BEACH VERSUS SHOREFACE NOURISHMENT EXPERIMENT

摘要

The present study investigates the evolution of a nourishment experiment carried out at Mariakerke (Belgium) coast. For two neighboring beach sectors beach nourishment was carried out, Raversijde and Mariakerke, while for the later one a shoreface nourishment was added. For a better understating of the local coastal dynamics two adjacent beach sectors were considered, Middelkerke and Oostende. Four years of topographic and bathymetric surveys were used to build digital elevation models in order to investigate the evolution of the nourishments. Results show a rather slow evolution with majority of the sand still in the local coastal system. As expected areas such as the intertidal beach or the shoreface at Mariakerke show an intense erosive trend initially, but the rates decrease after two years. At Mariakerke shoreface nourishment a local reorganization of the sand is observed with formation of submerged sand bar. The active beach profile extension seaward is larger than previously estimated. The human interventions such as extension of the Oostende harbor, frequent nourishments and local redistribution on the dry and intertidal beach have a major impact in the retention of the nourished sand in the local coastal system.