Grand Isle to get storm-surge protection before 2009 hurricane season

By Ron Bygness

Ending more than a dozen years of debate regarding plans to upgrade storm-surge protection for Grand Isle, La., Gov. Bobby Jindal’s administration signed an agreement in April with the U.S. Army Corps of Engineers (USACE) for a $50 million project to rebuild the island’s decimated flood barriers.

Grand Isle is located on the southernmost inhabited barrier island in Louisiana in southern Jefferson Parish, about 50 miles south of New Orleans (as the crow flies).

The fast-track project is expected to be completed before the peak of the 2009 hurricane season and includes an innovative “burrito levee” made from geotextile tubes packed with sand. The 13-ft-high levee is intended to protect the island from a 50-year storm that has a 2% chance of hitting in any given year, USACE officials said.

The agreement ends a dispute dating back to the mid-1990s between the state and federal government about who would pay for the project. The accord confirms that the USACE will pay all construction costs while the town and the Grand Isle Levee District will cover long-term maintenance costs.

The primary component of the improved flood protection will be a seven-mile-long storm-surge barrier on the south side of the island to replace barriers wiped out by hurricanes Katrina and Rita in 2005 and Gustav and Ike in 2008. Geotextile tubes will be packed with sand, forming a 6-ft-diameter core for the barrier. Sand will then be compacted around the tubes, eventually raising the height to 13 feet, according to the USACE. Construction is scheduled for completion by Aug. 31.

Grand Isle has a year-round population of 1,500 that swells to about 20,000 during the summer tourist season.

Ron Bygness is the editor of Geosynthetics magazine.