United States And Mexico Announce Colorado River Cooperative Agreement

The United States and Mexico signed a formal agreement for new Colorado River operating guidelines for 2027 and 2028.

Minute 334 of the International Boundary and Water Commission, United States and Mexico (IBWC), “Colorado River Basin Cooperative Measures through December 31, 2028,” was signed on September 2, 2026, in El Paso, Texas, and approved by the U.S. and Mexican governments.

The agreement extends and replaces Colorado River basin cooperative measures from Minutes 323 (2017) and 330 (2024), and includes provisions on the following topics, among others:

Distribution of flows under low elevation reservoir conditions. Given record low hydrologic conditions in the basin, guidelines in effect in the United States establish reductions in allocations to U.S. users in the Lower Basin of 1.25 million acre-feet (1,542 million cubic meters) annually in 2027 and 2028. Therefore, Colorado River water deliveries to Mexico will be reduced by 250,000 acre-feet (308,372,250 cubic meters) per year during the same period. Similarly, if forecasts worsen, the two countries will consult on potential additional reductions for both countries in 2028.

Distribution of flows under high elevation reservoir conditions. Should forecasts indicate a likelihood of Lake Mead reaching an elevation of 1,125 feet mean sea level or above during 2027 and 2028, IBWC will discuss procedures that could be adopted to increase deliveries to Mexico. Additional water available to Mexico would be in proportion to that available to the United States.

Salinity. The agreement establishes a Salinity Pilot Program for 2027-2028 to manage the salinity of waters delivered to Mexico.

Environment. The new Minute continues the Binational Environmental Work Group and a partnership among the governments and non-governmental organizations to maintain existing habitat and to conduct environmental monitoring.

Mexico’s Water Reserve. Minute 334 also permits Mexico to keep the option of continuing to defer delivery of a portion of its Colorado River allocation as Mexico’s Water Reserve to be able to use this water in the future.

Projects. This agreement continues studies on new water sources and desalination initiated under Minute 323.

“This Minute makes sure water is shared fairly among our users and protects the health of the Colorado River during these difficult times,” said Chad McIntosh, Commissioner of the U.S. Section of the IBWC (USIBWC). “Both countries deserve a lot of credit for agreeing to these water reductions and other measures. I want to thank the USIBWC negotiators, the Bureau of Reclamation, and our Mexican partners for their hard work.”

Adriana Reséndez, the Commissioner of the Mexican Section of the IBWC, said: “Given scarcity conditions faced by the Colorado River, additional measures are needed to preserve the basin’s sustainability to benefit all users.” Further, she emphasized that Minute 334 maintains the concepts of proportionality and parity between both countries that have characterized Colorado River Minutes, in accordance with the 1944 Water Treaty. “We will continue monitoring the evolution of basin conditions and working with interested parties to seek the best solutions during scarcity,” she said.

“The Department of the Interior and the Bureau of Reclamation are appreciative of the collaborative approach taken in development of this Minute with Mexico,” said Andrea Travnicek, Assistant Secretary for Water and Science at the U.S. Department of the Interior. “During this time of prolonged drought, reductions will be shared and innovative approaches in management will be implemented to sustain the Colorado River basin.”