We have a chance this year to watch a fascinating intersection of climate-change driven changes in the Rio Grande through Albuquerque as filtered through both physical infrastructure and what we call the “institutional hydrograph”.
Dust on snow is likely to accelerate Rio Grande headwaters snowmelt, meaning all that stored water comes off earlier. With nowhere to store it (see below, it’s an issue of both rules and physical infrastructure problems), we’ll be operating this year in a run-of-the-river situation on the middle Rio Grande through Albuquerque. Even though there’s still a lot of snow right now, once it comes off we’ll be down to base flow on the Rio Grande. Absent good summer rains, the river could dry through Albuquerque again this year.
Dust on Snow
The driver is a phenomenon researchers have identified in the past two decades called “dust on snow“. It’s when dry spring winds sweep across the arid uplands of, in our case, the Colorado Plateau, kicking up a layer or layers of dust that is then deposited atop the mountain snows in the high country. You can get multiple dust layers, and when the melt reaches them, the snow warms up and melts quicker. There’s a climate change connection to all of this, as hotter, drier springs seem to lead to more dust (which makes intuitive sense, and is discussed in Painter, Thomas H. et al. “Response of Colorado River runoff to dust radiative forcing in snow.” Proceedings of the National Academy of Sciences 107 (2010): 17125 – 17130.
We’ve got that going on this year in the Rio Grande headwaters. From this morning’s Downtown Albuquerque News:
April’s dry and windy conditions have deposited a lot of dust in the Rio Grande headwaters, so the snow will be generally less reflective and absorb more heat. That, in turn, “means runoff will likely be advanced, leaving less for the later summer months,” reported Angus Goodbody, a Natural Resources Conservation Service hydrologist.
The Physical Plumbing: El Vado Dam
In the “before times” (before the creation of the Middle Rio Grande Conservancy District in the early 20th century, which led to the construction of El Vado Dam) communities in New Mexico’s Middle Rio Grande depended on the run of the river. When the runoff dwindled in the summer, they couldn’t irrigate. (This is part of the reasoning behind our argument in the new book that claims that there once were ~125,000 acres irrigated in the Middle Valley are not credible.) Construction of El Vado allowed communities to do the classic “dams move water in time” thing – store some of the big spring peak and stretch it out through summer.
El Vado is busted, though, unusable while it undergoes repairs. As Dani Prokop reported last month, the repairs are dragging:
The dam’s unique steel faceplate is causing challenges for the contractors and storing water in 2024 is impossible, said Jennifer Faler, the area manager at the Bureau of Reclamation office in Albuquerque. Faler said the dam will possibly store some water in 2025, when another phase of construction on a spillway is underway.
That means no storage (other than a little bit in Abiquiu Reservoir for Native American communities) for irrigators, which means that once the snow is melted, the river will dwindle.
The Institutional Plumbing: Article VI
Even if El Vado wasn’t broken, though, we’d sorta be in the same bind thanks to Article VI of the Rio Grande compact, which says….
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
New Mexico’s compact debt to Texas – the net we’ve underdelivered in recent years – is 93,000 acre feet. So even if El Vado wasn’t broken, any water we were able to store up to 93,000 acre feet would have to stay there. (This is why the Middle Rio Grande Conservancy District has reduced its diversions this year to 80 percent of what the district otherwise be sending down its canals – to get more of that water to Elephant Butte Reservoir, to try to reduce compact debt, so they can usefully store water once El Vado is fixed. This is a whole other blog post, because the discourse around this has been fascinating as I do the “embedded writer” thing at MRGCD for my book research.)
Hydrology in the 21st century: understanding the rules
I was down at the Rio Grande yesterday morning to record an interview about western water stuff with a crew from Italian public television. (The were neat! It was fun!) A bosque walker asked what we were doing and Luca, the TV guy, explained that they were interviewing the professor (pointing to me). The woman asked if I was a hydrologist. No, I replied, I do water policy.
That’s the thing. To understand the flow in the river we were standing next to, you need to understand the physical science – climate, hydrology, and such. But then, crucially, you needs to think about how the actual wet water is filter through the system’s human-built physical plumbing, which then requires understanding who it all is filtered through the rules.
