Mississippi salt intrusion is a wakeup call for New Orleans


By Kevin McGill and Stephen Smith | Associated Press

NEW ORLEANS — The heating element removed from Monique Plaisance’s water heater in September was disintegrating, streaked with rust and covered in a dry crust. She blamed the corrosion on the water piped in from the area’s longtime drinking water source: the Mississippi River.

It was a similar story not far away at the Black Velvet Oyster Bar and Grill.

“We’re draining the hot water heater every few days to get most, or a good bit, of the salt out of that,” owner Byron Marinovich said. “The ice machine has been off since the third week of April.”

Plaisance’s home and Marinovich’s restaurant are in the Buras community of rural Plaquemines Parish, roughly 60 miles (about 96 kilometers) southeast of New Orleans and 20 to 30 miles (32 to 48 kilometers) upriver from where the Mississippi flows into the Gulf of Mexico. As in New Orleans, drinking water in the parish is drawn from the river.

But this year, the gulf pushed back. A wedge of salt water slipped up along the river bottom, beginning in the spring.

By early October, water intakes at towns such as Boothville, Port Sulphur and Pointe a la Hache had been inundated.

Plaquemines officials list a variety of measures to provide drinkable water to residents in the southeastern part of the parish, which juts into the gulf. Trucks of bottled water for drinking and barges full of fresh water to dilute the salt water before it goes into intakes are among the solutions.

Advisories against drinking tap water were lifted Oct. 18.

Plaisance and Marinovich are among residents who think remedial efforts began too late. They blame parish officials for not taking action until the water began posing a threat to more populated areas including the city of Belle Chasse, which is at the parish’s northernmost end and home to more than 10,000 people, roughly half the population of the mostly rural parish.

“We’ve been working on this since June the 19th,” Parish President Keith Hinkley said in a telephone interview. “We have not drug our feet. We moved as fast as we could in getting these projects up and running. We made a decision to get a water station, water plant, back up and running that had been down for two years. We got it back up in a position to start producing water in somewhere between six to eight weeks.”

Authorities cite multiple factors for the salt water intrusion. Most prominent this year has been a drought across the Midwest that has meant less water flowing into the Mississippi and the rivers feeding it.

At Vicksburg, Mississippi, north of New Orleans, the river flowed at a rate about 50% slower and at a stage height about 95% lower than normal during late September and early October between 2013 and 2022, according to analysis of data from the U.S. Geological Survey.

Parts of Kansas, Nebraska, Missouri, Iowa, Minnesota and Wisconsin — all part of the vast Mississippi River basin, which touches 31 states — are experiencing extreme drought conditions. Rainfall amounts are down in the watershed of the Ohio River, which contributes half of the Mississippi’s flow reaching new Orleans.

Another factor is dredging, according to Stephen Murphy, an assistant professor at Tulane University’s School of Public Health and Tropical Medicine and the director of the university’s Disaster Management Program. The lower Mississippi is frequently dredged by the U.S. Army Corps of Engineers to make way for huge cargo ships serving ports vital to the Louisiana and national economies.

The lower, slower river flow and a deep, wide river channel set the stage for gulf water to push inland.

Earlier in the fall, projections that the salt water would reach the New Orleans area by late October prompted residents to stock up on bottled water while public officials undertook emergency preparations as though there were a slowly approaching hurricane.

In Jefferson Parish, next to New Orleans, officials began laying out flexible piping resembling giant fire hoses in a plan to pipe water from farther up the Mississippi to dilute the salt water.

New Orleans officials also were working on a plan to build an emergency pipeline. The hope was that much of the projected cost, as high as $250 million, would be covered by the federal government under a presidential emergency declaration issued in September.

Updated projections have negated the need for the measure. The more favorable river forecasts are a result of various factors, including the Corps’ construction of what amounts to an underwater dam in Plaquemines to impede salt water progress. Recent rains in western Louisiana also have been a factor.

While the threat to the New Orleans area has been diminished, local leaders say it’s a wake-up call.

“If this is what we’re going to be facing every couple of years, we certainly want to make an investment in how to solve this problem,” Jefferson Parish President Cynthia Lee Sheng said.

This is the fifth year the Corps has built an underwater structure to slow the salt water flow. But this is the first time sill construction has been used in consecutive years. Before last year, others were built in 1988, 1999 and 2012.


Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button