From rubble to reefs
Motorists hurried over the old Interstate 10 Twin Span Bridge for years on their commutes and travels. But now some anglers are taking their time over the same bridge, or at least its crumbled debris.
Through a plan advocated by the Coastal Conservation Association of Louisiana (CCA), the state is now repurposing large portions of the old Twin Span now under demolition as artificial reefs in Lake Pontchartrain. One reef is complete and others are in progress, with the goal of creating acres of new hard-bottom habitat for fish in the lake between the replacement Interstate 10 bridge and the Highway 11 bridge linking New Orleans with Slidell.
“This is a restoration really because the lake used to have a lot of shell bottom where marine organisms would grow, but much of that was lost to shell dredging in the 70s and ’80s,” says John Walther, a volunteer coordinator for the CCA’s artificial reef and reef restoration programs.
Like naturally occurring reefs, these submerged piles of highway rubble would essentially become nurseries for the plants and small animals that form the first links of the marine food chain. In the past, such reef-building projects have had to rely on natural shell or small pieces of limestone imported from Kentucky to meet a state requirement that the material not pose a hazard to shrimpers’ trawling nets. Shipping that material is an expensive proposition, but CCA made the case that with proper marking these relatively small areas of new reef would not pose a conflict in the area.
The old Twin Span was severely damaged by the storm surge from Hurricane Katrina. It was repaired in record time but then replaced with stronger, higher interstate spans that opened to motorists earlier this year. Demolition on the old bridge meant an enormous source of reef-building material was available right where it is needed.
“Another good thing about this project is that we’re recycling this old building material in an ecologically friendly way instead of just sending it off to a landfill,” Walther says. “It’s also saving the state some money because instead of trucking it all off somewhere they just break it up on barges and place it on site here.”
Walther says CCA has proposals before BP to fund more reefs like this to help make up for fish losses from the company’s oil disaster.