What is a Watershed?

A Watershed is the area of land that drains to a common point, such as a stream, lake, estuary, wetland, aquifer, or even the ocean. The boundary of a watershed is formed by the topography of an area, and they’re usually divided by hills and ridges. Watersheds can be as small as a footprint or large enough to encompass all the land that drains the Atlantic Ocean. Small watersheds are part of larger watersheds, which in turn are part of even larger watersheds. Allegheny County’s watersheds are part of the Ohio River Watershed. The Allegheny and Monongahela Rivers converge at the Point in downtown Pittsburgh to form the Ohio River, which is part of the Mississippi River watershed, which flows into the Gulf of Mexico.