Assessing the Role of Framework Geology on Barrier Island Geomorphology
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Extreme storms, hurricanes, nor’easters, and tropical depressions can cause widespread erosion and washover on barrier islands and threaten coastal communities. The strong winds and waves of these storms can erode the beach and dunes, causing significant damage to coastal infrastructure and threatening human lives. Coastal vulnerability and resiliency depend on the coastal morphology (i.e. nearshore, beach, and dune morphology) in conjunction with storminess (i.e. storm frequency and magnitude) and the rate of sea level rise. Variations in the initial coastal morphology, such as undulations in dune height, can propagate through as heterogeneity in the modern barrier island morphology. Given that the modern landscape can inherit features and patterns of variability through time, it is important to understand what factors influenced the initial coastal morphology in order to more accurately predict future changes in response to storms and sea level rise. Improving the accuracy of future change models requires that we more accurately understand how a multitude of coastal processes interact to change the coastal geomorphology. This dissertation demonstrates that framework geology is a significant driver of barrier island evolution by setting up initial variation in the beach and dune morphology and modifying normal conditions and coastal processes. Field-based surveys and public DEM data were used to: (1) extract beach, dune, and island morphometrics using a multiscale relative relief approach, (2) quantitatively demonstrate that paleochannels in the framework geology interact with daily wave reflection and refraction patterns to influence the modern barrier island, and (3) demonstrate that paleochannels in the framework geology can have an asymmetric influence on the barrier island morphology, given a persistent alongshore sediment transport gradient. In light of new information about the effects of framework geology on barrier island evolution, this dissertation proposes that the currently accepted theory of formation for Padre Island National Seashore is incomplete and should be re-evaluated in context of framework geology.
Wernette, Phillipe Alan (2017). Assessing the Role of Framework Geology on Barrier Island Geomorphology. Doctoral dissertation, Texas A & M University. Available electronically from