Study shows skyrocketing groundwater use, IDs vulnerable areas
Intera hydrologist Neil Deeds gave a presentation to the Burnet County Commissioners Court on Oct. 24 on the condition of the county’s groundwater. Staff photo by Dakota Morrissiey
The results of a recently completed groundwater study in Burnet County shows use is way up across the county and wells in the northeastern portion could be negatively impacted if development in that area continues. The Burnet County Commissioners Court ordered the study in the hopes of using the data to change policy and better manage groundwater and conservation.
Neil Deeds, a hydrologist with environmental consulting firm Intera, gave a brief overview of the study’s findings to the court at its Oct. 24 meeting. He said the number of domestic wells in the county increased from 1,000 to 6,800 over the past 22 years and the amount of water used by permitted users rose from about 300 acre-feet a year to 3,200 acre-feet over the past 12 years.
Deeds also said northeast Burnet County appears to be the most at risk for dry wells and poor water quality.
“I’m not saying anything about regulation, but this study could be used as the basis for looking at areas of the county where you might want to have a little more scrutiny,” Deeds told commissioners at the end of his presentation. “There are certainly places where we have lower transmissivity and lower drawdown, where, if you have concentrated well drilling and production, the aquifer is going to struggle, and we are seeing that already.”
The term transmissivity is used in hydrology to determine the rate at which water can flow through an aquifer. Drawdown refers to the overall lowering of the water table.
Deeds’ presentation was on the entirety of Burnet County, but special attention was given to the Trinity Aquifer, which appears more susceptible to drawdown and lower transmissivity, according to Intera’s study. Depending on a well’s location in the county, it could be drilled into the Trinity, Ellenburger-San Saba Aquifer, Hickory Aquifer, Marble Falls Aquifer, Granite Gravel Aquifer, or Granite Aquifer.
Intera’s study shows northeastern Burnet County, which is on the Trinity Aquifer, has especially low transmissivity, abundant drawdown on shallow wells, and poor water quality.
“From that data we’re seeing, there are isolated zones that are different,” Central Texas Groundwater Conservation District General Manager Mitchell Sodek told DailyTrib.com after Deeds’ presentation. “(The zones) are different in water level, production, and quality. My take away from that is that they need to be treated differently from a management perspective.”
The district, which manages groundwater in Burnet County, provided the bulk of the data that Intera used to conduct its study.
The court commissioned the study in the spring of 2022 for just under $100,000.
A member of the audience at the Oct. 24 meeting asked the county about the study’s purpose. County Director of Development Services Herb Darling had an answer.
“The main thing we’re concerned about is that we don’t want a subdivision taking away your water,” he said. “What we’re looking at doing is possibly increasing minimum tract sizes.”
The Commissioners Court has viewed northeastern Burnet County as especially vulnerable to overdevelopment and poor groundwater availability and has attempted to reel in planned subdivisions such as Dominion Estates near Briggs.
County Judge James Oakley also chimed in on the study.
“(Potential changes would be a) regional approach rather than a subdivision approach,” he said. “It’s a bit of a bigger picture.”