Retention Basins reduce runoff during storm events
Retention Basins reduce runoff during storm events
As part of the permitting process, the Tennessee Department of Environment and Conservation mandates the City of Kingsport offer educational and outreach activities regarding stormwater, the city’s various control measures and why those measures are important to the general public.
The following article discusses retention basins and how they reduce runoff during storm events.
Retention basins, also called stormwater, wet, or water quality basins are a type of Stormwater Control Measure (SCM) that retains rain water and thus reduces runoff during storm events. Unlike detention basins, they have a permanent pool, which can serve as a wildlife habitat and an attractive amenity. Water quality is also improved through settling and biological uptake.
Most retention basins have the same basic components to help them function properly, including:
- Inlets – ditches or pipes that convey drainage into the ponds from the surrounding area during a rain.
- Forebay – shallow depression that catches trash, debris and sediment to keep it out of the main basin.
- Main Basin –collects and retains stormwater and may include plants to filter water pollution.
- Embankments –sides of the pond, usually vegetated to prevent erosion.
- Outlet Structure – allows water to exit the basin in a controlled manner.
- Emergency Spillway – allows water to safely overflow top of dam.
Retention basins may be inspected by the local municipality to ensure they are functioning correctly. However, all maintenance is the responsibility of the property owner.
In order for the retention basin to work efficiently, vegetation on embankments should be mowed at least twice a year and the vegetation should be thick and healthy and not include shrubs or trees. All trash, debris and sediment should be removed from the forebay at regular intervals. Any areas of erosion on the side slopes should be repaired.
The outlet structure should also be free of mud, debris and trash. Inlet pipes should be checked for clogs and inlet ditches should be checked for erosion. The basin should be observed during and after rain events to ensure it is functioning properly.
If you have a concern about a specific retention basin in Kingsport, you may call Water Services at 423-229-9454. You can also report any possible issues by using the ConnectKingsport app.
