Quantifying bedform migration using multi-beam sonar

The migration rates of both medium and very large dunes in a part of the North Sea were determined from high-resolution multi-beam echo soundings. From the bathymetric maps, crest positions were determined and compared. From changes in the positions of these crests relative to fixed markers, the migration rates within a tidal cycle and on a seasonal timescale were calculated. The sediment transport rates derived from the migration of the bedforms compare well with theoretical estimates of the residual transport in the area