Detention ponds primarily manage stormwater quantity, but also somewhat contribute to treating the water quality. When it rains over a detention pond’s drainage area, the runoff water either travels to the pond across the land surface or is routed there by gutters or underground pipes. In some cases, the water is passed through a pretreatment wetland or sedimentation tank. These additional treatment cells are included to remove extra sediment and dissolved pollutants from the water. Once the water leaves these pretreatment cells, it then enters into the permanent pond and slightly raises the water level. Because they are a designated area for water storage, detention ponds prevent water from flooding in the community’s developed areas.