Stormwater Share Print The City of Carson is part of the Dominguez Channel watershed. Its stormwater management is regulated by the Los Angeles Water Board and Carson is classified as a MS4, due to its medium-size municipal sewer system. Stormwater in Carson is caused by rain or excess water that flows over land, such as streets, parking lots, and building rooftops, and does not absorb into the ground. This runoff picks up pollutants such as trash, chemicals, oils, and dirt/sediment that can harm our ocean and coastline. The benefits of effective stormwater runoff management can include: Protection of wetlands and aquatic ecosystems Improved quality of coastal waters Conservation of water resources Protection of public health, and flood control