The protective levee ringing the Bayou Corne-area sinkhole in Assumption Parish has redeveloped cracks for a second time in less than two months amid an intensive wave of underground micro-tremors, parish officials said.
The cracks have formed along the southern levee, or berm, near the Bayou Corne waterway and in the same area where a previous round of cracks developed in late October, officials said. The cracking at that time, which has since been repaired, coincided with some sinking of the levee in that area.
The earth-and-limestone levee keeps the 26-acre sinkhole’s salty and at times oily contents from invading and killing the freshwater swamps surrounding the lake-like sinkhole.
The sinkhole appeared in August 2012 in swamps between the Grand Bayou and Bayou Corne communities after part of the supporting wall of a salt dome cavern operated by Texas Brine Co. collapsed deep underground.
The sinkhole has taken an oval shape with the longer ends focused along growth zones moving toward the northeast and southwest, or toward La. 70 and the Bayou Corne waterway.
The most recent projections do not suggest the sinkhole will reach either, but the sinkhole is edging closer to the southern levee just north of Bayou Corne, according to Texas Brine planning and survey documents filed with the state Department of Natural Resources.
John Boudreaux, director of the parish Office of Homeland Security and Emergency Preparedness, said Monday that a new hairline crack reappeared Sunday at the site of the largest crack from late October. The crack then had been about a foot wide before it was repaired.
Boudreaux said the new hairline crack went only a few feet across the levee top Sunday but had reached all the way across it by Monday.
In addition, another new half-moon-shaped crack has formed along the inner side of the southern levee where the previous round of tremors had caused the levee to sink.
Boudreaux said the half-moon shape suggests a small section of levee top may slough, or fall, into the sinkhole.
Since last week, micro-earthquakes have been increasing near the sinkhole and the failed Texas Brine cavern, halting work on the sinkhole and totaling 180 per day by Sunday.
Texas Brine told DNR earlier this month the company plans to keep maintaining the levee with fresh material after cracking or subsidence happens. Company officials have also pointed out the sinkhole is moving toward stabilization, though the timeframe for that remains uncertain.