A watershed is the land area off of which rain and/or snowmelt run off or “shed” eventually arriving into a receiving water body. A “watershed” is sometimes referred to as a drainage basin. You can define a watershed around a water body by following the highest points of land around that body of water. The scale of a watershed is relative to its receiving body of water, be it a river, stream, lake, pond or even a puddle in a parking lot. There are watersheds within watersheds.