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4 things to know about Colorado River water in California

As California and six other western states scramble to reach a deal to cut use of Colorado River water, what will the federal government do?

CALIFORNIA, USA — This story was originally published by CalMatters.

Southern California water districts are grappling with what the fallout could look like if supplies from a critical source — the rapidly drying Colorado River — are cut next year. 

The US Bureau of Reclamation warned at a U.S. Senate hearing in mid-June that seven western states had 60 days to voluntarily reach a deal: Cut Colorado River water use by 2 to 4 million acre-feet in 2023 or face federally-mandated cuts instead. It’s a massive amount — at least seven times more than Nevada is entitled to in a year. 

As of Monday morning, no agreement had been struck, said Robert Schettler, a spokesperson for the Imperial Irrigation District, which receives the vast majority of the river’s water in California. “Progress has been made and we remain hopeful and work continues,” he said in an email. 

The Department of the Interior is expected today to address the status of the negotiations, the drought and future Colorado River conditions.

The verdict is especially high-stakes for Southern California, where the river provides a quarter or a third of the region’s water supply. Seven Southern California counties rely on the river for water and hydroelectric power, and 600,000 acres of farmland draw on it for irrigation. 

“Our region, our economy, our way of life in Southern California depends on the Colorado River,” said Bill Hasencamp, Colorado River resources manager for the giant Metropolitan Water District, which supplies imported water to 19 million people. “It is vitally important.”

But climate change, drought and overallocation have been threatening the Colorado River’s supply for decades, even as the amount consumed and lost through reservoir evaporation regularly outpaces its natural flows.

And now, with the two major reservoirs — Lake Mead and Lake Powell — at historically low levels, more needs to be done, warned Bureau of Reclamation Commissioner Camille Calimlim Touton at a June U.S. Senate hearing. “The system is at a tipping point,” Touton said in her written statement. 

What exactly “more” means — and what that means for California — is still under negotiation. Here’s what to know:  

California gets the most of any state

The Colorado River and its tributaries cut through seven U.S. states and Mexico, from the river’s headwaters in Colorado and Wyoming to where it trickles toward — though rarely actually reaches — the Gulf of California. 

A century of deals, acts and legal decisions have carved up 15 million acre-feet between Colorado, Wyoming, Utah and New Mexico in the Upper Basin, and California, Arizona and Nevada in the Lower Basin. Native American tribes hold rights to this water as well, and a 1944 treaty set aside another 1.5 million acre feet for Mexico. 

The biggest straw, by far, is California’s. The state is entitled to 4.4 million acre-feet, or more than a third of the river’s natural flow. It’s enough water to supply more than 13 million Southern California households for a year. In the Lower Basin, Arizona comes in next with about 2.8 million acre feet. 

Most of California’s Colorado River water is used for irrigation. The Imperial Irrigation District gets as much as 3.1 million acre feet a year, mostly supplied to nearly 475,000 acres of farmland and a handful of communities in the southeastern corner of California. Another major recipient is the Metropolitan Water District, which last year diverted roughly 1.1 million acre feet of water from the Colorado River system.

“(For) 81 years now, it’s been the backbone of our supply,” Metropolitan’s Hasencamp said. “Today, on average, about half of our imported water is from the Colorado River.” 

In 2019, the Upper and Lower Basin states struck agreements laying out who gets cut in the event of water shortages. The Lower Basin’s Drought Contingency Plan, in place through 2026, allowed for cuts to California’s deliveries for the first time. 

Arizona and Nevada, with more junior rights than the Golden State’s, start seeing cutbacks when water levels in Lake Mead drop to 1,090 feet; California’s cutbacks start when water levels hit between 1,040 and 1,045 feet. Lake Mead, the largest reservoir in the United States, is projected to drop to less than 1,040 feet by the close of 2022

“California — by virtue of the legal structures — is in a relatively good position on paper,” said John Fleck, director of University of New Mexico’s Water Resources Program and author of two books about the Colorado River.

“But the problem is that ‘on paper’ is not the reality now.” 

The river’s reservoirs are at a historic low

Drought has been parching the Colorado River basin for more than two decades. Even in years with close to normal levels of precipitation, less runoff is reaching the river — the result of increasing temperatures and drier soils drinking up the flows as climate change continues. 

“We’re just not seeing the benefits that we used to that we once had to surface water, streamflow runoff and reservoir storage,” Christopher Harris, executive director of the Colorado River Board of California, said at a June meeting of the State Water Resources Control Board. “It’s definitely impacted the reservoir system significantly.” 

Last summer, the U.S. Bureau of Reclamation called the first level-one shortage for the Lower Basin states, prompting cuts to Arizona, Nevada and Mexico — but not California. 

At the end of July, levels in Lake Mead, according to NASA, “stand at their lowest since April 1937, when the reservoir was still being filled for the first time.” 

The Colorado River is critical to the Imperial Valley

For the Imperial Irrigation District, the Colorado River is “our only source of water. We live in a desert. And that’s it,” Schettler said. Now, he said, “the onus is to generate a lot of water, rather quickly.” 

Schettler laid out two strategies for conservation: The first, he said, is farms conserving more with use of efficient strategies such as drip irrigation. “That may take some money, and then it may take a little while to get that water.”

Another possibility is fallowing fields — paying farmers to leave fields dry. It’s a strategy that the Imperial Irrigation District has employed in the past, but it’s unpopular, Schettler said.

“Fallowing is like the F word around here,” he said.

Southern Californians could face more restrictions

The cuts could have ripple effects across the entire state’s water portfolio. Southern California’s other sources of imported water from the northern half of the state are low, too, after several years of drought.

“What do we do when both systems are stressed out? And how do we manage ourselves?” Harris asked at a state water board meeting in June.

For the region served by the Metropolitan Water District, which has characterized the negotiations as difficult, “every type of water user could be affected, including urban and agricultural uses,” according to a recent district board presentation

The Metropolitan Water District has already implemented unprecedented watering restrictions for the 6 million Southern Californians who rely on the parched State Water Project, which funnels water from Northern California south and this year reduced deliveries to just 5% of requested supplies.

The district warned customers that receive Colorado River water that they could face restrictions as soon as next year.

“The areas that get water from the Colorado River are also going to have to conserve more,” Hasencamp said. “We’re going to have to, because we know we’re going to get less water in the future than we’re getting today. How much less we don’t know.”

California has seen federal cuts before — about 20 years ago, after water users failed to reach an agreement to cut back by 800,000 acre feet and stay within its 4.4 million acre-foot allocation. 

“Importantly for the future of water agreements in the basin, despite predictions of doom, California absorbed the reductions with only modest impact,” reported Fleck and Anne Castle, a former assistant secretary for water and science at the U.S. Department of the Interior.  

Eventually California water systems hashed out a deal. And now, Metropolitan’s Hasencamp said, it’s time to do so again.

“I think we’re going to be in a permanent state of shortage into the future. And the question isn’t ‘if’ anymore,” he said: It’s how big. “How big of a shortage are we going to have to endure? How big of cutbacks are we going to have to live with?’” 

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