This story was originally published by The Guardian and appears here as part of the Climate Desk collaboration.

A 277-mile stretch of the Colorado River that snakes through the iconic Grand Canyon is America’s most endangered waterway, a new report has found.

The unique ecosystem and cultural heritage of the Grand Canyon is on the brink of collapse due to prolonged drought, rising temperatures and outdated river management, according to American Rivers, the conservation group that compiles the annual endangered list.

Its future hangs in the balance, as the Biden administration is poised to change the way the Colorado River’s dwindling water is divided. Further restrictions to the river flow risk turning the Grand Canyon into an ecological sacrifice zone, causing irreparable damage to wildlife, fish stocks and sacred sites, the report warns.

“The Colorado River is on the brink of collapse and the Grand Canyon is in the crosshairs ... trying to solve the basin’s water challenges by sacrificing the health of the Grand Canyon would be an utter tragedy,” said Sinjin Eberle from American Rivers. “This is an all-hands-on-deck emergency.”

The annual snapshot of the country’s most endangered rivers ranks the 10 waterways at a crucial crossroads, where key decisions in the coming months will determine their long-term fate.

Now in its 38th year, the annual ranking has helped spur the removal of outdated dams, cleanups and protective designations, and the prevention of destructive development.

The 2023 list includes rivers that traverse 17 states and scores of sovereign tribal nations, and supply drinking water, food, recreation and spiritual nourishment to millions of people. The waterways are under threat from mining, climate breakdown, dams, industrial pollution and outdated river management practices that for too long have rebuffed traditional knowledge and sustainable techniques tried and tested by Indigenous Americans.

Two-thirds of the country’s water supply comes from its three million miles of rivers, but almost half (44 per cent) of waterways are too polluted for fishing and swimming, according to the Environmental Protection Agency (EPA).

The Colorado River is on the brink of collapse and the Grand Canyon is in the crosshairs, according to American Rivers, the conservation group that compiles an annual endangered list. #EndangeredWaterways #ClimateCrisis #ColoradoRiver #GrandCanyon

America’s most endangered rivers

River Threat
1. Colorado (277 miles in Grand Canyon) — Climate crisis and outdated water management.
2. OhioPollution and climate crisis.
3. PearlDredging and dam construction.
4. SnakeFour federal dams.
5. Clark Fork —​​​​​​​ Pulp mill pollution.
6. Eel —​​​​​​​ Dams.
7. Lehigh —​​​​​​​ Poorly planned development.
8. Chilkat and Klehini —​​​​​​​ Mining.
9. Rio Gallinas —​​​​​​​ Climate crisis, poor forest and watershed management.
10. Okefenokee swampMining.

Sources: American Rivers, NOAA, U.S. Fish and Wildlife Service.

Stretching from the Rocky Mountains to the sea in Mexico, the 1,500-mile Colorado watershed provides drinking water to 40 million people — including some of America’s most populous cities, such as Los Angeles and Phoenix, as well as 30 tribal nations — and irrigation water for almost six million acres of ranch and farmland.

The Grand Canyon in northern Arizona boasts one of the region’s most biodiverse ecosystems and is considered one of the seven natural wonders of the world. The canyon connects the upper and lower basins of the Colorado River, and is bookended by two massive dams that form the largest reservoirs in the U.S., Lake Mead and Lake Powell.

More than a dozen tribes and pueblos consider the Grand Canyon sacred and have long acted as stewards in spite of the dams, development and pollution by U.S. governments dating back to the first settlers.

The climate crisis has led to prolonged drought across the entire river basin and reduced snowfall in the Rockies, which, along with chronic overuse, has left the reservoirs with historically low water levels.

As a result, river managers have overseen changes to the quantity and flow of water supplies along the course of the river to protect the dams and other infrastructure. Restricting water flows has contributed to severe erosion of beaches in the canyon, impacting essential habitat for native fish and wildlife that play an important role in food security, Indigenous cultures and the recreation industry, according to the report.

New mines threaten the future of the Chilkat and Klehini rivers in Alaska, relied upon by Indigenous villagers for food security and tribal culture Clouds over the Chilkat Range. Photo by Joseph/(CC BY-SA 2.0)

Despite some much needed respite after above-average rainfall and winter snowpack, the Biden administration is on the cusp of announcing major cuts to Colorado River water allocation, which could further impact the supply and flow to the ecologically fragile canyon landscape.

“The Colorado River is in poor health. We hope that agencies will listen and work with tribes on tackling these challenges of how to manage and protect the Colorado River and Grand Canyon,” said Jakob Maase from the Hopi Tribe.

Last year, the entire Colorado River was ranked as America’s most endangered waterway, and this marks its 12th appearance on the list since 1991. The river has been so overtapped since the mid-1900s that it runs dry in Mexico, leaving the Indigenous Cucapá —​​​​​​​ or river people — without water.

In the Midwest, the Norfolk Southern train derailment and chemical burn in East Palestine led to a major leak of hazardous butyl acrylate into the Ohio River, an already overly polluted watershed relied on by five million people for drinking. The report calls on Congress to designate the Ohio River as a federally protected system and provide funds to upgrade monitoring equipment and clean up the degraded waterway, which is contaminated with legacy industrial chemicals including mercury and dioxin, as well as newer toxins like PFAS, Gen-X chemicals and acid mine drainage.

“The economic future of communities along the Ohio River depends in large part on the protection and restoration of the water system,” said Ben Hunkler from the Ohio River Valley Institute.

Meanwhile, new mines threaten the future of the Chilkat and Klehini rivers in Alaska, relied upon by Indigenous villagers for food security and tribal culture, and the pristine Okefenokee swamp that borders Georgia and Florida. In both cases, fish and wildlife habitat, water quality and climate buffering wetlands face imminent and irreversible dangers, if mining operations are given the go-ahead.

“The natural riches of these lands and waters have allowed our people not only to survive but to thrive for untold generations. Endangering the Chilkat River ecosystem with a hard rock mine will have devastating effects on our tribal people that rely on the Chilkat River and Chilkat Valley as our sustainable food source,” said Kimberley Strong, president of Chilkat Indian Village.

“This report sounds the alarm. It is a national call to action to defend these rivers and all of the life they support,” said Tom Kiernan, president of American Rivers. “When rivers are sick, people suffer.”

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