A sand filter is a device that allows stormwater to percolate down through a sand media where pollutants are filtered out.
Sand filters are designed primarily for water quality enhancement; flow volume control is typically a secondary consideration. They are generally applied to land uses with a large fraction of impervious surface. Although an indivudual sand filter can only handle a small contributing drainage basin, multiple units can be dispersed thoughout a large site.
O&M_Sand Filter Operation and Maintenance Agreement_Rev 3 [pdf/61kb/3p]