The Severe Erosion of Cape Shoalwater, Washington

Abstract

Cape Shoalwater on the southwest Pacific coast of Washington State has been eroding at rates in excess of 30 meters per year since the turn of the century. It is the most active coastal erosion site along the Pacific coast of the United States. The region receives a plentiful supply of littoral sediments and the neighboring coastlines are advancing. Study reveals the erosion is resulting from the long term northward migration of the tidal channel towards the Cape leading to very rapid shoreline retreat. There is some evidence of a slowing erosion rate due to the development of a secondary channel opening to the south of the main channel.