Colorado River states face off over dwindling supplies

By Jennifer Yachnin | 03/06/2024 04:34 PM EST

The Upper Basin and Lower Basin states offered very different plans for how to split cuts if the drought-stricken river continues to shrink.

A bathtub ring of light minerals shows the high-water mark on the shore of Lake Mead.

A bathtub ring of light minerals shows the high-water mark on the shore of Lake Mead along the border of Nevada and Arizona on March 6, 2023, near Boulder City, Nevada. John Locher/AP

Officials from the seven states that share the Colorado River pitched dueling plans to the Biden administration Wednesday over how to dole out painful cuts, even as the states agreed that climate change means that water supplies could further dry up in the decades ahead.

In separate proposals, the Upper Basin states and Lower Basin states each acknowledge that in extreme conditions, the Biden administration should plan for cuts of up to 25 percent of the Colorado River’s flows.

But exactly how to spread the pain of those reductions remains a sticking point.


Divisions also remain on how to account for existing water in the Colorado River system. This includes whether to calculate waters based solely on the contents of the two largest reservoirs, Lake Mead and Lake Powell, or to add in smaller reservoirs that have been drained in recent years to make up for shortfalls elsewhere.

The Interior Department and Bureau of Reclamation must now review the proposals from the Upper Basin — Colorado, New Mexico, Utah and Wyoming — and Lower Basin — Arizona, California and Nevada — and work to find consensus. Acting Deputy Interior Secretary Laura Daniel-Davis on Tuesday said the Biden administration wants to ready a draft long-term operating plan by the end of the year. The next plan must be in place by 2027.

A series of existing agreements for the 1,450-mile river will expire at the end of 2026, including an interim agreement approved Tuesday and a pair of deals with Mexico, which also claims flows from the river.

Despite the split between basins on the initial proposals, officials from all seven states and the Interior Department have pledged to return to the negotiating table to attempt to find agreement.

Neither Interior nor the Bureau of Reclamation commented on the specifics of the plans Wednesday, referring to earlier comments by Daniel-Davis.

“We are all committed to a basinwide solution,” Daniel-Davis said Tuesday. “And we’ll continue to work honestly and collaborate collaboratively through any major sticking point until a consensus has been reached.”

How to split the cuts

The major split in the plans put forth Wednesday is on whether each of the seven states must take mandated reductions, or whether those cuts should fall squarely on California, Arizona and Nevada.

Under the 1922 Colorado River Compact, the river is divided into 7.5 million acre-feet for each basin. But persistent drought has reduced those flows to as low as 11 million acre-feet annually by some estimates.

The states’ plans agree that the most extreme scenarios show the river losing 3.9 million acre-feet each year out of the 15 million total.

An acre-foot of water is equal to about 326,000 gallons, or enough to supply three families for a year. The most extreme cuts presented in both plans would support nearly 12 million families each year.

Officials in the Upper Basin states have long contended that their water users already face cutbacks in water supplies based on naturally occurring precipitation — losing as much as 1.2 million acre-feet annually — while the Lower Basin has been largely unaffected by those changes, since it has drawn from existing reservoir supplies. The Lower Basin states have, however, taken reductions in recent years under temporary plans driven by persistent drought.

To balance those differences, the Upper Basin plan calls for cutting water to the Lower Basin by at least 1.5 million acre-feet annually under most circumstances and up to 3.9 million acre-feet in extreme circumstances.

“We can no longer accept the status quo of Colorado River operations,” said Becky Mitchell, Colorado’s Colorado River commissioner. “If we want to protect the system and ensure certainty for the 40 million people who rely on this water source, then we need to address the existing imbalance between supply and demand.”

Those cuts would be determined annually on Oct. 1 — when the “water year” begins to calculate annual flows into and out of reservoirs — based on a complicated formula that considers the total storage of lakes Mead and Powell; the actual water stored in both reservoirs on that date; and a “threshold volume,” or the minimum water required in each to avoid deadpool status.

According to the Bureau of Reclamation, Lake Powell is currently at 34 percent capacity, while Lake Mead is at 37 percent capacity. When full, Lake Powell can hold nearly 27 million acre-feet and Lake Mead can hold nearly 28 million acre-feet.

Amy Ostdiek, with the Colorado Water Conservation Board, described the plan in simple terms as releasing only the water that is added to the reservoirs each year, rather than supplementing dry years by draining stored supplies.

“We really do believe that balancing consumptive uses and depletions with available supply must be the foundation for sustainable management under the post-2026 operations,” Ostdiek said.

Colorado officials have been particularly critical of the Lower Basin states’ water use, with Mitchell pointing to data from the Upper Colorado River Basin and the Bureau of Reclamation that shows the Upper Basin used only 3.5 million acre-feet in 2021, while the Lower Basin received 10 million acre-feet in that same year.

In an unexpected change, the Upper Basin states are also recommending the next operating plan last for an unspecified “shorter interim period.” Both the Bureau of Reclamation and Lower Basin states have asserted the next set of guidelines for the river could govern it for 20 years.

‘Quite a chasm’

In stark contrast, the Lower Basin states put forth a plan that would share cuts to water use across all seven states in the most dire scenarios.

“Our proposal says if we’re getting down to the lowest elevations, that’s a responsibility of the entire basin to protect the system,” said J.B. Hamby, chair of the Colorado River Board of California, who appeared at a news conference with Arizona and Nevada officials.

Hamby added that the difference in plans is “quite a chasm,” although he expects the states to work to bridge the proposals.

Under its proposal, the Lower Basin states would determine potential cuts based on water stored throughout the entire Colorado River system, a total of more than 58 million acre-feet.

That includes not only in lakes Mead and Powell but five other sites: Lake Mohave in Arizona and Nevada; Lake Havasu in Arizona; Flaming Gorge Reservoir in Utah and Wyoming; Blue Mesa Reservoir in Colorado; and Navajo Reservoir in Colorado and New Mexico.

“The Lower Basin states have set forth what we believe is the most ambitious conservation effort ever designed with the goal of maximizing the long-term health and stability of the river system,” said Tom Buschatzke, director of the Arizona Department of Water Resources.

Buschatzke added that the plan would “dwarf” reductions made under two previous agreements to address shortfalls in the river.

The Lower Basin plan includes provisions to account for “structural deficit,” the term used to discuss an estimated 1.5 million acre-feet of water lost to leaks in canals or evaporation as it travels through those states to its end point in Mexico. Nevada, California and Arizona would absorb those losses, officials said.

“We know that the first part of the math problem on the river is the Lower Basin solving the structural deficit, so we have owned that part of the problem,” said John Entsminger, general manager of the Southern Nevada Water Authority.

But the Lower Basin plan would require all states to share the pain of further cuts.

The plan calls for the Upper Basin states to take on half of any reductions above 1.5 million acre-feet.

Hamby touted that the Lower Basin states already reached a record low usage of Colorado River water, reducing their reliance on the waterway last year to the lowest levels since 1984.

“If we want a sustainable Colorado River Basin for future generations, opting out or passing the buck is not an option,” Hamby said. “It will take investment and sacrifice from all of us, but we know we can and will do it.”