DredgeFest Louisiana Spotlights the State’s Erosion Crisis
The Future of Resilience

DredgeFest Louisiana Spotlights the State’s Erosion Crisis

Participants in DredgeFest Louisiana standing atop the pumping station for one of the state’s many freshwater diversions.

John McNally and Christopher Dols stood overlooking a channel dug into the bank of the Mississippi River, 15 or so miles upriver from New Orleans, as tons of debris — including what looked like massive wooden dock pilings 20 feet long and two feet thick — submerged into underwater concrete culverts beneath the U.S. Army Corps of Engineers-built platform on which we stood. Moments later, in a holding pond a few hundred yards behind us, on the other side of Highway 18 and the Union Pacific Railroad, the pilings spouted up like surfacing whales.

McNally, a manager for Clean Harbors in Newark, New Jersey, and Dols, an engineer for Great Lakes Dredge & Dock Company in Oak Brook, Illinois, leaned over the rails along with a dozen or so others to get a better view as water and objects alike were sucked under the pumping station of the Davis Pond Freshwater Diversion Project at 4,000 cubic feet per second. This diversion, like others already at work and even more to be built as part of the Louisiana Coastal Master Plan, is one of the primary mechanisms Southeast Louisiana is depending on to combat coastal erosion, which, among many other things, dramatically diminishes the natural barrier that protects New Orleans from hurricanes.

Freshwater diversions such as the one at Davis Pond siphon freshwater and attendant sediment from the Mississippi River to be diffused into nearby wetlands. The sediment builds back land that is fast disappearing, while the freshwater nurtures plants whose roots will hold the soil together and counterbalances pressure from saltwater threatening to push up canals into the wetlands from the Gulf of Mexico.

McNally, Davis and everyone else in attendance were participating in DredgeFest Louisiana, a symposium, field expedition and speculative design workshop focusing on the human manipulation of sediments. The two men had traveled to New Orleans to attend DredgeFest, which took place over a recent week earlier this month, for the precise reason its organizers chose to host the event here: few places in the country are as engaged with sediment manipulation as coastal Louisiana, and none have more riding on it. Sediment deficiency in the Mississippi Delta, caused by levees and dams upriver that trap sediment, is among the biggest contributors to coastal erosion, which threatens the resilience of New Orleans and the entire region more than any other factor.

In his work with Clean Harbors, McNally said he often deals with toxic remediation in dredged waterways. Louisiana, he said, is at the forefront of this issue because of the widespread dredging of canals by the oil and gas industry along the Gulf Coast and the dumping of noxious chemicals by the same. The next stop on the day’s expedition would provide a vivid backdrop for DredgeFest organizers to elaborate on the oil and gas industry’s role in coastal erosion.

We pulled into Holy Rosary Cemetery near Taft, Louisiana, as the sun reached an angle that sent bright glares ricocheting off the marble tops of aboveground tombs. Outside the graveyard’s periphery, the complex industrial intertwining of pipes, tanks, catwalks and steam stacks that comprise an immense petrochemical plant rose around us. Tim Maly, a member of the Dredge Research Collaborative, which organized the event, said they chose the cemetery as a stop because it would give us a good visage of one of the 17 plants that occupy this stretch of the river, commonly called “Cancer Alley,” without our motley caravan attracting the attention of plant security.

“The reason there’s a diversion down there,” Maly said, pointing toward where we had last been, “is directly related to the continued operation of this plant right here.”

Companies such as Dow Chemical, which owns the plant in question, selected this location because of the tremendous supply of freshwater for chemical processing the Mississippi River provides, favorable state tax policies, and because they can tap into the expansive network of pipelines funneling oil and gas from offshore rigs in the Gulf of Mexico. The estimated 26,000 miles of pipeline threaded through Louisiana’s wetlands since the 1930s by the oil and gas industry are another major cause, along with sediment deficiency, of coastal erosion. Oil pipelines are set into canals dredged by the industry that, among other things, allow saltwater to intrude into wetlands, where it kills the freshwater plants whose roots literally hold together the land. As the plants die, the land washes into the sea. The oil and gas industry’s role in coastal erosion is at the heart of several nascent lawsuits, by the Southeast Louisiana Flood Protection Authority – East and two coastal parishes, asking more than 100 oil and gas companies to pay significant damages for their reticence to remediate harm caused by dredging. Experts estimate these activities account for anywhere between 30 to 90 percent of all coastal erosion in the region. Whatever the number, the dredging they perform prompted, at least in part, the dredging required to build the Davis Pond and other diversions.

The Dredge Research Collaborative’s work examines these and other types of manmade movement of sediment through publishing projects, presentations, collaborations and the DredgeFest event series, of which DredgeFest Louisiana was the second installment. (The first took place in New York shortly before Hurricane Sandy.) The members say they became interested in sediment upon encountering discussions around what is being called “soft infrastructure,” which calls for replacing hard-edged civil engineering projects like levees and dams with structures that mimic or deploy natural systems. Members of the collaborative singled out sediment as an incredible force that humans shape and that radically shapes how humans live. Maly said the collaborative, which consists of multitalented designers and architects from across the nation, initially began by brainstorming what they considered outrageous and various ways in which sediment manipulation could be deployed — only to realize that “the scale of what’s happening [in sediment manipulation] dwarfed our imagination.”

Accordingly, discussions in the DredgeFest workshops that preceded this day’s expedition tended to focus not on new methods of moving sediment, but altering preexisting practices to improve outcomes. One group of students from Louisiana State University thought of ways to improve bay-bottom terracing, which involves dredging sediment from the floors of shallow bays — a prominent feature throughout Louisiana’s wetlands — and moving it to create small islands that break up waves and collect more sediment. The group looked at the process of dredging most commonly employed right now and the shape of the islands it creates. They speculated that a slight shift in the process, which would add little or no cost and would be easy to implement, could form islands in different shapes that have more edge for plants to grow and sediment to collect. With the Louisiana Coastal Master Plan already dramatically underfunded, and the task of combating coastal erosion growing increasingly daunting as the earth warms and sea levels rise, innovation such as this that keeps cost in mind will be crucial to finding workable micro-solutions that contribute to what will hopefully, one day, be an answer to the region’s most pressing problem.

Nathan C. Martin is a writer and editor in New Orleans. He is the author of the Wallpaper* City Guide to New Orleans and his writing has appeared in McSweeney’s, Oxford American, The Believer, VICE, and other places. He is the founder and editor of Room 220: New Orleans Book and Literary News as well as its related literary event series. From 2008 – 2010 he was associate publisher and web editor of Stop Smiling. He is currently at work on a book about Wyoming, his home state.

Tags: resilient citiesnew orleanssea levels

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