Groundwater report calls for more monitoring, sustainable management

The bulk of New Mexicans’ drinking water comes from below ground, but huge gaps in data on the state’s groundwater make it difficult to plan for a future that is projected to be hotter and drier, according to a newly released report.

“Groundwater is so often forgotten, but we rely on it so heavily here in New Mexico,” said Stacy Timmons, Hydrogeology Programs associate director at the New Mexico Bureau of Geology and Mineral Resources.

Groundwater supplies 78% of New Mexico’s drinking water and 52% of the overall water supply.

In a report authored by New Mexico Groundwater Alliance members, water policy experts call for the state to more closely and sustainably manage groundwater. The New Mexico 360 Groundwater Report recommends continued aquifer mapping, expanded groundwater metering, more regional planning and local management of groundwater and meaningful engagement with Native tribes, pueblos and nations on groundwater policy.

New Mexico’s surface water is projected to decline by up to 30% by 2050 as the state’s climate becomes warmer and precipitation patterns change, according to a 2022 report from the state Bureau of Geology and Mineral Resources. Surface water — from rain to snow to rivers — recharges some aquifers. Historically, New Mexicans have used groundwater pumping to make up for scarce surface water, at times pumping groundwater faster than aquifers recharge. Less surface water will “undeniably increase reliance on groundwater,” the groundwater report says.

But there are a lot of unknowns when it comes to the state’s aquifers. There are significant gaps in understanding how aquifers connect, their three-dimensional structures and behavior over time, the report says.

Since 2007, the New Mexico Bureau of Geology and Mineral Resources has been trying to map the state’s aquifers, “a monumental and costly task,” according to the report. The state Bureau of Geology is supposed to characterize all of the freshwater and brackish water aquifers within the next 12 to 15 years, and establish at least 100 wells dedicated to groundwater monitoring, based on the state’s 50-Year Water Action Plan. That work will cost an estimated $175 million, Timmons said.

Last year, the state Legislature allocated $7.5 million for aquifer mapping, and Timmons is optimistic more funding will be allocated in the upcoming 30-day session. Both the governor’s executive budget and the Legislative Finance Committee budget recommend allocating $22 million for aquifer mapping.

“Something on the order of $20 to $25 million per year for the next several years could really get us a lot further along with our aquifer characterization efforts, as well as drilling wells for monitoring,” Timmons said.

There are questions to be answered about aquifers all over the state, but generally there’s very little information about groundwater in places that are extremely rural or land where no one is living, like large Defense Department properties, Timmons said.

To answer those questions, researchers are doing airborne electromagnetic surveys, Timmons said. During the surveys, a helicopter flies over specific paths collecting data researchers can for mapping how electrically conductive the subsurface is, down to roughly 1,500 feet. That data helps them figure out what type of rock is below the subsurface, if it’s wet or dry and whether there is salty or fresh water below ground. Combined with other information, the survey data can be used to build detailed models of what’s underground.

“It's existing technology, but it's the first time it's been applied here in New Mexico in great detail for aquifer studies,” Timmons said.

During this fiscal year, the Bureau has covered approximately 11% of the state’s aquifers, Timmons said. They’ve just finished the Estancia Basin, the Lower Rio Grande and the Mimbres Basin.

The groundwater report also advocates metering groundwater use across the state. Irrigation accounts for an estimated 78% of the state’s groundwater use, but only 35% of that water is being metered, according to the report.

Gretel Follingstad, one of the groundwater report authors and a senior manager for climate resilient water systems with the Environmental Defense Fund, compares water management to a financial budget.

“If you overspend what you have in your bank account, that deficit eventually will catch up to you,” Follingstad said. “... If we are turning a blind eye to what we're using and not managing and metering what we're using — so the demand side of the equation — then we don't have a lever for when we need to pull back.”

In some regions, dependence on groundwater has caused aquifer levels to decline and triggered water saving restrictions.

Ladona Clayton, one of the report’s authors and the Ogallala Land and Water Conservancy’s executive director, has seen firsthand how reducing groundwater pumping can extend the life of an aquifer that does not recharge.

Eastern New Mexico has seen a serious water crisis because of groundwater scarcity, Clayton said. She works with voluntary landowners who have seen their wells drop 2 feet per year.

“These farmers could see this,” Clayton said. “And they said, ‘What can we do? Because we need to quit irrigating. But we can't just quit irrigating. We've got to have something to move to, some other way to make an income and stay in agriculture production. But in the interim, how can you help?’”

Clayton worked on a project to help landowners get compensation for voluntarily retiring 56 irrigation wells beginning in 2021, which saved roughly 4 billion gallons of water per year, she said.

The Eastern New Mexico Water Utility Authority is working on a pipeline to bring water from Ute Reservoir to areas like Clovis and Portales that depend on the declining Ogallala Aquifer, but that project is still years from completion. Without retiring irrigation wells and conserving groundwater, there would have been a gap in time between when the area’s groundwater is depleted and when the pipeline project is projected to finish, according to Clayton.

“I think the biggest takeaway is just how important our groundwater is to the state of New Mexico,” Clayton said. “It is a very precious resource, and we must rise to the challenge to protect it and preserve it, and the moment is more than urgent to do so now.”