Stormwater runoff collects pollutants, chemicals and debris as it flows over paved surfaces and into water bodies. Retention ponds or "wet ponds" are ponds constructed to treat and store stormwater runoff. Retention ponds are permanent pools of standing water and eventually empty into a receiving water body.
What is a retention system?
Retention System means a system, which retains runoff in a controlled manner through the use of storage facilities. Stored runoff is evacuated by percolation and evaporation.
What is water retention system?
Retention systems are closed systems, constructed so that storm water does not reach natural water bodies. Stormwater swale. Swales are either man-made or natural areas shaped to allow water to be quickly absorbed into the ground or to allow the water to flow to other waterways.
What is the difference between stormwater retention and detention?
By definition, a detention BMP is an area where stormwater is temporarily stored, or detained, and is eventually allowed to drain slowly when water levels recede in the receiving channel. On the other hand, retention stormwater BMPs hold or retain stormwater on a more permanent basis.Jun 4, 2020
What is the difference between detention and retention?
A detention, or dry, pond has an orifice level at the bottom of the basin and does not have a permanent pool of water. A retention basin or pond has a riser and orifice at a higher point and therefore retains a permanent pool of water.
What is the difference between detention time and retention time?
Detention and retention both refer to storing rain water on-site during a storm event, when the risk of flooding is highest. The difference is that when water is detained, it is slowly released into a stream or river and leaves the site. Retention is achieved in green-infrastructure such as rain gardens or bio-swales.
What is stormwater detention?
Detention consists on storing stormwater and releasing it at a controlled rate into the sewage systems. Retention consists on storing stormwater for on-site use or disposal. Two common disposal methods are evaporation and soil infiltration.
How do storm water retention tanks work?
Stormwater detention tanks are intended to remain empty, except during periods of rainfall and for a short time thereafter. Unlike normal rainwater tanks, the distinguishing feature of a stormwater detention tank is that it is specially fitted with a valve to slowly release water over time.
What is a stormwater retention tank?
Storm water retention tanks act as a buffer during periods of heavy rainfall. This is increasingly important as areas become more developed, with hard surfaces such as roofs, roads and parking lots that cannot absorb the rainwater.
How does a detention tank work?
Essentially, stormwater detention is slowing water down so that the peak of the storm is reduced. This means that the intensity of the water rushing to the ground, or into the sewer systems is reduced, which allows for better soil percolation and significantly reduces the pressure on the sewer systems.
What is difference between retained and detained?
As verbs the difference between retain and detain is that retain is (transitive) to keep in possession or use while detain is keep (someone) from proceeding by holding them back or making claims on their attention.