Rio Grande treaty shortfalls leave Valley facing multi‑year water deficit, keynote warns

Sonny Hinojosa, a long‑time Rio Grande water manager and current Rio Grande Water Advocate, told attendees at the Rio Grande Valley Utility Conference in McAllen that the most recent five‑year treaty cycle with Mexico ended Oct. 24 with a significant delivery deficit that now becomes a debt for the new cycle.

Hinojosa summarized reservoir and treaty mechanics and the consequences for regional water users. He said the U.S. share of storage in the two international reservoirs is limited — ‘‘So we have 906,000 acre feet, which is a lot better than where we were, but still not enough water,’’ — and that Mexico ‘‘was in arrears when this cycle ended, 865,000 acre feet.’’ The keynote laid out the arithmetic that determines monthly allocations and the order in which reservoirs are drawn down, including dead storage, the domestic/municipal/industrial (DMI) reserve and operational reserves.

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