Five key things to know about the Colorado River

Durango, Colorado, US – As the western United States faces historic drought, communities across the region are grappling with how to save the Colorado River, a key waterway that feeds some of the country’s largest cities but is in crisis.

Water levels have dropped to record lows, threatening the two largest reservoirs in the US – Lake Mead and Lake Powell – and the many millions of people who rely on the river.

Here are five key facts about the Colorado River.

It is the sixth largest river in the US

At 2,330km (1,450 miles), the river is the sixth largest in the United States. Beginning in the Rocky Mountains of Colorado, it cuts through the Grand Canyon and several US states before pouring out into the Gulf of California in Mexico.

The Colorado River basin spans about 647,000sq km (250,000sq miles), or approximately 8 percent of the continental US, according to the Bureau of Reclamation.

It provides water to 40 million people

Approximately 40 million people in Mexico and across seven US states rely on the Colorado River and its tributaries for their drinking water.

The seven Colorado River basin states are divided into an upper basin – Wyoming, Utah, New Mexico, and Colorado – and a lower basin, Arizona, California, and Nevada. Thirty federally recognised Indigenous tribes also live in this area.

The river’s water primarily goes to agriculture

The river is used to generate hydroelectric power, as well as for recreation activities. But its primary use is in the agricultural sector, which accounts for nearly 70 percent of the supply. This water irrigates more than two million hectares (five million acres) of land.

The Imperial Irrigation District, serving a rich agricultural area in southern California, is the single-largest Colorado River water user in the southern basin.

It was voted most endangered US river in 2022

American Rivers, a Washington, DC-based group that advocates for clean water and healthy rivers, voted the Colorado River as the most endangered river in the United States last year.

“There is not enough water in the Colorado River to meet all current needs,” the organisation said, adding that climate change is expected to reduce the river’s flow by between 10 and 30 percent by 2050.

“Drought has impacted large portions of the Colorado River Basin for years – shrinking snowpack, hotter temperatures and increasing evaporation have led to widespread aridification (ie, extreme dryness) that endangers water supplies and river health,” it said.

Efforts to save the Colorado River are continuing

For years, US authorities have sought to cut back on water use as drought, exacerbated by climate change, caused Colorado River water levels to drop.

Earlier this year, six of the seven US basin states put forward a proposal for cuts while California submitted its own plan. A federal decision on water cuts is expected by mid-2023.

This article was supported by The Water Desk, an independent journalism initiative based at the University of Colorado Boulder’s Center for Environmental Journalism.

Aerial photography was made possible through LightHawk donated flights.