Sea Level Rise (SLR) and storm intensification lead to re-evaluating inundation assessments along the North Atlantic US shoreline. A particular effort is devoted to assessing coastal community risk to “100-year storm” events in Rhode Island, US, using a chain of state-of-the-art storm surge, wave propagation, and coastal erosion 2D models. Damage risks imposed on infrastructures and services incited US federal and state agencies to come up with innovative engineering solutions to improve coastal resiliency while preserving natural coastal and marine environments. This study critically evaluates available design tools used to assess the performance of two types of Natural and Natural Based Features (NNBFs) for coastal protection: natural vegetated barrier islands and dunes reinforced with Geotextile Sand-filled Containers (GSCs), on urbanized barrier islands. Comparative analyses with field data identifies the capabilities and limitations of phase averaging and phase resolving hydro-morphodynamic models used for simulating bed level changes in dissipative beaches, during 3 Sallenger storm regimes. Recommendations are provided on modeling approaches for simulating effects of vegetation and using GSCs to limit coastal erosion.

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The objective of this paper is to present the results of on-going field studies to assess the performance of geotextile sand-filled container (GSC) reinforced dunes and to develop probabilistic fragility curves for a range of damage states to these structures. While numerous lab experiments and numerical models have been developed to predict the hydraulic stability of coastal revetments made of GSCs, there has been limited in situ validation of these systems, especially when they are used to reinforce the core of a natural system (Dassanayake and Oumeraci, 2012). Furthermore, the formulas and nomograms developed to characterize GSC systems are not intuitive for coastal community stakeholders to assess the level of resiliency provided by a beach and GSC dune system. The development of fragility curves offers a solution to assess the performance and understand the tradeoffs of reinforced dunes for coastal protection systems.