Saltwater Intrusion Threatens Drinking Water Supply in New Orleans Area


    NEW ORLEANS (AP) — Monique Plaisance noticed that the heating element removed from her water heater in September was deteriorating, marred with rust, and encrusted with dry salt. She attributed the corrosion to the water drawn from the area’s primary drinking water source, the Mississippi River.

    A similar story unfolded not far away at the Black Velvet Oyster Bar and Grill.

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

    Plaisance’s residence and Marinovich’s restaurant are situated in the Buras community, part of rural Plaquemines Parish, located about 60 miles southeast of New Orleans and 20 to 30 miles upriver from where the Mississippi flows into the Gulf of Mexico. Like New Orleans, the parish relies on the Mississippi River for its drinking water.

    However, this year, the Gulf of Mexico encroached on their territory. A wedge of saltwater began creeping up the river bottom during the spring.

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

    Plaquemines officials have implemented various measures to ensure that residents in the southeastern part of the parish, which extends into the Gulf, have access to clean water. Solutions include delivering bottled water for drinking and using barges to introduce freshwater to dilute the saline water before it enters the water supply.

    Advisories against consuming tap water were lifted on October 18.

    However, residents like Plaisance and Marinovich believe that these remedial actions were initiated too late. They hold parish officials responsible for not taking action until the water posed a threat to more populated areas, including the city of Belle Chasse, home to more than 10,000 people, approximately half the parish’s population.

    Parish President Keith Hinkley defended the timing of their response, stating, “We’ve been working on this since June 19th. We have not dragged 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, and 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 contributing to saltwater intrusion. The most significant factor this year has been a drought across the Midwest, resulting in reduced water flow into the Mississippi River and its tributaries.

    In Vicksburg, Mississippi, just north of New Orleans, the river’s flow rate was approximately 50% slower, with stage height about 95% lower than normal in late September and early October, compared to the period between 2013 and 2022, according to U.S. Geological Survey data.

    Extreme drought conditions in parts of states like Kansas, Nebraska, Missouri, Iowa, Minnesota, and Wisconsin, all within the vast Mississippi River basin, have exacerbated the situation. Reduced rainfall in the Ohio River watershed, which contributes half of the Mississippi’s flow reaching New Orleans, is also a contributing factor.

    Dredging in the lower Mississippi, conducted by the U.S. Army Corps of Engineers to accommodate large cargo ships serving vital ports, has played a role in the intrusion, according to Stephen Murphy, an assistant professor at Tulane University’s School of Public Health and Tropical Medicine.

    The lower, slower river flow, combined with a deep, wide river channel, has enabled gulf water to penetrate inland.

    Earlier in the fall, projections indicated that saltwater would reach the New Orleans area by late October, prompting residents to stock up on bottled water and public officials to undertake emergency preparations akin to those for an approaching hurricane.

    In Jefferson Parish, officials laid out flexible piping resembling giant fire hoses to transport water from farther up the Mississippi to dilute the saltwater.

    New Orleans officials also contemplated building an emergency pipeline, with the hope of federal government funding under a presidential emergency declaration issued in September. However, updated projections have rendered this measure unnecessary, with more favorable river forecasts and other factors, including the construction of an underwater dam in Plaquemines by the Corps, contributing to the improvement in the situation.

    Local leaders emphasize that this episode serves as a wake-up call.

    Jefferson Parish President Cynthia Lee Sheng noted, “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.”

    This marks the fifth consecutive year the Corps has constructed an underwater structure to slow saltwater flow. Rising sea levels add further concerns, with the sea level around New Orleans rising at a rate much higher than the global average. As a result, experts predict that large-scale reverse osmosis filtration systems may be the solution.

    Collaboration among Gulf Coast communities is essential to safeguard water systems and address the rising threat of saltwater intrusion.

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