A section of the Cambria Drive road south of Brushy Creek in Williamson County, Texas, has been closed off after a sinkhole was discovered on Friday 9 February 2018. The sinkhole was discovered by utility workers who were excavating the site after residents complained of a sudden drop in water pressure. The sinkhole had not reached the surface, but had opened up a seven metre void beneath water and power lines, causing the water main to break. The road has now been closed off and stabilised with wooden decking while civil engineers assess how to tackle the problem.
Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.
On this occasion the sinkhole was found to lead to a previously undiscovered cave system beneath the area, and is thought to have been caused by the collapse of a tunnel which extends roughly 77 m beneath the road and neighbouring properties, and varies in height between five and seven meters. The area of the tunnel roof beneath the utility lines appears to have been damaged when these lines were installed, about 30 years ago, weakening the structure and eventually leading to this week's collapse.
Cave system found beneath Cambria Drive in Williamson County, Texas, following the opening up of a sinkhole this week. Cambrian Environmental.
This cave system has been named Ogof Cambria, Welsh for Cambria Cavern - Cambria is the Latin name for Wales.
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