Colorado River named most endangered river in the U.S.

The Colorado River, which starts in Colorado and flows downstream to several other western states, has been named the most endangered river in the United States by American Rivers.

American Rivers is a nonprofit based out of Washington, D.C. and works to protect and restore rivers and conserve water around the country.

The group's new report released Tuesday, titled "America's Most Endangered Rivers" of 2022, lists the 10 most threatened rivers in the United States. The report not only highlighted the rivers most at risk, but also detailed solutions.

The rivers are ranked by their significance to people and nature, magnitude of threats against the waterway, and the presence of any major decisions in the near future that the public could help influence.

Here is the report's list of the 10 most endangered rivers in the United States:

1. Colorado River
2. Snake River
3. Mobile River
4. Main's Atlantic Salmon Rivers
5. Coosa River
6. Mississippi River
7. Lower Kern River
8. San Pedro River
9. Los Angeles River
10. Tar Creek

Data and graphic courtesy of American Rivers

The Colorado River runs over 1,450 miles and was named the No. 1 most endangered river in the country.

The Upper Colorado Basin includes Wyoming, Colorado, and partially Utah, Arizona and New Mexico, while the Lower Colorado Basin includes other parts of Utah, Arizona and New Mexico, plus Nevada and California.

United States Geological Survey

To understand what's at risk, it's first imperative to understand the far reach of the Colorado River. It supplies drinking water for 40 million people — providing about half the water used in the Denver metro area — and is vital to the nation's food supply, irrigating millions of acres of farms and ranch lands. The report says that almost 90% of the nation's winter vegetable crops are irrigated by water from the Colorado River. It supports a $1.4 trillion economy and hundreds of thousands of jobs. More than a dozen species of endangered animals call the river home.

READ MORE: The Colorado River's 1,400-mile journey, explained

According to the report, the two largest threats against the Colorado River are climate change, especially rising temperatures and the American West's megadrought, and outdated management and overallocation, which puts reliable water supplies, regional economies and the river's own health at risk.

Climate change is expected to reduce the river's flow by 10% — down to 30% — by 2050, according to the report. Climate experts say March marked the third straight month of below-average precipitation across the U.S. and areas of record dryness are expanding in the West, according to the Associated Press.

An ongoing drought across western states has been shrinking the snowpack amid hotter temperatures, which has in turn endangered the river's health.

READ MORE: Where Colorado's snowpack stands as water, fire concerns grow heading into summer

This is evident when looking at the dry, white rings of rock above the waterline at Lake Powell in Utah and Arizona and Lake Mead in Nevada and Arizona — two reservoirs off the Colorado River that have seen extremely low levels recently. Water is stored in Lake Powell for use in five states, including Arizona, Colorado, New Mexico, Utah and Wyoming, and the Lake Mead keeps water stored for parts of California, Arizona, New Mexico and Nevada.

Ross D. Franklin/AP

In July 2021, Lake Mead was 161 feet below full pool. As of March, Lake Powell fell below the critical threshold of 3,525 feet, the lowest level since the lake filled after the federal government dammed the Colorado River at Glen Canyon more than a half century ago. This month, the U.S. Interior Department proposed holding back water in Lake Powell to maintain the dam’s ability to generate electricity for about 5 million customers amid the driest conditions in more than 1,200 years, according to the AP.

If Lake Powell drops even more, it may soon "deadpool," meaning water would stop flowing into Lake Mead. In preparation for this, Arizona, Nevada, California, and Mexico have already started taking mandatory and voluntary cuts tied to Lake Mead’s levels, the AP reported.

Jae C. Hong/AP

Multiple groups have worked toward viable solutions to restore the Colorado River to a stronger state, but American Rivers' report says they do not go far enough to address the "significant and likely permanent decline in regional water supplies."

Aside from climate changes, the report also claims that the river's management plans were created on the notion that the river carries 18 million acre-feet. One acre-foot is the amount of water to cover a football field one foot deep. However, only 13 million acre-feet have been historically available for the river.

In addition, the report says that Tribal Nations along the river do not have modern water infrastructure and have been historically excluded from the major river management decisions.

Those Tribal Nations are among many groups in the ongoing nation-wide conversation to find a sustainable fix.

One of the most promising solutions stems out of the Infrastructure Investment and Jobs Act, which provides billions of dollars to states in the Colorado River Basin for projects addressing climate resiliency and support for those who depend on the river — animal and human alike.

American Rivers recommended in its report to de-prioritize projects that will not quickly build up the basin's resiliency to climate change.

"America's Most Endangered Rivers" named a separate report titled "Ten Strategies For Climate Resilience in the Colorado River Basin," which focuses on 10 investment strategies to prepare the river for more aggressive effects of climate change, as a possible guide on how to to proceed. The "Ten Strategies" report was authored on behalf of American Rivers and several other groups, including Environmental Defense Fund, National Audubon Society, The Nature Conservancy, and the Western Resource Advocates.

Those 10 strategies range from "well-demonstrated" to "theoretical but largely untested" concepts and include the following:

1. Urban conservation and re-use
2. Industrial conservation and re-use
3. Upgrading agricultural infrastructure and operations
4. Cropping alternatives and new market pathways
5. Forest management and restoration
6. Regenerative agriculture
7. Natural distributed storage
8. Coal plant retirement water
9. Covering reservoirs and canals
10. Reducing dust on snow

You can read more about the 10 Strategies Report here.

READ MORE: Colorado River levels continue to decline. What does this mean for the future?