Elephant Butte Reservoir in the early 20th century, courtesy USBR via Library of Congress
New Mexico once again fell short in 2023 of the requirement set out in the Rio Grande Compact to deliver water to Elephant Butte Reservoir for use in Southern New Mexico, Texas, and Mexico, delivering ~25,000 acre feet less than the Compact requires, according to preliminary estimates presented at Monday’s meeting of the Middle Rio Grande Conservancy District.
These numbers are preliminary. The final, official numbers will be sorted out at this spring’s meeting of the Rio Grande Compact Commission. But if they hold, that would put New Mexico’s cumulative Compact debt at ~125,000 acre feet.
Really bad things don’t start happening until New Mexico’s cumulative Compact debt rises above 200,00 acre feet, but less bad things are already happening now as a result of the debt. Under Article VI of the Compact:
Within the physical limitations of storage capacity in such reservoirs, New Mexico shall
retain water in storage at all times to the extent of its accrued debit.
Translated, that means any runoff we could actually store in upstream reservoirs in 2024 we can’t use, but rather have to hang onto to run down to Elephant Butte after the end of the irrigation season.
Run-of-the river again for Middle Valley irrigators, and for the fish
There’s a complex interaction here between physical storage* and rules. But the bottom line is that once again this summer, water users in New Mexico’s Middle Rio Grande Valley, the stretch of the river between Cochiti Pueblo and Elephant Butte Dam, will be entirely dependent on natural runoff available after the farmers in the San Luis Valley of Colorado take their share of the river.
I would predict, as a result, that:
- People who irrigate in the Middle Valley should expect a high risk of significant stretches with no ditch water in the summer,
- Water available for instream flows for the endangered Rio Grande silvery minnow will once again be extremely tight, with a high likelihood of drying in the Isleta and San Acacia reaches this summer, and
- The Albuquerque Bernalillo County Water Utility Authority is likely to shut down river diversions for its drinking water plant at some point in the summer and switch over to groundwater pumping so I can keep taking showers.
* Physical storage
El Vado Dam, built by the federal government and the Middle Rio Grande Conservancy District in the 1930s to store water during the spring runoff peak for irrigators to use in the late summer is under repair, a project taking way longer than expected. It’s likely that the necessary paperwork to store some water in Abiquiu Reservoir will be in place by runoff season, but the Compact Article VI debt means that water cannot be used for irrigation in 2024.
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