Water on the edge of the border. Crisis or platform for binational innovation?

The U.S.–Mexico border is at a hydrologic inflection point. In 2024, the Colorado River system operated under extraordinary cuts and conservation that momentarily stabilized Lakes Mead and Powell without fixing the river’s “structural deficit.” The current binational agreement (Minute 323) kept cooperation on track and, for 2024, meant a 50,000 acre-feet reduction for Mexico—about 5%—plus an additional 30,000 acre-feet contributed to Lake Mead as part of a lower-basin tri-national effort to conserve up to 3 million acre-feet by 2026. These adjustments mitigated immediate risks, though with unequal political and economic costs on each side of the border.

Meanwhile, 2024 left a stark picture on the Rio Grande/Río Bravo: the binational Amistad and Falcon reservoirs brushed historic lows and, in the lower Texas valley, storage fell below 15%, triggering the closure of the state’s last sugar mill and multi-year farm losses. As of September 1, 2025, Falcon hovers around 15% of capacity, confirming the fragility of recovery despite improved rains this year.

The year 2024 also accelerated regulatory and technological debates. The Bureau of Reclamation updated the process for post-2026 rules that will shape decades of operations at Powell and Mead, and in 2025 the Department of the Interior announced dozens of short-term conservation agreements while preparing a draft Environmental Impact Statement before year-end. The signal is clear: the scarcity regime will continue, with a real chance of deeper cuts in 2026 unless inflows or savings rise.

On the sanitation front, 2025 brought a historic turn with a roadmap and funding to dramatically reduce Tijuana’s sewage flows into California, including expanding the South Bay plant from 25 to 35 mgd and accelerating upgrades in Tijuana. By late July, governments announced the 10-mgd expansion completed in “100 days,” aiming to eliminate up to 90% of untreated coastal discharges. The ambition is enormous; the challenge is maintaining timelines and long-term operations on both sides.

Universities have been the technical hinge. The Water Resources Research Center (University of Arizona) and USGS led binational aquifer assessments—such as San Pedro—producing shared maps and metrics that now underpin rules for exchanges and joint monitoring. In 2025, academic and policy communities in Arizona and Sonora put back on the table instruments for transboundary groundwater, crucial amid aridification.

In 2024, “technology as insurance” advanced. El Paso broke ground on its direct potable reuse plant—up to 10 mgd by 2028—while other Southwest cities expanded smart metering, satellite-based evapotranspiration modeling, and increasing-block tariffs. For the Tijuana–San Diego corridor, the mix of treatment expansions, diversions, and real-time control is the bet to turn a sanitation liability into coastal resilience.

Politically, 2025 put the 1944 Treaty under the spotlight. Texas intensified pressure over deficits in the current five-year cycle, while recent data show an uptick in Mexican deliveries in 2025 after the severity of 2023–2024. Even so, delivery governance, calendars, and multi-year drought keep the risk of diplomatic tensions and internal litigation high. The ability to translate commitments into effective flows—without destabilizing agricultural basins in Chihuahua, Coahuila, or Tamaulipas—will be a stress test for the bilateral relationship.

My outlook for 2025 is twofold. On the Colorado, room to maneuver depends on institutionalizing “permanent-drought” savings and on a post-2026 package that allocates reductions by hydrologic reality and efficiency, not only by historical rights; the regional economy—from Imperial to Mexicali—needs certainty to invest in on-farm efficiency and productive shifts. On the Bravo, it is urgent to safeguard the rest of the cycle with verifiable calendars and a reservoir-recovery plan that prioritizes essential urban water and high-value crops, while enabling flexible exchange instruments and binational compensation. The opportunity lies in the tech-governance bridge: direct potable reuse, loss control, and shared aquifer monitoring—with open data—can turn the border into a global lab for water security. If 2024 showed that percentages matter—5% less for Mexico on the Colorado, 3 million acre-feet in conservation targets, Bravo reservoirs below 15%—then 2025 must show that cooperation turns figures into resilience, with clear rules, enforceable timelines, and stable financing on both sides of the line.

Written by: Editorial

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