America may be filled with beautiful rivers and streams, but some of the country's most notable waterways are also its most endangered. Released Tuesday, the 2012 America’s Most Endangered Rivers list examines the most threatened waterways in the U.S. and the human activities that jeopardize their quality.

At the top of the list is the Potomac River. According to American Rivers' report, the river is threatened by both agricultural and urban pollution, along with attempts to roll back the Clean Water Act. The group notes that the polluted Potomac was deemed a "national disgrace” by President Johnson in 1965, and, according to TreeHugger, was a catalyst for the 1972 Clean Water Act.

American Rivers president Bob Irvin said in a statement that the list, "underscores how important clean water is to our drinking water, health, and economy. If Congress slashes clean water protections, more Americans will get sick and communities and businesses will suffer. We simply cannot afford to go back to a time when the Potomac and rivers nationwide were too polluted to use.”

Several rivers on the list -- in Wyoming, Ohio and West Virginia -- are threatened by natural resource extraction, including natural gas development and mountaintop removal coal mining. Wyoming's Hoback River, the report explains, could face the "likely impacts" of fracking, including pollution, water loss and wildlife displacement.

For the Hoback, the report recommends that "the leaseholder should agree to sell or donate its oil and gas leases to a conservation buyer." The report argues that to protect northeastern Ohio's Grand River from negative impacts of natural gas development, the state must "require the highest standards" for monitoring and testing chemicals and wastewater related to fracking.

American Rivers notes in their report that theirs "is not a list of the nation’s 'worst' or most polluted rivers, but rather it highlights rivers confronted by critical decisions that will determine their future."

List and captions courtesy of American Rivers. Click here to read the full report.

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  • 10. Kansas River (KS)

    Threat: Sand and gravel dredging <br><br> At stake: Public health and wildlife habitat

  • 9. Coal River (WV)

    Threat: Mountaintop removal coal mining <br><br> At stake: Clean water and public health

  • 8. Crystal River (CO)

    Threat: Dams and water diversions <br><br> At stake: Fish, wildlife, and recreation

  • 7. South Fork Skykomish River (WA)

    Threat: New dam <br><br> At stake: Habitat and recreation

  • 6. Grand River (OH)

    Threat: Natural gas development <br><br> At stake: Clean water and public health

  • 5. Hoback River (WY)

    Threat: Natural gas development <br><br> At stake: Clean water and world-class fish and wildlife

  • 4. Missouri River (IA, KS, MO, MT, NE, ND, SD, WY)

    Threat: Outdated flood management <br><br> At stake: Public safety

  • 3. Chattahoochee River (GA)

    Threat: New dams and reservoirs <br><br> At stake: Clean water and healthy fisheries

  • 2. Green River (WY, UT, CO)

    Threat: Water withdrawals <br><br> At stake: Recreation opportunities and fish and wildlife habitat

  • 1. Potomac River (MD, VA, PA, WV, DC)

    Threat: Pollution <br><br> At stake: Clean water and public health

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