Typically a detention system temporarily holds stormwater so it can be slowly released at a predetermined rate. The stormwater can also be treated as part of the detention process as is the case with the patented Jensen Precast StormVault®.
Collecting rainwater from impervious surfaces and storing it for later use is a technique that has been used for a millennium. Since the U.S. has been identified as a country that faces imminent water shortages, the role that rainwater harvesting can play for water supply is being reassessed.
Bio-Retention areas, or rain gardens, are landscaping features adapted to provide on-site treatment of stormwater runoff. They are commonly located in parking lot islands, intersection traffic islands, roadway medians, near buildings with roof drains or within small pockets of residential land uses.