The monitoring of sand extraction on the Flemish sandbanks of the Belgian continental shelf is based on multiple types of data: statistics derived from the extraction registers, data from the Electronic Monitoring System (EMS = “black-boxes”) on board the dredging vessels (complete records are available since 2003), and regular bathymetric surveys with the multibeam echosounders MBES) EM1002 and EM3002D (installed on the R/V Belgica) across the sandbanks along parallel lines and on specific areas. The analysis of the various types of data provides a 4D (space and time) view of the evolution of the extraction and admits robust and pragmatic conclusions about the real impact of the sand extraction on the marine environment. From 2003 to 2012, the global bathymetric evolution, based on MBES EM1002 and EM3002D measurements along lines across the control zones, confirms thestraightforward relation between the extraction and the bathymetrical evolution. On a larger scale, virtually all ofthe bathymetric variation can be explained by the extraction itself. In areas without any extraction, no significanttrend of the bathymetry is observed.