Planning Tool to Support Louisiana's Decisionmaking on Coastal Protection and Restoration

A planning tool helped develop a range of different alternative comprehensive solutions to Louisiana's coast problems to support deliberation among stakeholders and decisionmakers.

• Predictive models estimated the effects of a large set of possible risk-reduction projects and restoration projects for two environmental scenarios (one of moderate conditions and another of less optimistic conditions).
• The Planning Tool evaluated the costs and effects of these projects.
• The tool used an objective function that selected groups of projects (or alternatives) that maximizes flood risk reduction (in terms of expected annual damage) and land building (in terms of area of land) for several funding scenarios between $20 and $100 billion over a 50-year period.
• The tool also calculated the following metrics for risk-reduction projects: residual damage at 50-, 100-, and 500-year flood intervals.
• The tool also calculated the following ecosystem-service metrics for restoration projects: alligator, oysters, shrimp, saltwater fisheries, waterfowl, carbon sequestration, freshwater availability, nutrient uptake, and storm surge and wave attenuation.
• The tool also considered other decision criteria including: distribution of risk across socioeconomic groups, use of natural processes, sustainability, operations and maintenance costs, support of cultural heritage, flood protection of historic properties, support of navigation, flood protection of strategic assets, support of oil and gas, and restoration of critical landforms.
• The tool applied four types of constraints when developing alternatives: financial and natural resource constraints, mutually exclusive project constraints, project inclusion and exclusion constraints, and outcome constraints.
• A process of deliberation with analysis framed and illustrated key policy trade-offs between alternatives in the two scenario types in a future without action and a future with the identified alternative implemented.

Louisiana can significantly reduce hurricane flood risk and stabilize the coastal landscape under favorable future assumptions with the implementation of a 50-year, $50 billion comprehensive master plan.

• The master plan resulting from this analysis, if implemented, would significantly reduce flood risk under either of the two environmental scenarios.
• The master plan, if implemented, would stop the loss of coastal land by 2040 and lead to land growth after that under moderate assumptions. Under less optimistic assumptions, land loss would continue but at a significantly slower rate.