Stormwater runoff is a significant source of water pollution in urbanizing areas. In addition, the increased volumes of flow resulting from added impervious areas during urbanization results in increased runoff volumes. Detention ponds mitigate both scenarios in providing a treatment basin for pollutant removal as well as a collection basin to detain the larger flows and thus reduce the peak runoff rates downstream. Properly maintained detention ponds can be very effective at removing certain pollutants and providing necessary storage volumes during larger storm events. Improperly maintained ponds can increase the discharge of pollutants downstream, increase the risk of flooding downstream, increase the instability of downstream channels, and lead to aesthetic and nuisance problems.