Non-Structural vs. Structural: Strategizing Long-Duration Coastal Protection in Southern Louisiana

The state of Louisiana is losing a football field of land every hour (2012, coastal.louisiana.gov) due to subsidence, erosion, and sea-level rise. This land loss occurs at the thick, flat, earth/water interface of the Mississippi Delta where nutrient rich sediments and fresh waters mix with the Gulf to create one of the most productive deltaic estuaries on the planet. Most of the state’s population centers, including New Orleans, Lake Charles, Houma, and Morgan City are also sited within this highly managed hybrid ecological-infrastructural deltaic zone in order to capitalize upon the rich natural resources this working coastline provides. In 2012, the state issued its most comprehensive Coastal Master Plan to date, which was developed utilizing state-of-the-art hydrological and ecological modeling and designed to guide planners and policy makers. This essay examines the planning process that resulted in the Plan’s bias for structural protection, questions the lack of emphasis on nonstructural measures, and proposes a more appropriate framework for designing and implementing nonstructural measures in populated sub-tropical dynamic deltaic geographies across the globe.The State of Louisiana 2012 Coastal Master Plan determined specific risk reduction and restoration projects the state would appropriate funds to implement over the next fifty years. This Master Plan employed a quantitative modeling process to generate predictive data about the future morphological and ecological conditions of the coast. This data was then optimized in a hybrid quantitative and qualitative planning tool to determine which constellations of projects would produce the most ecologically, culturally, and financially effective outcomes. The plan is a timely example of a rigorous analytical and research driven planning process that grapples with the uncertainties of climate change, sea level rise, and catastrophic storm behaviors increasingly affecting sub-tropical coastal communities, particularly those located within deltaic systems.Despite its rigor, the plan falls short in its vision and assumptions about the nature of a sustainable developed coast. The delta is an intensely dynamic landscape, driven by dramatic short-term (pulse) and chronic long-term (press) disturbance regimes (2010, Collins et. al.) such as hurricanes, flooding, salt water intrusion, petro-chemical pollution, and subsidence, in addition to some of the highest relative sea level rise rates in the U.S. (2012, NOAA). These disturbance regimes are particularly destructive to urban infrastructures and buildings built via more conventional land-centric methods. Defensive measures comprised of coupled hard and soft solutions, in addition to new socio-cultural paradigms for water-centric urban strategies are necessary to ensure long-term occupation. But the Master Plan does not address many of the socio-cultural issues it implicates, instead it prioritizes the predictive power of rigorous science, and the promised performance of large scale engineering, to guide decision makers. It also relegates the bulk of non-structural measures to the private sector, rendering future, large-scale resilient landscapes contingent on the availability of substantial federal funding.

Volume Editors
Anthony Abbate, Francis Lyn & Rosemary Kennedy

ISBN
978-0-935502-90-9