Drought conditions in the Midwest over the summer have created a growing water problem in the New Orleans area this fall.
Water levels in the Mississippi River have dropped enough to make the river less resistant to a mass of salty water flowing north from the Gulf of Mexico. This situation, known as saltwater intrusion, endangers drinking water systems in and around the city, as well as in smaller municipalities to the south.
Louisiana and U.S. Army Corps of Engineers officials say a ‘salt water wedge’ could reach water treatment plants near New Orleans in October and are working to slow the influx while bringing more fresh water to the region. Many water treatment facilities cannot treat water with high salinity levels, which corrodes the pipes and causes metals in the pipes to leach into the water.
“This is a serious situation,” Gov. John Bel Edwards said at a news conference Friday. He said he was seeking a federal emergency declaration, and Mayor LaToya Cantrell of New Orleans signed an emergency declaration for the city on Friday. But Mr. Edwards urged people to remain calm and state officials advised against overstocking water.
In July, the Army Corps of Engineers built an underwater sill, or levee, in the Mississippi River aimed at preventing the flow of salt water, which moves beneath fresh water, closer to the bottom of the river. Officials said Friday that within a few days they would begin work to raise the threshold 25 feet.
But even that will only delay the saltwater wedge’s progress by 10 to 15 days, they said. Unless significant rains fall soon — and forecasts indicate they won’t — the threshold will eventually be exceeded, said Col. Cullen Jones of the Army Corps.
The Corps of Engineers also obtains barges to transport water that can be combined with water at treatment facilities for safe consumption. Col. Jones said about 15 million gallons would be delivered in the coming days, but demand at processing facilities could ultimately reach at least 36 million gallons per day. Col. Jones said the corps was working to gain access to more barges, but was confident that figure could be reached.
Many coastal communities, such as parts of the Jersey Shore, Long Island, and the Outer Banks of North Carolina, are no stranger to saltwater intrusion, which also occurs when storm surges or high tides exceed low-lying areas. As sea levels rise along coastlines, so does the threat of saltwater intrusion. Other countries like Bangladesh are grappling with this reality.
Saltwater intrusion also affected Louisiana in 1988, when levels of the Mississippi River, whose mouth is below sea level, reached historic lows. An earlier than expected increase in water flow then helped alleviate the problem. But this is the second year in a row that the river’s water levels have fallen drastically due to extreme heat and drought linked to climate change.
Chris Anderson, a professor of wetland and coastal ecology at Auburn University, said it’s normal for there to be upward movement of salt water. But the more intense the drought, the more salt water can rise upstream of the river.
Although the problem has received more attention in recent days as salt water moves toward more populated areas, officials have been aware of the problem since early summer. Lower Plaquemines Parish, on the state’s southern edge, has had alcohol advisories in place since June and is working with the state to provide bottled drinking water to residents.
But a spokesperson for the state’s Office of Homeland Security and Emergency Preparedness said there is no reason for the public to stockpile bottled water.
Ms. Cantrell, mayor of New Orleans, also sought to allay people’s fears. “The most important thing for residents right now is to stay informed and stay calm,” she said in a statement.
Mr. Edwards took a similar stance Friday, although he said the challenge was daunting and the problem could last longer than 1988. “We don’t experience this very often, at least not this far from the world. river,” he said.
nytimes
