U.S. and Mexico finalizing Colorado River water-sharing deal
The level of Lake Mead has been declining dramatically, and climate change is expected to put additional pressures on water supplies. Richard Lui and Marilyn Chung/The Desert Sun
The U.S. and Mexican governments may be sharply at odds on President Trump's plan for a border wall, but when it comes to water – and the potential for a major shortage along the Colorado River – the two sides seem to be on the same page.
Mexican and American officials are finalizing a water-sharing deal for the Colorado River, and a newly released summary of the accord’s key points shows negotiators have agreed on a cooperative approach geared toward boosting reservoir levels and trying to stave off a severe shortage.
The document, which federal officials have circulated among water agencies, outlines a series of joint measures that build on the current 5-year agreement, which expires at the end of this year.
The new accord – titled Minute No. 323 to the 1944 Mexican Water Treaty – is expected to be signed sometime this fall, perhaps as early as September, and would remain in effect through 2026.
It would extend provisions in the current agreement, known as Minute 319, that specify reductions in water deliveries during a shortage, as well as increases in water deliveries during wet periods. The agreement also provides for Mexico to continue storing water in Lake Mead, near Las Vegas, helping to boost the reservoir’s levels, which in the past few years have dropped to historic lows.
The accord would also establish a “Binational Water Scarcity Contingency Plan,” in which Mexico would join U.S. states in temporarily taking less water out of Lake Mead to reduce the risks of the reservoir reaching critical levels.
Those commitments by Mexico would only take effect if California, Arizona and Nevada finish their own Drought Contingency Plan, under which the states would forgo larger amounts of water than they’ve previously agreed to as the reservoir's level declines.
“The Mexicans have demonstrated their interest in pursuing this, and it’s a clear benefit to the river to have more storage in Lake Mead,” said Bart Fisher, chairman of the Colorado River Board of California. He said the agreement would benefit water suppliers in California, Arizona and Nevada by giving them “certainty in case of shortage that Mexico will also share in the shortage.”
“All of those things put together, it’s a big win-win for both countries,” Fisher said.
The Colorado River and its tributaries provide water for nearly 40 million people and more than 5 million acres of farmland.
The legal framework that divvies up the Colorado River was established during wetter times nearly a century ago, starting with the 1922 Colorado River Compact. That and subsequent agreements have handed out more water than what flows in the river in an average year, leading to chronic overuse.
On top of that mismatch between supply and demand, the river has dwindled during a drought that has persisted for 17 years. Climate change is adding to the strains on the river, and scientists have projected that warming will likely cause the river’s flow to decrease by 35 percent or more this century.
Talks on the U.S.-Mexico agreement began during President Barack Obama’s administration and have continued with negotiating sessions held on both sides of the border by the International Boundary and Water Commission, which includes representatives of both governments. Representatives of U.S. states have also participated in the talks.
Even as political tensions have grown over Trump’s immigration policies and his vows to have Mexico foot the bill for a border wall, the Colorado River negotiations seem to have moved ahead relatively smoothly – pressed on by the approaching expiration of Minute 319.
“We largely concluded the framework for these negotiations a year ago,” Fisher said, “and the only fine-tuning has been the drought contingency portion, and cleaning up a little bit of inconsistent language.”
The agreement itself has not yet been publicly released. The summary provided by the U.S. Bureau of Reclamation was presented Wednesday at a board meeting of the Imperial Irrigation District, which holds the biggest single entitlement to water from the river.
In a memo, IID officials said in order to implement the U.S. commitments under the deal, several agreements must first be completed between the states, water agencies and the Interior Department.
Those agreements include a U.S.-funded program to invest $31.5 million in water conservation projects in Mexico, including infrastructure upgrades such as concrete lining for leaky canals and other improvements to reduce water losses from distribution systems.
The federal government will provide $16.5 million, while the remaining $15 million will come from four water agencies, including IID, the Metropolitan Water District of Southern California, the Southern Nevada Water Authority and the Central Arizona Water Conservation District.
Each of the water agencies will contribute a fourth of the funding. In return, they will receive a portion of the water freed up through conservation in Mexico.
The conservation projects are intended to generate a total of 229,000 acre-feet of water – enough to cover an area two-thirds the size of Los Angeles with a foot of water. Of that, 50,000 acre-feet will be used to give a boost to the Colorado River system and 70,000 acre-feet will be used to “satisfy the U.S. commitment to provide water for the environment.”
The accord lays out a cooperative strategy for Mexico and the U.S. states to jointly put the brakes on water use to reduce the risks of a crash in the system if the drought persists.
As of this week, Lake Mead stood at just 38% full, with its level at an elevation of nearly 1,080 feet, not far above the initial shortage threshold of 1,075 feet.
Under federal guidelines, the Interior Department would declare a shortage – which would trigger cutbacks for Arizona and Nevada – if Lake Mead’s level is projected to be below 1,075 feet as of the start of the following year.
In April, the Bureau of Reclamation estimated the odds of Lake Mead hitting shortage levels in 2019 at 31 percent. A previous projection had put the odds at 50-50 before the winter brought a substantial snowpack, which was measured at 113 percent of average across the Colorado River basin.
The government’s summary of Minute 323 says the United States and Mexico “share a common vision on a clear need for continued and additional actions to reduce the risk of reaching critical reservoir elevations at Lake Mead.”
The document details how continued declines at the reservoir would trigger a rising scale of cutbacks in water deliveries, with Mexico contributing alongside the states – as long as the states have a similar plan in place.
By developing this type of plan to reduce water use effectively, the aim is to reduce risks of severe shortages threatening water deliveries and the generation of hydroelectricity, said Jennifer Pitt, who leads the National Audubon Society's Colorado River project.
“It’s avoiding the shocks of sudden disruptions in water supply that is most important,” Pitt said. “But with these agreements, where the states and countries … commit together to a planned decrease in water use, I think the prospects for sustainable management increase greatly, and likely without severe economic impacts.”
The U.S.-Mexico deal includes a list of other measures, including establishing several joint working groups. One of them, according to the government’s outline, will focus on studying the potential for desalinating seawater from the Sea of Cortez.
One difference from the current U.S.-Mexico accord is that there is no mention of plans for a “pulse flow” that would send large quantities of water gushing into the long-dry Colorado River Delta. When this was tried in 2014, the huge release of water into the delta restored vegetation and brought back birdlife.
This time, the focus is instead on securing a more steady flow of water to sustain wetlands south of the border. Goals include expanding restored habitat areas from about 1,000 acres to 4,300 acres.
Under the agreement, Mexico, the U.S., and nongovernmental organizations will team up to secure water for environmental purposes, plus $18 million for habitat restoration and monitoring.
“It seems like everybody’s in agreement on how to address these challenging issues,” said Tina Shields, IID’s water manager, who presented an overview of Minute 323 to the district’s board.
Last year, water managers in California, Arizona and Nevada had expressed hope they would soon finish negotiating their Drought Contingency Plan. But those efforts have been delayed and the deal hasn’t been finalized.
Once the U.S.-Mexico deal is signed, Shields said she expects all of the water agencies and states will “double down on our efforts to get the Drought Contingency Plan through the finish line.”