Corps drilling wells to save remote but vital levee
In a corner of Memphis where fox and deer far outnumber people, Andrew Smothers and Grant Butler are driving atop a levee so tall it dwarfs the trucks and drilling equipment at the edge of some woods below.
Six years after the historic 2011 flood strained levees all along the Mississippi River, this remote, barely accessible area of southwest Memphis is the scene of an unusual but crucial construction project. The Corps of Engineers, for whom Smothers and Butler work, is busy sinking 121 wells into the base of a levee to prevent future floods from undermining it.
In a project costing about $4.5 million, these relief wells, as they’re known, will be drilled 90 to 125 feet deep near the southern edge of Frank C. Pidgeon Industrial Park. The wells should prevent a recurrence of a problem noticed during the 2011 flood, when water from the Mississippi pressed against the river side of the levee and seeped under it in numerous places, bubbling up on the protected side in what are called sand boils. ee.The sand boils are indicative of potentially dangerous liquefaction of soil, which could lead to the failure of a lev
“Seepage is OK as long as the water’s clear,” said Smothers, a civil engineer with the corps. “When it’s not clear, when you have sand boils, it means it’s moving material from the foundation.”
The scale of the project reflects the importance of the Mississippi River levee system in general and this section in particular. Since the 2011 flood, which came within inches of the record river elevation at Memphis set in 1937, the industrial park protected by the levee has attracted some major economic development projects, including the $266 million Electrolux plant, which will employ up to 1,200 people, and the Tennessee Valley Authority’s $975 million Allen Combined Cycle Plant, which is set to begin generating 1,070 megawatts of power next year.
In addition the industrial park is home to the burgeoning CN Railway intermodal yard, the Nucor Steel mill and wastewater treatment and public works facilities operated by the city of Memphis.
The relief well project is not the first effort to reinforce the levee. During the 1990s, the corps built a seepage berm on the protected side of the levee, using, among other material, fly ash from the nearby TVA Allen Fossil Plant, a coal-fired facility being retired next year.
The effort to bolster the levee is crucial to the industrial park, said Randy Richardson, executive director of the Memphis-Shelby County Port Commission, which manages the acreage. But he added that no one working in the industrial park “has ever been in any danger” from flooding.