Treatment Control Measures
Stormwater treatment controls (also known as best management practices or BMPs) are structural or landscaped facilities designed to treat or remove pollutants in stormwater and/or reduce the volume or rate of stormwater. The major types of treatment controls include bioretention, vegetated swales, media filters, detention basins (dry and wet ponds), water quality wetlands and solids separators.
Stormwater treatment BMPs must be designed to treat a specified volume or flow of stormwater per permit requirements, depending on how they function. Volume-based BMPs detain stormwater for a certain period and treat primarily through settling and infiltration. Flow-based BMPs treat pollutants from a moving stream of water through filtration, infiltration, and/or biological processes.
The Program’s C.3 Stormwater Handbook provides information on the selection, use and sizing of stormwater treatment controls.