A watershed is all the land area that drains into a particular body of water.
John Wesley Powell said that a watershed is "that area of land, a bounded hydrologic system, within which all living things are inextricably linked by their common water course and where, as humans settled, simple logic demanded that they become part of a community."
Watersheds are sometimes referred to as "drainage basins", which is defined as the extent or area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean.
There are 2,110 watersheds in the continental United States; 2,267 watersheds when you count Hawaii, Alaska and Puerto Rico (Source: EPA website).
IslandWood houses an almost complete watershed, where students can see the entire water cycle at work. Rain water falls anywhere within the watershed and collects in Mac's Pond, the bog, or the marsh and runs through the ravine down to the estuary and into Blakely Harbor. Water in the harbor joins the Puget Sound, then evaporates and falls again as rain.
For students, it is important to convey that watersheds can come in many shapes and sizes, and that they include the land around the waterways in addition to the water itself.
The IslandWood Watersheds Map in the Welcome Center shows the IslandWood campus and surrounding areas, as well where the water flows. The Watershed Model is a great visual way to show how a watershed works. Also, check out the Watersheds song.