Local activists nominated the Shenandoah River because of high levels of nitrogen and phosphorous, which reduce oxygen levels and damange the river's ecosystem. For example, in Virginia's Warren County last year, about 80 percent of redbreasted sunfish and smallmouth bass were found dead with lesions on their bodies for reasons that state officials are still trying to determine.
The American Rivers report also focuses on planned development in six rural counties in the river's watershed. Decisions must be made now before damage is beyond repair. "This report is about timing," said John Eckman, executive director of the Valley Conservation Council, which worked with American Rivers. "It's about the fact that there is some critical decision-making going on as far as where we put houses, how do we tighten up the zoning...Fredericksburg is almost developed, and when you drive around the Shenandoah Valley, what looks like open farmland is already platted."