NEW ORLEANS, La. – In mid-August, the Corps will begin construction of a demonstration section with a new technique to raise and cap portions of Mississippi River levees in Plaquemines Parish.
The cap will be made with a stabilized soil mixture that has been successfully used on levees in Vicksburg, Miss. and Memphis, Tenn., but would be used for the first time in Southeast Louisiana.
Stabilized soil is being used to build a steeper slope to stay within the existing right-of-way and minimize impacts to the surrounding community.
“The 1,000 ft. demonstration section will help the Corps and the nonfederal sponsor, the Office of Coastal Protection and Restoration, to fully understand the construction and operations and maintenance requirements of the stabilized soil mixture,” said Julie LeBlanc, senior project manager.
This week, clay from the Bonnet Carre Spillway will be excavated and mixed at the spillway to produce the stabilized soil mixture. The material will later be transported to the demonstration site after grass is removed on a 1,000 ft. stretch of Mississippi River levees near F. Edward Hebert Blvd. in Plaquemines Parish, approximately two miles north of Belle Chasse.
The majority of the demonstration section will be unvegetated and will appear similar to clay. This area currently sits at approximately 18-19 ft. above sea level and the section will be raised with the stabilized clay to approximately 22 ft. The demonstration will take approximately six weeks to construct and will include construction of an asphalt inspection road and curbs on top of the levee. It will remain in place and become part of the 2011 commitment, if successful.
“One of the advantages of the stabilized soil is that it is highly resistant to erosion without grass covering,” said LeBlanc. Relieving the nonfederal sponsor of costs of cutting grass could represent a substantial savings in maintenance.
The Mississippi River levee system was designed to protect against a high water river event, not hurricane storm surge. However, to reduce the risk from storm surge events, the Corps is using new techniques and analysis to increase the size and function of the Mississippi River levees co-located with the Hurricane and Storm Damage Risk Reduction System.