US to reduce Colorado River water deliveries to Mexico

A new Colorado Treaty amendment reduces Mexico’s Colorado River water allocation by 250,000 acre feet.

1 minute read

September 11, 2026, 7:00 AM PDT

By Zachary Whalen


The Hoover Dam blocking the Colorado River. The river's water level is noticeably low. The cliffs surrounding the blue water are brown and jagged.

An ongoing drought and record-low water levels at the Colorado River’s largest reservoirs has brought the river to critically low levels. | Mathew Risley

The United States and Mexico have signed a Colorado Treaty amendment under which the United States will reduce Colorado River water deliveries to Mexico by 250,000 acre feet, the International Boundary and Water Commission announced on Sept. 9. Mexico’s share of the Colorado is normally 1.5 million acre-feet. 

An ongoing drought and record-low water levels at the Colorado River’s largest reservoirs has brought the river to critically low levels. On Aug. 21, the Bureau of Reclamation released its two-year operating plan for the Colorado River, which requires the lower basin states — Arizona, California and Nevada — to reduce their use by 1.25 million acre-feet over the next two years. The plan called on Mexico to take 250,000 acre feet per year in reductions, which the temporary amendment, formally known as Minute 334, confirms. 

The agreement also ensures a continuation of environmental restoration projects in the Colorado River delta in Mexico, Brandon Loomis writes for Arizona Republic.

Wednesday, September 9, 2026 in The Arizona Republic

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