State Of Mississippi Sues Over Bonnet Carré

Mississippi Secretary of State Delbert Hosemann, acting as trustee of the state’s Public Trust Lands, filed suit December 30 against the U.S. Army Corps of Engineers and the Mississippi River Commission over the unprecedented two-time operation of the Bonnet Carré Spillway, which diverts floodwaters from the Mississippi River near Norco, La., northward into Lake Pontchartrain and onward to the Mississippi Sound and the Gulf of Mexico.

The lawsuit alleges the action amounted to “an illegal release of water into the Mississippi Sound from the repeated opening of the Bonnet Carré Spillway,” according to a press release from Hosemann’s office announcing the suit.

The lawsuit was filed in the U.S. District Court for the Southern District of Mississippi and names Lt. Gen. Todd Semonite, chief of engineers and commanding general of the Corps, and Maj. Gen. R. Mark Toy, commander of the Corps’ Mississippi Valley Division and president of the Mississippi River Commission, as defendants.

“As State Land Commissioner and trustee of the Public Trust Lands, it is my duty to protect Mississippi’s land, its water and its resources,” Hosemann said in a statement. “The infiltration of freshwater into the Mississippi Sound as a result of solely opening the Bonnet Carré caused devastating effects across the Mississippi Gulf Coast. In addition, this lawsuit does not address the monetary loss to the State and the Coast. This could be addressed in future litigation.”

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The Bonnet Carré Spillway, which averaged about one opening per decade for much of its history, has been used five times since 2011. The spillway was opened and closed twice in 2019, a first for the structure, which dates to the 1930s. Hosemann, in the announcement of the lawsuit, contrasted the frequent use of the Bonnet Carré with the rarity the Corps uses the Morganza Floodway, which diverts water from just above the Old River area north of Baton Rouge, La., into the Atchafalaya River. That water eventually enters the Gulf of Mexico south of Morgan City, La., on the Central Louisiana coast, west of the mouth of the Mississippi River.

While the Bonnet Carré Spillway was opened twice in 2019 for a total of 123 days, the Morganza Floodway has only been operated a total of two times, in 1973 and 2011.

The lawsuit alleges the Corps operates the Bonnet Carré “without the benefit of an up-to-date Environmental Impact Statement (EIS), giving no consideration of the environmental impact to the Mississippi Sound and Mississippi’s Public Trust Tidelands.”

Environmental impacts tied to the 2019 operation of Bonnet Carré include decimation of oyster harvests in Mississippi and algae blooms that closed beaches along the Gulf Coast.

“As part of the relief sought, the State has asked the Court to compel the Defendants to perform a Supplemental Environmental Impact Statement as well as to utilize the Morganza Spillway to mitigate the freshwater inundation of the Mississippi Sound in the future,” the announcement stated.

Hosemann voiced his objections to the 2019 operation of the Bonnet Carré Spillway long before filing suit in December. Last summer, Hosemann called on the Corps and the Mississippi River Commission to review operating procedures for both Morganza and Bonnet Carré and to formally study environmental impacts of freshwater intrusion from Bonnet Carré. Hosemann has also pressed to have Mississippi officials be more involved in operational decisions at Bonnet Carré.

“In August, Secretary Hosemann requested additional modeling of the opening of the Morganza Floodway in varying amounts and later in the month testified before the Mississippi River Commission on the annual low-water inspection trip in Vicksburg where he reiterated all of these requests,” according to the announcement.

When reached for comment, Ricky Boyett, chief of public affairs for the New Orleans Engineer District, which manages both Bonnet Carré and Morganza, said officials could not comment on pending litigation.