Sinkhole evacuees stranded for some time
26th November 2012 · 0 Comments
By Susan Buchanan
At the eight-acre, Bayou Corne sinkhole in Assumption Parish, owners of slab houses are waiting for methane-gas monitors to be installed next month. Residents are watching natural gas being flared from the site and are keeping their homes ventilated while bayous around them bubble. Over 200 people, who were evacuated or voluntarily left 110 homes since August, are staying away. Many of them felt tremors last summer when the hole formed after an underground cavern wall was breached.
Local businesses have lost regular customers but have gained government responders and contractors as clients. The hole on the western edge of the Napoleonville Salt Dome contains salt water and crude oil, and is near La. Highway 70 on swampland leased by Texas Brine in Houston from Occidental Chemical Corp.
Since caverns mined for brine are also used to store natural gas, propane and butane, and because of the presence of crude oil in the hole, residents worry about possible explosions. Natural gas pipelines cross the region. Bayou Corne is 35 miles south of Baton Rouge and about 80 miles west of New Orleans.
What are conditions like for the forty households that have stayed? Dennis Landry, a local resident and businessman, said “gas remains in the aquifer, and a little crude oil is still coming out of the top of sinkhole. Texas Brine contractors laid boom around the sinkhole to keep any oil or other fuel from escaping.” He continued “Texas Brine and Shaw Environmental are flaring natural gas off from several wells they drilled. The sinkhole was growing in size but it seems to have stabilized in recent weeks.”
Last week, Sonny Cranch, spokesman for Texas Brine, said “one of our wells is flaring gas now. Shaw Environmental, a DNR subcontractor, has another three wells nearby that are flaring, but they aren’t on our site.” Shaw Environmental, Inc. is based in Baton Rouge.
On Monday, Texas Brine shut one of its two vent wells burning off gas after a small amount of hazardous, hydrogen sulfide gas was released into the atmosphere. The company said the release didn’t present a public risk. The Assumption Parish Police Jury, however, warned residents that “H2S is an extremely dangerous gas. Unlike methane, it is heavier than air and collects at low-to-the-ground levels.”
Cranch said “we flared a total of 598 thousand cubic feet, or mcf, of natural gas from the cavern between September 24 and November 16 . In addition, we got a lot of natural gas–420 mcf—out of our newly installed, shallow-aquifer vent well in just the last two weeks.”
In comparison, one mcf or 1,000 cubic feet of natural gas is enough to fuel an average U.S. home for space and water heating and cooking for four days.
Texas Brine has also captured a considerable amount of crude oil at the site. Cranch said “we collected a total of 4,530 barrels, each containing 40 gallons of crude oil, from the cavern from Sept. 24 to Nov. 16, along with another 1,500 barrels of crude from the sinkhole’s surface since October 8.”
Landry said “the hole’s still bubbling from natural gas and so is the bayou around us, including the bayou water behind my house. We’re told that’s because natural gas takes the path of least resistance and comes up though the bayou’s soft, sandy bottom. The state Dept. of Environmental Quality says the gas emissions aren’t a health hazard, and I don’t know of anyone who’s sick. DEQ checks gas emissions twice a day, and it says the levels they’ve detected so far are not explosive.”
But in community meetings residents continue to ask whether the area around the sinkhole is unhealthy.
Tim Beckstrom, DEQ spokesman, said last Tuesday “as of today, 34 homes at Bayou Corne have had indoor air tests run since last August, with four more homes scheduled. We’ve found no levels of concern. We’ve also done some outdoor monitoring in residential areas and found no levels of concern there.”
Landry said odors have subsided since Texas Brine contractors cleared oil, trees, oiled vegetation and other debris from the top of the hole.
But he said “Texas Brine will pay for air monitors in homes on slabs because natural gas can accumulate in slab houses. For homes built up off the ground and on piers, gas dissipates more quickly.” At a residents’ meeting on the sinkhole on November 13, air monitors for slab homes were discussed, he noted.
Cranch said “we’re now trying to find the right methane-gas monitors, which are more sophisticated than smoke detectors and aren’t something you typically find in a hardware store. The ones we choose will have to send signals to a monitoring station.” He said the company hopes to have monitors installed in slab homes sometime in December.
Landry said last week “my house is on a slab, and while I’m talking to you, I’m opening my garage and storage room doors to keep everything ventilated.”
As for tremors, Landry said “I haven’t felt them, but other people have. U.S. Geological Survey experts tell us the August 3 collapse of the cavern knocked off large chunks of salt, causing tremors. USGS says the tremors are internal or localized and were not caused by broader seismic activity.”
On Oct 1, Texas Brine was ordered by the state to do a geologic survey and collect relevant data. Cranch said “we submitted a subsurface survey plan to the state’s Dept. of Natural Resources and are waiting to hear back about it.”
Fish appear to be unaffected by the event, Landry said. “We haven’t seen any dead fish or wildlife from the sinkhole,” he said. “A modest fish kill in the area in late August was caused by Hurricane Isaac. If there were oil slicks or other noticeable pollution in the bayou, we would have seen it by now since many of us are out in the water in our boats.”
The sinkhole’s impact on businesses has been mixed. “I’ve lost thousands of dollars in cancellations at my Cajun Cabins since last August,” Landry said. “I own three cabins on Bayou Corne. But at the same time, I’m renting my cabins and recreational-vehicle spaces to responding state agencies and to Shaw Environmental.”
Landry said “boaters don’t stop as often at my Bayou Corne landing, where they launch boats for a fee, because they see the response activity and think we’re closed.” He also said “highway traffic is down in this area but stores, restaurants and other businesses that lost customers are now frequented by responders.”
Texas Brine is helping people stay afloat. Landry said “every household in the 1.5 mile-long, evacuation zone has received $875 a week from Texas Brine since August, whether they’ve evacuated or not. People who had to leave are staying in their camps or house boats, or with relatives or in rentals. Most local kids are still attending the same schools.”
Landry said “this is a beautiful, bayou community that’s not exactly in the sticks because we’re a half hour drive or less to Baton Rouge, Gonzalez, Morgan City and Thibodaux. But our homes have declined 50 to 100 percent in value because of the sinkhole. We’re hoping Texas Brine will give us lump-sum payments for what we’ve lost.”
On the north side of Highway 70, about 75 percent of the houses at Bayou Corne were evacuated. Those homes are 2,000 to 2,500 feet from the hole, Landry said. “No homes have been swallowed by the hole but cypress trees have been,” he noted. “Many residents on the north side of the highway felt tremors. Many of them don’t want to return but they can’t sell their houses right now.”
On the south side of Highway 70, 27 homes are located in a subdivision that Landry has been developing for the past eighteen years. “They’re substantial brick homes on concrete slabs on the bayou. Twenty of the homes are occupied right now. I’m staying there now, and those of us on my street, Sportsman’s Drive, don’t want to move.” But he said “most of us on the south side haven’t felt tremors.”
Evacuees don’t know when they’ll be able to return. “We’re waiting for air monitors, waiting to see more flaring of gas,” Landry said. “We expect to attend another community meeting in the first or second week of December.”
He continued “I feel the authorities and Texas Brine are telling us most of what we need to know, and people in the community are staying on top of that information. But we’re frustrated because there are still so many unknowns. Florida and other states have sinkholes but the dynamics here are fairly unique in that oil and gas are involved. And from what I can tell, this shouldn’t even be called a sinkhole. Geologically, what we had was a collapse.”
This article was originally published in the November 26, 2012 print edition of The Louisiana Weekly newspaper