Searching for Solutions: Planning for Climate Change Critical for Breaux Act Projects, Experts Say

LOUISIANA'S COASTAL wetlands are rapidly disappearing, and scientists predict that rising seas and possible changes in storms, rainfall and temperature could further damage these fragile ecosystems. Although no Breaux Act projects have been specifically designed to address the adverse effects of climate change, some projects, such as barrier-island marsh restorations and river diversions, may help.

Workers planting cordgrass on the Chandeleur Islands. Courtesy of NOAA Restoration Center, Erik Zobrist

Barrier-island Restorations

Breaux Act marsh restoration efforts on the Chandeleur Islands provide a case in point. In 2001 some 81,000 sprigs and pots of smooth cordgrass (Spartina alterniflora) were planted along 6.6 miles of back barrier-island salt marsh to alleviate the damage caused by Hurricane Georges in 1998. When Tropical Storm Isidore and Hurricane Lili ripped through the gulf last fall, this marsh, now lush with cordgrass, caught sediment that was washed and blown from the beach — crucial soil that, otherwise, would have been lost to the sea.

The growth of cordgrass after one year is already acting to trap sediment on the Chandeleur Islands. Courtesy of NOAA Restoration Center, Erik Zobrist

Although Isidore and Lili packed the cumulative punch of a Category 4 hurricane, the back barrier-island marsh remained "relatively unscathed," said Dr. Shea Penland, director of the Pontchartrain Institute for Environmental Sciences at the University of New Orleans and a long-time authority on coastal Louisiana. "The back barrier-island salt marsh restoration project was the key to building a storm-resistant island," said Penland.

Mature cordgrass on the Chandeleur Islands, prior to Hurricane Lili. Courtesy of Dr. Shea Penland

During hurricanes, barrier islands play two essential roles: shielding coastal communities from tidal surge and wind; and guarding productive wetlands and estuaries that support a $10 billion-per-year fishing industry. As sea levels rise, and future storms perhaps intensify, barrier islands and projects to restore them will become increasingly important to these communities and wetlands.

River Diversions

River diversions, another Breaux Act approach to coastal restoration, may soften the combined impact of rising seas and subsidence. For example, the West Bay Sediment Diversion Project will unleash sediment-rich water from the Mississippi — restoring more than 10,000 acres of marsh that have been lost to erosion by the gulf. The U.S. Army Corps of Engineers and Louisiana Department of Natural Resources will share the cost of the $22.3 million project. Construction will begin in spring 2003.

The grassy portions of the Chandeleur Islands prevented a devastating loss of land during Tropical Storm Isidore and Hurricane Lili. Courtesy of Dr. Shea Penland

"Diversions give the marshes a fighting chance," said Dr. Denise Reed, a geology professor at the University of New Orleans, whose research includes coastal marsh response to sea-level rise. By allowing fresh water, sediment and nutrients to flow in from the river, "coastal marshes can build themselves up," she said.

Planning for the Future

On East Timbalier Island, sediment is being pumped onto the marsh platform. Courtesy of NOAA Restoration Center, Erik Zobrist

As Breaux Act decisionmakers design and fund new projects, they now face the challenge of adjusting for climate change. "Every project, no matter what the size, will have to deal with the consequences of global climate change," said Dr. Robert Twilley, a biologist at the University of Louisiana in Lafayette and a leading expert on climate change. "We have to plan the sustainability of projects if we want to maximize taxpayers' investments," said Twilley.

The West Bay Diversion will build sediment on the western side of the Mississippi Delta. Courtesy of USACE

A concept called "adaptive management" is gaining momentum among Breaux Act planners today. The idea is to learn from past projects and incorporate more comprehensive understanding into future ventures. "Our No. 1 goal is to get the civil engineers to talk to the ecologists in the design phase," said Twilley." They need to ask basic questions like, 'Will your plants be able to keep their heads above water in 10 years, given what we know about sea-level rise?' "

"When we first started wetlands restoration projects, we didn't have much data on global climate change," said Penland. "But in the last decade, we have seen that global climate change is a reality — something we absolutely must include in future Breaux Act planning."

A dustpan dredge, the "Beach Builder", used in the restoration of East Timbalier Island. Courtesy of NOAA Restoration Center, Erik Zobrist

 

In the Atchafalaya Sediment Delivery Project, dredged sediments were pumped through a pipeline toward the marsh creation disposal area. Courtesy of NOAA Restoration Center, Erik Zobrist