COASTAL FLOODING & SOLUTIONS, Workshop Case Studies
Assessing sustainable restoration measures to increase barrier island resilience through data collection, integrated modeling, and decision support – the Alabama Barrier Island Restoration Assessment
Dauphin Island, AL
US Geological Survey St Petersburg Coastal and Marine Science Center, Research Oceanographer
The Alabama Barrier Island Restoration Assessment was a science-based effort funded by the National Fish and Wildlife Foundation in collaboration with the State of Alabama, the U.S. Geological Survey and the U.S. Army Corps of Engineers, focused on assessing viable restoration measures for Dauphin Island, Alabama to increase island sustainability and restore vital habitats for species affected by the 2010 Deepwater Horizon oil spill. Completed in 2020, the project included field data acquisition to understand present conditions on the island and to inform a suite of integrated, predictive models capable of forecasting decadal island evolution and resulting habitat suitability under scenarios of sea level rise and storm variability. Together, the predictive morphological and habitat models were used to assess a no-action alternative and stakeholder-developed restoration measures including beach and dune nourishment, marsh and back-barrier restoration, and nearshore sand placement. Structured decision-making was used to gauge the ability of each restoration measure to meet multiple stakeholder objectives for habitats, sustainability, residents, and conservation values. Working with decision-makers from Alabama, a storymap was developed to communicate the results of the restoration assessment to the citizens and other stakeholders of Dauphin Island. The State of Alabama used the findings of our assessment to target over $150M worth of restoration measures for implementation.
Restoration measures for this effort were developed to address multiple objectives related to the social and ecological concerns of stakeholders on Dauphin Island and surrounding areas. The stakeholder defined objectives were to: (1) maximize ecological function and physical processes (i.e., sustainability); (2) minimize social impacts and costs; (3) maximize coastal and marine resources; and (4) minimize time that it would take for a restoration action to provide benefits for the island. In all, 23 restoration and land acquisition measures were developed and assessed relative to their ability to meet these objectives on Dauphin Island. Since completion of the project in 2020, three measures have been selected for implementation thus far.
This effort could be expanded by increasing our understanding of barrier island vegetation recovery and succession, including overwash response and marsh productivity and drowning, in response to sea-level rise and reoccurring storms. Insight from these analyses can be used to better calibrate models used in this study and lead to more thematic detail in habitat model outputs. In this study, we used expert elicitation to discern habitat importance to species of concern. Future work is needed to develop models that can be used to more explicitly understand how barrier island changes may impact important fauna (e.g., shorebirds and sea turtles) that utilize these islands. Additional enhancements are needed to increase the efficiency of data exchange between models and dissemination of outputs. Collectively, these enhancements could lead to more robust and efficient models that could be used to make operational decisions related to restoration, such as: (1) quickly running different scenarios; (2) addressing new morphologic change (e.g., a newly formed breach); and (3) re-weighting stakeholder values in risk assessment.