Louisiana Sinkhole Prompts Study for Alternative Road

State highway officials say they’ll start a six-month study early next year into the feasibility of an alternative route around an eight-acre sinkhole in northern Assumption Parish, La.

The Advocate says the study is the initial step the Louisiana Department of Transportation and Development takes to consider a proposed highway.

DOTD spokesman Dustin Annison says the study will determine if “the route could be built in the affected area in the event that Louisiana 70 is compromised.”

Louisiana 70 carries an estimated 6,000 cars a day and cuts through isolated swamp and is a key connector between some areas.

The sinkhole is believed to have been caused by a failed Texas Brine Co. LLC cavern in the Napoleonville Dome.

“The study is the first step in the project development process and will help identify possible roadway alignments and cost,” Annison said.

He said DOTD is in the process of defining the scope of work and expects to finish midyear.

Though no cost estimate is available, Annison said that a new two-lane rural highways cost $4 million to $6 million per mile to build, including right of way and wetlands mitigation costs.

The announcement comes as community concerns linger about the long-term viability of the highway despite authorities’ assurances that the sinkhole does not appear to be threatening the future of Louisiana 70.

The sinkhole was found early Aug. 3 on property that Texas Brine leases from Los Angeles-based Occidental Petroleum Corp., swallowing up forested swamps on the western edge of the 40-acre site.

The discovery prompted an evacuation of about 150 homes in the area but also temporarily closed a four- mile stretch of Louisiana 70 between Bayou Corne and Pierre Part when the sinkhole bent a gas pipeline a day after the sinkhole was found.