Earth’s Water: Rivers and Streams – http://ga.water.usgs.gov/edu/earthrivers.html
This site by the USGS discusses rivers and streams including what they are, their sources, and their impact on the landscape.
River Anatomy – http://www.americanrivers.org/rivers/about/
Learn about the parts of the river. This site also hosts some great diagrams including river anatomy and the water cycle.
The Watershed Game – http://www.bellmuseum.umn.edu/games/watershed/
Learn about the importance of watersheds as you quiz yourself in this interactive game from the Bell Museum of Natural History.