Advancement of the Southeast Conservation Adaptation Strategy (SECAS) for Project-Scale Planning: Chandeleur Islands (Breton National Wildlife Refuge) Restoration

This study had two primary goals: 1) to develop and evaluate metrics for characterizing the restoration and conservation value of barrier islands that could inform the application of the Southeast Conservation Adaptation Strategy (SECAS) Southeast Conservation Blueprint; and 2) to characterize the geomorphic evolution and ecosystem value of the Chandeleur Islands with and without restoration action. The first phase of this study included evaluating the ecosystem value and long-term geomorphic evolution of the Chandeleur Islands (Figure I). Based on that analysis, a holistic island restoration concept for maximizing system resiliency was developed (Figure II). In the second phase, two “end member” restoration designs for enhancing the resiliency of the Chandeleur Islands were evaluated using a numerical modeling framework to identify sediment transport pathways and evaluate the performance of restoration alternatives (Section 3.0). One design represented a “traditional” dune and berm restoration that is widely used in the Gulf of Mexico, and the other represented a more novel approach of sediment placement in the backbarrier without the construction of a dune. A new set of metrics to characterize ecosystem value based on model results was developed and used to contrast the two restoration alternatives to a future without action (FWOA) scenario.