The Brandywine Watershed covers 330 square miles beginning in the Honey Brook area of northern Chester County including Coatesville, Downingtown, West Chester and the central part of Chester County and ending in Wilmington, Delaware where it joins the Christina River.  The source of the Brandywine Creek is in the Welsh Hills near Honey Brook.  Both the east and west branches begin in that area.  From top to bottom the stream traverses about 60 miles.  The west branch flows through the City of Coatesville, the east branch through the Borough of Downingtown.  The two branches join at Lenape and flow southward as the main stem through Chadds Ford, crossing the Delaware state line and on to Wilmington.

The Brandywine Watershed is the home to over 300,000 people.  About 85% of the watershed is in Chester County, Pennsylvania and the lower 15% in New Castle County, Delaware. 

The Brandywine Creek supplies the drinking water for the City of Wilmington, Coatesville, Downingtown, West Chester and areas surrounding those cities and boroughs. On an average day about 30 million gallons are taken from the Brandywine Creek for residential, commercial and industrial use. 

There are three major wastewater treatment plants in the watershed at Downingtown, Coatesville and West Chester.  These three plants along with several smaller plants and an industrial treatment plant at the ArcelorMittal Steel facility in Coatesville treat about 11 million gallons daily.

Flows in the Brandywine Creek vary throughout the year.  Levels at Chadds Ford can range from over three hundred million gallons a day in the higher flow seasons during the spring to less than 50 million gallons a day during low flows in late summer.  Streamflows can be augmented by discharges from Marsh Creek Reservoir and Chambers Lake.  Under normal flow conditions treatment plant effluent makes up three to five percent of the streamflow and during the extremes of historic low flow about 30 percent. 

The Brandywine Creek provides recreation for fishermen as well as water for canoeing and kayaking.  The Brandywine is stocked by the Pennsylvania Fish Commission in the spring at a number of locations.  In addition, local sportsman’s groups also work to improve stream quality and provide fish for stream stocking.

The Brandywine Watershed has been a showcase for conservation programs which BVA began in 1945.  Farmers employ modern conservation practices, industries have been leaders in reducing water use and treating wastewater, spray irrigation was introduced into the watershed in 1972 and is now found in many municipal and private systems throughout the valley.  In 1955 BVA initiated the planning which resulted in the Brandywine Watershed Work Plan for flood control and water supply.  The resulting structures include Marsh Creek Reservoir, Chambers Lake and flood control dams at Struble Lake, Barneston and on Beaver Creek.  These dams have helped to reduce the extremes of flooding and drought in the Brandywine Watershed.  

Today BVA continues its mission through the Red Streams Blue Program and with its watershed education programs.  The Red Streams Blue Program will help raise the quality of substandard streams and the watershed education programs will bring the message of conservation to the next generation of decisionmakers, our school students.