Two Nations, One Aquifer: ‘The river pays for all of it’

Most of the year, southern New Mexico farmers rely on groundwater from the Mesilla Bolson to irrigate their crops. Previous installments in this five-part series were published on June 25 and July 2 and 3.

MESILLA VALLEY – “Ultimately, like they say, the river pays for all of it.”

Pecan farmer John Clayshulte is talking about groundwater and its ancient link to the Rio Grande. He has come in from the orchards, a quick respite.

Irrigation season is beginning, but Clayshulte has been dealing with a pest on his trees, and he needs the ground to be dry. Today he is running his groundwater pumps to soak green fields of alfalfa.

The Rio Grande “is the lifeblood of this valley,” he says in his living room overlooking rows upon rows of pecan trees. “No river, no life. Period. Because we wouldn’t have this aquifer if it wasn’t for the river. We sit over a huge, huge amount of water – there is no question about that. The questions are how much is physically recoverable, how much is economically recoverable and how much is legally recoverable.”

When the Rio Grande isn’t running – and most of the year, south of the Elephant Butte Dam, it isn’t – southern New Mexico farmers irrigate their pecan orchards and onion, chile and alfalfa fields with groundwater from the Mesilla Bolson.

The less water there is in Elephant Butte, the less the river runs and the more farmers will pump groundwater.

They are by far the largest users on the aquifer, accounting for between 60 and 80 percent of groundwater withdrawals on the U.S. side in a given year, depending on drought conditions.

“We had 19 straight years of above-average runoff into (Elephant Butte reservoir),” Clayshulte said. “Now, I’m not a statistician. But I kept telling people, ‘Don’t get used to it.’ Because 19 years of above-average (runoff), somewhere out there is 19 years of below-average. It tells me there is a stretch of dry to make up for that stretch of wet. When we found it, we found it with a vengeance.”

A study by a New Mexico universities working group estimated in 2015 that the cumulative volume of groundwater loss over the past 25 years due to pumping – factoring in water that is recycled to the river and aquifer – is comparable to the entire capacity of Elephant Butte Reservoir, more than 2 million acre-feet.

“The aquifer has not yet recovered,” the report warned, “which suggests that the Mesilla Valley aquifer may no longer have the capacity to provide a reliable, supplemental supply during extended drought conditions and with the current levels of intensive use of groundwater.”

Through the desert’s hottest months, a skim of water covers the orchard floors, reflecting blue skies and the leafy tops of thousands of pecan trees. The technique known as flood irrigation is meant to mimic the historic flooding of the Rio Grande.

Pecan farmers saturate their orchards each spring by pumping groundwater until the river water comes available to them, which this year happened in mid-May – months after they needed to start watering their fields. And thirsty orchards are inflexible in a way that seasonal row crops are not: Pecans can’t be fallowed or shorted water without harming the trees, says groundwater resources manager Eric Fuchs, who monitors water levels for the Elephant Butte Irrigation District.

“The preference would be if we had a full allotment (of river water) and could run from early mid-March to September,” he says.

That hasn’t happened since 2008 – a one-year respite. Farmers have been dealing with substantially lower allotments of river water since 2003, Fuchs says.

EBID serves the farmers of the Mesilla Valley, managing allotments of river water across the irrigation season.

Fuchs has seen the declines in well water levels – “a bit concerning,” he says.

He attributes the drops at wells near the border to the Ciudad Juárez well field at Conejos Medanos, which, when it was turned on in 2010, added a burst of consumption nearly the size of what Las Cruces consumes annually.

The drops at wells in the green belt of row crops and pecan orchards he blames on the heavy groundwater pumping farmers have used to get through the drought.

“To the extent that it is all an interrelated resource, and to the extent you have collective stresses on that resource, eventually all those effects will have a tendency to accumulate,” he said. “It’s the interrelated nature of the system.”

But as the largest users on the Mesilla Bolson, southern New Mexico farmers have been drawing down the binational aquifer in far greater volumes. Yet as Clayshulte knows, they are limited by what they can afford to draw out and what the law allows.

To appease Texas in a 2008 water dispute, southern New Mexico farmers traded some of their rights to surface water in the reservoir for the guarantee that their groundwater wouldn’t be shut down, according to EBID general counsel Samantha Barncastle. They’re allowed to pump 4.5 acre-feet of groundwater per acre after using all their river allotment.

“It’s set by court order, but it’s also set by what I like to call farmer economics,” Barncastle said. “Groundwater is extremely important to these farmers here, especially in the Mesilla Valley, because it’s their storage, their savings account. It provides them a level of flexibility that they wouldn’t necessarily have in years of short supply with surface water. It’s extremely expensive to run those pumps. They only pump what their crop needs and they only pump when their crop needs it.”

Even as they experiment with conservation techniques such as capturing stormwater, farmers with the money and means to do so are drilling wells ever deeper. With pecan prices close to a historic high above $3 a pound – high prices that have lasted nearly a decade, thanks to demand from China – groundwater pumping for some farmers is worth it.

Irrigated farmland in the Mesilla and Rincon valleys has grown by thousands of acres over the past decade to roughly 95,000 acres, according to Phil King, a civil engineer at New Mexico State University. Pecan acreage currently totals about 30,000 acres.

New trees are popping up all over the region, across the Mesilla Valley to the Valle de Juárez east of Ciudad Juárez and south toward Casas Grandes in Chihuahua.

On a cloudy afternoon, with the sky spitting quick showers, the ditches along Clayshulte’s property are running full of groundwater. Pumps spew up to 2,500 gallons per minute into the canals that slide the water onto his fields.

He is fortunate in that his wells haven’t dropped at the levels seen elsewhere in the valley, he says.

Many farmers are sensitive to critics – often city folk – who balk at their water use. The cities that sprung up in this region did so because farmers settled the floodplain of the Rio Grande, they say. And they are, after all, growing food – protein, in the case of the pecans.

Clayshulte boils it down further.

“Bear in mind what these trees do with this water,” he says. “They’re sucking up all the carbon dioxide we make and they’re producing oxygen. We do get criticized for how much water we use – I think justifiably so. But people need to remember you’re breathing that water. I’m breathing it.”

This season’s snowmelt was running above-average; the Elephant Butte Reservoir is rising and the river may run a month longer than expected, well into September.

Now comes the question that only time will answer: Is New Mexico swinging back to a wet cycle, as wet as it once was, or is 2017 another blip on the climate chart, an exception in the trend lines toward higher temperatures and harder-to-reach groundwater?

“I don’t think anybody knows the answer to that one,” said Dave DuBois, New Mexico state climatologist. “Is it a turn for the better? I don’t know. For this year, I tell people, enjoy it while you have it.”

This report was produced in partnership with the McGraw Center for Business Journalism at the City University of New York Graduate School of Journalism.


Submit a Comment