Without major efforts to rebuild Louisiana’s wetlands, particularly in the westernmost part of the state, there is little chance that the coast will be able to withstand the accelerating rate of sea-level rise, according to the Connecticut and Tulane Universities’ new study.
The study shows that the rate of sea-level rise in the region over the past six to 10 years amounts to half an inch per year on average.
“A lot of culture, history, trade and infrastructure is tied to the Mississippi Delta. Losing it would be potentially catastrophic for the American economy,” said Anjali M. Fernandes, a visiting assistant professor at UConn’s Center for Integrative Geosciences and co-author of the study.
“About 65 percent of study sites are probably still keeping pace, but in the westernmost part of coastal Louisiana, more than 60 percent of sites are on track to drown,” said fellow co-author and Tulane University geology professor Torbjörn E. Törnqvist.
Fernandes and Törnqvist conducted the study with lead author Krista L. Jankowski, a Ph.D. candidate at Tulane University.
Together they measured sea-level change by integrating information from hundreds of monitoring sites maintained by Louisiana’s Coastwide Reference Monitoring System, according to Fernandes, a sedimentologist.
The researchers analyzed measurements of shallow subsidence rates at 274 sites across the coast and combined these with published GPS-measurements of deeper subsidence rates.
Adding published satellite observations of the rise of the sea surface in the Gulf of Mexico, they were able to calculate how rapidly sea level is rising with respect to the coastal wetland surface.
“It’s important for us to understand these things because it would help us detangle the natural signal from human influence,” Fernandes added. “It is also important for us to better understand the composition, behavior and geographic variability of the Delta sediment so that we can determine the amount of sediment needed to restore the wetlands.”
The research was made possible through publicly available data collected under the auspices of Louisiana’s Coastal Protection and Restoration Authority and the US Geological Survey.