Wind-driven expansion of marsh ponds on the Mississippi River Delta is a significant factor in the loss of crucial land in the Delta region, according to research published by scientists at Indiana University and North Carolina State University.
The study found that 17 percent of land loss in the area resulted from pond expansion, much of it caused by waves that eroded away the edges of the pond.
The findings add to scientists’ understanding of the processes that shape the Delta and present new challenges for scientists and engineers seeking ways to protect sensitive coastlines.
“The Mississippi Delta is undergoing collapse as land disappears from the coast and marshes,” said study co-author Douglas Edmonds, assistant professor and the Malcolm and Sylvia Boyce Chair in the Department of Earth and Atmospheric Sciences at IU Bloomington. “Yet we know surprisingly little about what processes are driving land loss.”
River deltas are ecologically important and highly productive, and they are home to about 5 percent of the world’s population.
Under naturally occurring processes, coastal land is created in deltas when river sediment is deposited. But sea-level rise and human engineering of river channels have starved the Mississippi Delta of sediment, creating widespread land loss.
Any hope of reversing the trend, Edmonds said, requires a clear understanding of the processes at work.
To conduct the study, the researchers analyzed satellite images taken from 1982 to 2016 across the Delta.