A watershed is the area where water from rain and snowmelt runs off and drains to a body of water. These bodies of water can be rivers, lakes or ponds. Watershed boundaries are defined by hills, mountains or other higher ground that keep the water in like a big bowl. All water eventually flows to a particular body of water no matter where it comes from. Every piece of land is located in a watershed of some kind.
A good way to think of a watershed is a sink. The “sides” of the sink define the boundary of the watershed, these are the hills or highlands. While the “bottom” is the land area that slopes slightly towards the “drain” or body of water.
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