As Water-Sharing Negotiations Heat Up, Wildlife Habitats Along the Shrinking Colorado River Are at Risk

Until the 20th century, the Colorado River moved freely through the West, from forested Rocky Mountain headwaters through canyons, deserts, and lush wetlands and then out to sea. But by 1922, as cities and farms expanded, the seven states in the river basin divvied up its flow, and a growing number of dams and irrigation projects tamed its majesty. Today more than 40 million people rely on its water. 

These demands are now too great for what the Colorado River can supply. Since 2000, average annual flows have declined about 20 percent, and conditions are now dire: Sparse winter snowfall plus melt from an early spring heatwave left the basin with its lowest snowpack ever recorded for April 1. “This year is stunningly bad, without any parallel in the recent historical record,” says Colorado State University climate scientist Brad Udall. As the basin warms and dries, flows could decline another 20 percent by midcentury. 

Water users have dealt with precipitation shortfalls by drawing down the system’s major reservoirs, Lake Mead and Lake Powell, but those buffers are now critically low. This year, managers are bracing for reductions: farmers letting fields go dry, city residents paying more, and ecosystems going without. “It’s a crisis,” says University of Colorado Boulder water policy expert Doug Kenney. “But it’s such a slow-moving crisis that we all saw it coming for decades.” 

The predicament comes as a deadline looms to set the Colorado River on a more sustainable course. Rules for managing the river expire this year, and states of the Upper Basin (Colorado, New Mexico, Wyoming, and Utah) and Lower Basin (Arizona, California, and Nevada) are negotiating how to handle future shortages. All recognize there’s not enough water to meet obligations in century-old agreements. What Upper and Lower Basin states haven’t settled is how to share in cutbacks. If they can’t reach a consensus, the federal Bureau of Reclamation is preparing to impose its own plan—an outcome, Kenney says, that could hamstring river operations through years or decades of likely lawsuits.

Finding a way out of chronic crisis is crucial to the future of the river’s rich, diverse ecosystems, says Jennifer Pitt, Audubon’s Colorado River Program director. These habitats support dozens of types of fish and more than 400 bird species, but their water supplies are tenuous and are often disrupted in times of scarcity.

A journey along the river’s length shows what’s at stake. Take the Dolores River, a tributary in Colorado and Utah. A dam diverts most of its water before it joins up with the main river, and large farms have top priority rights, says Rica Fulton of Dolores River Boating Advocates. Though some flow is supposed to go downstream to support fish, these allocations have been reduced to a trickle during recent droughts, shrinking fish habitat and draining prized rapids.

Hundreds of miles downstream, the Grand Canyon’s ecology, which supports Southwestern Willow Flycatchers and Western Yellow-billed Cuckoos, also depends on how states manage supplies. Here, releases from Lake Powell into the Lower Basin feed the river. As the reservoir drops, water coming into the canyon becomes warmer, says American Rivers communications director Sinjin Eberle—a shift that “completely changes the aquatic ecology,” boosting nonnative smallmouth bass and harming humpback chub. 

The Colorado River ends at its delta in Mexico, where conservationists have shown the power of water to spark a revival. For decades, upstream diversions left the floodplain dry: “People thought this was a dead ecosystem,” says Osvel Hinojosa-Huerta, who has worked for years on restoration in the region. Starting in 2012, the United States, Mexico, and a nonprofit coalition that includes Audubon agreed to release pulses of water to nourish these habitats. With intensive restoration, vibrant pockets of marsh and riparian forest now host endemic Yuma Ridgway’s Rails and many migrant species. Yet the delta’s future is also unclear: The current water-sharing agreement expires soon and will need to be renegotiated after new U.S. management plans are in place, Pitt says.

Going forward, conservationists hope that officials will plan for the Colorado River’s health more holistically. “We're not talking about a plumbing system. We're not talking about a series of buckets,” Kenney says. “This is a river—and it’s a magical river.” Nothing can change a diminishing supply, but legal and technical tweaks could incentivize water conservation, for example, or allow for more flexible management decisions, such as enabling reservoir releases when and where they’ll have maximum ecological benefit. 

To foster a long-term outlook, the Colorado River Indian Tribes in Arizona formally recognized the river’s “personhood” in 2025, declaring it a being with its own rights. It’s a reminder that the waterway, which winds a ribbon of life through the West, must be allowed to live, too. Says chairwoman Amelia Flores: “We have to consider the wholeness of what this river brings to us.”

This story originally ran in the Summer 2026 issue as “A Very Big Deal.” To receive our print magazine, become a member by making a donation today.