July 3, 2020

A river runs dry: Climate change offers opportunity to rethink water management on the Rio Grande

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Rio Grande (CC BY 2.0) by City of Albuquerque

The Rio Grande near Albuquerque in 2012.

Albuquerque residents coping with the COVID-19 pandemic have flocked to the Rio Grande this spring and summer in droves, said John Fleck, director of the Water Resources Program at the University of New Mexico.

“What we’re seeing in Albuquerque is stunning. People are in the river in ways that we’ve never seen before,” Fleck told NM Political Report. “People are out wading in the river, splashing around, playing, setting up family picnics on the emerging sand banks.”

That fun may soon come to an abrupt end. For the first time in decades, Albuquerque is facing a dry Rio Grande. Despite a nearly-normal snowpack over the winter, that water never made it down into the river this year. Instead, water managers had to release stored water from reservoirs to keep the Rio Grande flowing. Those stores are running out, and some 28 miles of the river south of Albuquerque has already gone dry. 

“We’re going to have a flat sandy dry riverbed with a little ribbon of water meandering through the sand very soon,” Fleck said. 

It’s not unusual for stretches of the river, especially south of Albuquerque, to go dry in summer months. But as temperatures rise due to climate change, and the region’s climate becomes more arid, it’s likely that we’ll see more and more dry years for the river, even if snowpacks remain at near normal levels. 

The Rio Grande is a highly managed river. The water that flows into and is diverted out of it is governed by the Rio Grande Compact of 1938, which dictates how water is managed and distributed between various communities across Colorado, New Mexico, Texas and Mexico. 

In New Mexico, every drop of water that flows through the river is owed to someone. And while the Compact itself is designed to accommodate wetter and drier years, the state has very little wiggle room in how it manages that water in the face of a large, system-scale shift in climate, like we’re beginning to experience now. 

Some say now’s the perfect time to rethink water management on the Rio Grande. 

“This is not going to work, going forward,” said Jen Pelz, a biologist, attorney and Wild Rivers Program Director at WildEarth Guardians. “Communities, as well as the river itself, are going to be in great danger if we keep operating on a year-to-year basis, praying for rain and hoping we’re going to have another 1980. That’s not going to happen under the new climate regime.” 

New Mexico is already using more water than it has access to

The Rio Grande Compact is a complex interstate legal agreement between governments and districts that rely on the Rio Grande to supply drinking water and irrigation water to their respective communities. Under the pact, Colorado delivers each year a certain amount of water to New Mexico, and New Mexico, in turn, is required to deliver a certain amount of water to the Elephant Butte Reservoir. That water is then distributed to irrigators in New Mexico and Texas south of the reservoir. 

The delivery obligations are based on the amount of precipitation received each year. In dry years, New Mexico has lower delivery obligations to the reservoir, and in wet years, the state has higher delivery obligations. Mike Hamman, CEO and chief engineer of the Middle Rio Grande Conservancy District, said the Compact was designed with an eye towards the boom and bust water cycle of the Rio Grande. 

“The states that are in the Rio Grande Compact have designed and developed whole operating procedures around wide swings in water supply,” Hamman told NM Political Report. “The Compact is scaled to try to encompass that as best as it can, it functions reasonably well since its inception.”

This chart, taken from the Interstate Stream Commission’s June 16 2020 meeting packet, shows New Mexico’s compliance with the Rio Grande Compact from 1940-2019. Source: New Mexico Interstate Stream Commission.

New Mexico is already out of step with its water supply as determined by the Compact. A 2004 study commissioned by the Interstate Stream Commission (ISC) and the U.S. Army Corps of Engineers offered a first thorough look at the state’s water budget since the 1930s. The study found that, given average water flows and average water depletions, New Mexico is short 40,000 acre feet of water each year, on average. 

“If you add everything up, according to this study, our uses of the river, plus natural uses that we’re responsible for under the Compact accounting, exceed the average supply by 40,000 acre feet per year,” said Norm Gaume, a retired licensed professional water engineer who formerly served as director of the ISC. Gaume commissioned the study in the 1990s, though it was published after his tenure at the ISC.

“Our uses of water, on average, exceed our average supply. Not in the future, because of climate change, but [in 2004],” he said. 

The study has never been updated, but there’s some hope that the state’s water use has actually decreased in the interim — even if just slightly — thanks to the water conservation efforts in the cities of Santa Fe and Albuquerque, the Rio Grande’s two largest municipal water users. 

“They’ve been very, very successful in their water conservation programs, so their per-capita use is going way down,” said Fleck. He added that the acreage of irrigated land in the Middle Rio Grande is also declining, which may translate into some smaller water savings. 

Pelz commended water conservation progress, but noted that even in wet years, the water budget shortfall can be seen in some stretches of the river in southern New Mexico

“Last year, when the river was flush with water because it was an above-average water year, the river still went dry in the San Acacia reach, below the San Acacia diversion dam,” Pelz said. “That’s because we’ve over-allocated our system, and we’re not doing anything to protect the right of the river to have any water.”

