Cave Network Underneath Cambria Drive Bigger Than First Believed

WILLIAMSON COUNTY, TX — Like a summer cinematic thriller, a recently discovered fifth chamber in an underground cave network — exposed only after a street buckled after a partial subterranean collapse — is much bigger than previously believed, according to a Wednesday press advisory.

It's almost like it's growing. Call this continuing drama The Fifth Chamber.

Last week, county officials disclosed the discovery of a fifth chamber of the cave network underneath Cambria Drive, writing the newly discovered void ran toward Ephraim Drive. By Wednesday, it became official: "Fifth Chamber Extends under Ephraim Drive," the headline to an updated press advisory read.

Some background: On Feb. 8, a cave under Cambria Drive was discovered when the grotto roof collapsed, which led to a water pipe rupture affecting service to nearby homes. That cave roof collapse was long in the making, with a water pipe leak slowly eroding the rocky surface drip by drip by drip over an unknown period of time.

By early morning on the February day, the cave collapsed upon itself — taking a chunk of Cambria Drive with it. Fortunately, the collapse occurred in the wee hours of the morning without traffic being swallowed by the buckled cave portion. The previously undiscovered cave starts at around the middle of the Cambria Drive 20 feet west of the curb and heads east some 200 feet and north about 45 feet. The cave has five chambers along a cave of varying heights reaching a high clearance of 22 feet near the entrance down to only three feet high in the fourth chamber and even lower level of the fifth chamber.

Cambria cavern profile view with fifth chamber shown courtesy of Williamson County

The discovery of a fifth chamber previously undetected in the cave below Cambria Drive was found this week running toward Ephraim Road, prompting a work stoppage on efforts to seal the underground network and repave the buckled roadway, county officials said.

Environmental consultants returned to the fifth chamber near Cambria Drive on Tuesday to pinpoint the precise location relative to Ephraim Road. Their assessment: "The fifth chamber’s lower level is found to extend approximately eight feet into Ephraim Road and does not stop at the curb as previously estimated," county officials reported. "The lower level of the fifth chamber is located about 20 feet below the road, so structural engineers do not feel there is any immediate danger for vehicles passing over the road due to the depth of the cave. In an abundance of caution, however, heavy construction vehicles will not be allowed to park over portions of the upper level of the fifth chamber."

Williamson County officials continue to work alongside Texas Commissioner on Environmental Quality (TCEQ) officials to determine how to handle any remediation work for the fifth chamber. Until this has been determined, county officials added, all remediation work at the cave has stopped.

The underground cave network was exposed in February when a portion of Cambria Drive collapsed at around 3 a.m. near 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.

Map previously released by county officials

County officials in this continuing saga have continually updated the public in detailing their finding's narrative twists and turns befitting the labyrinthine nature of the subject matter. It's likely we'll continue to learn more about this county cave in the coming days and weeks.

While angst-inducing to some residents, the county's cavern exploration is the envy of speleologists and spelunkers everywhere. But the curious — included suspected trespassers whose interloping prompted officials to block access — should be warned to the unknown stability of the underground formation.

Williamson County image

Meanwhile, the cavern continues to reveal its impressive, subterranean scale, while the plot thickens. Meanwhile, the cave's topography is likely being studied by top men. Top. Men.

Stay tuned.

Related stories:

Work Sealing Cambria Drive Cave Stops After New Chamber Found

Williamson County To Seal Underground Cambria Drive Cave

Williamson County Shares Pics Of Underground Cave That Ate Street

Engineers To Assess 20-Foot Williamson County Sinkhole

4th Chamber Found At Williamson County Cave

Williamson County Officials Block Cave From Trespassers

Williamson County Officials Begin Stabilizing Underground Cave

Williamson County Map Shows Homes Directly Above Underground Cave

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>>> Photos courtesy of Williamson County