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- Saltwater will soon rush into the Mississippi River, which hit its lowest flow rate since 1988.
- That means the drinking water for thousands of Louisiana residents will be polluted.
- Gov. John Bel Edwards said the crisis could last until January and affect 20% of the state.
For the second year in a row, the Mississippi River water level is at an extreme low.
The problem is thanks to an ongoing drought event. The river's current levels are comparable to last October when barges got stuck on sandbars and US agricultural exports suffered.
We're already seeing those crises repeat themselves: This summer brought 40 days of river closures, meaning the boats that travel along the Mississippi river carrying roughly 60% of the country's grain exports faced significant delays.
If a receding water level sending shocks through the supply chain wasn't enough, the river is also facing its lowest flow rate since 1988, threatening the drinking water for southern Louisiana residents in and around New Orleans.
That's because a low flow rate could allow saltwater from the Gulf of Mexico to push into the river and pollute the source of drinking water for thousands.
Mississippi River water flows may reach as low as 130,000 cubic feet per second this year, according to Matt Roe, a spokesperson for New Orleans' US Army Corps of Engineers (USACE). That number should be at 300,000 cubic feet per second to keep ocean water out, he said.
Officials built two sills — which are underwater concrete barriers — in the last two years to help raise the water levels. The USACE built the second sill in July after it became apparent saltwater was moving upriver, Roe told Insider. As the saltwater wedge approaches, USACE officials are working 24/7 to augment the second sill.
While the augmentation won't stop the saltwater from invading, it will buy affected communities more time.
"The augmented sill is expected to provide an additional 10 to 15 days for communities upriver to continue their preparation efforts," Roe said.
The augmentation process began September 24 and will take 24 days to complete, according to Roe. As of September 27, officials reported the wedge was at River Mile 69.4, less than 30 miles downstream from New Orleans' Algiers Water Purification Plant.
Louisiana Governor John Bel Edwards requested a federal emergency declaration from President Joe Biden last week, writing that 20% of the state could be impacted by the saltwater intrusion and experts predict the crisis could last until January 2024.
Plaquemines Parish, just south of New Orleans, has already purchased 200,000 bottles of water in anticipation, Edwards wrote.
USACE officials beyond Louisiana are also working to mitigate the effects of low water levels and low flow rates.
Further upriver in Missouri, the USACE is working 24/7 with two dredgers — boats that suck up accumulated sediment — to move sediment from the river bank and into the channel with the goal of raising water levels, according to Lou Dell'Orco, chief of operations and readiness at the USACE St. Louis District.
Ultimately, rain — and a lot of it — is what the Mississippi River will need to reach its average water level and flow rate again, Roe and Dell'Orco both agreed.