Multibeam Echosounder Cartography and Monitoring of the Dredging Activities on the Belgian Continental Shelf

Marc Roche

Continental Shelf Service of Belgium

Friday, Jan. 27, 2012, 3:00pm
Chase 130

The Continental Shelf Service of Belgium conducts a regular monitoring of the sand extraction on the Belgian Continental Shelf since November 1999. This monitoring is based on two types of data: data from the Electronic Monitoring System ("black box") on board of dredging vessels, and regular bathymetric surveys with the multibeam echosounders EM1002 and EM3002D (installed on the R/V Belgica) on monitoring areas and across the sandbanks. The analysis and combination of these different types of data provide a 4D view of the evolution of the sandbanks in the area of extraction and allow the assessment of its environmental impact. The purpose of this talk is to present a summary of the essential facts observed since 1999 in the framework of the management and control of marine sand extraction on the Belgian Continental Shelf. These facts mainly concern the improvement of the methods used for the control on the extraction, the statistics and mapping of the extracted volumes, and the impact of dredging on the seabed bathymetry, morphology, and sedimentary nature. The question of the confidence interval of the Backscatter Strength measurements and the survey and processing conditions required for its use to evaluate the sedimentary variations on different time scales is an issue that should be discuss in the seminar