What is a Watershed?
A watershed (also called a drainage basin) is an area on the land surface from which water flows or has the potential to flow into a stream or lake. Watersheds are naturally separated from adjacent basins by topographic divides.
Watershed Basics
Houses, open fields, office buildings and forests are all part of a watershed. While every inch of land belongs to a complex, physical network of watersheds, the natural high areas of land describe a watershed's boundary. High and low points of the land determine how rain water that falls onto tree leaves and rooftops eventually finds its way into our waters.
Because we all belong to a watershed, our actions affect the health of our watershed. Common activities like walking the dog, taking care of the lawn and driving the car leave behind pollutants. As rain water moves through the watershed, it picks up bacteria and chemicals, and carries them to our streams, rivers, lakes and coasts. Improper disposal of motor oil, pet waste and overfertilization of a lawn all contribute to this pollution. Because of its many random sources, we all share responsibility for this pollution, called nonpoint-source pollution.