Corps: South Lafourche levee stable, meets design criteria

As the South Lafourche Levee District moves forward with planned improvements to the 44-mile ring levee surrounding the 10th Ward of Lafourche Parish, one thing it will not have to be concerned with is the strength of the levee itself.

After conducting soil borings at targeted locations on the levee, the U.S. Army Corps of Engineers confirmed in a letter to the levee district that, “analysis shows the levee at its current grade is stable and meets all Corps stability design criteria.”

Levee district general manager Windell Curole touted this acknowledgment by the Corps as significant because the stability means the berms on the levee will not have to be extended as the work begins to raise it to even greater heights.

“What the Corps is saying is that the clay and the soils that form the heart of the levee have compacted and become strong enough that additional berms, which are typically built to provide strength to a levee, are not really necessary,” said Curole. “The levee has ‘matured’ and can for the most part stand on its own.”

He noted that berms to the levee system were important in the early years of constructing the system, especially after the first lift was put in place. “As the dirt settles as you place additional lifts, the crown of the levee becomes stronger, thereby lessening the need for support from the berms,” he said.

The district is embarking on various projects that will first shore up weak spots in the system to be followed by using the proceeds of a one-cent sales tax to bring the entire ring levee system back to design grade height. In some places, the levee has sunk as much as three feet from its originally built elevation.

Original design heights of the system are approximately eight to 10 feet above sea level in the Larose area and going as high as some 13 feet above sea level near the Leon Theriot floodgates south of the Golden Meadow.

The penny sales tax is projected to bring in over $4 million annually for the district. Costs to raise the levee back to design level are approximately $12 million. However, when the raising of floodwalls and “hard structures” such as pump stations are included in the projections, the cost moves upward to nearly $60 million.

Once back to design level, the district will look at possibly raising the levee to a uniform height of 15 feet, Curole said. That cost is expected to reach $100 million, which includes the raising of the levee, floodwalls and pump stations.