Responding to climate change

Meanwhile, climate change is shifting how the region experiences precipitation. And that, water managers say, will likely impact New Mexico’s water future and its ability to meet its delivery obligations year to year. 

“We’re entering a period now where there’s a shift in temperatures and precipitation as a result of the climatic changes going on. That can definitely be a compounding factor,” Hamman said. “It creates higher demand for existing crops and vegetation, as well as changes the way snowmelt accumulates and runs off. It’s not only affecting the volumes, it’s affecting the timing. That’s a little different than what we have historically experienced.”

Hamman said the Middle Rio Grande Conservancy District began implementing what he called adaptation strategies since the mid-1990s. Those include minimizing diversions, maximizing storage and optimizing what water is in the river. 

“There’s a bunch of different pieces to that puzzle that we’re working on already,” Hamman said. 

But a significant amount of the state’s water budget cannot be controlled by water management. Looking back to the 2004 study, Gaume pointed out that nearly half of Rio Grande water depletion is caused by evaporation and other natural mechanisms, not human activity.

“The natural depletions are not very controllable, and they keep going, even if we don’t have much flow going in,” he said. 

This chart, from the 2004 Middle Rio Grande Water Supply Study, shows how much water is lost to natural depletions (to things like evaporation and riparian habitats) and human-caused activities such as agricultural.

Climate change and aridification will likely cause these natural depletions to increase, the effects of which will ripple throughout the communities that rely on water from the Rio Grande. 

“What happens when temperatures go up? Evaporation goes up even faster — much faster than temperature, it’s not a linear function at all,” Gaume said. “So reservoir evaporation is going to go way up, evaporation from the bosque and the river is going to go up. We’re not sure what’s going to happen to our supply, but what we do know is that our net supplies are going to go down, because evaporation losses are going to go up.”

What kind of future for the Rio Grande do we want?

Water experts agree there are big conversations to be had around what kind of future New Mexico residents want for the Rio Grande. But experts also agree those conversations haven’t happened yet. 

“This is a values question. What does the community value?,” Fleck said. “We do not have in the Middle Rio Grande Valley a management framework where we can even have those conversations about what our community values are. What do we want that river to look like?”

Pelz and WildEarth Guardians have a few ideas. Pelz authored a 2017 report that looked at what she called out-of-the-box thinking about water management on the Rio Grande. It proposes exploring whole-basin approaches to managing the river, rather than the piecemeal management structure that currently exists. 

“We’ve been advocating for a long time to have the National Academy of Sciences study this idea — have [people] who don’t have an interest in the basin, who are scientists, look at all the different reservoir authorizations, and the Compact, to see if there are better ways we could operate reservoirs that would help make sure farmers got delivered water, also make sure that there’s water in the river when the environment and species need the water, communities could ensure they have water when they need it. That’s more of a long-term solution,” she said. “These three states have three different laws around allocating water. If the whole basin were managed together, it’d probably be a different story.”

Altering the state’s Rio Grande water management would require renegotiating parts of the Rio Grande Compact, which is something that all three states would need to agree to do. At present, there doesn’t seem to be much support for considering renegotiating any parts of the Compact among the parties. 

In an email to NM Political Report, Office of the State Engineer spokesperson Kristina Eckhart said New Mexico isn’t interested in opening up negotiations, given the current litigation between the state and Texas over water. 

“Texas mediated a 2008 agreement in the Lower Rio Grande that takes water apportioned to New Mexico by the Compact away from New Mexico, and then in 2013 sued New Mexico in the U.S. Supreme Court claiming Texas is being harmed. Given those actions, New Mexico sees no reason to renegotiate the Compact at this time,” Eckhart said. She added that there’s currently no drought contingency planning occurring, either. 

The U.S. Bureau of Reclamation has just begun work on a Rio Grande River Basin study in New Mexico, which will include “projections and water supply and demand within the basin and analysis of how existing water and power infrastructure and operations will perform in the face of changing water realities,” said Mary Carlson, a spokesperson for the Bureau. 

The Bureau partnered with the Middle Rio Grande Conservancy District, the ABCWUA, the New Mexico Interstate Stream Commission, as well as tribes, environmental organizations, educational institutions, and community organizations for that study. 

The Bureau is also working with the ISC “on the development of forecasting tools to help better project delivery requirements under the Compact, to improve decision-making related to how much water to store upstream, and how much to send down to Elephant Butte for Compact delivery,” she said. 

Could the basin study open up an opportunity for the three states to consider coming back to the negotiating table to deal with climate change in the future?

“Potentially,” Hamman said, adding that there are some other aspects of the Compact that need consideration, too. 

“There are some definite reservoir regulation issues that need to be looked at, and maybe a whole different idea of net precipitation, if it’s moving towards more of a monsoon-driven system, then a snow melt system, a lot of those kinds of things need to be looked at,” he said. “Once those options are developed, then I think the interest of the other Compact states would increase.”

In the meantime, New Mexicans will have to make do with a sandy Rio Grande this year.