NeoPanamax Vessels and How to Engineer a Water Crisis

Without context (and based on my kids’ latest fixation), Panamax sounds like a rare Legendary Pokemon with high base attack stats. In actuality, it’s a class of shipping vessels specifically designed to fit through the Panama Canal. In 2016, the Panama Canal’s third set of locks opened, allowing larger and heavier vessels to access the shipping shortcut. Enter NeoPanamax vessels, ships designed specifically to fit these expanded canal locks. 

Describing a vessel’s specifications apparently involves learning a new language of acronyms, conceptualizing the world through twenty foot equivalents (TEUs), and understanding the difference between dead-weight tonnage and gross tonnage—DWT and GT, respectively. There’s also the physics of draft measurements and how ships float in saltwater versus freshwater. For the purpose of this essay, let’s just agree that NeoPanamax ships are really big. Like truly enormous. They aren’t as big as Ultra-Large Container Vessels (yes, that’s what they are actually called) but they are still enormous. NeoPanamax vessels are about 1,200 feet long and 161 feet wide; for scale, a football field is 360 feet long and 160 feet wide. They are able to carry between 120,000-170,000 tonnes of weight–three times more than the smaller Panamax vessels. So despite the adage and risk involved with putting all our eggs in one (floating) basket, NeoPanamax vessels make commercial shipping even more profitable, one enormous load at a time. 

As the saltwater continued climbing slow-and-steady up the low-flow Mississippi River these last couple of months, NeoPanamax showed up a few times in my research. At first, the connection between these enormous ships and the salt wedge contaminating municipal water sources wasn’t clear. But the more I learned about the connection between the ongoing water crisis in Plaquemines Parish and these vessels, the saltier I was feeling with the U.S. Army Corps of Engineers (USACE), the Big River Coalition, and the Louisiana Department of Transportation and Development (DOTD). 

Quick Explanation of How these Salt Wedges Form and Move

These wedges form when saltwater from the Gulf of Mexico makes its way into the Mississippi River. With rising sea levels in the Gulf and more subsidence along the river’s basin, the Mississippi is already more vulnerable to these salt wedges. Susceptibility is higher during drought years when river levels are especially low, and downstream flow is unable to stop the saltwater’s encroachment. Since saltwater is denser than freshwater, it sinks to the bottom of the river—forming a wedge shape—and moves upstream, unless there are significant increases in river flow. Changes in the wind, slope, or water temperature can also increase or decrease the saltwater’s movement. 

This is not the first—and certainly not the last—time that saltwater from the Gulf of Mexico has made its way into the river. Saltwater and fresh water regularly interact where the the mouth of the river meets the Gulf of Mexico. The real problems start when the salt moves upstream and sticks around long enough to compromise municipal water, like it’s doing in Lower Plaquemines Parish now. In 1988, saltwater reached as far inland as Kenner, 115 miles upriver from the Gulf. Of course, in 1988, the saltwater stuck around for a few days while this year we’re looking at weeks, maybe months of compromised water.

It’s not just the duration of these salt wedges that is concerning; it’s also their frequency. Historically there’s been a significant encroachment every ten years or so, requiring the Corps to intervene with costly mitigation efforts every decade. But 2023 is the second year in a row that the Corps had to intervene and build a mitigation sill to slow down the saltwater’s progress. These sills are underwater levees that act like a really expensive and temporary speed bump for the salt wedge. 

So why are these salt wedges happening more often? No doubt the Corps and other navigation advocates such as the Big River Coalition and Department of Transportation and Development would point to rising sea levels, increased subsidence, and the drought conditions of 2022 and 2023. And they are correct; all of those have increased the frequency and duration of these salt wedges.

But we cannot ignore that in the two years since the Corps has started their massive project to deepen the Mississippi River navigation channel from 45’ to 50’ all the way to Baton Rouge, we’ve had two major saltwater intrusions in the lowermost river. Instead of sill mitigation efforts every ten years, the Corps needed to intervene 3 times in the last twelve months with multimillion dollar sill projects. In October of 2022, the Corps constructed a 12.8 million dollar sill near mile marker 64 to slow saltwater intrusion. Just 9 months later–in July of 2023–drought conditions forced the Corps to build another sill to slow the encroaching saltwedge. That sill sat 55 feet below the river’s surface, but it was overtopped by salt on September 20th. So in late September, the Corps continued construction on the overtopped sill, raising it to 30 feet below the water in hopes of slowing the wedge by 10-15 days. While I couldn’t find any information on how much the renovations to the sill cost, the initial July 2023 sill project was 8.9 million dollars.

