What is the difference between a retention pond and detention pond?
A retention system is designed to store runoff for about 72 hours. A dry detention system is normally dry and holds stormwater runoff long enough for it to be slowly released into an adjacent water body. A wet detention system or pond is designed to allow material to settle and be absorbed. After a storm, water slowly drains from the pond through a pipe in the “out flow” structure. Part of the pond – known as the permanent pool – is always below the level of the drain structure. Sometimes aquatic plants are planted around the pond’s perimeter to help filter sediment in stormwater runoff.
