Transboundary river basins are geographic areas where a river system crosses political borders of two or more countries. These shared regions cover nearly half of the world’s land surface and support over half of its population, making their management critical for global water security. The U.S. and Mexico allocate water from the Colorado River and the Rio Grande under conditions of the 1944 Water Treaty. While there have been adjustments to use of the Colorado River water supplies in the U.S. among bordering states, there has been no comparable change negotiated for the Rio Grande. Researchers Vianey Rueda and Andrew D. Gronewold conducted a historical resimulation of water deliveries to evaluate the streamflow conditions required to uphold the treaty’s original allocations.
In their paper, “Evaluating Historical and Future Compliance with the 1944 US–Mexico Water Treaty under Changing Climate and Use Conditions,” they examine how rigid water-sharing agreements struggle under climate change and rising demand and suggest alternative delivery mechanisms that balance treaty compliance with community needs. This research is important because it demonstrates how outdated treaties can hinder sustainable water management and offers insights into adaptive strategies. These transboundary treaties were largely designed for a stable climate and based on optimistic streamflow estimates. Mexico is trying to balance the mounting political pressure around treaty compliance with the water needs of its communities. Learn more about how engineers can apply adaptive governance principles to develop resilient water allocation frameworks, optimize reservoir operations, and support equitable resource distribution in transboundary basins worldwide. Read the full paper in the Journal of Water Resources Planning and Management at https://ascelibrary.org/doi/10.1061/JWRMD5.WRENG-6884. The abstract is below.
Abstract
About half of the earth’s land surface is composed of international transboundary basins, half of which are managed by formal agreements. However, climate change, population growth, and other changing conditions are straining these agreements, leading to conflicts as riparian countries seek to protect historical water rights. The 1944 Water Treaty between the United States (US) and Mexico, which outlines specific allocations for Colorado River and Rio Grande waters, is one example. For the Rio Grande (known as the Río Bravo in Mexico) the Treaty prescribes Mexico’s mandated delivery of water to the US, and for the Colorado River it prescribes the US’s mandated delivery of water to Mexico. Overallocation of the Colorado River prompted negotiations that resulted in amendments to the Treaty, adapting water allocations to the basin’s conditions. Despite parallel overallocation of the Rio Grande and ongoing challenges to meet delivery obligations, the allotment of Rio Grande waters has not been revised. The Treaty’s inability to cope with the system’s variability exerts pressure on local communities as Mexico balances its local needs with its international duties amidst ongoing drought. This study evaluates the conditions necessary to uphold the Treaty by conducting a historical resimulation of treaty deliveries under various streamflow scenarios. An alternative delivery strategy was developed to assess the benefits of flexible deliveries. Results indicate that prolonged periods of above-average streamflow are necessary to meet mandated deliveries without disproportionately impacting Mexican communities. We also find that flexible deliveries increase treaty compliance and distribute the impacts of decreased flow between both countries.
Learn more about how to cope with dated water management guidelines in the ASCE Library: https://ascelibrary.org/doi/10.1061/JWRMD5.WRENG-6884.
