Rio Grande overbanking May 3, 2023 finally topped my little bike trail north of Albuquerque’s Central Avenue Bridge. ~4k cubic feet per second.

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”.

The tl;dr

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
accrued debit.

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.

If you squint you can see the ribbons of green between the power poles and buildings of downtown Albuquerque

There’s a weird bench at the edge of a lovely little ten acre patch of desert sand hill scrub a ten minute walk from my office at the UNM School of Law.

The path circles the edge of the university’s north golf course, which is green and lovely in its pumped-groundwater way. The path (It’s a formal county recreational path, there are even signs!) cuts through some medical school buildings and emerges into one of the only patches of what feels like old open desert in the heart of the city.

For much of the history of human habitation of this valley, the line between valley floor and sand hills was sharp, a defining characteristic of the social ecological system. The main north-south route through this part of the valley is a mile downhill from my bench, skirting the bottom edge of the sand hills – high enough to be out of the Rio Grande flood plain, but just barely. It’s obscured in the picture by buildings, and even when you’re driving it in a car (or cycling it, which I don’t recommend), the urbanscape of pavement and irrigation draped across the landscape renders the edge between sand hills and valley floor unrecognizable.

That’s the literary trick – the use of contrast – that is at work in John Van Dyke’s famous “ribbons of green” passage (it of the title for our new book) in The Desert:

The desert terraces on either side (sometimes there is a row of sand-dunes) come down to meet these “bottom” lands, and the line where the one leaves off and the other begins is drawn as with the sharp edge of a knife. Seen from the distant mountain tops the river moves between two long ribbons of green, and the borders and the gray and gold mesas of the desert.

The line was especially obvious on an epic bike ride yesterday across Pajarito Mesa on Albuquerque’s west side. Through an accident of tangled property ownership, it’s sorta undeveloped, home to feral horses, some scraggly cattle, and some ramshackle off-the-grid colonias. After a couple of hours on the mesa’s informal dirt roads (surprisingly ridable – the dirt roads out on the sand hills are notorious), we dropped over the edge of the escarpment, past the dump and down Pajarito Road, toward the valley, and Scot drew my attention to the ribbons of green flanking the Rio Grande, spread out across the valley floor.

The contrast, after miles of desert riding, was visceral.

It was, as Van Dyke noted, “drawn as with the sharp edge of a knife”. I’ve read that passage umpty times, but with the detritus of a city draped over the landscape it’s sometimes hard to see with any clarity the central point Van Dyke was making in the way he drew his contrast.

This would bear no mention in a landscape where everything is green. It’s the contrast, and Van Dyke’s effortless portrayal of it, that makes the passage work.

This is why the little patch of desert out behind the law school is so useful. In a city where we’ve largely erased the knife-line of the ribbons’ edge, it is helpful to pop out for a lunchtime walk to make it real.

(update: Scot’s travelogue is here.)

Rio Grande overbanking, Albuquerque, April 22, 2023. By John Fleck

In the early 1990s, a group of New Mexico scientists set up experimental plots at the Bosque del Apache National Wildlife Refuge on the Rio Grande south of Albuquerque for in an effort to determine what might happen when water was reintroduced to the flood-starved woods flanking the river. Their description of what happened is a delight:

The forest floor at the leading edge of the floodwaters came alive with hopping crickets and running spiders.

Molles Jr, Manuel C., et al. “Managed flooding for riparian ecosystem restoration: Managed flooding reorganizes riparian forest ecosystems along the middle Rio Grande in New Mexico.” BioScience 48.9 (1998): 749-756.

From time immemorial, this must have been a near-annual event, as the crickets and spiders scurried ahead of rising water each spring as the Rio Grande spread across the valley floor – bad for people trying to live here, great for the flora and fauna. From the same group of authors:

Extensive valley flooding would have occurred when heavy spring rains accompanied rapid snowpack melting. Whatever social disruption these floods may have caused, they would also have recharged the floodplain’s water table, saturated newly formed seedbeds, allowed fish access to nutrients released by flooded detritus on the forest flood, and accelerated nutrient fluxes in the bosque soil.

