A watershed is an area of land where all rainwater and snowmelt run downhill to the same place. A watershed can be as small as the creek in your backyard that drains only a few acres or as large as the Chesapeake Bay watershed, which drains 64,000 square miles.
Four of Virginia’s 14 major watersheds drain to the Chesapeake Bay: the Potomac, the Rappahannock, the York and the James. The Rivanna River Watershed, part of the James River Watershed, is located in Central Virginia and drains approximately 766 square miles of the eastern foothills of the Blue Ridge Mountains. Portions of Albemarle, Green, Fluvanna, Louisa and Orange Counties, as well as the entire City of Charlottesville, are part of the Rivanna River Watershed.
When it rains, pollution that may be carried into a stream in one part of a watershed will affect all of the the waterways downstream within that watershed. When land is developed, this runoff process can be exaggerated since development changes the capacity of the land and waterways to handle stormwater. Learn more about stormwater runoff and ways any individual can control the pollution in runoff.