Skip to main content

Aquifer is No Quick Fix for Central Texas Thirst

As drought continues to grip Central Texas, those looking to provide water to the region’s fast-growing cities and suburbs see a solution in the Carrizo-Wilcox Aquifer. But others fear the resource will be drained at their expense.

By Neena Satija, The Texas Tribune and Reveal
Darwyn Hanna grows pecans and runs cattle on some of the land he owns in Bastrop County. He is contesting a water marketer's bid to pump about 15 billion gallons a year from the Carrizo-Wilcox Aquifer in Bastrop County, saying the plan would devalue his property.

As drought continues to grip Central Texas, those looking to provide water to the region’s fast-growing cities and suburbs see a solution in a relatively untapped aquifer.

Water marketers, who bundle groundwater rights and sell the water to cities, say the region’s Carrizo-Wilcox Aquifer holds hundreds of trillions of gallons of water. They say that is enough water to sustain growth for centuries in areas around Austin, whose reservoirs are only 34 percent full, and San Antonio, whose own aquifer is at such low levels that federally protected species are at risk.

But those who live above the Carrizo-Wilcox in rural Central Texas counties tell a different story, along with some environmental advocacy groups. They say bids from three prospective water providers to pump a combined 50 billion gallons of water a year from the aquifer will accommodate urban growth at the rural counties’ expense and drain a precious resource within just a few decades.

Scientists say determining who is right depends on the answers to a few key questions: Who is the water for? How much is the user willing to pay to get it? And how much will that user compensate others who may no longer be able to access the water as a result?

“It’s not a matter of availability,” said James Beach, a hydrologist for the firm LBG-Guyton who studies the Carrizo-Wilcox for a groundwater management district, the Central Texas water provider Aqua and San Antonio’s water utility. “The volume of water is there. It’s more a question of impact,” and how to measure and deal with those impacts, he added.

For example, shallow farm wells could run dry because of other pumping unless their pumps are lowered — which could cost thousands of dollars. Most hydrologists say those wells would have to be deepened if proposals to remove large amounts of water from Burleson, Bastrop and Lee counties proceed.

But they also say that water companies can compensate landowners, pointing out that many — including mining companies and water utilities — have done so in recent decades across Texas and in other portions of the aquifer. The water marketer End Op, which hopes to pump about 15 billion gallons a year from underneath Bastrop County, has agreed to pay millions of dollars into a fund to help landowners who may have to lower their pumps.

Not everyone is satisfied by that response. “I think that’s just saying, ‘We’re going to throw money at this so that we can bankrupt the system and overpump it,” said Darwyn Hanna, whose family has owned land in Bastrop County for five generations. Hanna grows pecans and runs cattle on some of his 250 acres, and while he does not pump groundwater, he is contesting End Op’s permit because he believes it will devalue his land.

Even the water marketers themselves could run into trouble as the region continues to grow. Drilling in the deepest portions of the Carrizo-Wilcox should help minimize the impact on rural landowners with shallower wells, and water marketers argue that they only need to remove a small percentage of the total water believed to be stored in the aquifer.

But sustained groundwater removal from even the deepest portions will cause water levels there to decline, and lowering pumps will not always do the trick. Eventually, the user will have to drill more wells to continue removing water at the same rate, said Robert Mace, deputy executive administrator at the Texas Water Development Board, the state’s water planning agency.

“If you wanted to set out and drain 5 percent of the storage of the Carrizo, I think you could do it” and leave most of the aquifer intact, said Mace. “But would it be economical to do that?” Adding extra, deeper wells can be a significant expense, he said.

Aqua Water Supply Corporation, which sells Carrizo-Wilcox water to thousands of Central Texans, has already protested attempts by other marketers to pump from the aquifer, saying that they would impact its ability to provide water to its customers.

James Bene, a hydrologist who consults for BlueWater Systems, which hopes to pump 16 billion gallons a year from the Carrizo-Wilcox in Burleson County to sell to San Antonio said pumping by nearby users “a substantial risk for the financial backers of projects like this.”

“They’re trying to figure out what a good payback on a 30-year loan will be,” Bene said. “Well, that’s easier said than done when you’re not sure whether you’ll be pumping water from 100 feet below ground level or 300 feet below ground level. So nobody is really sure.” But, he added, “I can tell you that any reasonable designer of a well field builds in some safety margin.”

Another related concern for environmental advocates is the relationship between the Carrizo-Wilcox aquifer and the Colorado River, whose flow has been at its lowest in decades. Studies show that the aquifer contributes some water supply to the river each year.

Modeling by George Rice, a former Edwards Aquifer Authority hydrologist, suggests that pumping by companies like End Op and BlueWater Systems could cause Carrizo-Wilcox to begin pulling water out of the river instead of putting water into it. That could cause further damage downstream to fishermen, who depend on the river’s freshwater flows for a steady supply of oysters and shrimp in Matagorda Bay. But no one has ever firmly established the relationship between the river and the aquifer.

“Give us a million dollars and give us a 20-year time to study it, and we’d come to an inconclusive result,” said Alan Dutton, a professor of hydrogeology at the University of Texas at San Antonio who has worked on state models of the aquifer. “The margin of error is much greater than the effects we’re trying to distinguish.”

There is also less funding for such research, and technical staff for groundwater modeling at the state water planning agency has been reduced by half.

But no matter how much more data is collected, basic questions will still remain over how to allocate a limited resource — especially one that is considered private property under Texas law.

“That’s going to be a political and socioeconomic issue in 30 years,” Bene said.

“Is the economic growth along the I-35 corridor worth a little bit extra drawdown for ranchers or farmers or landowners to the east? I can’t answer that,” Bene said. “But again, I can speak to the inevitability. We have no other source of water, really. We have to look to our major aquifers.”

Disclosure: The University of Texas at San Antonio is a corporate sponsor of The Texas Tribune. A complete list of Texas Tribune donors and sponsors can be viewed here

Wait! We need your help.


Explore related story topics

Energy Environment Water supply