California – Facing a widening gap between the available water supply and demand from the Colorado River, three states in the Southwest announced a new plan today. This plan will reduce California’s water share by roughly 10% in most years. The states of California, Nevada, and Arizona have presented their proposal to the federal authorities. These authorities are currently considering how to oversee the river’s resources after 2026, when a significant existing agreement ends. This decision is crucial for the future management of the Colorado River, which serves as a crucial water source for 40 million people, including 30 tribal nations and supports 5.5 million acres of farmland.
For over 100 years, the Colorado River’s water has been divided among seven states, several tribes, and Mexico through a series of agreements, laws, treaties, and judicial rulings collectively referred to as the Law of the River. A prolonged and severe drought, marked by the driest 23-year stretch in over a century, has significantly reduced the river’s flow, which was already over-committed.
Although recent storms have brought some relief, the main reservoirs in the basin, Lake Mead and Lake Powell, are still at near-record low levels. According to a recent report by the U.S. Bureau of Reclamation, long-term conservation efforts are still essential. California is the largest consumer of Colorado River water, with an annual entitlement of 4.4 million acre-feet. The largest single consumer within California is the agricultural sector in the Imperial Valley, which uses over two-thirds of California’s water share (3.1 million acre-feet annually) to irrigate crops such as alfalfa and winter vegetables across half a million acres through the Imperial Irrigation District.
Another significant user is the Metropolitan Water District, which supplies water to 19 million people in Southern California. It typically uses about 1 million acre-feet of river water annually, as noted by Bill Hasencamp, the district’s manager of Colorado River resources. An acre-foot of water can supply three households in Southern California for one year.
It’s a big change that we will have to adapt to as a state,” Hasencamp said, adding “it’s 10%, so we should be able to tighten up our belt 10%.”
Under a new plan, the three states have decided to reduce their water consumption based on the water levels in the reservoirs. They will start cutting back when the water levels fall below 69% capacity, increasing to cuts of at least 1.5 million acre-feet per year when capacity drops below 58%. This amount represents about 17% of their combined water allocations and is enough to supply 3.75 million households in Southern California for a year. For the past decade, the reservoirs have generally been below these levels. If the reservoirs drop below 38% capacity, any further reductions up to 3.9 million acre-feet would be equally divided between the states in the Upper and Lower Basins.
Arizona will take on the largest reduction, cutting its usage by about 27% in most years. Nevada will reduce its usage by about 17%, and Mexico might also cut its use by 250,000 acre-feet, or 17% of its 1.5 million acre-feet entitlement under its agreement with the U.S. The new proposal introduces a mechanism for activating these reductions based on the water levels in seven basin reservoirs, not just Lake Mead, as explained by Bill Hasencamp.
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John Entsminger, general manager of the Southern Nevada Water Authority, emphasized during a briefing today that the goal of this new approach is to prevent any suspicion of states manipulating water levels for their benefit. He pointed out that even a small change in water levels at Lake Mead or Lake Powell can significantly affect water distribution, and there have been ongoing concerns about states adjusting these levels to their advantage. The proposed system aims to eliminate such possibilities and even the suspicion of such manipulation.
Despite having senior rights to Colorado River water, California has mostly been exempt from mandatory water cutbacks during droughts. However, a drought contingency plan established in 2019 included provisions for potential reductions in California’s water supply, although these have not yet been activated. With the recent severe drought conditions, the U.S. Bureau of Reclamation has called for further cuts beyond what the existing agreements require.
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All seven states that use the Colorado River basin—Colorado, New Mexico, Utah, Wyoming in the Upper Basin, and Arizona, California, and Nevada in the Lower Basin—had been collaborating on water management. However, negotiations have broken down, leading the Upper and Lower Basin states to submit competing plans to the U.S. Bureau of Reclamation, which is preparing to assess these proposals in December.
“Ideally, the seven states would be able to come to a degree of compromise like the three Lower Basin states have. And we hope that occurs. But that requires a spirit of collaboration and compromise by all seven states… We’ve not been experiencing that lately,” said J.B. Hamby, the state’s chief negotiator as chairman of the Colorado River Board of California, and also vice president of Imperial Irrigation District’s board of directors.
The Upper Basin states, which include Colorado, New Mexico, Utah, and Wyoming, have put forward a stringent plan for water cuts for California, Arizona, and Nevada. This plan would initiate reductions in water use when reservoir levels reach 90%, with further cuts of 1.5 million acre-feet as levels drop to 70%, and escalating to cuts of up to 3.9 million acre-feet if levels fall below 20%.
“We can no longer accept the status quo of Colorado River operations,” Becky Mitchell, Colorado’s Commissioner to the Upper Colorado River Commission, said in a statement. “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.”
However, the response from the Lower Basin states, particularly through the voice of Hamby, suggests these measures are excessively harsh.
“Those are pretty draconian scenarios that the Upper Basin states are suggesting, which would mean real devastation to Southern California, and trickle up throughout the rest of the state,” Hamby said.
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The plan agreed upon by Arizona, Nevada, and California does not specify the exact reductions for individual water users like the Imperial Valley Irrigation District, nor does it address compensation for these cuts. Hamby highlighted the need to first determine implementation strategies within the Lower Basin, and subsequently at the state and user levels
“The first stage here is just figuring out how do we make this happen within the Lower Basin. The next step is how do you make this happen within each individual state at the user level,” Hamby said. “And then a later phase is figuring out okay, what are the resources necessary to materialize all this?”
According to the Lower Basin’s proposal, no water reductions would be needed if reservoir levels are at 69% capacity. However, reservoir levels have not reached this mark in the past 20 years. Even with increased rainfall in 2023, major reservoirs are only at 43% capacity.
Mark Gold, from the Natural Resources Defense Council, acknowledged the significance of the Lower Basin states’ proposal for sustainable management but noted that it alone is insufficient. He emphasized the importance of federal and Upper Basin cooperation and proposed that water lost through evaporation should be deducted from each state’s river allocation.
In May, a major conservation agreement among California, Arizona, and Nevada aimed to save 3 million acre-feet of water through 2026, with substantial funding from the federal government. The Biden administration recently reported having paid approximately $670.2 million to support these conservation efforts, securing over 1.58 million acre-feet of water for the Basin.
The U.S. Bureau of Reclamation announced in October that recent conservation efforts, coupled with plentiful rain and snow, have averted immediate threats to water supplies and power generation. Yet, the agency highlighted the ongoing need for long-term solutions.
“Despite near-continuous drought-response actions in recent years, low-reservoir conditions have persisted and new infrastructure risks at Glen Canyon Dam have arisen,” the U.S. Bureau of Reclamation wrote last October. “More robust and adaptive guidelines are needed.”