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Seasonal to Interannual Storm Controls on Coastal Morphology at NASA-Kennedy Space Center
  • Matthew Conlin,
  • Peter Adams,
  • John Jaeger
Matthew Conlin
Department of Geological Sciences, University of Florida

Corresponding Author:[email protected]

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Peter Adams
Department of Geological Sciences, University of Florida
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John Jaeger
Department of Geological Sciences, University of Florida
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Abstract

Large storms are considered to be influential drivers of morphologic change on open sandy coasts. Whereas storm-driven morphologic changes and the recovery processes that typically follow have been robustly documented, less well understood is the concept of storm-driven coastal behavior over seasonal to annual timescales, which integrates multiple storm response and recovery cycles. In this study, storm controls on coastal evolution are evaluated using a topographic dataset containing monthly measurements of the intertidal and subaerial beach for 5 years (2009-2014) along a 10 km reach of open sandy coast fronting NASA-Kennedy Space Center near Cape Canaveral, Florida. In addition to shoreline and volume change analyses, a novel Empirical Orthogonal Function (EOF) analysis has been applied to these data to extract dominant spatial and temporal patterns of morphologic change over the full beach surface, as opposed to being applied over individual cross-shore transects or alongshore contours as previously practiced. Results indicate that the most dominant pattern of morphologic evolution within these data describes an isolated change of state to this system initiated by the impact of Hurricane Sandy (2012). This is exhibited physically as a southward migration of a previously stable cuspate foreland beginning immediately after the storm, resulting in nearly 600 m of propagation over the following 1.5 yr observation interval. Additionally, remaining dominant patterns describe a seasonal erosion cycle linked to storm driven seasonality in nearshore water levels, and a spatially variable berm formation cycle on inter-storm timescales likely driven by storm-induced variations in sediment storage locations and associated availability to non-storm hydrodynamics. These results illustrate that coastal response to an individual storm may control the recovery processes that follow by shifting morphologic equilibria such that processes of recovery drive the beach toward a configuration unlike its pre-storm state. Because these post- event processes influence morphologic response to the next event, the results presented here highlight a largely unexplored coupling between storm response and recovery that may be considered a dominant control on interannual-scale coastal evolution in storm-prone regions.