New development requires the management of stormwater. Depending on the size of development, different types of Best Management Practices are employed. The following is a list of commonly used Best Management Practices used to control stormwater.
Retention Facilities permanently pond water. Stormwater is stored above the permanent pool elevation. Water quality is improved because pollutants can precipitate from water before discharging.
Detention Facilities, also known as dry ponds, become dry within 24 hours of a storm event.
Extended Detention Facilities store the first flush of rainfall for a period of time usually between 24 and 72 hours. After 72 hours, the facility should be dry.
Infiltration Basins and Infiltration Trenches allow runoff to percolate through the ground, thereby recharging groundwater instead of allowing water to flow off site. Infiltration rates can be affected by the type of soil present on site.
Underground Facilities can be used for infiltration, extended detention or detention. Underground facilities are typically used in commercial development where tight site constraints do not allow areas to be designated solely for stormwater management.
Bioretention Facilities are water quality and quantity control practices that use natural processes to remove pollutants from stormwater. Water is filtered through natural medium and once the water holding capacity is reached, water will begin to pool above ground.
Grassy Swales prolong the flow path of water, which can reduce the peak discharge of water leaving the site and improve quality.
Rain barrels are systems that collect and store water from a roof that would otherwise be lost as runoff.