What is a Watershed

What is a Watershed

A watershed describes an area of land that contains a common set of streams and rivers that all drain into a single larger body of water, such as a larger river, a lake, or an ocean. Not only does water run into the streams and rivers from the surface of a watershed, but water also filters through the soil. Some of this water eventually drains into the same streams and rivers.

These two processes, surface runoff and infiltration, are important for a number of reasons, especially water quality. Naturally, the water that runs off the surface of the Earth picks up pollution and deposits it in streams and rivers as it drains from the watershed. These pollutants come from many sources, including agricultural, industrial, and commercial, along with many different types of pollution that are carried by surface runoff. Soil also becomes a water pollutant as it is eroded from construction sites and farm lands, for example. Water that filters through the soil can also become contaminated with these pollutants that are left over from the above sources and other types of human activity. 

The network of streams and rivers that drains our watershed can carry water pollution far away from the original source, contaminating larger bodies of water, such as lakes and oceans. Oceans of the world become the final resting place for tons of pollution, and this is why maintaining our watershed is so critical to our future. 

Delaware County Watershed

map of the Delco watershed

The Brandywine campus sits on the Chester Creek Watershed. On campus, you will see a stream which is a tributary to Rocky Run Creek which enters the east branch of the Chester Creek.

The East Branch of Chester Creek is 17.1 miles (27.5 km) long. Rising near Kirkland, it crosses under the junction of U.S. Route 202 and Pennsylvania Route 100. Just below, it is dammed to form the West Chester Reservoir. Flowing southward, it is dammed just above the Pennsylvania Route 3 crossing to form the Milltown Reservoir. It flows south from there to Westtown, where Goose Creek enters. The stream runs easterly about two miles, then turns south and passes a large stone quarry at Glen Mills. It turns southeasterly where Rocky Run joins the stream, passing through Darlington and Wawa and meeting the West Branch at Lenni. From there, Chester Creek proceeds to the Delaware River.