In this study, the possibility to get sedimentological (density, compaction) and hydrodynamical (suspended sediment concentration, turbulence) information from ALB surveys is demonstrated. ALB laser reflectance was found to be higher on the lee-side and on the crest of the ripple bedform than in the trough and on the stoss-side. Moreover, laser reflectance was also found to be higher on "active† subtidal dunes, located within the depth of action of the waves, than on deeper "passive† bedforms. Based on lab experiments conducted in a hydraulic flume under X-ray CT-Scanner, these observations were related to sediment compaction and suspended sediment.