Clogged arteries cause heart attacks. Clogged rivers cause floods.
If plaque clogs your widowmaker artery and you don’t get a stent, you may have a serious heart attack. The Mississippi River is the country’s main transportation artery. It’s vital to our economy and national security. It is clogged with plaque. It needs a stent.
River engineers call the plaque an aggravated reach of the river. I call it Mudberg. It’s a big mound of sediment that clogs the river, restricts its flow, and makes floods higher and longer. It sits just downstream of the Mississippi-Louisiana state line at the Old River Control Complex (ORCC).
The ORCC was built in stages from 1963 to 1980 to keep the Mississippi from changing course down the Atchafalaya and discharging to the Gulf near Morgan City, LA instead of below New Orleans. It keeps the country’s main transportation artery open. The US Army Corps of Engineers (Corps) operates it.
Congress put the Corps in charge of flood control on the lower Mississippi River (1928 Flood Control Act) to prevent another disastrous 1927 flood. The Corps has spent billions on levees, reservoirs, cutoffs, spillways, and other flood control projects. But now its own 2019 “Future Flood Conditions” flow line study says levees will overtop again anyway.
Flood control projects block the river’s natural floodplains, like the Yazoo River basin, that once helped relieve floods. They have turned the river into a big, leveed ditch. Now the Corps has clogged the ditch. Not with a flood control project — but by changing how it operates the ORCC to favor a privately owned power plant (the Sidney A. Murray Hydroelectric Plant). This change jeopardizes the Corps’ primary flood control mission.
The ORCC works by diverting 23% of the Mississippi’s flow to the Atchafalaya. That was the natural diversion in 1950 before the river began to change course. The Corps operated the ORCC to maintain that flow diversion for 27 years (1963-90).
The ORCC was carefully sited to divert sediment-rich flow and designed to convey most of its sediments to the Atchafalaya. It didn’t convey all of them. But it minimized the sediments left behind to fall out in the main channel. That minimal fallout aggraded (raised) the main channel slightly, but didn’t clog it. No Mudberg.
Then in 1990 when the power plant started up, the Corps changed how it operated the ORCC, decreased the sediments conveyed to the Atchafalaya, and increased the sediments left in the main channel. They fell out and created Mudberg.
The power plant is not for flood control or to keep the river from changing course. It is a commercial plant that generates and sells electricity. It is sited just upstream of the ORCC to skim sediment-lean flow for its turbines that sediments would damage.
The Corps sent the sediment-lean flow to the plant and reduced sediment-rich flow through the ORCC by 80% to maintain the 23% total flow diversion. This increased the concentration of sediments in the main channel. By the mid-1990s, Corps measurements showed sediments were beginning to clog the main channel. The clog got bigger.
In 2011, the highest Mississippi River flood ever recorded occurred. Its flow was not the largest ever. But its crest was the highest because Mudberg slowed its discharge. Like a clogged drain makes your sink run over.
In 2015, there was a step change increase in flood frequency and duration. In 2016, the third winter flood ever recorded closed the deer season early along the river. It was the second in a cluster of six straight major floods — including the longest flood ever in 2019. Floods were above flood stage three times longer in the five years after 2015 vs before.
Mudberg slowed the river’s discharge and made floods longer. Like a clogged drain makes your sink take longer to drain.
The Corps said the higher and longer floods were due to more rain. But rainfall in the Mississippi River basin was about the same in the decades ending 2019 and 2009. The floods were mainly due to less drain: Mudberg.
Flooded landowners inside the levees learned about Mudberg in 2018 from a paper published in late 2017 by LSU’s Dr. Yi-Jun Xu. It explains the cluster of floods and why the Corps 2019 study predicts higher and longer floods inside the levees until they overtop or fail. Dr. Xu says it could cause the Mississippi to change course in a big flood too.
But the Corps doesn’t talk about any of this. Or do anything about it — like dredging a “stent” channel through Mudberg. Or stopping flow to the power plant to decrease sediment fall out and keep Mudberg from getting bigger. Why?
Landowners inside the levees want to know. Landowners outside the levees in the Delta and the Atchafalaya floodplain might too. So might our US Senators responsible for Corps oversight. So might Mississippi’s Secretary of State responsible for flooded 16th Section Land inside the levees. The Lieutenant Governor sued the Corps for taking Mississippi’s 16th Section Land when he was Secretary of State. He might ask Corps officials: Why don’t you stent the river’s clogged artery? Why are you making the clog bigger?
Floods come in clusters now. So do droughts. Big Mississippi Floods happen about every ten years. The last one was in 2019.
We are in the midst of a drought. That’s the time to stent Mudberg — not after the next flood. If you survive a heart attack and don’t try to prevent the next one, you may become a fatal statistic. Your cardiologist should stent you. He may be guilty of malpractice if he doesn’t.
The river equivalent of a serious heart attack is a big flood that overtops levees or makes the river change course — or both. The Corps is our river’s cardiologist. It might prevent or delay both if it stented Mudberg and stopped diverting flow to the power plant.
It might be malpractice not to.
Kelley Williams, a Northsider, is chairman of Bigger Pie, a Jackson-based think tank promoting free markets and government efficiency.
