In this activity, you can make a watershed model. Remember, a watershed is all the land that "sheds" water from rain and snowmelt into a specific stream, river, or lake. The boundaries of a watershed are the mountains, hills, or other high points where land slopes towards that water. Watersheds can be very small or very large. A large watershed may have many smaller watersheds. It's like the branches of a tree. The tiny twigs join bigger twigs, the bigger twigs join larger branches, and the branches join the trunk. Small streams flow into larger streams, larger streams flow into rivers, and rivers flow into larger rivers or even gulfs, seas, and oceans.