A note on sources, methods, and business models
At this point in a post like this, I often drop in a thanks to my supporters, who make this work possible, including the Utton Center and Inkstain’s contributors. But I’d also point you to the linked information sources above – Downtown Albuquerque News is subscription-supported and one of my favorite local news reads, and Source NM (Dani Prokop’s employer – she’s doing great water stuff, invaluable to the community). Information is a public good, and as my economist friends like to point out, because of the free rider problem, public goods are under-provided.
Evenl if it wasn’t…? This is a conditional statement and requires the conditional for of the verb – “weren’t” Failure to use the conditional has always grated on me. IN German war become waere.
As to El Vado, it seems as no one understands dams like Arthur Cassagrande and the old times did. I worked under Cassagrande for a little bit on Tarbella Dam in norther Pakistan. El Vado should be scraped. It was poorly built. The phreatic surface of the saturated zone in the porous media of the dam seem to intersect the front face of the dam and piping has occurred. For one thing I do not believe it has a chimney drain or a toe drain. You can’t fix it. the USBR boys should go look at Wolf Creek Dam in Kentucky.. I worked on that too for the Corps and my report was declared top secret for five years to give them time to try and fix it. I finally published my report. A steel face plate is not going to solve the problem. The USBR boys should have involved some of the engineers and contractors that are members of ICOLD and who do this stuff every day.
I couldn’t find a definition for the use of “piping” in Bill’s comment. So, I looked up ICOLD. As a building contractor, we occasionally found problems that were beyond fixing. Bill is probably right. But the politics of removal may not be surmountable.
“Most Frequent Causes of Dam Failures:
Overtopping of a dam is often a precursor of dam failure. Overtopping can be due to inadequate spillway design, debris blockage of spillways, or settlement of the dam crest
Foundation defects, including settlement and slope instability, are another cause of dam failures.
«Piping», that is internal erosion caused by seepage, is the third main cause. Seepage often occurs around hydraulic structures, such as pipes and spillways; through animal burrows; around roots of woody vegetation; and through cracks in dams, dam appurtenances, and dam foundations.
The other causes of dam failures include structural failure of the materials used in dam construction and inadequate maintenance.”
Perhaps not as important in the American Southwest as elsewhere, but dark anthropogenic aerosols are also leading to early snowmelt, according to some. I recall reading a paper or two a while back on this. Here is one and some others in the right sidebar.
Journal of Geophysical Research: Atmospheres
Impact of snow darkening via dust, black carbon, and organic carbon on boreal spring climate in the Earth system
Teppei J. Yasunari, Randal D. Koster, William K. M. Lau, Kyu-Myong Kim
First published: 07 May 2015
Nice blog post John, a few thoughts: 1) when it comes to reduced runoff, dust on snow certainly can result in more melt earlier. But, I think the lack of any meaningful snow and rain in the mountains since late March will have more impact. The April 1 most probable forecast assumes average precipitation will occur and that didn’t happen. Better to look at Gus’s 70% and 90% chance of exceedence volumes in the April 1 forecast to project the volume that will actually flow past Otowi.
2) as to the total farmland that may have been irrigated in the middle valley in the 1800s, it’s important to remember lands were farmed all the way south into what is now Bosque del Apaches, what was San Marcial, and what is Elephant Butte Reservoir. I remember seeing aerial photography of the San Marcial/Tiffany area from the early 1930s and most of the land looked as if it were irrigated or people were trying to do so. As to water, it’s important to remember that surface water was flowing from Colorado into New Mexico in the 1800s and earlier that no longer does.
3) As to El Vado, I think Reclamation had a good plan going in to rehabilitate the structure. And, like all plans, they get modified and refined as work begins and the crews learn from actual experience. Got my fingers crossed refinements to rhe grouting process will achieve the intended results
And, given how the Rio Grande Compact constrains storage of water (as you ably describe), it’s important for the entire middle Rio grande, not just MRGCD, that the dam be able to operate to near its 185,000 acre-foot capacity.
Without El Vado operations to re-regulate flows, the middle valley will see and feel the impacts of the natural variability of Rio Grande flow in New Mexico….highly variable with 60-70 percent of the annual flow occurring late March into June and very low late summer flows when the summer rains dont occur.
Looks like the Maysoon is… helping? keep the snow around? Even though there’s some rain on snow going on, the cooler temps seem to be keeping the SWE above 100% in all the basins of the Rio grande whereas before the Maysoon some of them were around 100%.
I suppose the rain may be moving the temp up in the snow column and creating conditions for faster melt when higher temps come back. But I am not protesting for now!