High water driven by heavy rains poured inside a containment levee around the Assumption Parish sinkhole overnight Thursday and much of Friday, forcing workers to try to cut off the flow and to contain the hole’s brew of crude oil and brine.
The floodwater that piled up in surrounding swamplands cut five breaches in a low, incomplete section of the earthen berm along the sinkhole’s western and southwestern sides, pushing 3 feet of water into the 71-acre area the berm encircles, parish officials said.
By Friday afternoon, Texas Brine Co. contractors were able to block two of the smallest breaches and part of a third, a company spokesman said.
But the largest breaks remained open Friday evening because of access problems on the mucky berm’s top and continued rain and lightning.
Oil-retardant boom had been deployed in an attempt to block any flow of the sinkhole’s oily contents into the freshwater swamps surrounding the sinkhole between the Bayou Corne and Grand Bayou communities, officials said.
John Boudreaux, director of the parish Office of Homeland Security and Emergency Preparedness, said the breaches occurred where prior subsidence problems had led Texas Brine to take corrective action by extending the berm to contain the low areas.
He said water overtopped portions of the berm where the sand base had not yet gotten a clay cap.
“One little trench can turn into a 50-foot gap in no time when it’s just sand,” Boudreaux said.
Assumption Parish emergency officials posted two dramatic videos on their blog site that were taken before noon Friday from an airboat inside the berm area.
As the boat moves toward the southwest corner of the berm in the first video, progressively larger cuts in the earthen levee can be seen with increasingly heavier water flow and occasional collapses of sand. At the largest gap shown in that video, a yellow curtain once used to contain silt from the berm floats off in the rushing current.
Containment boom had not been laid out at that point, parish officials said.
A second video shows the largest breach of all, about 75 feet across, with water levels nearly equalized between the swamps and inside the berm area, leaving an idle excavator sitting in shallow water.
Boudreaux said the smallest breaches were 10 feet wide or less. The second-largest was 30 feet across.
The Louisiana Office of Conservation ordered Texas Brine to build the berm to contain brine and oil in the sinkhole, now 15.1 acres at the surface, and protect the surrounding swamps. The berm remains under construction and is in various stages of completion.
Scientists believe an underground Texas Brine salt dome cavern failed and caused the sinkhole to surface in August, prompting an evacuation of residents in Bayou Corne and Grand Bayou.
Parish and state officials said they did not believe a risk of contamination existed while floodwater flowed from the swamps into the berm-protected area.
But Patrick Courreges, spokesman for the Louisiana Department of Natural Resources, said regulators focused immediately on getting into place protective booms once water levels of the swamp and 71-acre containment area equalized and currents subsided.
These floating booms would be needed to prevent any hydrocarbons on the sinkhole’s surface from flowing out into the freshwater swamps, they said.
“The major issue is to make any contaminants that are in there, stay in there,” Courreges said Friday.
When asked, he said the brine in the sinkhole is dense and should remain in place beneath the layer of less-dense freshwater that flowed into the berm area. But he said the brine will be monitored.
Because of problems going over wet clay on part of the berm’s southern leg, contractors worked Friday to finish the first phase of the V-shaped extension, or “bump out,” as a route to reach the largest breaches.
But poor weather, including close lightning strikes, halted Texas Brine’s work Friday afternoon, Boudreaux said. The berm extension was nearly finished except for a small gap.
“They can haul sand in the rain. I think their intention is to do that and finish the bump out and give good access to the bigger breaches,” he said.
Sonny Cranch, Texas Brine spokesman, said one line of boom was placed at the remaining open breaches and two more redundant layers of boom will be installed on the inside and outside of those gaps once weather improves.
“This weather is kind of shutting everything down,” Cranch said.
Videos of the flooded sinkhole area are attached to this story at http://theadvocate.com.
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