"There isn't a river or creek in the country - or there are very few - that doesn't have some small group of people working on a restoration or creek cleanup project. Let me give you one example that's a great metaphor: In Washington, D.C., there is a group called the Anacostia Watershed Society. Two rivers converge and define Washington - one which everybody knows about, the Potomac, and the Anacostia, which they don't. The Anacostia is one of the most polluted urban rivers in the country."