Crawford, Clifford S., Lisa M. Ellis, and Manuel C. Jr. Molles. “The Middle Rio Grande Bosque: An Endangered Ecosystem.” New Mexico Journal of Science 36 (November 1996): 276–99.

This changed in the early 1930s, dramatically, in an ecological instant as the newly formed Middle Rio Grande Conservancy District dug drainage ditches on either side of the Rio Grande and across the valley floor, throwing up the excavated dirt in spoil bank levees flanking the river’s then-main channel.

We understand what happened next thanks to a University of New Mexico biology student named Marjorie Van Cleave, who for her 1935 masters thesis documented the change. In that historic moment, plants and animals dependent on the wetlands spread across the valley floor disappeared.

As the water table was lowered three to ten feet with the construction of the Conservancy drains the swamps and lake disappeared almost immediately, leaving bare areas with water tables at various levels where succession advanced and is still advancing rapidly.

Van Cleave, Marjorie. “Vegetative changes in the Middle Rio Grande conservancy district.” (1935).

Cattails – gone. Sedges, with deeper roots, hung on for a bit longer before fading into the ecological mists. Cocklebur, Russian thistle, lamb’s quarters, sunflowers, and pigweed colonized the old marshlands of the valley floor. We are forever in Van Cleave’s debt.

What we’re seeing this spring on the fringes of the Rio Grande bears so little resemblance to the valley-wide ecosystem that it seems cheap to even compare, but the careful work of Cliff Crawford, Manual Molles, and their colleagues three decades ago trying to address this question – What would happen if we reintroduced just a bit of flooding to the forests on the river’s edges? – nevertheless draws a critical connection between the Rio Grande and the community that surrounds it.

For our forthcoming book Ribbons of Green, Bob Berrens and I are interested in that critical moment in the 1930s when, with levees and drains, the valley floor around Albuquerque was disconnected from the river. The ecology was changed, suddenly, as was the connection between human communities and their river.

From my Sept. 8, 2010 obituary of Cliff Crawford, in the Albuquerque Journal

Much of our modern understanding of the bosque ecosystem is built on the work of Crawford and Molles, who started taking students down to the river in the 1980s. For much of the time between Van Cleave’s exhaustive work and the return of Crawford, Molles, and their students in the 1980s, little scientific attention seems to have been paid to the riverside ecosystem.

I can’t find the newspaper story I wrote based on a visit to the bosque with Cliff Crawford and his then-grad student and now my good friend Mary Harner. But I did find the obituary I wrote when Cliff died in 2010.

It’s a model in my mind for public-facing science, and I’ve been thinking about it a lot as Bob and I wrestle with how to explain, in our book, Albuquerque’s modern relationship with the Rio Grande.

Mary has done an amazing job with her Witnessing Watersheds project of thinking about and documenting Albuquerque’s historic relationship with the river, and the time I have spent with her – mostly walking in the bosque, some to think of it – has been a huge influence on how I think about and approach this question.

Given flood control flow constraints, it’s hard to to get enough water through town to rise up out of the main channel and get back into the woods these days, to get it to “come alive with hopping crickets and running spiders,” but with 2023’s big snowpack, but there enough low spots providing delightful exceptions, and we’re already starting to see it rising up into those. Lissa and I were on a bosque trail near downtown Saturday when we were stopped by the water you see in the picture at the top of the blog.

There’s a sciency thing going on here – nutrient cycling, clearing out all the dry crud built up on the forest floor that in a more “natural” system would be wetted most years. (It was, in fact, Mary Harner who turned me on to the Molles et al paper I quoted above, with the hopping crickets and running spiders, when I asked for help running down the nutrient cycling piece. It turns out to be super nerdy and I probably won’t put it in the book.)

But it’s the cultural piece that I’m more interested in – the way we as a community have shifted from a desire in the 1930s to fence ourselves off from the river completely, to embracing overbanking with delight.

As often happens with these little mini-essays – sketches, really, for the book – this didn’t end up where I expected. I started with the intention of writing about nutrient cycling – printouts of research papers scattered across my desk, underlined bits, an excessive number of browser tabs.

But I realize that this is, in fact, a story about the relationship between a community and its river.