well as post-construction stormwater ponds.

Location Name
National Harbor 6