Drought-like conditions in the Midwest over the summer have resulted in a significant water issue in the New Orleans area this fall. The water levels of the Mississippi River have dropped to an extent that makes the river susceptible to the intrusion of saltwater from the Gulf of Mexico moving northward. This phenomena, known as saltwater intrusion, is posing a threat to the drinking water systems in and around the city, as well as smaller municipalities to the south.
Authorities in Louisiana, alongside the U.S. Army Corps of Engineers, have raised concerns that a “saltwater wedge” may reach water treatment plants near New Orleans as early as October. In response, they are working to slow down the influx of saltwater while increasing the supply of fresh water to the region. Unfortunately, many water treatment facilities are ill-equipped to handle water with high salinity levels, leading to the corrosion of pipes and the leaching of metals into the water.
At a news conference on Friday, Governor John Bel Edwards emphasized the seriousness of the situation and requested a federal emergency declaration. Mayor LaToya Cantrell of New Orleans also signed an emergency declaration for the city. Despite these actions, officials urged the public to remain calm and cautioned against panic buying of water.
To combat saltwater intrusion, the Army Corps of Engineers built an underwater sill, or levee, in the Mississippi River in July. The sill aims to impede the flow of saltwater, which naturally moves beneath fresh water closer to the riverbed. In the coming days, officials will be raising the sill by an additional 25 feet. However, this intervention will only delay the progression of the saltwater wedge by a mere 10 to 15 days. If there is no substantial rainfall in the near future, the sill will inevitably be breached.
In response to the imminent threat, the Corps of Engineers is mobilizing barges to transport water that can be mixed with water from treatment facilities to ensure safe drinking water. Approximately 15 million gallons of water are set to be delivered in the coming days, with the demand potentially reaching at least 36 million gallons per day. The Army Corps is actively securing additional barges to meet these needs.
Saltwater intrusion is not a new phenomenon for coastal communities, and areas such as the Jersey Shore, Long Island, and the Outer Banks of North Carolina are familiar with its effects. Rising sea levels exacerbate the risk of saltwater intrusion, as witnessed in countries like Bangladesh.
Louisiana previously experienced saltwater intrusion in 1988 when the water levels of the below sea level Mississippi River reached historic lows. Fortunately, an unanticipated increase in water flow mitigated the problem at that time. However, this is the second consecutive year that the river’s water levels have drastically dropped due to extreme heat and drought resulting from climate change.
Chris Anderson, a professor of wetland and coastal ecology at Auburn University, noted that saltwater movement upriver is typical, but the severity of the drought determines how far the saltwater can advance.
Although concerns about saltwater intrusion have intensified as it approaches more populous areas, officials have been aware of the issue since early summer. The lower portion of Plaquemines Parish, located on the southern edge of the state, has been under drinking advisories since June and has been collaborating with the state to provide bottled drinking water to residents.
Nevertheless, the Office of Homeland Security and Emergency Preparedness for the state assured the public that there is no need to stockpile bottled water. Mayor LaToya Cantrell echoed this sentiment, urging residents to remain calm and stay informed.
Governor John Bel Edwards shared a similar perspective, acknowledging the daunting challenge and the potential for the problem to persist longer than in 1988. He added, “We don’t experience this all that often, at least not up this far of the river.”