An area of land that feeds all the water running under it and draining off of it into a body of water.
A watershed is the area of land where all of the water that falls in it and drains off of it goes to a common outlet. Watersheds can be as small as a footprint or large enough to encompass all the land that drains water into rivers that drain into Chesapeake Bay, where it enters the Atlantic Ocean. The word watershed is sometimes used interchangeably with drainage basin or catchment. Ridges and hills that separate two watersheds are called the drainage divide. The watershed consists of surface water--lakes, streams, reservoirs, and wetlands--and all the underlying ground water. Larger watersheds contain many smaller watersheds A watershed is an area of land that drains into a particular river, lake or other body of water. Watersheds are sometimes called “basins” or “drainage basins.”. We all live in a watershed. Some watersheds, like that of a stream or creek, are small. Others, like the Chesapeake Bay watershed, are large. We asked people in Alexandria, Virginia, to share their definition of a watershed. Find out what they said in the video below. And oviously, polluted water affects water quality. 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. For example, the Mississippi River watershed is an enormous watershed.  Watersheds are defined by the way water flows across the land and are shaped by features and elevations on the surface of the land. Springsheds, on the other hand, are defined by the way water flows beneath the land and are shaped by the geology and pressure below the surface of the land. A watershed is an area of land that water flows across as it moves toward a common body of water, such as a stream, river, lake or coast. A watershed is an area of land that drains all the streams and rainfall to a common outlet such as the outflow of a reservoir, mouth of a bay, or any point along a stream channel. The word watershed is sometimes used interchangeably with drainage basin or catchment. Ridges and hills that separate two watersheds are called the drainage divide. The watershed consists of surface water--lakes, streams, reservoirs, and wetlands--and all the underlying ground water. Larger watersheds contain many smaller watersheds ­A watershed is an area of land that feeds all the water running under it and draining off of it into a body of water. It combines with other watersheds to form a network of rivers and streams that progressively drain into larger water areas. Topography determines where and how water flows. Ridge tops surrounding a body of water determine the boundary of a watershed. Imagine turning an open umbrella upside down in the rain. The umbrella is like a watershed; it collects everything that falls into it. Waterways within the watershed all feed into that main body of water, which could be a river, lake, or stream. The beginnings of a water source are called headwaters. Watersheds. New York's waters (lakes, rivers and streams) fall within one of 17 major watersheds, or drainage basins. A watershed is an area of land that drains water into a specific body of water. Watersheds include networks of rivers, streams, and lakes and the land area surrounding them. Watersheds are separated by high elevation geographic features (mountains, hills, ridges).  What is a watershed? A watershed is simply the geographic area through which water flows across the land and drains into a common body of water, whether a stream, river, lake, or ocean.  A watershed is an area of land in which all of the water that enters it, drains into a common waterbody. Also known as a drainage basin, it can be thought of as a funnel that collects surface water and ground water and drains it into a single stream, lake, ocean, or other reservoir. 
http://water.usgs.gov/edu/watershed.html http://www.chesapeakebay.net/discover/baywatershed http://www.mbgnet.net/fresh/rivers/shed.htm http://www.swfwmd.state.fl.us/education/watersheds/ http://water.usgs.gov/edu/watershed.html http://science.howstuffworks.com/environmental/conservation/issues/watershed1.htm http://www.dec.ny.gov/lands/26561.html http://www.dep.wv.gov/WWE/watershed/Pages/watershed_management.aspx http://www.dep.state.fl.us/Water/watersheds/index.htm
what are watersheds