Williamson County Officials Begin Stabilizing Underground Cave

WILLIAMSON COUNTY, TX — County officials have secured approval from environmental regulators on a plan to stabilize the ground around an underground cave that was exposed after a street buckled after its partial collapse.

The Texas Environmental on Environmental Quality (TCEQ) approved the county plan that calls for stabilizing the cave entrance on Cambria Drive and create a new cave cover, officials said in an email. The cover previously used was meant as a temporary stopgap measure to secure the entrance until it became warped and started to sag under rainy conditions, officials noted.

A 20-foot sinkhole on Cambria Drive emerged overnight on Feb. 8 alerting to a 200-foot cave trail under the surface. Officials explained at the time that a leaking water pipe had slowly disintegrating the roof of the cave entrance, causing it to partially collapse — taking a good size chunk of road with it.

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The street collapse occurred around 3 a.m. at the Woods of Brushy Creek neighborhood situated between Highway 183 and Cedar Park on the west and Interstate 35 and Round Rock to the east. Several residents said they thought the sound of collapsing asphalt was thunder.

Since the collapse, county officials have shared photos of the cave with residents along with continual updates on the progress of seeking repair work. County officials also previously released an aerial map of the site that showed the presence of a pair of homes situated directly above the cave trail.

County officials said the new cover approved by TCEQ is structurally designed to be in place for myriad weather conditions over the course of several weeks. On Tuesday, workers began using an excavator to stabilize the edges of the cave entrance by breaking back crumbling material to expose firm and stable ground, officials said. The latter step was taken to prevent pieces of rock to fall on workers inside the cave, county officials noted.

The stabilized entrance is about 20 feet longer than the previous one, officials said. The new cover accommodates the larger entrance and is being constructed on-site using pre-treated lumber with a joist and truss system, officials added.

Consultants also finished a draft profile view of the cave that illustrates the degree of difficulty faced by consultants and scientists experienced in exploring the cave with narrow passages between the cave chambers. Moreover, Williamson County expanded the fenced in area around the cave for safety. Cambria Drive will remain closed for several weeks while Williamson County works with the Texas Commission on Environmental Quality (TCEQ) on the remediation effort, officials said.

>>> Photo of new cave covering courtesy of Williamson County