Although the state of Texas seems to have finally emerged from drought, it continues to assess the state of its groundwater resources, which remain below normal, according to a University of Texas at Austin analysis of NASA satellite data.
The analysis shows the state lost 84 million acre-feet of water during the peak of the drought and had recovered only roughly 10 percent as of January 2015, according to scientists at UT Austin’s Center for Space Research. The deficit is roughly equivalent to five years of water use in the state.
Pressures on Water Supplies
Texas policymakers continue struggling with water management issues as the population continues growing. “We’re short about three Lake Meads,” said Gordon L. Wells, an earth scientist at the Center for Space Research. The Arizona reservoir holds some 26 million acre feet of water. What is contributing to the continued loss? “This is a deep mystery.”
The analysis was based on images of the Earth’s surface taken by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite constellation during its five-year mission. A NASA analysis found groundwater supplies worldwide are being so rapidly emptied that aquifers may be depleted in decades.
Texas experienced its hottest year on record in 2011, according to John Nielson-Gammon, the state’s climatologist. Information from GRACE shows that both surface and groundwater stores had dropped significantly even before the drought. Some regions are faring better than others.
Wells, who is also primary investigator at the Mid-American Geospatial Information Center, told the El Paso Times that the situation is concerning. Despite above-normal rainfall in August 2015, total water storage hasn’t changed significantly.
What has caused water storage to be “stuck” is unclear. It could be overuse by agricultural users; however, the losses are big enough that pumping alone does not explain it. Evaporation also could be responsible for depleting surface storage and water found in soil. These scientists will have to work together to solve the issue.
Groundwater is water trapped below the earth’s surface in fissures and crevasses. Rain and melting snow help naturally recharge the groundwater in aquifers — any water not used by plants may flow into lakes or other surface bodies of water or seep underground. Pumping too much water out of an aquifer before it can be naturally replenished can overdraw the groundwater.
As water becomes an increasingly valuable commodity, more efforts are being made to assess and preserve groundwater supplies. It is becoming increasingly difficult to achieve balance, particularly in areas with exploding population growth.
Texas is facing unprecedented growth, with a current population of 26 million. The number of residents skyrocketed by 76.7 percent between 1980 and 2010. For comparison’s sake, Florida is a distant second, adding roughly 1,000 new residents per day. Three Texas cities — Austin, Fort Worth, and San Antonio — were among the fastest-growing cities in the United States between 2010 and 2014.
The Texas Hill Country is one of the fastest growing regions in the nation. It is among the areas that must balance growth against protecting its water resources, which was examined in a study released in 2016 by regional planning experts and graduate students at The University of Texas at Austin School of Architecture. One of the study’s recommendations is to establish a Hill Country Trinity Water Conservation Area to manage groundwater in the Trinity Aquifer.
Christy Muse, executive director of the Hill Country Alliance, an organization that works on protecting that region’s natural resources, explained:
We have some of the most environmentally sensitive areas in the country west of I-35, and they are being threatened by suburban sprawl. Unmanaged growth from the larger cities is increasing pressure on our water resources, our aquifers and springs, and could destroy the cultural lifestyle of our small-town communities and heritage ranchlands.
Statewide, Texas policymakers should be using current GRACE data now to craft a comprehensive water management plan. They are not, scientists say.
The state is basing its worst-case scenario plan on the 1950s “drought of record” rather than looking at other, more severe droughts. They are also not looking at population growth, climate change, and other human factors contributing to drought, if not accelerating it. Nielson-Gammon told the El Paso Times:
So we’re not really planning for the worst-case scenario. […] The current statewide plan says that climate change is so uncertain that we have no idea what will happen, therefore we shouldn’t plan for it at all. […] It’s a bit backwards. If you think it might have an effect, you have to allow for an error margin in your planning.
Scientists say they need more satellite data collected over a longer period to make more useful observations. A second GRACE mission, which should provide more refined data, is expected to launch in 2017.