Building New Land in the Mississippi Delta - Is It Feasible?

Can coastal Louisiana’s land loss be reversed, could the land even be rebuilt? A new physically-based model developed by NCED alumnus Wonsuck Kim and principal investigators David Mohrig, Robert Twilley, Chris Paola, and Gary Parker suggests that engineered river avulsions opened below New Orleans could do just that. Using a conservative sediment supply rate and a range of rates of sea level rise and subsidence, the model predicts that between 700 and 1200km² of new land could be built over the course of a century by diverting 45% of river flood sediment and water discharge through two new avulsions.

 

In the past, arguments for restoring deltaic land by opening engineered river avulsions have been met with concerns that upstream dams have reduced river sediment supplies below the level sufficient to rebuild land and that area subsidence and sea level rise are high enough to inhibit land-building.  The model developed by NCED researchers is the first to answer such concerns with quantitative predictions of land evolution based on river sediment supply, subsidence rate, rate of sea level rise, delta topography, bathymetry, and other key factors.