The United States and Mexico have signed a new agreement establishing cooperative Colorado River operating measures for 2027 and 2028, including reductions to Mexico's water deliveries as the basin continues to face historically low reservoir conditions.

Minute 334, signed Sept. 2 in El Paso, Texas, extends and replaces cooperative measures established under Minutes 323 and 330. The agreement will remain in effect through Dec. 31, 2028.

Under the new guidelines, Mexico's annual Colorado River deliveries will be reduced by 250,000 acre-feet in 2027 and 2028. The reductions correspond with guidelines that call for U.S. Lower Basin users to reduce annual allocations by 1.25 million acre-feet during the same period.

The two countries also agreed to consult on potential additional reductions in 2028 if hydrologic forecasts worsen. Conversely, if forecasts indicate Lake Mead could reach an elevation of 1,125 feet or higher, the International Boundary and Water Commission will discuss procedures for increasing deliveries to Mexico, with additional water distributed proportionally to availability in the United States.

The agreement also establishes a salinity pilot program for 2027 and 2028, continues binational environmental work and allows Mexico to continue deferring portions of its allocation through its Water Reserve for future use. In addition, Minute 334 continues studies into new water sources and desalination that began under the previous agreement.

“Given scarcity conditions faced by the Colorado River, additional measures are needed to preserve the basin’s sustainability to benefit all users,” said Adriana Reséndez, commissioner of the Mexican Section of the IBWC, in a press release.

U.S. Section Commissioner Chad McIntosh said the agreement continues the principle of shared reductions between the two countries during ongoing drought conditions.