LA Works to Stop Saltwater Wedge
Residents in Jefferson Parish, Louisiana, are expecting construction to begin this week on a system of drinking water pipelines intended to help mitigate a pressing saltwater intrusion issue.
Recent reports state that the new temporary pipelines are planned to be installed in order to get clean water up the Mississippi River if the saltwater wedge contaminates the area’s current drinking water supply.
If the pipelines are built in time, Axios reported last week, they could provide clean water to the 424,000 residents that live in Jefferson Parish.
About the Issue
According to the report, because of the drought across the Mississippi River Valley, salt water is making its way upriver, where many communities, including the city of New Orleans and the adjacent Jefferson Parish, get their drinking water.
The most recent forecast called for it to reach New Orleans around Oct. 22, and Gretna, Louisiana, on Oct. 24. The water in both Orleans and Jefferson parishes is reportedly safe to drink until then.
However, once the salt is there, it is reportedly expected to stick around for weeks to months, depending on rainfall.
Great news for Jefferson Parish residents about saltwater intrusion:— Carlie Kollath Wells (@carlie_kollath) September 30, 2023
Leaders say construction could start next week on temp pipelines to get clean water upriver.
This is separate from NOLA's pipeline plan, which isn't approved yet.
Current plan: https://t.co/xkNyRcYfhy
The report states that Louisiana Governor John Bel Edwards had approved Jefferson Parish's plan last week, according to Parish President Cynthia Lee Sheng. Workers have reportedly started mapping the routes along the Mississippi River batture.
Leaders in Jefferson Parish also anticipate planning to build four temporary pipelines on the West Bank and five on the East Bank of the river.
The pipelines are reportedly expected to connect the West Jefferson and East Jefferson water treatment plants to the Mississippi River near Kenner, Louisiana, where the river has a natural feature that could potentally stop the wedge.
The report adds that workers will begin on the West Bank, where saltwater intrusion is expected to happen first. Mark Drewes, Director of the Parish's Public Works Department, said at a press conference that they are now just waiting for the equipment to arrive.
Drewes stated that the pipelines are planned to be built in five-mile sections and powered by diesel pumps. Drewes added that Jefferson Parish is coordinating with the levee districts, U.S. Army Corps of Engineers and Orleans Parish officials.
Additionally, Jefferson Parish leaders have stated that they are trying to be mindful while working on the batture to ensure that they don't compromise the levees.
"This is what we're calling a flexible waterline system, sometimes known as lay-flats in the industry, to draw in fresh water from up the river,” Parish President Cynthia Lee Sheng said in a report from NOLA.com.
The West Bank system is planned to contain four, 12-inch diameter lay-flat pipes. There will also reportedly be four diesel pumps at five-mile increments. Drewes added that the system is buildable and may not need to reach the full 15 miles officials have planned.
"We do believe it's doable with the timeframe and the schedule the Corps has set out," Drewes said.
Meanwhile, the City of Gretna has its own water intake and plans to use a combination of mitigation efforts, Mayor Belinda Constant said last week. The city will reportedly use reverse osmosis machines to desalinate the water as well as barging in freshwater to dilute the salt at the intake.
Water restrictions are also reportedly expected in Gretna, Constant said, adding that things could become difficult at times. The report adds that the city has water tanker trucks prepared for these issues.
Jefferson Parish currently injects a type of phosphate into the water to stop corrosion and leaching of heavy metals, said Sidney Bazley, the Parish's Water Department Director. Bazley added that they are working on an analysis of existing lead pipes and now seeing how much phosphate may be needed if the intrusion happens.
Constant stated a barge would be secured last Saturday (Sept. 30) sometime in the afternoon.
"We really want the constituency to understand that we stand ready," Constant said, adding that “there may be challenges" and that residents might be asked to reduce water use so it can be targeted for emergency purposes.
In March, the U.S. Army Corps of Engineers has reportedly begun repair work on pumping stations in New Orleans after discovering corrosion on the systems earlier this year.
The pumps were supposed to last 35 years but have only been in operation since 2018, reports say. While corrosion was only found at one of the three stations, the finding resulted in an inspection of all 16 pumps in the system.
The three permanent canal closures and pump stations at London Avenue, Orleans Avenue and the 17th Street Canal cost a total of $726 million and were constructed as one of the last projects of the $14.6 billion redesign and construction of the New Orleans hurricane levee system following Hurricane Katrina.
The new stations were designed to keep surges from Lake Pontchartrain from entering the city and threatening the interior floodwalls along the canals, while the pumps were designed to match the flow of water entering the canals from interior pump stations in moving it into the lake.
In February, corrosion was discovered on the London Avenue pump after water was removed from the bay and the outer covering was removed. The severity of the corrosion was reportedly “well beyond what was expected during its entire 35-year service life,” said Bradley Drouant, senior project manager for the three lakefront stations.
The pump had previously overheated in May 2022 and was taken out of service. At the time, officials speculated that the overheating could have been caused by the possibility that its equipment became misaligned because the heavy pump station structure was sinking, or that a temperature sensor was faulty.
As a result of the findings, inspections got underway on the 16 pumps across all three stations. The Corps reported the preliminary findings show the pumps are seeing varying levels of corrosion.
Officials said that they had plans to temporarily repair both aspects of the flood protection system by June 1, in preparation for hurricane season. Lakey Inc. was reportedly hired to complete the repairs, which were anticipated to cost several hundred thousand dollars.
A contract had not been finalized for the long-term review, but was anticipated to take at least two years and will need a funding source. The Corps also was evaluating alternatives for removing water from the canals in the event that pump capacity at individual stations drops below what is needed during hurricanes.