Detention Basins
Acknowledgement: http://www.ecn.purdue.edu/runoff/ubmp0/detention_systems.htm
Where there is possibility of past discharges of hazardous substances to the environment, and where a detention basin exists in the vicinity of the investigated locale, we sample at the basin to find clues to the problems that may have occurred.
Detention basins are designed to intercept a volume of storm water, temporarily impound the water and release it shortly after the storm event.
The main purpose of a detention basin is quantity control by reducing the peak flow rate of storm water discharges.
They are designed to not retain a permanent pool volume between runoff events. and most basins are designed to empty in a time period of less than 24 hours.
The treatment efficiency of detention basins is usually limited to removal of suspended solids and associated contaminants due to gravity settling.
The efficiency can be increased by incorporating a forebay or pre-settling chamber for the accumulation of coarse sediment, facilitating periodic cleaning in order to prevent washout by subsequent runoff events.
Detention basins can limit downstream scour and loss of aquatic habitat by reducing the peak flow rate and energy of storm water discharges to the receiving stream, but their removal of pollutant of potential water quality concern can be limited. |
