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The City of New Orleans

Lower Mississippi Saltwater Intrusion Updates

Fri
Sep 22
2023
4:54 PM
Lower Mississippi Saltwater Intrusion

Mayor Cantrell, Sewerage And Water Board Of New Orleans Prepare For Potential Impacts From Saltwater In Mississippi River

NEW ORLEANS — Mayor LaToya Cantrell and Sewerage and Water Board of New Orleans (SWBNO) Executive Director Ghassan Korban today joined Governor John Bel Edwards, the Governor’s Office of Homeland Security and Emergency Preparedness (GOHSEP), Louisiana Department of Health (LDH), U.S. Army Corps of Engineers (USACE), New Orleans Office of Homeland Security and Emergency Preparedness (NOHSEP) and officials from Jefferson, St. Bernard and Plaquemines parishes to discuss potential impacts to drinking water in the event of saltwater intrusion into the Mississippi River from the Gulf of Mexico.

Water in Orleans Parish remains safe to drink and use for all purposes. 

“We have been and will remain in daily, close coordination with local, regional and state agencies to actively monitor the saltwater wedge moving up the Mississippi River and establish unified, collaborative efforts, strategies and public engagement,” said Mayor LaToya Cantrell. “This goes beyond New Orleans – it is a regional problem, and we will continue working to support our neighboring parishes of Plaquemines, who have already been impacted, and St. Bernard, who may soon be affected. SWBNO is working with USACE to explore potential actions to mitigate the salt content in water entering the system, including bringing in fresh water on barges, pumping it from parishes further upriver and researching filtration methods and systems. The most important thing for residents at this time is to stay informed and remain calm. As we continue monitoring this situation, we will communicate all necessary information to residents as it becomes available.”  

Mayor Cantrell today signed an Emergency Declaration allowing City agencies to thoroughly prepare for and respond to any impending impacts. It also allows for a more streamlined response and for state and federal agencies to deploy resources, if necessary. This declaration is aligned with Governor Edwards’ emergency declaration and other parishes in the region. To read the declaration in full, please view here

USACE continues its efforts to mitigate impacts to drinking water in the region by increasing the height of a sill, or underwater barrier, in the river that was built in July. USACE today provided an anticipated timeline for potential saltwater impacts, which includes the Algiers and Carrollton water treatment plant locations along the Mississippi River. USACE anticipates impacts in late October. Please note that this timeline is subject to change, and the City will keep the public informed as the timeline is updated. 

The City is working closely with USACE, GOHSEP and surrounding parishes to track the progress of the saltwater wedge and prepare in a regionally coordinated way for the potential impacts of it reaching New Orleans.  

To prepare for this event, the City of New Orleans, NOHSEP and SWBNO are exploring several options for bringing in freshwater, as well as filtration methods and systems. A few options to address this issue include: 

  • Blending – bringing in fresh water from an alternate source, likely by barge or tanker ship, and mixing it with the salty river water to reduce the overall salt content; this is already being done in Plaquemines Parish 
  • Desalination/Reverse Osmosis – process of converting saltwater to freshwater by filtering out the salt content by passing the water through a semi-permeable membrane that separates the water from any other molecules (salt, mineral content, impurities, etc.). While SWBNO does not currently have these capabilities in-house, the utility is looking at outside options to utilize this solution 
  • Alternate Water Sources – drawing from another source of fresh water further upriver and pumping it into the east bank water systems of New Orleans and Jefferson Parish; this option will require a regional approach, including the participation of state and federal partners    
  • Connections to Other Systems – it may be possible in some cases for one jurisdiction to connect their water system to that of another system further upriver beyond the location of the wedge, such as parishes downriver connecting with New Orleans’ east bank system, allowing them to draw fresh water from neighbors upriver for as long as possible. This option may not be feasible for the city due to the smaller municipal intake facilities upstream of SWBNO and Jefferson Parish intake facilities 

“We are making preparations for potential impacts at both of our drinking water treatment plants,” said Korban. “As always, customers’ health and safety remain our top priority. Alongside our partners, we will do everything in our power to mitigate saltwater intrusion and safeguard all residents and visitors.”

Should New Orleans experience saltwater impacts, SWBNO will notify customers well in advance of any changes that should be made to their water usage. The Carrollton Water Treatment Plant that serves the Eastbank of New Orleans treats approximately 150 million gallons of water per day, and the Algiers Water Treatment Plant that serves the Westbank treats approximately 12.5 million gallons of water per day.  

The City urges all customers to sign up to receive NOLA Ready emergency alerts to your phone or email. To sign up, text NOLAREADY (one word) to 77295 for alerts. 

For more information about the Saltwater Wedge from the U.S. Army Corps. of Engineers, please visit their Saltwater Wedge Overview webpage

 

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