After reading the Corps’ and the state’s reports leading up to different phases of the dredging project, it’s frustrating that they want to brush over its connection with the salt wedge. For over 4 decades, the Corps knew that deepening the river channel from its then 40’ depth would be good for industry but potentially bad for water quality and conservation. The 1981 feasibility report for the project plainly states that “the deepening of the 40 foot channel in Southwest Pass and the Mississippi River would cause an increase in the frequency and duration of saltwater intrusion up the Mississippi River. Saltwater intrusion is a primary concern to the municipal and industrial users of the Mississippi River waters…Mississippi River waters would be unsuitable for municipal water supplies along the lower reaches of the river during infrequent periods of extremely low flows.” 

In 2018, in preparation to further deepen the river’s navigation channel to 50’,  the Corps reevaluated the original 1981 feasibility report. Once again in its analysis, the Corps explained that “the municipal water supply for all of Plaquemines Parish…is put at risk for saltwater intrusion…during low water events.” Phases 1 and 2 of that 250 million dollar project were completed in 2022; phases 3-5 are estimated to be completed in the next few years, deepening the river to 50 feet all the way to Baton Rouge.  

If the connection between these salt wedges and the NeoPanamax ships is still unclear, look no further than Governor John Bel Edwards’s July 2020 statement announcing the river deepening project’s approval: “This is a great day for the people of Louisiana who depend on the Mississippi River for their livelihood. When completed, this project will allow larger vessels that can currently use the widened Panama Canal to reach Louisiana ports as far north as Baton Rouge. It will also allow for some vessels to carry heavier loads.” 

During the same signing ceremony, Major General Diana Holland with the Corps celebrated what this deepening project would mean for industry: “More capacity means greater efficiency in transportation and less costs for our Nation’s producers.” (Because those producers have proven to be super-generous with all that money they trickle down on the rest of us.)

So while knowing that these saltwater intrusions were a possibility and while knowing that this deepening could contaminate the water supplies for entire parishes, while knowing that sea level and subsidence would be remarkably more problematic 4 decades after their initial 1981 report, the DOTD and the Corps pushed forward the plan to deepen the river—with the full support of the Big River Coalition. And they are very clear about why they are willing to sacrifice these communities’ water during low-river events: money. Simply put, a deeper, more powerful Mississippi River means heavier, larger ships can pass through it—specifically the NeoPanamax vessels—carrying more cargo, which means more money. 

(You’d think after a decade of living here and after years of researching the petrochemical industries here, I would stop being surprised by the state and federal government’s willingness to sacrifice Louisiana’s health and natural resources to any industry that wants to set up shop along the river. But I was still shocked while reading prophetic public comments and environmental impact reports from 1981 and 2018 that outlined the threat of salt wedges so plainly.) 

In the last two weeks, the saltwater has slowed enough that Jefferson and Orleans Parish—the second and third most populated parishes in Louisiana—are no longer considered at risk. Even though the saltwater is no longer supposed to move into New Orleans, there are still over 20,000 people in Plaquemines Parish whose water is either undrinkable or soon to be undrinkable. The saltwater has also caused skin problems and hair loss, killed crops and livestock, wrecked businesses and appliances and hot water heaters for thousands. There’s concerns of salt water corroding older pipes, which could cause lead contamination. And without a significant rain event, the salt water could stick around for weeks, even months. 

It’s easy for people who live far away from industrial sacrifice zones to forget that industry requires sacrifice. Maintaining our comfortable lifestyles that depend on fossil fuels requires sacrifice. So many of us participate in consumerism without ever seeing the extraction, production, distribution, or disposal phases of the materials economy. But in Louisiana, especially along the Industrial Corridor, all phases of the materials economy are visible—sometimes even while standing in a single spot. (If you don’t believe me, check out the view from the top of the Sunshine Bridge in St. James Parish.) 

The enormity of these NeoPanamax vessels and these engineering projects remind me of the overwhelming scope of the climate crisis. When I think about the power a relatively small number of people have to design and build those vessels, to change the depth of one of the most powerful rivers in the world, all at the whims of industry, I feel dizzy and nauseated. I’m reminded of my own smallness and how none of the decisions that I make as a consumer, a parent, a citizen, happen in a vacuum. I’m reminded that I exist in an interconnected web of goods and highways and waterways and plastics that has become impossible to avoid; in fact, many of us exist within that web without ever seeing it, even though it’s always visible.

I’m reminded that this fight is more than just David and Goliath. It’s David and a Goliath who is arrogant enough to see a river rushing by with 600,000 cubic feet of water per second and presume that he can manipulate and control it in perpetuity. And I think these huge vessels and engineering projects are a reminder of the enormous power of nature; look at the monstrous dimensions we have to achieve in order to convince ourselves that we have control.