Years of drought have dropped the Colorado River below historical levels/Rrainer Krienke

Climate-change impacts and over-allocation of available water have landed the Colorado River, which flows through some of the country's most iconic national parks, at the top of American River's annual list of endangered rivers.

Diminished flows and dams have altered the once-mighty river that runs from Rocky Mountain National Park in Colorado to the Gulf of California. As the National Parks Traveler has documented in a series of stories, the waning river has dropped the reservoirs at Glen Canyon and Lake Mead national recreation areas to levels not seen since the country's two largest reservoirs were initially filled. Warming water temperatures and dams have allowed invasive species to take hold, and long-range forecasts are not encouraging when it comes to higher spring runoff into the river basin.

“On the Colorado River and nationwide, the climate crisis is a water crisis,” said Tom Kiernan, president of American Rivers. “Just, equitable solutions for rivers and clean water are achievable and essential to our health, safety and future. We must come together to speak up for these 10 endangered rivers, and for all of the rivers that are vital to our lives.”

While that might be so, that vision isn't putting more water into the Colorado River now.

“The Colorado River Basin is ground zero for the climate and water crisis. America’s Most Endangered Rivers® is an urgent call to action,” said Matt Rice, director of the Southwest Region for American Rivers. “The seven Basin states and the Biden administration must work with Tribal Nations and Mexico to act urgently. Failure is simply not an option, given all that depends on a healthy Colorado River.

"As the region learns to live with the river that we have, it is critically important that we continue to work together on equitable solutions for a healthy river, productive farms and thriving communities. I fear that if we dig into our corners and pursue litigation over collaboration, we will not be able to meet the challenge,” he said.

As runoff dwindles, the dropping reservoir at Lake Powell has a dark cloud hanging over the boating season. As of April 1, the runoff inflows to the reservoir were forecast at just 64 percent of average by the Colorado River Basin Forecast Center. Currently, just one of a dozen boat ramps at Lake Powell can handle trailered boats, though the National Park Service hopes to be able to bring another into service later this spring.

The annual America’s Most Endangered Rivers report is a list of rivers at a crossroads, where key decisions in the coming months will determine the rivers’ fates. Over the years, the report has helped spur many successes including the removal of outdated dams, the protection of rivers with Wild and Scenic designations and the prevention of harmful development and pollution.

The Colorado River previously received this designation in 1991, 1992, 2004 and 2013 (with portions of the river designated in 1997, 2010, 2014 and 2017). Arizona’s San Pedro River is also included on the list this year due to excessive groundwater pumping and rollbacks of the Clean Water Act. Other rivers in the region listed as most endangered in recent years include the Pecos River (2021) and Gila River (2019).

American Rivers reviews nominations for America’s Most Endangered Rivers from local groups and individuals across the country, and selects rivers based on three criteria: 1) the river’s significance to people and wildlife, 2) the magnitude of the threat to the river and communities, especially in light of climate change and environmental justice, 3) a decision in the next 12 months that the public can influence.

America’s Most Endangered Rivers® of 2022

#1 Colorado River

State: CO, UT, AZ, NV, CA, WY, NM, Mexico

Threat: Climate change, outdated water management

#2 Snake River

State: ID, WA, OR

Threat: Four federal dams

#3 Mobile River

State: AL

Threat: Coal ash contamination

#4 Maine’s Atlantic Salmon Rivers

State: ME

Threat: Dams

#5 Coosa River

State: TN, GA, AL

Threat: Agricultural pollution

#6 Mississippi River

State: MN, WI, IL, IA, MO, KY, TN, AR, MS, LA

Threat: Pollution, habitat loss

#7 Lower Kern River

State: CA

Threat: Excessive water withdrawals

#8 San Pedro River

State: AZ

Threat: Excessive water pumping; loss of Clean Water Act protections

#9 Los Angeles River

State: CA

Threat: Development, pollution

#10 Tar Creek

State: OK

Threat: Pollution