Watersheds are those land areas that catch rain or snow and drain to specific marshes, streams, rivers, lakes, or to ground water.  EVERY piece of land belongs to a watershed.

Imagine yourself standing in a stream and looking at the water at your feet.
The area that contributed water to that spot is its watershed.

Watersheds are of overwhelming importance as they affect not only the amount of water flow, put also potential nutrients and polutants.