Column: Dredging, river diversion needed for La. coastal restoration

River diversion and dredging are necessary in combination to help rebuild the Louisiana coast, where wetlands are eroding into the ocean, according to a column by Bryan Piazza, director of freshwater and marine science at The Nature Conservancy.

In a study of Breton Sound in Louisiana, Piazza found the Mississippi River contributed 61 percent of the energy found in a flooded marsh containing 8,000 calories per square meter. The energy leads to healthy and productive fisheries.

Dredging is also necessary in restoration of the Louisiana coastline as it rapidly moves earth to create diversions and add sediment to wetlands.

About 25 square miles of coastal wetland wash away each year.  Levees and dredged limit sediment deposition and facilitate wetland erosion.

Image: Aerial view of Louisiana wetlands (Credit: U.S. Fish and Wildlife Service, via Wikimedia Commons)