Colorado River named America’s #1 Most Endangered River of 2022

April 18, 2022

Climate change, overallocation threatens water source for seven states, 30 Tribal Nations and Mexico

Contact: Matt Rice, American Rivers, 803-422-5244

Washington, D.C. – American Rivers today named the Colorado River the #1 Most Endangered River in the country, highlighting the threat climate change and outdated water management pose to 30 federally-recognized Tribal Nations, seven states, Mexico and the drinking water for 40 million people. Also threatened is vital habitat for wildlife, as the Basin is home to 30 native fish species, two-thirds of which are threatened or endangered, and more than 400 bird species.

Rising temperatures and drought driven by climate change, combined with outdated river management and overallocation of limited water supplies, threaten the entire region. In March 2022, water levels at Lake Powell fell to the lowest point since the lake first filled in 1980 and have continued dropping. The Colorado River system is already operating at a deficit, and climate change is expected to further reduce the river’s flow by 10 to 30 percent by 2050. 

“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,” said Rice 

“Collaboration is the only path to avoid catastrophic water shortages for people and nature,” said Jennifer Pitt, Colorado River Program Director for National Audubon Society. “We know how it works — ten years ago, the United States and Mexico modernized Colorado River management, collaborating to share the Colorado River’s water proportionately, while boosting cross-border investment in water conservation and beginning to restore the Colorado River in its delta.” 

In 2023, mandatory cutbacks triggered by water shortage will cause Arizona to lose more than 500,000 acre-feet in Pinal County alone (roughly the drinking water supply for nearly 1.5 million households). 

“What we’re facing now is the permanent warming and drying of the American Southwest,” said Brad Udall, Senior Water and Climate Research Scientist/Scholar at Colorado State University. “Scientists have a new term for this, called ‘aridification’. What we’re seeing here is anything but normal, because normal implies predictability. And unfortunately we don’t have predictability — climate change has ‘change’ in it for a reason. We’re going to need to apply some serious pressure to decision makers because we are running out of time to solve this problem.” 

The river is the lifeblood for some of the country’s largest cities including Denver, Salt Lake City, Albuquerque, Las Vegas, Los Angeles, San Diego and Phoenix, and supports a $1.4 trillion economy. Yet many Tribal Nations across the Basin, despite holding significant senior water rights, suffer from a lack of modern water infrastructure, due to systemic inequities and historic disinvestment and continue to be marginalized in Basin-wide policy making. Forty-eight percent of tribal homes do not have access to reliable water sources, clean drinking water or basic sanitation. 

American Rivers called on the seven Basin states and the Biden administration to engage with the Basin’s tribes to address this emergency. The administration and the seven Basin states must work together to allocate funds from the Infrastructure Investment and Jobs Act to implement proven, equitable solutions that prioritize river health and water security. 

The Ten Strategies for Climate Resilience Report is one example of a road map for investment of federal infrastructure dollars in the Colorado River Basin as well as innovative practices to keep more water flowing in the Colorado River and reduce the pressure on the regional water supply. The old approaches of the past – more dams, diversions and concrete – are not the answer now. Natural infrastructure solutions, such as those outlined in the Ten Strategies report, are necessary at every scale across the Basin to ensure a future of healthy rivers and flexible, durable water supplies for all people. 

“On the Colorado River and nationwide, the climate crisis is a water crisis,” said Tom Kiernan, President and CEO of American Rivers. “Just, equitable solutions for rivers and clean water are achievable and are essential to our health, safety and future.” 

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 


American Rivers believes a future of clean water and healthy rivers for everyone, everywhere is essential. Since 1973, we have protected wild rivers, restored damaged rivers and conserved clean water for people and nature. With headquarters in Washington, D.C., and 300,000 supporters, members and volunteers across the country, we are the most trusted and influential river conservation organization in the United States, delivering solutions for a better future. Because life needs rivers.