The Rio Grande’s Institutional Hydrograph: December 2025

Blue sky above a bluff to the left and a brown river flowing through a landscape, the vegetation having winter colors.

Rio Grande, rising. Nov. 30, 2025, by John Fleck

After a dry summer, the Rio Grande is up through Albuquerque – ~900cfs as I write this, above the median flow for early December.

We are heading into “institutional hydrograph” season, as water management rules dominate the river’s flow. They always dominate, but December is when it’s most obvious. Water stored for Pueblo farmers but then not needed is moved from one bucket (Abiquiu Reservoir) to another (Elephant Butte) to meet Rio Grande Compact obligations to southern New Mexico and Texas.

Releases out of Abiquiu jumped over the weekend from ~100 cfs to ~800 cfs, so we should expect Albuquerque flows to rise in response soon. This is normal December practice, as we do the physical movement of water to accomplish the legal accounting task.

New Mexico began 2025 with a compact debtof 124,000 acre feet owed to southern New Mexico and Texas. We don’t have any official/public number for how we’ve done this year but the gossip (We only bring you the highest quality gossip here at Inkstain, but it’s just gossip.) is that New Mexico will fall another 10,000 acre feet deeper into the hole when the 2025 accounting is completed.

The forever task

Getting the water currently parked in Abiquiu down to Elephant Butte requires us to confront a fascinating set of questions that are at the heart of what’s looking like my/our next book: when you take on the “management” of a river, the unruliness of geomorphology makes it a forever obligation. A river is sediment as much as it is water, and you can’t manage one without managing the other. Forever.

The Rio Chama

Exhibit 1 is the Rio Chama below Abiquiu. In June 2024, a storm blew out the Arroyo la Madera and dumped a mile-long pile of sediment deep enough to completely block the Chama. A technically complicated, and even more bureaucratically complicated effort followed to clear the channel to allow water through that segment of the river. By the start of 2025, river managers (that appellation needs such careful qualification) thought they had the capacity to move a thousand cfs, but this year was so dry we still haven’t been able to test it.

Now’s our chance! 800 cfs and counting!

River Mile 60 and the Lower San Acacia Reach

Exhibit 2, the other geomorphologic bookend on this stretch of the Rio Grande, is what is called, in the poetic language of the engineers, “River Mile 60,” at the head of the Elephant Butte Reservoir delta.

Reclamation over the holiday weekend dropped the 302-page draft Environmental Impact Statement for the Lower San Acacia Reach Improvement Project, a hundred-and-umpty-million dollar project to realign the river at the bottom end of the Rio Grande Valley because the marriage of sediment and water management is not going real well down there.

I played with that sentence for a while, because the metaphor is tricky. The “marriage of sediment and water” is going just fine – the river doin’ river things. As at the confluence of the Rio Chama and the Arroyo la Madera, the problem isn’t the sediment and the river, the problem is that we’ve built a bunch of stuff that requires rivers to act one way to support human flourishing, which becomes stunningly expensive when rivers want to behave in a different way.

In the Lower San Acacia Reach, we have huge sediment inputs from the Rio Puerco and the Rio Salado (glorious ephemeral desert rivers, mostly dry but impressive in full flower), plus lots more side arroyos that happily contribute more clays and sands and gravels. Rivers doin’ river things.

For our purposes as humans who have built a metro area of a million people upstream of the Lower San Acacia Reach, and another metro area of many more millions to the south, keeping the water moving between A and B poses a forever challenge.

Map of the Middle Rio Grande, showing Rio Chama sediment plug to the north of Albuquerque and River Mile 60 to the south

Middle Rio Grande

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