By Mark Schleifstein

The federal government's regulation of Mississippi River water flowing through the Old River Control Structure north of Baton Rouge has caused repeated flooding that has taken a portion of the value of farmland owned by school boards in three Mississippi counties, the state of Mississippi argues in a lawsuit filed Monday (Feb. 12).

The state contends that's a violation of the U.S. Constitution's 5th Amendment requirement that the federal government compensate landowners when "taking" a portion or all of the value of their property.

The lawsuit was filed in the U.S. Court of Claims in Washington, D.C., by Mississippi Secretary of State Delbert Hosemann, Mississippi Attorney General Jim Hood, and the Claiborne County, Natchez-Adams and Wilkinson County school districts.

The Old River Control Structure, completed by the Army Corps of Engineers in 1963, was designed to block the majority of the flow of the Mississippi River shifting west into the Atchafalaya River. Old River was upgraded following a 1973 flood that nearly broke through portions of the structures. In 1985, the city of Vidalia built the Sydney A. Murray Hydroelectric Station using water passing through one of the structures to generate 192 megawatts of electricity for local use.

Congress has required that no more than 30 percent of the Mississippi's flow pass through the structure into the Atchafalaya. That split guarantees freshwater levels in the Mississippi River south of Baton Rouge are high enough for the river to be used as drinking water supplies in New Orleans and Jefferson Parish, as well as a by more than 190 petrochemical plants and other industries along the river's path.

The high flow levels, combined with a narrowing of the river's mouth by jetties in Southwest Pass also reduce the cost to the corps and federal government of keeping the mouth of the Mississippi River free of sediment and navigable by ocean-going vessels.

In their lawsuit, Mississippi officials point out that Congress and the corps did not take into account the potential effects of the Old River complex on their state's public school lands, and never purchased "flowage rights" from the school boards, allowing higher water caused by the structure to flood their land.

The lawsuit charges that today, the structure actually is diverting only 23 percent to 25 percent of the Mississippi's flow into the Atchafalaya, and contends the failure to release more water has meant more sediment has stayed in the Mississippi, narrowing its channel by about 2,600 feet and raising the river's bottom.

In a presentation to the American Geophysical Union on December 2017, Louisiana State University research hydrologist Yi-Jun Xu warned that the infill of the river both above and below the Old River structure had the potential of creating a shift of the river to the Atchafalaya channel during a major high-river flood event.

Such a shift would result in salt water from the Gulf of Mexico moving far enough up the Mississippi River to threaten the drinking water supply for 2 million people. It also would make the freshwater aquifer used by Baton Rouge for its drinking water too salty.

Xu did not address flooding in Mississippi during his presentation.

But Mississippi officials say the narrowing and rising river bed, plus other actions the corps has taken to straighten and shorten the river to eliminate curved oxbows upstream, have resulted in more severe flooding and more flood days on more than 7,900 acres, or 12.4 square miles, of school-owned land in Adams, Claiborne and Wilkinson counties.

That land is used for recreation and for growing and harvesting timber, the suit said, with money from its use supporting the public schools. The school boards should be paid not less than $25 million for the lost value of their property, the suit said.

"This 8,000 acres that is owned by the state of Mississippi, we believe it is being turned into a permanent reservoir," Hosemann told reporters Monday.

He said only 75 days of flooding were recorded in the area from 1950 to 1972, while more than 1,000 days were recorded from 1973 to 2016.

The Republican, who is running for lieutenant governor this year, said he appealed to the Mississippi River Commission in 2016 for relief. The commission oversees the levees and dams that are meant to prevent flooding and enhance navigation along the river.

Private property owners in southwest Mississippi have also complained about increased flooding in recent years, and Hosemann acknowledged that if the state's lawsuit is successful, private landowners would likely follow suit.

Despite the assertions in the lawsuit, Hosemann said the state has not yet conducted studies of the river's water flow meant to scientifically prove that siltation from Old River is to blame for increased flooding. Hosemann said such studies would be conducted over the next two years at a cost of $50,000.

There could be other factors driving flooding as well. Some experts say increased upstream development is sending more water downstream. In addition, in two of the last three years, the lower Mississippi has seen unusual wintertime floods sparked by heavy rains upstream that could be related to climate change. Historically, the Mississippi's peak flood has been in the spring.

The Associated Press contributed to this story.

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