Oct 1, 2023 - Energy & Environment

New Orleans bracing for major threat to drinking water supply

Estimated timeline for saltwater intrusion into the New Orleans metro area
Data: GOHSEP; Map: Axios Visuals

Salt water creeping up the Mississippi River is threatening the drinking water supply in New Orleans for the first time in more than 30 years.

Why it matters: The water supply for more than 1.2 million people is expected to become unsafe to drink by late October.

  • President Biden declared the situation a national emergency last week.
  • If contaminated, it could be weeks or months before freshwater returns, unless there is significant rainfall, leaders say.

Catch up quick: A drought across the Mississippi River Valley means salt water from the Gulf of Mexico is coming upriver, threatening drinking water supplies in New Orleans and two nearby parishes.

  • Many municipalities in southeast Louisiana, including New Orleans, pull their drinking water from the river.
  • Communities further south have had salt in their water since June.
  • The Army Corps of Engineers expects the saltwater intrusion to reach New Orleans by Oct. 22. Officials are working on plans to mitigate water disruption.

Driving the news: A massive reverse osmosis machine that desalinates water is being installed in Plaquemines Parish, just southeast of New Orleans, and two more machines are on the way.

  • But these units won't be able to produce enough water to meet the demand in metro New Orleans.

Plans to protect the drinking water include building 10- to 15-mile-long pipelines to draw water from further upriver.

  • Gov. John Bel Edwards approved plans Friday for Jefferson Parish, which includes suburbs west and south of New Orleans, to build multiple pipelines. Construction could start this week.
  • New Orleans' pipeline plans also were approved Friday but details haven't been released yet.
  • In other parts of the region, the Army Corps of Engineers will barge in water for dilution.

Threat level: Salt water is not safe to drink for humans or animals, and it can damage crops.

  • It's also corrosive and could damage pipes and appliances. Much of New Orleans' water infrastructure consists of lead and iron piping.
  • Louisiana's top medical official is concerned about the salt causing heavy metals to leach into the drinking water supply.
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