What’s the project?
The Carrizo-Wilcox Aquifer Group is composed of several sand aquifers, including the Simsboro aquifer at the intersection of the Colorado and Brazos Rivers. Unfortunately, current permits already authorize the withdrawal of twice as much groundwater that is available to sustainably meet the “Desired Future Conditions” of the Simsboro aquifer. And if applications for new permits are granted, total water withdrawals could exceed five times the amount of water that the Simsboro can sustainably provide. The Carrizo-Wilcox aquifer, is known as a “fossil aquifer,” where water was deposited thousands of years ago, but today recharges very slowly.
What’s at risk?
Pumping from this aquifer group will reduce flows of water in the Colorado River and threaten local species, such as the threatened blue sucker. The City of Austin Watershed Protection Department has already warned “excess withdrawals from the Carrizo-Wilcox and Simsboro aquifers would have severe negative impacts to local wells and creeks in eastern Texas counties.”
What’s the alternative?
In 2014, the Austin Water Resource Planning Task Force (PDF) recommended against pursuing water from the Carrizo-Wilcox. Instead, the task force found that Austin could meet its future water needs from a combination of strategies, including widespread adoption of rainwater capture and optimizing existing supplies on the Colorado River through automation of the Longhorn Dam Gates and varying the operating level of Lake Austin.