The Mississippi flows in a broad, reverse curve, just above Cairo, Illinois. The narrowest distance across the neck of the large meander, an agriculturally rich 10,000-acre land mass known as Dry Bayou-Thompson Bend, is just 1.25 miles. Massive erosion across this Bend, could destroy thousands of acres of valuable farmland, create a disastrous Bendway Cutoff, and erode a section of the Commerce/Birds Point Mainline Federal Levee. The potential results include farmland destroyed, river transport stopped for decades, and an eroded levee flooding 5,700 square miles, rendering 300,000 people homeless.
Both parties recognized the potential for disaster. In the 1980’s they had initiated measures to limit scour and revent the catastrophe. The Corps and landowners developed a plan: they designed successive lines of vegetative screens perpendicular to flow-lines across the Bendway and, in 1986, began plantings of vegetation that eventually totaled 150 acres, all on private land The vegetation would decrease velocities at each successive line, thus limiting scour and encouraging deposition.
The Great Flood of 1993 provided the ultimate test. Trees 70 feet tall were bent over and completely submerged for months. And though they died they remained rooted in place, preventing erosion There was scour and erosion, but the estimate was more net gain due to deposition than loss due to scour Measurements showed velocities cut in half by each screen. The theory was proven.
The Project was too limited in scope and too expensive for private interests to restore. It was clearly necessary and in the best interest of the Government to become involved. Again, Corps personnel and locals developed a plan: the Thompson Bend Riparian Corridor Project. The Corps is purchasing easements to restore the destroyed tree screens. It is responsible for planting and initial maintenance. Landowners retain timber rights.
The Project will stretch for 14 miles. It will be a minimum of 300 feet wide, but will extend up to one mile in critical areas. Costs will be less than those which would occur if a cut-off developed or if traditional measures were used.
The methodology and magnitude of the Thompson Bend Riparian Corridor Project represents a revolutionary and unprecedented blending of various sciences and technologies. The result is expected to be effective for the long term. Cost-effective, environmentally proactive, unique, and essential.