Army Corps of Engineers Failed to Protect Dolphins in Spillway Openings, Lawsuit Alleges

The Army Corps of Engineers failed to protect bottlenose dolphins and other marine life in the Mississippi Sound and Lake Borgne by opening the Bonnet Carre Spillway in 2019 without obtaining proper permits under the Marine Mammal Protection Act, according to a lawsuit filed Monday in federal court in Mississippi.

The suit was filed by the cities of Biloxi, D’Iberville, and Pass Christian, along with Harrison County, the Mississippi Hotel and Lodging Association and Mississippi Commercial Fisheries United, Inc. It asks the U.S. District Court in Gulfport to declare that the Corps failed to get a permit from the National Oceanic and Atmospheric Administration before the 2019 openings of the spillway that would allow an “incidental take” — killing, injuring or harassing the dolphins — as required under the Marine Mammal Protection Act.

The local governments and other organizations are all members of the Mississippi Sound Coalition.

“The Mississippi Sound, our way of life, really, and our whole economy are in grave danger,” said Gerald Blessey, manager of the coalition and former mayor of Biloxi, at a Monday morning news conference announcing the suit.

“The Bonnet Carre Spillway is killing our dolphins and other marine life. Scientists have referred to the bottlenose dolphin as a sentinel of the health of the whole marine ecosystem. So the dolphins are telling us something. We must listen to the dolphins.”

The suit also asked the court to require the Corps to get such permits for any future openings.

The spillway was opened twice in 2019 to prevent the Mississippi River from overtopping levees as it flowed through New Orleans. Even with the two openings, water levels along the levees in the city reached as high as 20 feet at times, while floodwalls protected the city from water levels of 25 feet.

Moby Solangi, a marine biologist, director of the Institute of Marine Mammal Studies in Gulfport and chair of the coalition’s science committee, pointed to NOAA statistics for dolphin and sea turtle deaths linked to Bonnet Carre openings between 2011 and 2020 as proof of the threat to both species.

In 2019, 10.3 trillion gallons of freshwater were released during the two spillway openings that lasted a total of 120 days, and resulted in 153 dead dolphins and 201 dead sea turtles. Dolphins and turtles also were killed during openings in 2011, 2016, 2018 and 2020.

The lawsuit points to the severe risks to bottlenose dolphins when water salinity drops, including death, skin lesions, abnormal blood chemistry and infections. In addition to the numerous dead dolphins, scientists also found a large number of dolphins showing the effects of the low salinity water in both Mississippi Sound and Lake Borgne.

Solangi said the freshwater and nutrients carried by the river also destroyed oyster beds in the sound, most of which have still not recovered, nearly five years after the 2019 openings.

Nutrients carried into the Mississippi Sound by the diversion water also have resulted in repeated bouts of toxic algae blooms, which have disrupted use of beaches by tourists, and pose health hazards to residents, the lawsuit said.

Robert Wiygul, an attorney representing the coalition in the suit, said it’s time for the Corps to move quickly to find other ways of dealing with the flooding threat to New Orleans without such major openings of the spillway.

“Go back, if you’re an agency like the Corps, and figure out if there are ways you can keep from doing that,” he said. “Are there things you can do differently, like operate Bonnet Carre Spillway differently?”

Those alternatives could include opening the Morganza Spillway, which directs Mississippi River water into the Atchafalaya River basin, or supporting Louisiana’s proposals to build new sediment diversions farther upriver that could also funnel a portion of the river to its western side during high river periods.

A spokesperson for the Army Corps of Engineers declined to comment on the suit.

Monday’s lawsuit will be heard by U.S. District Judge Louis Guirola, Jr. In a Jan. 18, 2023 ruling involving a similar challenge, Guirola ordered the Corps to consult with the National Marine Fisheries Service about ways to avoid future harm to fisheries habitat in the Mississippi Sound and Lake Pontchartrain caused by openings of the Bonnet Carré.

The coalition is now challenging a November Corps essential fish habitat report that concludes the spillway’s effects are transitory and reversible.


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