A watershed is an area of land in which water drains into a common point, such as a stream, river, lake or groundwater.
Watersheds come in all shapes and sizes and include many different uses.
Watersheds can include hills or flatlands, forests or cities, and any combination of these. In 1990 the USDA water quality initiative classified 74 regions in the United States and Puerto Rico as HUAs. Two regions in northern Indiana are classified as HUAs. Ag Communication Service., Purdue University.