One of the websites that I regularly follow deals with both educational topics about rivers as well as political issues. American Rivers has a great overview on rivers that talks about the key parts of a river’s anatomy. Included in the article you will find definitions of tributaries, headwaters, mouths and deltas, wetlands and flow.
There are also important updates on legislative activity like a bill that has made its way through the House Natural Resources Committee that would take away “authority exercised for decades by federal land management agencies like the BLM and U.S. Forest Service to ensure adequate water flows down our rivers as part of their role in approving water rights transactions on federal land across the country.” Thank goodness our government is set up to make it difficult for special interests to have their way. See more at the American Rivers blog.