Beach erosion during storms: sensitivity to inner surf-zone morphology and geology

Abstract

Development and application of new technology, such as Coastal Lidar And Radar Imaging System (CLARIS) -- which enables integrated mapping of waves, nearshore bathymetry and beach topography over large areas, during storm events - reveal a strong relationship between beach erosion and the state of nearshore morphology at the onset of storms. Specifically, data from CLARIS and the cross-shore wave array at the Field Research Facility, located in Duck, North Carolina, indicate a sensitivity of runup to the position and shape of sandbars in the inner surf zone. Results from recent Hurricanes (Irene and Sandy) and numerous nor'easters suggest, in turn, that regions of shoreline that experience higher runup suffer greater beach erosion. We hypothesize that these areas of higher runup and subsequent beach erosion, often called erosional hotspots, can be predicted by pre-storm sandbar morphology and meso-scale shoreline shape. We continue to explore fundamental factors such as the role underlying geology plays in sandbar morphology and three-dimensional sandbar evolution but, in the short-term, we also work towards methods to parameterize and simplify equations predicting runup and beach erosion.