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Saltwater Intrusion Updates

During unusual circumstances or emergencies, GNO, Inc. strives to provide our stakeholders with concise, accurate, actionable information.  With this in mind, please find an update below on the current status of saltwater intrusion in the Mississippi River.  We will continue these updates as needed.

Saltwater Intrusion October 13, 2023 Update

Summary

  • Overall, good news.  According to the U.S. Army Corps of Engineers (USACE), the Algiers water treatment plant in New Orleans and Gretna water treatment plant in Jefferson Parish are no longer expected to see chloride levels above federal limits from salt water moving up the Mississippi River.  The new forecast, based on water flow modeling by the Corps, also delays by two weeks the expected arrival of salt water at the Belle Chasse and Dalcour water treatment plant intakes in Plaquemines Parish.  Salt water is now expected to reach the Belle Chasse plant on Oct. 27, and the Dalcour plant on Nov. 1.  “The change in forecast is largely the result of augmentation of the existing underwater sill and increased flows of the Red River, requiring less diversion at the Old River Control Structure,” said a Corps news release.

GNO, Inc. Action

  • Yesterday, GNO, Inc. provided a briefing to our Board of Directors on up-to-date information and regional actions taken to mitigate the saltwater intrusion emergency.  GNO, Inc. continues to work with regional partners to gather and regularly supply the latest information.  GNO, Inc. also continues to work with partners on long-term solutions to future salt water intrusion.  You can see the GNO, Inc. Board update here

News

  • Saltwater in Retreat – The location of the saltwater wedge toe was estimated on Oct. 9 at river mile 63.9 above Head of Passes (AHP).  The Corps’ estimation predicts that the saltwater wedge has retreated approximately 5.5 river miles since the last estimation conducted on October 2.
  • Updated Saltwater Forecasts – Today the U.S. Army Corps of Engineers (USACE) released the latest Saltwater Wedge Timeline forecast of when water treatment facilities may be impacted by saltwater intrusion.  Updates based on the latest forecast:
Treatment Plant October 12 Forecast October 5 Forecast
Belle Chasse Oct. 27 Oct. 13
Dalcour Nov. 1 Oct. 17
St. Bernard Nov. 8 Oct. 28
New Orleans Algiers Not anticipated to experience chloride levels exceeding 250 ppm Nov. 23
Gretna Not anticipated to experience chloride levels exceeding 250 ppm Nov. 26
West Jefferson No change Not anticipated to experience chloride levels exceeding 250 ppm
New Orleans Carrollton No change Not anticipated to experience chloride levels exceeding 250 ppm
East Jefferson No change Not anticipated to experience chloride levels exceeding 250 ppm
  • Underwater Sill Completed – USACE completed work to augment the underwater sill today, and the result is delaying the encroaching saltwater intrusion.  Construction has brought the underwater sill up from an elevation of -55 to -30 feet from the river surface, while maintaining a channel, or “notch,” at -55 for deep-water draft navigation on the Mississippi River.
  • Red River Basin Rainfall – Rainfall in the Red River Basin has increased flows on the Red River, requiring less diversion at the Old River Control Structure.  With increased flows, less water is required to maintain the authorized 70/30 distribution at Old River Control Structure allowing greater flows down the Mississippi River.  The change in forecast is largely the result of augmenting the underwater sill and increased flows of the Red River.

Regional Mitigation

Resources

  • Emergency Updates – If you are looking to keep track of updates on the emergency, search the Gov’s Office of Homeland Security and Emergency Preparedness’s (GOHSEP) Saltwater Intrusion page.
  • Saltwater Wedge Location – If you would like regular updates on the estimated location of the saltwater wedge, search USACE’s Live Saltwater Wedge webpage.
  • Sewerage & Water Board Dashboard – Visit SWBNO’s new online saltwater dashboard to find up-to-date river salinity data and learn more about the utility’s plans and next steps.
  • Axios Frequently Asked Questions – For updated answers to frequently asked questions regarding saltwater intrusion, search the Axios New Orleans resource.
  • Plaquemines Parish Updates – If you’d like to sign up for the Plaquemines Parish Notification System, sign up here.
  • St. Bernard Parish Updates – To sign up for alerts from the St. Bernard Parish Emergency Management Office, sign up here.
  • Orleans Parish Updates – If you’d like to register for Orleans Parish updates, register for alerts here or text NOLAREADY to 77295.
  • Jefferson Parish Updates – For Jefferson Parish updates, sign up by texting JPALERT to 888777.

Please feel free to contact President & CEO Michael Hecht, [email protected], or SVP of Public Policy Jasmine Brown DeRousselle, [email protected], with questions or suggestions.