Water that flows along the ground after a rainfall (or during snowmelt) is known as stormwater runoff. As it crosses roofs, roads, and parking lots, stormwater picks up pollutants like oil, pesticides, bacteria, sediments, and heavy metals. These pollutants are washed into the storm sewers, streams, and rivers that eventually drain into Casco Bay. Polluted runoff can contaminate drinking water, degrade water quality, impair fish and wildlife habitat, and reduce biological diversity.
Casco Bay Estuary Partnership. (2011). Minimizing Stormwater Pollution (Fact Sheet). Portland, ME: University of Southern Maine, Muskie School of Public Service, Casco Bay Estuary Partnership.