Annualmeeting:2017 CSDMS meeting-045
Using coupled geo-economic models to explore the interplay between coastal protection, natural processes, and economic values along developed shorelines
As coastal regions become more developed, many communities are considering costly engineering solutions to address coastal change, including "soft" approaches, such as beach replenishments or dune constructions, and hard structures, such as seawalls, revetments, bulkheads, or groins. Given current rates of sea level rise and the associated shoreline losses that coastal communities face, however, it is unclear whether the benefits generated by these protection measures justify the costs. We are building a set of integrated geologic and economic models to better understand the coupled evolution of developed shorelines under alternative protection policies. The first model incorporates dune construction and sediment overwash relocation into a morphodynamic model for dune evolution. We use this model to assess the costs of constructing an optimal cross-sectional area for a long-term dune system, and we explore the “geo-economic” effects on ocean views that may be diminished by constructing a dune system of particular size seaward of protected properties. A second model simulates beach width dynamics for two adjacent communities, each with their own groin structure. We use the model to analyze both coordinated and uncoordinated strategies between the two communities, reflecting individual community decisions to protect or retreat. A third model incorporates beach nourishment practices into a morphodynamic model for barrier evolution that accounts for shoreface dynamics. Results show that the efficiency of beach nourishment can be affected by the dynamic state of the shoreface during each nourishment episode. In general, these models reinforce the need to refine numerical coastal management tools to incorporate bi-directional interactions between natural processes and human responses to shoreline change.