SACRAMENTO, Calif. — California could receive less water from the Colorado River under a new proposal from the U.S. Department of the Interior.

The cutbacks could happen as early as 2024 and last through 2026, according to a draft Supplemental Environmental Impact Statement the department released Tuesday to protect the Colorado River’s sustainability as one of the western states’ main water supplies endures 23 years of drought. 

The draft statement offered three alternatives to address the very real possibility that the river’s unprecedented water shortages will continue.

While one option is to take no action, so-called “action alternative 1” calls for reduced water releases based on the existing priority of water rights among the seven states that rely on the river and would preserve California’s ability to claim the lion’s share.

“Action alternative 2” would require all states to cut their Colorado River water use by the same percentage.

California is the largest user of Colorado River supplies and has senior rights to its resources based on agreements and court rulings over the past decades. It is one of seven states that relies on the river not only for water but hydropower, recreation, fish and wildlife habitat, according to the U.S. Bureau of Reclamation.

Last year, the Bureau of Reclamation asked the seven states that rely on the Colorado River to reduce their usage by as much as 4 million acre-feet each year because of diminishing water flows. While Arizona, Nevada, Colorado, New Mexico, Utah and Wyoming agreed in January to reduce their Colorado River water usage by 2.9 million acre-feet, California offered to reduce its usage by only 400,000 acre-feet.  

The Interior Department’s Supplemental Environmental Impact Statement is designed “to address the continued potential for low run-off conditions and unprecedented water shortages in the Colorado River Basin,” the agency said in a statement. It will govern Colorado River operations on an interim basis until the end of 2026 when the existing water rights are set to be renegotiated.

“The Colorado River Basin provides water for more than 40 million Americans. It fuels hydropower resources in eight states, supports agriculture and agricultural communities across the West and is a crucial resource for 30 Tribal Nations. Failure is not an option,” Deputy Secretary of the Interior Tommy Beaudreau said in a statement on the department’s website.

He said the Biden-Harris administration is “bringing every tool and every resource to bear” in recognition of the severity of a worsening drought. 

The Department of the Interior began developing its environmental impact assessment in Oct. 2022 in collaboration with the seven states and 30 tribes that rely on Colorado River water, as well as water managers, farmers, irrigators, municipalities and other stakeholders.

The draft statement is open for public comment through May 30, after which the department is expected to make a final decision this summer.