Market Matters Blog           09/25 11:24

   Low Water in Mississippi River Causing Saltwater Breach in Louisiana

   The low water in the Mississippi River has caused salt water from the Gulf 
to breach the river, threatening the drinking water supply in certain Louisiana 
parishes.

Mary Kennedy
DTN Basis Analyst

   The current National Weather Service Mississippi River forecast indicates 
the Mississippi River will fall to historic lows over the next several weeks. 
As a result, salt water from the Gulf of Mexico is heading upstream and 
Plaquemines Parish has been affected by this issue since June. Drought 
conditions have only gotten worse since then, which means additional 
communities along the Mississippi River in Louisiana could be impacted, noted a 
press release from Louisianna Governor John Bel Edwards. 

   "Unfortunately, without any relief from the dry weather we are starting to 
see the saltwater intrusion creep further up the river despite efforts to 
mitigate the problems by the Army Corps of Engineers," said Edwards. "Our team 
at Governor's Office of Homeland Security and Emergency Preparedness (GOHSEP) 
is working with all of our local, state and federal partners to determine what 
additional support will be needed and what steps can be taken to protect water 
systems and water intake points. Most importantly, this is not a time to panic 
or listen to misinformation. We have been through this situation before in 
1988, and we are monitoring this situation very closely and applying the 
lessons learned. It is extremely important for the public to stay informed and 
only rely on credible sources for updates during this event."

   USACE did construct an underwater barrier sill in July 2023 to create an 
artificial basin to help delay any intrusion of saltwater. Just recently, the 
upriver intrusion of saltwater from the Gulf overtopped the sill's existing 
elevation.

   "The Corps of Engineers will pursue every effort within our authority to 
support the state and local response to the extreme low-water conditions," said 
Col. Cullen Jones, USACE New Orleans District commander in the news release. 
"Next week (week of Sept. 25), we will begin augmenting the existing underwater 
sill to further delay the upriver saltwater progress by an estimated 10 to 15 
days. Concurrently, we are establishing the capability for barging freshwater 
to municipal water treatment facilities to support local production of safe 
drinking water.

   "We just executed the contract to get the initial capacity for 15 million 
gallons on site next week, and then we are rapidly moving through the Corps of 
Engineers to obtain more," said Jones. "The barges will range in size from 
100,000 gallons to 1 million gallons." He noted he will also ask FEMA to issue 
a federal emergency declaration, which he said could help in getting federal 
funds to help pay for the response, according to NOLA.com.

   Jones added the barges would gather water upriver and deliver it to water 
treatment plants that will have installed reservoir barges. The fresher water 
will be mixed with the water already being removed from the river to lower the 
salt content to acceptable levels. The barges, of course, must be cleaned to 
standards allowing water transport.

   The Corps said the increase in the sill height could delay the saltwater 
intrusion by 10 to 15 days, but without significant rainfall in the Ohio River 
Valley, there's a chance the salt water will once again top the sill.

   LINKS

   The National Weather Service Advanced Hydrologic Prediction Service 
estimates the Mississippi River at Memphis will hit a new low-water record of 
-11.2 feet on Wednesday. See more at the Mississippi River hydrograph Memphis 
site: 
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwater.weather.
gov%2Fahps2%2Fhydrograph.php%3Fgage%3Dmemt1%26wfo%3Dmeg&data=05%7C01%7CCheri.Zag
urski%40dtn.com%7C5006fde632ee476b49e908dbbde249af%7Cd945da26f07f451496e79b8f78a
743d0%7C0%7C0%7C638312551823172729%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiL
CJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=bCGQ8fQtvWNK
PC8v5dBKZtCizrO582UcyYt6ikN4NjA%3D&reserved=0

   Mississippi River at New Orleans hydrograph: 
https://water.weather.gov/ahps2/hydrograph.php?gage=norl1&wfo=lix

   Link to USACE tracking the saltwater wedge: 
https://www.mvn.usace.army.mil/Missions/Engineering/Stage-and-Hydrologic-Data/Sa
ltwaterWedge/

   Press release from Governor of Louisianna: 
https://gov.louisiana.gov/index.cfm/newsroom/detail/4269

   Saltwater intrusion facts: 
https://gohsep.la.gov/Portals/3/Docs/Intrusion/Saltwater%20Intrusion%20FAQ%20(On
line).pdf

   Ohio River at Cairo hydrograph: 
https://water.weather.gov/ahps2/hydrograph.php?wfo=pah&gage=ciri2

   Mississippi River hydrograph Baton Rouge: 
https://water.weather.gov/ahps2/hydrograph.php?gage=btrl1&wfo=lix

   Mary Kennedy can be reached at Mary.Kennedy@dtn.com

   Follow her on X, formerly Twitter, @MaryCKenn




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