Corps of Engineers planning second saltwater sill in less than a year in Plaquemines Parish

NEW ORLEANS (WVUE) - Less than two weeks ago, Plaquemines Parish officials began trucking freshwater to Boothville due to a saltwater wedge moving up the Mississippi River from the Gulf of Mexico. Now the Corps of Engineers is taking action to stop that wedge from threatening water supplies even further upriver.

For the second time in a year, the gauge at Carrollton is out of the water, a sign of low river levels and potential problems.

Approximately two weeks ago, Plaquemines Parish officials issued a water advisory for the Boothville area in Venice due to the encroachment of saltwater up the river caused by low river levels.

“We sent down 200,000 bottles of freshwater to the Boothville-Venice since this began,” said Plaquemines Parish President Keith Hinkley.

Just nine months ago, the Corps of Engineers invested nearly $10 million in constructing a sill near Myrtle Grove to impede the saltwater wedge, which proved successful. However, the sill was designed to be washed away when the river rose in the fall, and now the Corps plans to rebuild it.

In response to the threat of the saltwater wedge continuing to move up the Mississippi River, Governor John Bel Edwards declared a state of emergency in Plaquemines Parish on Thurs., July 6.

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“With the construction of the sill, the riverbed is about 90 feet deep and we will bring it down to 50 to 45. We will probably not have any navigation impacts,” said Ricky Boyett with the Corps.

Despite the gauge at Carrollton indicating a reading of 1.6 feet, the Corps officials clarify that the river’s depth is still significant in areas such as Myrtle Grove and those below Baton Rouge.

“This river in south Louisiana is a minimum of 45 feet. At Algiers Point, it is 190 feet. So it’s still one million gallons of water moving past. And it is still a very dangerous river,” said Boyett.

Plaquemines Parish officials are encountering difficulties in acquiring specialized equipment to remove salt from the water at Boothville. As an alternative, they are exploring the installation of booster pumps to push freshwater supplies downstream through existing water pipes from Belle Chasse. However, this solution will take time to implement.

“The whole process would take four weeks but we’re still looking at pumps at West Pointe a la Hache to start producing water there and that’s a six week process,” said Hinkley.

In the meantime, the transportation of thousands of bottles of drinking water to Boothville continues as multiple efforts are underway to address the ongoing challenge of saltwater intrusion.

The Corps of Engineers is considering the potential closure of natural river cuts at Neptune Pass and Mardi Gras Pass to enhance the river’s flow and deter saltwater intrusion upriver. Construction of the new saltwater sill is expected to commence next week, according to the Corps.

Additionally, Plaquemines Parish officials are exploring options to place a reverse osmosis unit at the Boothville treatment plant, complete emergency repairs at the Port Sulphur treatment plant, which suffered damage during the recent IDA hurricane and place a temporary booster at Alliance to boost water from Belle Chasse to Venice.

A drinking water advisory remains in effect for the Empire Bridge to Venice area until further notice.

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