Enabling Adaptive Management on the Mississippi River

The Problem We Aimed to Solve

The Mississippi River Delta is influenced by persistent geomorphic forces and extreme events, such as winds, tides, currents, and hurricanes, influence the deposition and erosion of materials along the shoreline. This area lies at the interface between the Gulf and Mississippi River which is additionally influenced by the input of freshwater, sediments, and nutrients. Human activities, such as levees, flood control structures, and navigation channels have altered the area and changed the natural patterns of deposition and erosion, as well as salinity levels. These processes are interacting in a way that has led to significant land losses in recent years, which are projected to be even more significant in the face of sea level rise and an increasing severity of storm surges. The Mississippi River Delta is also a highly valued ecosystem which supports a variety of fish and wildlife species. These ecosystem components are broadly valued since they support a commercial seafood industry and recreational fisheries, which are significant contributors to the local economy.

The Mid-Barataria Sediment Diversion is one project that is currently being contemplated to facilitate the passage of freshwater, sediment, and nutrients from the lower Mississippi River into wetlands in the Mid-Barataria Basin that will help build and sustain coastal wetlands in the Delta. There are significant uncertainties, however, that affect the ability to assess the project’s impacts and understand how best to operate it. These unknowns include:

• seasonal and annual variation in the availability of flow and sediment from the Mississippi River;
• a lack of understanding which conditions would best support wetland creation;
• ambiguity regarding the environmental, economic, or social management objectives that should be considered while operating and evaluating the project’s performance;
• an imperfect understanding about how changes in flow and sediment will affect wetland habitats, salinity levels, vegetation establishment, as well as fish and wildlife species;
• uncertainty in the projected extent of sea level rise and severity of storm surges, as well as their effects on environmental, social, and economic components of the project.

How We Helped

To acknowledge these uncertainties, and ideally reduce critical ones over time, there has been an interest in using Adaptive Management plan for operating the sediment diversion. However, there are limitations in the capacity and awareness of how to implement Adaptive Management. ESSA undertook a “situational review” of this diversion project to identify the enablers and inhibitors that are currently affecting the application of Adaptive Management.

Our Project’s Impacts

This review led to a diagnosis of the factors that would contribute to or inhibit the success of Adaptive Management, and development of recommendations on how rigorous Adaptive Management could be applied. This work also involved facilitating a workshop that brought together diverse federal, state, and stakeholder interests to hear insights from leading experts about how Adaptive Management is being applied elsewhere in North America and discuss ways of how Adaptive Management could be applied to the project.