Louisiana’s “ghost swamp” is being resurrected by the New Orleans company Glass Half Full. 

Bayou Bienvenue used to be teeming with biodiversity. Over half a century ago, cypress and tupelo trees, turtles, alligators and fish that were resources for residents of the neighboring Lower Ninth Ward filled the bayou. But in the 1960s, levee and canal construction led to a saltwater intrusion, killing the wildlife and turning Bayou Bienvenue into what is now called a ghost swamp. 

“Now that the salt levels are back to normal, it’s ripe for restoration,” Franziska Trautmann, co-founder and CEO of Glass Half Full, said.  

Trautmann and her co-founder, Max Steitz, founded Glass Half Full in 2020, when they were both seniors at Tulane University. The lack of glass recycling in the area frustrated them. “We decided to jump in and do something about it,” Trautmann said. 

“One of the first ideas for starting Glass Half Full was, glass comes from sand; what if we could turn glass back into sand and then use the sand for coastal restoration?” 

Trautmann worked with Tulane professors across multiple departments in the School of Science and Engineering to come up with a solution, and they received a grant from the National Science Foundation. 

Sunshine Van Bael, a professor in the ecology and evolutionary biology department, is one of Glass Half Full’s colleagues at Tulane. Van Bael studies the impact of Glass Half Full’s sediment on marsh vegetation.  

Now, Glass Half Full’s processing facilities produce sand to restore sediment to Bayou Bienvenue, bringing back its original biodiversity. 

“Before the islands were built there, if you went to the area, you could see it was kind of an old dump site, and there was garbage everywhere,” Van Bael said. Glass Half Full is not just building islands in Bayou Bienvenue, she said; they are cleaning it up. 

The sediment is essential to restoring the biodiversity of Bayou Bienvenue, such as the cypress trees and marsh grasses, Trautmann said.  

As hurricanes become more powerful each season, swamps become more vital.  

“Because that swamp was gone during Hurricane Katrina, the hurricane and the storm surge was able to come right directly into the city and into the Ninth Ward, which was the area of the city which was hit the worst and where most mortality occurred,” Van Bael said.  

“If that swamp had been there, that swamp would have acted like a sponge to reduce all of that water and catch all of that storm surge before it hit the urban area of New Orleans,” she said. “By growing that swamp back, we are protecting ourselves.” 

Swamps like Bayou Bienvenue can also serve as biodiversity hotspots, carbon sinks, water filters, flood barriers and economic hubs.

Glass Half Full is also a partner for Tulane’s service-learning classes. “When we have service-learning students, we always have them guide what they want to work on. So whether it’s marketing and they might do a video about the islands, or if they’re doing more of an environmental science angle, they might learn more about the islands,” Trautmann said. “I think it’ll be fully integrated.” 

The company is growing fast. “We’re actually hoping to build at least two more islands in the area,” Trautmann said. “We just broke ground on our new processing facility, which is just next to the island…so once that’s up and running, we’ll have sediment literally right there to be able to contribute to more islands and marsh restoration.” 

The islands are one of the many restoration attempts in Bayou Bienvenue. After Hurricane Katrina, the Army Corps of Engineers decommissioned the area under the U.S. Congress’s instructions. This blockage allowed the salinity levels to drop and restoration efforts like Glass Half Full’s islands to begin.  

“I hope that we attract more funds and that we get private donors to come in and help us build more of these islands so we can put more trees in and really help grow this swamp back,” Van Bael said.  

“Since we got the National Science Foundation grant in 2021,” Trautmann said, “Tulane researchers in the ecology and evolutionary biology department have been doing greenhouse experiments with native Louisiana species.” The team discovered that the most successful mixture for plant growth is 50% dredged sediment from the Mississippi River and 50% recycled sand from Glass Half Full.  

Glass Half Full created two islands: one “control island” made of native sediment and one of the half-and-half mix. Marsh grass is already growing on the islands, and this fall they will plant trees.