The U.S. Army Corps of Engineers is shipping fresh water on barges to small treatment plants south of Gretna, in anticipation of the saltwater wedge that’s moving up the Mississippi River.
The fresh water will be used to dilute the wedge’s briny water, as it’s pulled into the plant to be treated. The Army Corps of Engineers hopes the strategy will keep clean tap water flowing for the communities served by the plants.
But it won’t be possible to barge in enough fresh water to support larger plants in New Orleans and Jefferson Parish, which go through hundreds of millions of gallons of water a day.
Both parishes have decided to build pipelines to draw fresh water from the river north of Kenner. The plans received state approval Friday, and officials are in the process of securing contractors.
Collin Arnold, New Orleans’ director of homeland security and emergency preparedness, told All Things Considered host Bob Pavlovich that bids were due Monday.
Arnold said the city’s sewerage and water board will select a contractor quickly, so pipe — 48-inch PVC — can be laid starting this week.
“They’ll be moving as fast as possible to get this started immediately,” he said.
A race against the wedge
Officials in both parishes are racing to make sure the pipelines are in place before the wedge reaches their water treatment facilities. The salt water is forecast to reach New Orleans’ Algiers plant on Oct. 22 and its Carrollton facility a week later.
The U.S. Army Corps of Engineers’ estimated timeline takes into account the effects of an underwater barrier in the Mississippi River in Plaquemines Parish that was overtopped and is being heightened. The process will take at least another week, but once it’s complete, should slow the wedge’s movement by 10 to 15 days.
Arnold estimates that, once pipeline construction begins, it could take between 25 and 45 days to lay enough pipe from the plants to Kenner. The good news, he said, is that the entirety of the pipeline doesn’t have to be finished in order to work, it just has to outpace the wedge.
“That’s a real benefit for us,” Arnold said. “If the wedge continues up, we can continue moving with it.”
The cost of pipeline construction could run between $100 and $250 million, with the federal government expected to pick up 75% of the cost. President Joe Biden approved Louisiana’s request for an emergency declaration last week.
The parishes are building separate pipelines, because the project requires multiple pipes to carry enough water to support all of the plants, but Arnold said they are coordinating closely.
Contingency plans in motion
The focus of the pipeline approach is to preserve water quality — to dilute the salty water enough so it can be treated at the plants and sent along safely to customers’ taps.
Arnold said the process should also stave off any problems that might arise with the tens of thousands of lead pipes still in use in New Orleans. Salt water is corrosive, and can cause lead pipes to leach chemicals.
The Sewerage Water Board and the Louisiana Department of Health are working together to monitor lead levels, Arnold said. They plan to share that data with the public, and will also send testing kits to residents to have on hand.
“I believe we’ll address this situation,” he said.
But the city is making contingency plans, too — including preparations for emergency water distribution.
The city plans to give out bottled water to vulnerable residents, like seniors and people with medical conditions, if needed, Arnold said, adding that they also have a distribution system set up with the Louisiana National Guard.
He said his office has checked with retailers and doesn’t anticipate any supply issues. If anything, they’re increasing their bottled water stock, so there’s no need to panic-buy bottled water, he said.
