Report: Too much water pumped from earth
Groundwater levels declining; aquifers could be depleted
The future of water looks murky in the Lone Star State.
Groundwater levels are declining in Texas, according to two reports published last week by Texas State University and the Environmental Defense Fund. Seven of 20 aquifer systems analyzed in the state are being overpumped, and that number could double by 2070, which would leave only six aquifers sustainable for future groundwater use in the state.
Unsustainable pumping of aquifers can lead to wells drying up, less groundwater storage and the degradation of rivers and springs that depend on aquifers for their ecosystems.
“We’re heading in the wrong direction,” said Vanessa Puig-williams, director of the Environmental Defense Fund’s Texas Water Program. “In Texas, none of us want to see our aquifers be depleted or be unavailable as a water source in the future. And unfortunately, we’ve made a decision to allow our aquifers to be pumped beyond what is sustainable.”
Groundwater conservation districts, which manage local aquifers, are not practicing sustainability to the degree that they should, Puig-williams said, with many districts pumping more than they can withstand in the long term. And while some districts have good management practices employed to maintain spring flow, groundwater in Texas is greatly connected, meaning one aquifer’s supply can impact another.
For the Edwards Aquifer, groundwater is protected by the Endangered Species Act, limiting the amount of water pumped in order to protect local creatures. Currently, the Edwards Aquifer is being pumped sustainably and will continue to be in 2070, according to the Texas State University report.
But the Edwards is connected with the Trinity Aquifer, which stretches north from San Antonio through the Texas Hill Country.
“Most of the Edwards Aquifer’s recharge comes
from rivers across the recharge zone that leak into the aquifer, and then most of that water flowing through those rivers is a source for the Hill Country,” said Robert Mace, a professor at Texas State University and executive director of the Meadows Center for Water and the Environment. “But there’s water that also flows underground from the Trinity aquifer into the Edwards, so if there’s less water in the Trinity, there’s going to be less water flowing into the Edwards.”
While the Trinity Aquifer as a whole is projected to be managed sustainably in the future, the Trinity within the Hill Country is not, Mace said. The Trinity’s groundwater levels are projected to decline by 30 feet by 2070.
If that occurs, San Antonio would need to impose drought restrictions more frequently.
The Trinity is like a leaky bathtub, Mace said. The tub’s faucet refills it while a certain amount drains for spring flow, and there are further leaks flowing to the Edwards. In order to pump the Trinity sustainably, management plans must account for such leaks.
“Aquifers are a lot more complicated than just recharging and draining,” Mace said.
There is good news, Puigwilliams said, in that the Texas Legislature has empowered groundwater conservation districts with the authority and the flexibility to manage groundwater sustainably.
“We have the framework to build upon groundwater conservation in Texas,” Puig-williams said. “Districts can choose to manage groundwater sustainably, and they just need to take the steps to do so.”