What is a Watershed?
We all know that water flows downhill, right? When it does so, it follows
the path which is easiest for it to go -- the area which requires the least
energy for it to go there. So, when it rains, water which is not absorbed by
the soil and used by plants or animals runs downhill. Eventually, this water
will run into a stream or river. So, since water will follow the path of the
smallest resistance, it will run the same way all the time (it will never go
uphill!). All of the land whose water runs into a certain stream is
called the watershed of that stream.
Rivers have larger watersheds. Their watersheds are made up of all the streams
that run into them, as well as the land whose rainwater runs into them.
