Understanding California’s relationship with the Colorado River

Relationship Which states get water from the river?

The Colorado River begins as a trickle from snowmelt in the Rocky Mountains and flows for 1,450 miles across the U.S. Southwest and into Mexico. It provides drinking water to almost 40 million people and irrigates 5.5 million acres of farmland across seven states. 

Each state’s annual water allotment is based on a series of compacts, agreements, congressional acts and court decrees made over many years. Under the agreements, the U.S. river states are divided into two “basins.” Colorado, New Mexico, Utah and Wyoming form the “Upper Basin” and have the rights to a combined 7.5 million acre-feet of water annually. (Each acre-foot can supply about two households with water for a year.) These states’ allotments are broken down by percentage of the available supply: Colorado has 51.75%, New Mexico 11.25%, Utah 23% and Wyoming 14%. 

The three “Lower Basin” states also receive 7.5 million acre-feet. Of that, California has the right to take up to 4.4 million acre-feet from the river each year; because they have the oldest legal rights to the river, Californians are also the last to see cuts during drought. The two other Lower Basin states are Arizona, which receives 2.8 million acre-feet, and Nevada, which receives 300,000. Arizona is additionally entitled to 50,000 acre-feet of water from the Upper Basin share, according to Chris Arend, a spokesperson for the Colorado Water Conservation Board.

Mexico, meanwhile, is entitled to 1.5 million acre-feet.

Relationship Why are states being asked to cut back their water allotments?

The Colorado River is diminishing due to long-term overuse and a 23-year megadrought accelerated by climate change. The water allocations were based on a historical water flow of 15 million to 18 million acre-feet annually, according to a spokesperson from the Department of the Interior. But in recent years, under 13 million acre-feet a year have flowed down the river on average. That’s less than the U.S. and Mexico take from the river annually, with the remainder of the water coming out of the river’s reservoirs.

Its two largest reservoirs, Lake Mead and Lake Powell, are currently at their lowest levels since being created, and both are at serious risk of reaching the state of “dead pool,” when water stops flowing downstream from the dams. Even before that crisis is reached, lower reservoir levels result in less power being generated by the hydroelectric plants at the base of the dams. 

Last year, the U.S. Bureau of Reclamation asked the seven states that rely on the river to propose ways to cut allocations by 2 million to 4 million acre-feet across all seven states to prevent the reservoirs from dipping to those dangerously low levels. 

“The reservoirs are a blinking red light on the dashboard,” said Lisa Lien-Mager, a spokesperson for the California Natural Resources Agency, whose many departments include the Colorado River Board of California.

Relationship What are states doing to reduce their water usage?  

At the end of January, six states joined together and released a proposal to cut the water rights of the Lower Basin states by 2.9 million acre-feet, including more than 1 million acre-feet from California’s take, according to CalMatters. California was the only state to oppose that plan, issuing a competing proposal the next day, restating a commitment to cut its usage by just 400,000 acre-feet. The state also outlined a tiered plan that would require additional cuts for California, Nevada and Arizona if reservoirs drop to certain levels. Federal water officials must now analyze the two proposals and make a final determination to allocate water to each state.

“Everyone agrees on the problem statement,” Lien-Mager said. “This is a really extraordinary situation, and extraordinary actions are going to be needed.”

Relationship What does California do with the water from the Colorado River?

California uses about two-thirds of its allocation for agriculture, mainly in the Imperial Valley, which stretches between the Mexican border and the Salton Sea east of San Diego. The other third is used as drinking water in urban areas of Southern California, including Los Angeles and San Diego. 

Relationship Why does California get so much water compared to other states?

California was the first state to divert water from the Colorado River, and its legal claims go back more than 120 years. The California Development Company began pulling water from the river in 1901, transporting it to the Imperial Valley through the Alamo Canal and helping transform the California desert into a farmland oasis.

The Imperial Irrigation District later purchased the company, along with its right to take 2.6 million acre-feet annually from the Colorado River. The irrigation district now takes 3 million acre-feet a year, using 98% percent of it to grow crops, including water-intensive ones like alfalfa and winter vegetables, on land that would otherwise be inhospitable to most farming.

The other big user in California is the Metropolitan Water District of Southern California, a wholesaler that sells its Colorado River rights to agencies serving 19 million residents across Los Angeles, Orange, Riverside, San Bernardino, San Diego and Ventura counties, as well as agriculture. It’s this system that allowed Los Angeles to evolve into a thriving metropolis with sprawling suburbs, despite having few natural sources of fresh water. 

Metropolitan has a basic allocation of 550,000 acre-feet, according to spokesperson Rebecca Kimitch, although it can access up to a total of 1.1 million acre-feet through long-standing partnerships with agriculture, if needed. 

Relationship What does less water from the Colorado River mean for California?

The Imperial Irrigation District receives the largest share of California’s Colorado River allotment and would see the biggest impact if the federal government requires reductions. In California’s proposal to cut 400,000 acre-feet of water, about 250,000 acre-feet of that would likely come from the irrigation district’s allotment, according to district spokesperson Robert Schettler. 

The district currently offers monetary incentives to farmers who conserve water, such as by using sprinklers or drip systems instead of flooding fields. Those programs would be enhanced if there’s less water to go around, Schettler said. The district is also looking at ways to incentivize farmers to let their land go fallow a few months of the year. 

A significant portion of the water California receives from the Colorado River is used for farming in the Imperial Valley. (RJ Sangosti/MediaNews Group/The /Denver Post Via Getty Images)
A significant portion of the water California receives from the Colorado River is used for farming in the Imperial Valley. (RJ Sangosti/MediaNews Group/The /Denver Post Via Getty Images)

“This is difficult for us to swallow here because we’re already a disadvantaged community that’s dependent on farming for jobs and our livelihood,” Schettler said.

Metropolitan is also facing an urgent need to conserve. The agency has historically imported about 60% of its water, from both the Colorado River and Northern California. Kimitch said the agency is on track to reduce that to 40% by 2040, through both conservation and recycling. 

To meet that goal, Metropolitan has begun paying farmers not to grow anything during certain times of the year and offering rebates to homeowners who replace lawns with drought-friendly landscaping. The agency is also building a water recycling facility that is projected to produce 150 million gallons of water a day, enough to supply 500,000 homes.

While Southern California stands to see the greatest impact, Lien-Mager said the diminishing river system is emblematic of the bigger threat of climate change, which impacts all Californians. Preventing future water crises will take massive efforts at every level, she said, from city ordinances on water use to major state-funded infrastructure projects, including desalination plants and stormwater systems to capture rain more efficiently during big storms. California lawmakers have set aside approximately $5.6 billion to support such “water resilience projects,” according to Lien-Mager.

“With climate change manifesting, our conditions overall are going to become hotter and drier, with weird storms every now and then,” she said. “The water supplies for the future are going to be less and more unpredictable than they were in the past. We’ve got to be using water as efficiently as we can.”