Restoring Louisiana Wetlands Requires More Sediment, Say Scientists
Based on a newly conducted study, an independent scientific panel reported today that existing Mississippi River freshwater diversions have not slowed the ongoing loss of Louisiana’s wetlands. Restoration of Louisiana wetlands may only be possible through significant inputs of sediment.
In the report, “Mississippi River Freshwater Diversions in Southern Louisiana: Effects on Wetland Vegetation, Soils, and Elevation,” the panel states that existing freshwater diversions have demonstrated both positive and negative impacts on the wetlands. Sediment delivery by existing projects is insufficient to tackle the problem of coastal land loss facing Louisiana.
The panel convened to examine the specific effects of freshwater and nutrients delivered by existing projects on the soils and vegetation of coastal marshes. The panel acknowledged that the emphasis on sediment diversions in Louisiana’s 2012 Comprehensive Master Plan for a Sustainable Coast could well be a more viable restoration approach than freshwater diversions on their own. They supported the master plan’s focus on flexible management to ensure a scientific framework for moving forward.
The report was produced by a technical panel of national expert academic and government scientists with broad backgrounds in wetland science. They based their assessment on proceedings from the “Workshop on Response of Louisiana Marsh Soils and Vegetation to Diversions,” held in Lafayette, Louisiana in 2011 and on an extensive literature review.
The workshop and panel were convened by the National Centers for Coastal Ocean Science, National Marine Fisheries Service Southeast Regional Office, and the Louisiana Coastal Area program established by the U.S. Army Corps of Engineers and the State of Louisiana.
The panel was organized by the Louisiana Coastal Area program and NOAA.