When the water hit last spring, the Mississippi River rose to 58 feet with a forecast of 60 feet or higher in May 2011.
The emergency plan to naturally or intentionally breach the levees, established over 80 years prior, was put in motion. The flood of 1937 did top the frontline levee and water passed into and through the New Madrid Floodway, but being floodfree since then caused area landowners to oppose the plan being put into action.
"After a delay due to a legal appeal from area landowners, the U.S. Army Corps of Engineers was finally given permission by the U.S. Supreme Court to open the floodway, but by that time, the Mississippi River was 4 feet higher than planned for," says University of Illinois researcher Kenneth Olson. "The initial additional force and depth of floodwater caused more damage to buildings and more deep land scouring than was predicted. The strong current and sweep of water through the Birds Point, Missouri, breach created deep gullies in 133,000 acres of Missouri farmland, displaced tons of soil, and damaged irrigation equipment, farms, and homes."
Olson has followed the drama of the deliberate flooding closely and believes it will create long-lasting, if not permanent, agricultural damage to hundreds of acres of land. The rushing water gouged large deep gullies on parcels of land adjacent to the blown levees and on some distant fields. The land was also covered with a thick sand deposit and in some areas adjacent to where new crater lakes were formed.
"Reclamation efforts by the Corps of Engineers included patching the frontline and fuse plugs levees with the sand, and topsoil was trucked in," Olson adds. "The former 60.5 feet fuse plug and the 62.5 feet front line levee was rebuilt, raising it initially to 51 feet and then, after input from local farmers, to 55 feet. Proper drainage in the area has been restored, but the unanticipated fields with large and deep gullies located five miles from the levee breaches will not be repaired very easily."
Olson believes that even if the fields of gullies are reclaimed, the soils are likely to have lower productivity. "The resulting land surface will have less soil aggregation, less organic carbon, and be more sloping, making it difficult to farm the land," he adds. "Some of this lost cropland could be restored as wetlands and wildlife habitat adjacent to the patched levees."
The Impacts of 2011 induced levee breaches on agricultural lands of Mississippi River Valley, coauthored by Lois Wright Morton, was published in the Jan.-Feb. 2012 issue of the Journal of Soil and Water Conservation.