Sep 29, 2023 - News

Jefferson Parish to build temporary pipelines to thwart saltwater threat

The U.S. Army Corps of Engineers is increasing the height of an underwater levee in hopes of slowing down the saltwater wedge in the Mississippi River. Photo courtesy of U.S. Army Corps of Engineers

Jefferson Parish leaders say construction could begin next week on temporary pipelines to get clean water upriver if the saltwater wedge contaminates the current drinking water supply.

Why it matters: If the pipelines are built in time, they could provide clean water to the 424,000 residents in Jefferson Parish.

  • But they wouldn't help New Orleans, which is planning its own temporary pipelines.

Driving the news: Gov. John Bel Edwards approved Jefferson Parish's plan Friday, according to parish President Cynthia Lee Sheng, and workers have begun scouting the routes along the Mississippi River batture.

Catch up quick: Because of the drought across the Mississippi River Valley, salt water is creeping upriver, where many communities, including New Orleans and Jefferson Parish, draw their drinking water.

  • The latest forecast calls for it to reach New Orleans around Oct. 22 and Gretna on Oct. 24. The water in Orleans and Jefferson parishes is safe to drink until then.
  • Once the salt is here, it is expected to stick around for weeks to months, depending on rainfall.
Estimated timeline for saltwater intrusion into the New Orleans metro area
Data: GOHSEP; Map: Axios Visuals

How it works: Jefferson Parish leaders plan to build four temporary pipelines on the West Bank and five on the East Bank.

  • The pipelines will connect the West Jefferson and East Jefferson water treatment plants to the Mississippi River near Kenner, where the river has a natural feature that should stop the saltwater wedge.
  • Workers will start on the West Bank, where the saltwater intrusion will happen first, Mark Drewes, director of the parish's Public Works Department, said at the press conference Friday. They're just waiting on the equipment to arrive.
  • The pipelines will be built in 5-mile sections and be powered with diesel pumps, he said.

Zoom in: Jefferson Parish is coordinating with the levee districts, Army Corps and Orleans Parish officials, Drewes said.

  • Leaders say they are being mindful while working on the batture and making sure they don't compromise the levees.

Meanwhile, Gretna has its own water intake and plans to use a combination of mitigation efforts, Mayor Belinda Constant said Friday.

  • The city will use reverse osmosis machines to desalinate the water in addition to barging in freshwater to dilute the salt at the intake.
  • Water restrictions are likely in Gretna, Constant said, noting that things might get "uncomfortable" at times. The city has water tanker trucks prepared.

As far as pipe corrosion, Jefferson Parish currently injects a type of phosphate into the water to prevent corrosion and leaching of heavy metals, said Sidney Bazley, the parish's Water Department director.

  • Salt water is corrosive and can damage pipes, especially lead and iron ones, and possibly leach heavy metals into the water.
  • Bazley said they're working on an analysis of existing lead pipes now and seeing how much phosphate may be needed if the intrusion happens.

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