SEA-LEVEL RISE AND IMPACTS ON NEARSHORE SEDIMENTATION - AN OVERVIEW

Impacts on nearshore sedimentation arising Introduction from potential sea level change of the magnitude predicted in Intergovernmental Pane l on Climatic Change scenarios associated with global warming are revi ewed. For sandy duned coasts, the obvious sedimentation impacts includ e potential erosion of coastal dunes with implied deposition of the er oded material in the nearshore, possible deepening of embayments, and flooding of wetlands. For the sandy coasts a number of two-dimensional models are available for predicting shore line change, but there are significant difficulties in applying Bruun-type models for dune erosio n and assessment of sediment redistribution over the inner shelf, and for predicting the amount of shoreline retreat for a given rate of sea level rise. If the beach profile contains excessive sand relative to its equilibrium profile, sensu Dean (1991), then shoreline retreat may not occur upon sea level rise. From the evidence of Kiel Bay, at leas t in these semi-enclosed basin types, it is during major transgression s that maximum deposition in adjacent basins occurs, due to the sea er oding weakly consolidated and weathered surface regolith. But at the s ame time climatic patterns were re-adjusting and probably contributed to maximum deposition in adjacent shelf and basins below wave base.