The Colorado River breakthrough: How we got here

On Monday, the seven states in the Colorado River basin submitted a historic proposal to reduce the amount of water California, Arizona and Nevada draw from the river through 2026. The announcement comes after more than a year of disagreements and false starts as the states have negotiated how to distribute shares of the heavily overtapped water source. 

Since the 1920s, use of the river has been governed by the Colorado River Compact, a document drafted during an unusually wet period for the basin. Since then, the states have struggled for years to develop a new agreement that reflects modern water levels.   

The urgency of reaching a deal was compounded by the once-in-a-millennium drought that has hit the Western U.S. since the early 20th century, pushing the Colorado River to a breaking point. 

This winter was an unusually wet one in the region, but the water levels in lakes Powell and Meade dipped low enough last summer to prompt concerns that the vast Colorado River reservoirs might hit “dead pool” status, or the point at which their water would be too low to flow downstream to their respective dams, threatening their capacity to generate power. 

The initial agreement in 1922 allocated 7.5 million acre-feet from the river each to its Upper and Lower basins, which include Colorado, New Mexico, Utah and Wyoming; and Arizona, California and Nevada, respectively, while an international treaty in 1944 allocated 1.5 million acre-feet to Mexico. 

In 2007, the states drafted interim guidelines to govern water use during shortages in the Lower Basin, set to expire in 2026. Under those guidelines, if Lake Mead’s elevation fell to 1,075 feet or lower, Arizona would see a cut of about 11 percent to its annual water apportionment, while Nevada would see a cut of about 3.7 percent. 

The guidelines also stated that if Lake Mead’s levels reached 1,025 feet, Arizona’s allocation would be cut 80,000 acre-feet, while Nevada’s would be cut 80,000 acre-feet. 

More recently, in 2019, the basin states reached a stopgap contingency plan after months of talks intended to stave off disaster over the next five years. The states also negotiated regional contingency plans for the Upper and Lower basins.

The plans outline a process for temporary transfers of water stored in reservoirs above Lake Powell into the lake once it is projected to reach its target elevation, allowing it to maintain a level of at least 35 feet above the minimum required to produce hydropower. 

In the meantime, the threat of the federal government unilaterally imposing cuts has loomed over the negotiating process. In 2021, the U.S. declared a water shortage on the river for the first time in history, calling on the seven states to reach a deal to voluntarily cut 2 million to 4 million acre-feet from their use of Colorado River water with the implicit risk of federal cuts if they couldn’t strike a deal. No consensus had been reached by the rough August 2022 deadline.

The deal submitted this week marks a breakthrough in the process, though it still must be approved by the Bureau of Reclamation before taking effect 

The agreement would cut some 3 million acre-feet from the amount of water allocated to California, Arizona and Nevada through 2026. While the exact breakdown of how the cuts will be distributed among the states is not yet available, California has agreed to give up slightly more than half of the total allocations.  

It comes after the other six states in the basins signed off on a proposal that assigned California the bulk of the cuts in February, drawing pushback from the Golden State. Gov. Gavin Newsom (D) and other members of the California negotiating team have argued the state’s allocations are protected by Western water law.  

However, when the tentative agreement was announced Monday, California presented it alongside Arizona and Nevada, offering to collectively take a 13 percent hit to their Colorado River allocations. The river is the source of about one-third of Southern California’s municipal water, as well as its Imperial Valley’s agriculture sector, which generated about $2.3 billion in 2021.   

The agreement is funded by a combination of voluntary commitments and about $1.2 billion from the federal government in Inflation Reduction Act funds. The federal funds alone will cover about 75 percent of the reduced allocation, according to officials.