MOZES – Research on the Morphological Interaction between the Sea bottom and the Belgian Coastline. Working year 3

The MOZES project (MOrfolgische interactie kustnabije ZEebodem en Strand)) aims to improve understanding of coastal morphodynamics across time scales for better coastal management. Year 3 Progress Summary: WP1: • Continued vectorisation of historical topo-bathymetric maps (1970s–1990s). • Shoreface-connected ridges (sfcr) migrated up to 5 km east and several hundred metres landward over two centuries, mainly due to residual sediment transport and sea-level rise. • Tidal sand ridges (tsr) lost sediment; sfcr accreted slightly. • Dredging deprives downdrift sandbanks of sediment; Stroombank analysis estimates 300 m³/m/year longshore transport. WP2: • Coupled shelf-shoreline model replicates shoreline progradation near sfcr crests and retreat near channels; tsr have minor effects. • Morphodynamic model simulates simultaneous sfcr and tsr development under waves, wind, and tides, though with differences from observations. • Sfcr formation is shown to be independent of specific sediment transport formulations. WP3: • Scaldis-Coast and FlemCo models match observed wave heights and directions, but fail to fully capture tide-wave interaction in the Appelzak gully. • FlemCo overestimates offshore directional spreading; Scaldis underestimates nearshore, exaggerating NW wave peaks. WP4: • FlemCo reproduces beach and shoreface morphodynamics at Knokke-Heist, with increasing discrepancies offshore. • Scaldis-Coast captures erosion trends (1999–2003), but with spatial and magnitude deviations. • Both models need further calibration for detailed erosion studies.