IMPACTS OF SLR-UPSCALED NOURISHMENT SCENARIOS ON DECADAL CROSS-SHORE DYNAMICS

Abstract

Projections of high rates of sea level rise have stimulated proposals for adaptation strategies with increasingly high nourishment volumes. Nourishment strategies involving higher sand volumes can be accomplished by increasing the volume of individual nourishments or by decreasing the time interval between successive nourishments. The optimal placement of the sediment volumes in the cross-shore and alongshore to attain our coastal management goals is still under debate. From a long term, large scale perspective only the added sediment volume may be considered, regardless of the placement. A widely accepted perception is that coastal profiles respond to nourishment by rapid equilibration to an equilibrium shape including the added sand volume. However, the timescale of the redistribution of the sediment may be slower than the desired spreading rate of the added sediment, causing sediment to accumulate at some parts of the profile, while leaving other elevations sediment starved. This research aims to examine decadal-scale coastal profile response to nourishment strategies upscaled with sea level rise (SLR) whereby potential nourishment strategy impacts for beach width (fluctuations), dune growth potential and momentary coastline are mapped.