INVESTIGATING SHOREFACE-LITHOLOGY EFFECTS IN A PROCESS-BASED MODEL OF COASTLINE CHANGE

摘要

We have developed a numerical model that couples geologic framework effects and alongshore sediment transport processes to investigate large-scale, long-term shoreline evolution in sediment-limited environments. Shoreline segments underlain by material composed of higher proportions of fine sediment (I.e. mud) than adjacent segments tend to form shoreline indentations. However, wave-driven alongshore transport tends to fill in such indentations where wave climates are dominated by ‘low-angle’ waves that smooth shorelines. In the long term, shoreline retreat rates become spatially uniform, and the indentations remain fairly subtle. The modeling suggests that sea-level-rise acceleration will tend to increase the amplitude of the indentations. In the limit of very rapid sea-level rise, and associated high rates of shoreline retreat, continuous and relatively smooth sandy shorelines may not be possible, giving way instead to headland-and-pocket beach coastlines.