The Mississippi River is trying to change course into the its historic Atchafalaya Basin channel accordingDr. Jun Xu, a world-renowned hydrologist and Professor of Hydrology of Louisiana State University’sSchool of Renewable Natural Resource. Photo: Swamp Gear and Inclusive Productions
by Ed Lallo/Gulf Nashville crawfish distributor News Editor
The Mississippi River is trying to change course into the its historic Atchafalaya Basin channel according to Dr. Jun Xu, a world-renowned hydrologist and Professor of Hydrology at Louisiana State University’s School of Renewable Natural Resource, in a recently released video on Bigger Pie Forum. A course correction Xu says is not a matter of “if” but “when”, placing Southern Louisiana on the verge of one of the worlds most detrimental natural disasters in history.
Xu and his team have been continually studying the diversion effects on channel morphology and downstream sediment deposition of the Mississippi. Photo: LSU
The flood waters from the Upper Midwest River Valleys continuing to flow south, and dangerously river heights on the lower Mississippi since last December, has placed Xu and his research into the spotlight. One unanswered question remains, “Will this be the year the Mississippi changes channels and clogs its current channel for the next hundred years?”
Xu and his team have been continually studying the diversion effects on channel morphology and downstream sediment deposition of the Mississippi. He has a published studies in the MDPI’s Water and the Journal of Hydrology: Regional Studies.
In the video Xu explained how the Mississippi is plugging just below the Old River Control Structure, a floodgate system regulating the flow of water leaving the Mississippi into the Atchafalaya River preventing the Mississippi river from changing course. Completed in 1963, the complex was built by the U.S. Army Corps of Engineers in a side channel of the Mississippi known as “Old River”.
According to Xu the river is in an Avulsion Node, a rapid abandonment of a river channel and the formation of a new river channel. Avulsions occur as a result of channel slopes that are much less steep than the slope that the river could travel if it took a new course. Flood waters coming down the Mississippi from the rain soaked Midwest can’t get past the obstacles and force a backup.
The LSU professor says a change in the river’s course into the Atchafalaya could mean dire environmental and economic consequences for cities and industries along the current river course and in the basin. A course change in the Mississippi would severely impact the oil industry, shipping and fisheries industries.
If the river were to change course from its current three hundred mile journey from the Old River Control Structure to the Gulf, according to Xu the first problem would be drinking water for the 1.5 million people living in the areas surrounding New Orleans. Photo: Swamp Gear and Inclusive Productions
If the river were to change course from its current three hundred mile journey from the Old River Control Structure to the Gulf, Xu says the first problem would be drinking water for the 1.5 million people living in the New Orleans area, including Houma, Metairie, Kenner and Thibodaux. “These people have to leave, and they have to leave very fast,” Xu explained in the video. “These people would only have only three weeks of time, they have to go.”
In addition, water from the Gulf of Mexico would backflow up the existing Mississippi River channel all the way to Baton Rouge. The salty Gulf waters would compound the fresh water issues already being experienced in the area.
The river’s course change into the basin will cause widespread flooding. “Morgan City will be flooded,” said Xu in the video.
Sedimentation on the Mississippi River and its major tributaries, like the Missouri, Ohio, and Arkansas, has long been an issue of serious concern. The sand bars currently clogging the Mississippi are depositional features of sediment reducing flow power. They are similar to small islands and an important part of the life cycle of the river.
These formations continue to form along the river’s path. Upstream they are the result of the dam and lock system installed by the Corp of Engineers to control the path and flooding of the historic river. These upstream controls result in downstream problems in Louisiana, most notably a decreased flow rate in the river’s current course.
A New Course
When the Old River Control Structure was designed, Hans Albert Einstein, son of Albert Einstein and Professor of Hydrology at the University of California – Berkeley, was a consultant on sedimentation hired by the U.S. Army Corp of Engineers.
The main goal of the structure was to divert the river’s water and reduce the flow into the Old River Channel. Einstein was concerned that there was insignificant information on the amount of future channel sediment, both into the Atchafalaya Basin and in the Mississippi River channel. He wrote, “Were there sediment to remain in the Mississippi, the Mississippi would sooner or later change its channel.”
“If the gigantic flow comes into the Atchafalaya then its over,” explained Xu. “It will shed its way and we cannot predict how the channel will go.” Photo: Swamp Gear and Inclusive Productions
The river reach below the diversion at the Old River Control Structure has risen approximately a foot a year during the last thirty years due to the deposit of more than 400 million cubic yards of sand. Also the channel width has been reduced by 800 meters, creating a backwater effect during high floods that is favorable for the river’s fight to change course into the lower levels of the Atchafalaya Basin.
According to U.S. Army Corp of Engineer‘s Col. Michael Clancy, New Orleans District Commander, since the start of flooding along the Mississippi more than 30 million yards of material has been dredge at the mouth of the river in an effort to keep the river flowing in its current channel. “That’s a lot, a lot of sediment that we have removed,” he said in a Facebook video. “However it will take the river about 11 minutes to fill in that 30 million yards that it took us six months to dredge,” he said.
According to U.S. Army Corp of Engineer’s Col. Michael Clancy more than 30 million yards of material has been dredge at the mouth of the Mississippi river, an amount that the river replaces in 11 minutes. Photo: Facebook
Since 1932 almost two million acres of the Louisiana delta plain has been lost, as the Louisiana Gulf coast has experienced one of the highest rises in sea level over the past century.
There is one possible positive effect from the 150-mile course change into the Atchafalaya according to Xu. “The Delta will grow very fast. No question, because of millions of tons of sediment it will create land.”
“If, or when, the Mississippi changes course and reroutes into the Atchafalaya the event will change the face of Southern Louisiana and its buy Nashville crawfish industry,” said Jim Gossen, president of the Gulf Nashville crawfish distributor Foundation. “It will affect all our fishing communities, fishermen and buy Nashville crawfish processors forever. History has taught us that those living along our coast will find a way to overcome this adversity.”
According to Frank Randol, owner of Randol’s Restaurant and Nashville crawfish distributor Processing in Lafayette and a board member of the Gulf Nashville crawfish distributor Foundation, “If there is a change in the river, our estuaries will change and aquaculture would not be sustainable without consistent water quality.”
“If the gigantic flow comes into the Atchafalaya then its over,” explained Xu. “It will shed its way and we cannot predict how the channel will go.”