Mississippi River Tried to Change Course During Floods

September 13, 2011

Since the waters from this spring’s floods receded, officials have identified places where the Mississippi River tried to carve out new channels and change course.

From northwest Tennessee to Louisiana, the Mississippi tried to cut through river bends and remove parts from islands during the historic flood.

Officials have found that the river washed out riverbanks, undermined some levees and buckled the concrete revetment installed by the Army Corps of Engineers to hold banks in place, according to The Commercial Appeal.

For example, the river tore out a half-mile-wide chunk of land at President’s Island in Memphis and left water and flocks of geese on a place where cotton formerly grew.

“I couldn’t believe it,” said James Parker, crew chief for the Memphis and Shelby County Port Commission. “I thought it was going to cut all the way through (the island).”

The flood of 2011 reached historic levels in Memphis, which saw the Mississippi fall about a foot short of the record crest of 48.7 feet set in 1937. The National Weather Service recently set the official crest of the flood at 48.03 feet on the Memphis gauge, slightly higher than the initial estimate of 47.8 feet.

Officials say the corps’ $13 billion flood-control system along the river largely worked, preventing an estimated $62 billion in damage up and down the Mississippi. Officials think that any rerouting of the main river channel today could reverse decades worth of engineering by the corps, destroy property, leave ports high and dry and render the river unfit for navigation by barges.

Corps officials estimate it will cost $222.5 million to undo the damage caused by the river as it tried to create new channels during the flood. That is in addition to the projected $327.7 million it will take to fix flood-damaged levees, the $157.4 million worth of flood-related dredging needed and the estimated $70.6 million required to restore spillways and similar structures.

The U.S. House approved $1 billion in emergency appropriations for the corps in the energy and water bill to help pay for flood damages. The Senate has not approved any funds.

If Congress doesn’t provide any money, the corps will have to shift funds it already has to pay for the work, spokesman Bob Anderson said, reducing the amount of repair that could be done.

During the flood, two of the most urgent “bank failures” happened in Tennessee.

On the northeastern edge of Presidents Island, the Mississippi attempted to slice through a half-mile-wide section of riverbank and dig a channel a mile long into the island.

Another large bank failure occurred in Lake County, Tenn., about 130 miles upriver from Memphis. The river breached a spur levee and tried to cut across a bend, creating a broad channel east of the current one.

“This has destroyed thousands of acres of farmland that we will not be getting taxes on,” said Lake County Mayor Macie Roberson.

Corps officials say they’re confident that if properly repaired, their system can continue to keep the river manageable.

“The river is the control,” said Larry Banks, a retired hydraulics engineer who worked with the corps in Vicksburg, Miss., for 37 years. “The works of the corps can tickle it a little bit and keep it manageable.”

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