Driven in part by the ongoing western megadrought, the foundation governing how Colorado River water is shared may be cracking, threatening drinking water supplies for millions from Denver to Los Angeles, farmers and ranchers throughout the southwest, and the ecosystems that rely on water flowing through the 1,450 miles of the Colorado and its tributaries.
The U.S. Bureau of Reclamation should start planning to modify the Glen Canyon Dam, which plugs the Colorado to form Lake Powell. The plan will help ensure water and sediments will continue to flow through the Grand Canyon, and into Lake Mead, the nation’s largest reservoir.
In late June, Colorado’s representative to the Upper Colorado River Commission told an audience, “we stand on the brink of system failure.”
Earlier last month the leader of the Colorado River Authority of Utah suggested some states are considering an “amicable divorce” from the 103-year old Colorado River Compact, which established the basic rules for apportioning Colorado River water among its seven-member states.
Despite a 2026 deadline, the Bureau and seven states have been grappling unsuccessfully with how to share the river equitably. There is significantly less water in the river compared to what was expected when the Compact was ratified: 12.5 million acre-feet annually this century, compared to no less than 17.5 million acre-feet assumed in 1922.
Lake Powell, the nation’s second-largest reservoir, was almost full in 1999. Today it is less than one-third full. The reservoir’s water level has dropped 29 feet compared to the same date last year — almost three feet in the last two weeks — and it will continue to drop, as rivers feeding it are running about 36% below average.
In mid-July, the Bureau forecast that by December 2026, under “probable minimum inflow” conditions, the reservoir could reach “minimum power pool elevation,“ below which the dam would be unable to generate power. If the reservoir continued to drop it would eventually reach the river outlet works, the only remaining method for getting water through the dam.
These outlets were never intended to be used on a continuous basis, and have been damaged previously from extended use. When the water level in the reservoir reaches the elevation of the outlet works it is known as “dead pool,” even though water at the face of the dam would 240-feet deep.
At dead pool limited water could flow to the Grand Canyon, which starts a few miles below the dam, and into Lake Mead, the nation’s largest reservoir, eventually threatening those dependent on Colorado River water in Arizona, California and Nevada. It also could require the upper basin states, including Colorado, which receives about 40% of its water supply from the Colorado River, to curtail their use of the river’s water.
The lower basin states understand the potential danger of reaching dead pool. In February, their representatives urged the Secretary of the Interior, who oversees the Bureau, to consider “structural modifications … that would eliminate the infrastructure limitations at Glen Canyon Dam.”
While current trends do not necessarily portend destiny, it would be prudent for the Bureau to start evaluating ways of getting water and sediments around or through Glen Canyon Dam downstream to Lake Mead. The Bureau has stated “a decade is optimistic” to analyze and select the best option, appropriate funds to design the conveyance system, procure contractors, and construct the system.
Failing to start planning now is irresponsible. It will increase the probability that insufficient water will flow through or around the dam, resulting in endless lawsuits about how to allocate dwindling supplies, threaten drinking water for millions of people in the lower basin, jeopardize the amount of water provided to farmers and ranchers, and further despoil Glen Canyon, and the Grand Canyon.
Ron Rudolph was the assistant executive director of Friends of the Earth, and vice president in some of the largest Colorado-based architect/engineering companies, including MWH Global (now part of Stantec), and CH2M Hill (now part of Jacobs Engineering).
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