Watershed

Watershed

A watershed is the total land area that drains water into a given river, lake, estuary or other body of water. A watershed can be quite large (e.g., the Missouri river watershed) or small (e.g., the watershed of a local stream).

A watershed carries water "shed" from the land after rain falls and snow melts. Drop by drop, water is channeled into soils, groundwaters, creeks, and streams, making its way to larger rivers and eventually the sea. Hills organize the land into watersheds.

All land surface is in some watershed because all runoff and groundwater goes somewhere.