The drying of New Mexico’s Rio Grande

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I went on a bike ride this morning to get a look at the Rio Grande through Albuquerque. Flows dropped below 100 cubic feet per second Thursday evening for just the second time since we moved here in 1990. Flows this low are hard to measure – we didn’t get a numerical picture of just how bad things are until the USGS river measurement people calibrated their Central Avenue gauge Friday morning.

The other time we had flows this low during my tenure as an Albuquerque resident was September 2013 (I remember it well, I was covering the heck out of the river for the Albuquerque Journal at the time). But it’s worth looking back in time, because the flows we’re seeing this year, which are freaking me out, used to be a nearly annual affair. Here’s a plot of annual minimum flow, based on USGS data:

Annual Rio Grande low flows

This is a classic result of what I’ve come to call “an institutional hydrograph”. A hydrograph is a graph of flow on a river over time. In its normal form, it responds to seasons, weather, and climate. But in its institutional form, it responds to rules and policies and norms of human behavior in managing the river.

Those zero-flow points on the left half of the graph are institutional. From the mid-1940s to the early 1980s, we dried the river through Albuquerque almost every year. I phrased it that way on purpose – not “the river went dry” but “we dried the river”. If you look at upstream gauges, there was water in the Rio Grande, flowing into the central valley where Albuquerque sits. But the irrigation agency that provides water to this valley’s farmers diverted it all, running its ditches full, so that by the time the Rio Grande reached Albuquerque, it was dry.

I’m hazy on some of the history, but by the time I started paying attention to the Rio Grande in the 1990s, a combination of community environmental values and the strictures of the Endangered Species Act had triggered changes in irrigation management. As a matter of policy we now leave water in the river. So for my generation of river-watchers, this is a really striking thing to see:

Rio Grande south of Albuquerque’s Central Avenue Bridge, Sept. 15, 2018, by John Fleck

Tough to be a fish in the Colorado River

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As Lake Powell drops, a waterfall forms at the reservoir’s upper end as the San Juan cuts down through sediments dropped when the reservoir was fuller. The resulting waterfall is a bit of an obstacle to fish:

The razorback sucker population estimate for 2017 alone was 755 individuals and, relative to recent population estimates ranging from ~2,000 to ~4,000 individuals, suggests that a substantial population exists seasonally downstream of this barrier. Barriers to fish movement in rivers above reservoirs are not unique; thus, the formation of this waterfall exemplifies how water development and hydrology can interact to cause unforeseen changes to a riverscape

Cathcart, C. N., Pennock, C. A., Cheek, C. A., McKinstry, M. C., MacKinnon, P. D., Conner, M. M., & Gido, K. B. Waterfall formation at a desert river–reservoir delta isolates endangered fishes. River Research and Applications

Draining the reservoirs on New Mexico’s Rio Grande

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A rapidly drying Rio Grande at Albuquerque, Sept. 9, 2018. Photo by John Fleck

tl;dr

Total reservoir storage on the Rio Grande in New Mexico at the end of August was the lowest it’s been since at least 1980.

longer (with graphs!)

In our University of New Mexico Water Resources Program class, we’ve been discussing the state of the Rio Grande in real time. This feels like a remarkable moment, for teaching.

The water managers down on New Mexico’s Lower Rio Grande have made the conscious decision to essentially drain Elephant Butte Reservoir – the primary source of surface water supplies for farmers in the Hatch and Mesilla valleys. Elephant Butte, a 2 million acre foot reservoir, ended August with just 85,000 acre feet of water, something like 4 percent of capacity. That’s the lowest it’s been at this point in the year since 1972.

Simultaneously, we’ve made a similar decision upstream – draining Abiquiu, El Vado, and Heron reservoirs on the Rio Chama in order to continue deliveries to farmers in this part of the state, with some water devoted to instream flows for the endangered Rio Grande silvery minnow.

We essentially manage the two parts of the system separately, but I was wondering what it would look like if we looked at them together:

Combined end-of-August storage in Heron, El Vado, Abiquiu, Elephant Butte, and Caballo reservoirs

The US Bureau of Reclamation datasets available on a Sunday afternoon lack the necessary detail prior to 1980 for some of the reservoirs, so that’s as far back as the graph goes.

We’re draining these things and hoping for a wet winter.

Don’t forget Lake Powell

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From 2000 through the end of 2018 (projected), Lake Powell’s elevation will have dropped approximately 94 feet despite Upper Basin consumption only averaging about 4.5 million acre?feet (maf)/year. Several particularly dry years—including 2018—in a process of continuing aridification contributed to the drop, but ultimately it is the operational rules that are slowly but surely draining Lake Powell. Through 2018, cumulative releases since 2000 from the reservoir will be approximately 11 maf higher than the 8.23 maf/year baseline traditionally utilized by Reclamation (see figure on page 3). Had those excess releases remained in Lake Powell, the lake level would not have declined. However, those extra releases—now governed by the 2007 Interim Guidelines—are the only thing that has kept Lake Mead from dropping into shortage conditions.

That’s from the a new white paper – It’s hard to fill a bathtub when the drain is wide open: The case of Lake Powell – from the folks at the Colorado River Research Group.

