Click the link to read the paper on the Getches-Wilkinson Center website (Eric Kuhn, Anne Castle, Carlos de la Parra, John Fleck, Jack Schmidt, Kathryn Sorensen, Katherine Tara). Here’s the abstract:
March 26, 2026
Since 1945, the United States and Mexico have managed common interests on their two largest shared rivers systems, the Colorado and the Rio Bravo/Rio Grande, under the terms of the 1944 international treaty that was designed from the beginning with tools to adapt to changing hydrologic and societal conditions. A recent emergency agreement on the Rio Bravo/Rio Grande illustrates what is possible, and with old river management rules on the Colorado both within the United States and between the United States and Mexico about to expire, we are at a moment of opportunity for meaningful change. The core problem on the Colorado River, which we address in the analysis that follows, arose from decisions made in the first half of the 20th century to allocate fixed volumes of water. As usage patterns and hydrology change in the 21st century, fixed volumes no longer work. [ed. emphasis mine] A shift to a percentage-based split between the United States and Mexico on the Colorado River, based on the river’s actual natural flow, would provide a solid foundation for the two countries’ joint management of the Colorado in the decades to come.
