The no. 1 endangered river in America is the Potomac, according to a leading environmental group. The body of water, which separates Maryland from Virginia, has been polluted over time by the 5 million people that live in its watershed, leading to its current fragile state.

The conservation group American Rivers releases a report each year detailing what the most-threatened rivers in the United States are, and for this year's study, released Tuesday, the organization chose for its no. 1 endangered river the Potomac, which should be familiar to anyone who has ever visited Washington, D.C.

The idea behind naming the Potomac the no. 1 endangered river in the county rests in the hope that it will draw attention to its plight, which by nature of having been listed, is considered to be at a turning point that could see it fall into even greater environmental decline if nothing is done to protect it.

The report highlights ten rivers whose fate will be decided in the coming year, and encourages decision-makers to do the right thing for the rivers and the communities they support, American Rivers wrote. It presents alternatives to proposals that would damage rivers, identifies those who make the crucial decisions, and points out opportunities for the public to take action on behalf of each listed river.

The report goes on to outline the specific threats facing the Potomac River, and explains what needs to be done in order to ensure that it is not named the no. 1 endangered river in the nation again in 2013.

While the Potomac is cleaner than it used to be, the river is still threatened by urban and agricultural pollution- and it could get much worse if Congress rolls back critical clean water safeguards, an American Rivers release about the report states. Before the Clean Water Act was enacted in 1972, the Potomac was a cesspool of sewage and industrial pollution. Thanks to the Clean Water Act, the Potomac and rivers across the country are cleaner and safer for drinking, boating, and fishing. But the Potomac is still suffering - a University of Maryland report card has given the river a D grade for water quality for the past two years.

As such, the American Rivers release detailing the no. 1 endangered river rating given to the Potomac spends quite a bit of time discussing what needs to be done to ensure that rivers including the Potomac get the protections they need:

We need strong federal leadership as we redouble our efforts at the local level to achieve the goal of a healthy, clean Potomac, Hedrick Belin, President of the Potomac Conservancy, said in the statement. We look forward to partnering with American Rivers, Potomac Riverkeeper, and others to continue to make progress cleaning up the Nation's River. This regional treasure contributes so much to our community's quality of life, and our neighborhoods deserve healthy, clean streams and creeks.

Below is the full list of the ten rivers that have been named on American Rivers' list of the nation's rivers that are most endangered. Click on a river's name to view a release about the threats that face that individual river and what steps the advocacy organization would like to see taken in order to help protect it:

#1 Potomac River
#2 Green River
#3 Chattahoochee River
#4 Missouri River
#5 Hoback River
#6 Grand River
#7 Skykomish River
#8 Crystal River
#9 Coal River
#10 Kansas River