What is the purpose of retention basins in relation to stormwater management?

The purpose of retention basins in stormwater management is primarily to capture stormwater on-site. These basins are designed to hold water during and after rainfall events, allowing it to gradually infiltrate into the ground or evaporate, rather than allowing it to flow quickly into nearby water bodies or drainage systems. By capturing stormwater on-site, retention basins help control runoff volume and reduce the risk of flooding, as well as promote the infiltration of stormwater, which can support groundwater recharge.

This on-site capture is crucial for managing the quality and quantity of stormwater, as it can significantly reduce the pollutants that enter local waterways by allowing sediment and nutrients to settle out of the water before it moves off-site. Retention basins, therefore, serve a vital ecological function, supporting both stormwater management and water quality improvement in the landscape.