Beach–dune morphological relationships and erosion/accretion: An investigation at five sites in England and Wales using LIDAR data

The critical relationships between beach and nearshore parameters and the erosion/accretion status of frontal dunes have been investigated using LIDAR data, complemented by data obtained from conventional topographic and bathymetric surveys, at five dune systems in England and Wales. Morphometric parameters calculated from the LIDAR data demonstrate the presence of a general relationship between beach morphology, dune morphology and erosion/accretion. Eroding dunes were found to be associated with narrower, steeper beaches whilst accreting dunes were associated with wider, low-angle beaches. However, the critical beach width/mean slope angle separating eroding dunes from stable or accreting dunes was found to vary between sites. At any given site, changes in beach width/slope over time can be used to provide an ‘early warning’ of changes in frontal dune erosion/accretion behaviour.