Sinkhole offers rare glimpse at inner workings of Barton Springs aquifer

The failure of a water quality pond near a shopping center in southwest Austin has created a sinkhole that has drawn the attention of the Save Our Springs Alliance. The collapse of the pond will also provide officials with the Barton Springs/Edwards Aquifer Conservation District a rare opportunity to learn about groundwater flow in the area.

 

The collapse occurred after a heavy rain during the last week of January. Over time, a cave formation opened up beneath the structure either through natural activity or a leak in the pond. As the water continued to collect during the recent downpour, the weight became too much for the weakened ground to support.

 

Despite concerns from Save Our Springs Alliance Executive Director Bill Bunch, officials with the aquifer district are more focused on using the situation to learn about groundwater flow – knowledge that district senior hydrologist Brian Hunt says could be used in the event of a hazardous materials spill. “(We can) use this as a little window into the aquifer,” Hunt told In Fact Daily.

 

The hole opened up near the Shops at Arbor Trails, which is located near the intersection of William Cannon Drive and MoPac Expressway. The property is owned by a local shopping center development group called Christopher Commercial Inc. 

 

According to Hunt, though the Austin region is littered with karst formations – often caves – a collapse such as the one near Arbor Trails is unusual. “Rarely like this do we have catastrophic failure,” he says.

 

Hunt and his team have begun using the opening to find out what direction the groundwater flows through the area with dye tests. He adds that once testing is concluded, it will take as long as a month for the district to receive the results, and a “bit longer” to get a full picture of where the water goes. “This is a unique opportunity to understand where the water flows,” he says.

 

Hunt adds that Christopher Commercial has been cooperative both in terms of gathering the information required to repair the collapse, and in their willingness to let Hunt conduct the dye study. He says that work done around the sink hole has been “very productive.”

 

In an email to the offices of Council Members Kathie Tovo and Laura Morrison, Bunch was a bit more concerned. “The pond’s impermeable liner broke so the nasty runoff is going straight into the aquifer,” he wrote.

 

Scott Hiers, a geologist with the City of Austin’s Watershed Protection department, told In Fact Daily that his office would “guide the repair” in the ways it determines are most prudent. He added that, in keeping with normal procedure, the Texas Commission on Environmental Quality had been notified of the collapse.

 

“Anytime you have a recharge feature open up, you want to make sure that you get it addressed,” said Hiers.