For not fighting over

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Wolf and his colleagues combed through thousands of newspaper clippings and historical accounts of anything having to do with water at international borders. He ranked every event on a scale of -7 to +7, with numbers below zero indicating worsening degrees of conflict, and numbers above zero pointing to increasing degrees of collaboration. “It turns out two-thirds of the time we do anything over water, we cooperate,” Wolf says. “There was a whole rich history that isn’t covered anywhere.”

In a warming world, the fight for water can push nations apart—or bring them together

Colorado River shortage looming because Lower Basin is using too much water

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tl;dr The Lower Colorado River Basin has gotten 10 million acre feet of “bonus water” since 2000, above and beyond its entitlement under the Colorado River Compact. But we’re about to have a formal shortage declaration because the Lower Basin keeps using more water than it perhaps ought to. (bad words in earlier draft deleted)

courtesy Brad Udall

Today’s release of the Bureau of Reclamation’s August 24-month study is what in my old newspaper days we would have called “a  great news peg”. It’s been clear for a while that we’ll likely have a first-ever federal shortage declaration in the Lower Colorado River Basin in 2020, and that chance is growing. But in the interests of never letting a good Colorado River shortage news peg go unused….

A shortage on the Colorado River, which would force water supply cutbacks for users in Arizona and Nevada, is likely in January 2020, according to a new analysis from federal scientists released Thursday.

In the Bureau’s “most likely” scenario – essentially the median of a bunch of model runs reflecting various hydrologic scenarios under the current rules – Lake Mead would end 2019 at elevation 1,070.35. Anything below 1,075 and Arizona and Nevada have to reduce their use of Colorado River water. 

This will happen even though Lake Mead is forecast to get more “bonus water” in 2019 – water released from Lake Powell above and beyond the Upper Basin’s legal compact delivery obligations* of 8.23 million acre feet. The current projected release is 9 million acre feet, but despite that bonus water, Lake Mead is projected to drop 9 feet next year.

I’m in the midst of a book chapter diving into this stuff, so let me obsessively share numbers because I spent all day staring at them, and they might shed some light on where the problem lies. That “bonus water” delivered by the Upper Basin is a big clue.

The Upper Basin has only been using ~4-4.5 million acre feet of water a year, well below its Colorado River Compact entitlement of 7.5maf.

Since 2000, the Upper Basin has delivered 9.7 million acre feet above the amount required under the current rules (8.23 million acre feet per year). So the Upper Basin is a) using less water, and b) delivering more to the Lower Basin. (Brad Udall, who’s been helping me think about all these numbers, sent me the graph above showing the accumulating surplus.)

By the time next year is over, the Lower Basin will have gotten 10 million acre feet of “bonus water” in the 21st century. 10 million acre feet more than the Colorado River Compact requires. Yet Lake Mead keeps dropping. It’s pretty clear where the “supply-demand imbalance” lies here. Looking at you, my Lower Basin friends.

Everyone can plausibly argue that they’re living within the rules here, but if we keep defending our actions with “But the rules say it’s OK!” the Colorado River system is going to crash.

* Upper Basin lawyers who wanna quibble take it up in the comments

Cutter Reservoir

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CUTTER CANYON – Cutter Reservoir is an incongruous sight.

The 10ish miles of dirt road it takes to reach it, up San Juan County Road 4450, is not suggestive of water. Thanks to oilfield money, the road is good as northwest New Mexico washboard dirt roads go. )We counted 21 well pads between the reservoir and the main highway.) But it is the sort of dusty that makes your mouth feel parched.

There are signs, until there aren’t, and Lissa and I got lost when we missed the turn, not having been attentive enough to the available maps and GPS advice on our devices, but eventually we rounded a corner and saw a big earthen plug in the arroyo ahead, parked at the foot of the dam and walked up the dirt road leading up the river right side of the dam. 

 

Cutter Canyon
Cutter: No Swimming, Dangerous Waters

Cutter is part of the Navajo Indian Irrigation Project, approved by the United States Congress on June 13, 1962 – PL 87-483 – as a “participating project” in the Colorado River Storage Project (CRSP, we call them “crisp projects”). It sits downstream of the much larger Navajo Reservoir, if you can call a tunnel through desert sandstone a “stream”. With a surface area of just 64 acres, it’s a tiny thing, and with the dirt road access not as popular as Navajo among the local fishing and boating set, but we found a family from Farmington out on a Sunday morning, fishing near the outlet works. Dad was delighted that we actually cared, and stood on top of the dam pointing to the remarkable irrigation works – canals, tunnels, siphons – that carry Cutter water toward the Navajo Agricultural Products Industry farms (yeah, we do pronounce it “nappy”) on the mesas to the west. At 72,000 acres, NAPI is the largest single-ownership farm in the Upper Colorado River Basin (maybe in the entire Colorado River Basin? please jump into the comments if you have any help on that question).

Water from Navajo Reservoir is staged at Cutter Reservoir before being shipped on the Navajo farmers, and (the reason for our visit) it’s also the holding tank for water to be delivered via the Cutter Lateral, a part of the Navajo-Gallup Water Supply Project. This is one of the last big engineering projects in the Colorado River Basin, finally delivering on a promise made to the region’s indigenous communities in the negotiation of the 1948 Upper Colorado River Basin Compact and the 1962 law that authorized Navajo Reservoir.

It’s a remarkable bit of water in the desert.

Cutter Reservoir, near Farmington, New Mexico