Detention Basins are bermed or excavated areas designed to temporarily detain runoff to allow sediment and particulates to settle out prior to runoff being discharged. Detention Basins treat runoff through sedimentation and infiltration when the basin is unlined. A Detention Basin may also be known as a detention pond.

For a dry basin or extended detention basin, the control elevation of the single outlet, or lower outlet, is set at the bottom elevation of the structure. The size of the pipe/weir serves to control the outflow rate as a function of the pool elevation (head) above the pipe inlet/weir.

Dry detention ponds (also called dry ponds, extended detention basins, detention ponds and extended detention ponds) are basins that detain stormwater for some minimum time (e.g., 24 hours) to allow particles and pollutants to settle and reduce peak flow rates.

All detention basins are designed with a secondary outlet, sometimes called an emergency or auxiliary spillway. The secondary spillway is provided to convey the release of the maximum runoff discharge for the 100-year storm event.

Minimize demolition in and grading of the sub-basin by designing detention facilities to enable a retrofit and reuse of an existing 54-inch storm sewer.

design of pond BMPs for environmental protection purposes. Pond BMP types are grouped into three categories: 1) dry detention basins including extended detention basins, 2) wet basins including both retention ponds and wetland ponds, and 3) infiltration basins. This volume provides specific design criteria for stormwater treatment by these types of

Detention basin is designed for the entire upstream watershed area, including the future development flows from offsite areas without providing credit to offsite detention facilities.

Description: Retention basins are a best management practice intended to mitigate storm water runoff. Essentially, water is detained in the basin while pollutants are treated by natural processes and water exits the basin slowly over time, or during the next storm.

This presentation covers the design of detention basins, including treatment goals, preliminary sizing, siting analysis, shape and detailed sizing, water quality outlet, primary outlet, overflow weir, and other considerations.

Wet detention basins are constructed stormwater basins that have a permanent pool or micropool of water. Runoff from each rain event is detained above the permanent pool and released at a designed flow rate to reduce downstream water quantity impacts.