Spatial and Temporal Evaluation of Dune, Beach and Nearshore Bar Interactions : Cape Cod, MA

Abstract

Coastal features and processes interact with each other, producing complex patterns of shoreline changes in different beach segments. Coastal dune systems have been studied in detail, looking at their evolution through time, sediment budget and aeolian processes but few researches have combined the studies of the processes that occur in the nearshore with changes in the dune systems. This research explores how the foredune changes are not only affected by beach width and wave/wind conditions, but also by the formation of sandbars in the nearshore and by changes in beach orientation. This study focuses on a 14.6km shoreline section in the Province Lands Dunes area of Cape Cod National Seashore, an area characterized by wide to narrow beach segments containing dunes and foredune features. Dynamics along the coast are not homogeneous. Beach segments are exposed to different wind/wave regimes and therefore have different energy conditions. The effect of shoreline orientation is examined by dividing the study area into five zones each with a different shoreline trend. This research relies on GIS and remotely sensed data sources to quantify and describe shoreline changes. Orthophotography from the 1951-2012 and 2001-2012 period was collected from various sources and digitized in order to compare changes in the coastal features throughout the years. Patterns of dune, shoreline and nearshore bar changes were quantified using DSAS extension in ArcGIS.