Modelling resuspension in the Bothnian Bay, Northern Baltic

A resuspension model was added to a 3D flow and water quality model. The resuspension model consisted of a wind-wave model, an orbital current model and an erosion model. Erosion was modelled using the critical current velocity. The wave-induced orbital current was added to the advection current calculated by the 3D model. Sediment trap measurements were made in the Bothnian Bay near the Island of Hailuoto. The model results were compared with the field observations. The comparison revealed both discrepancies and agreements. Heavy storm conditions and differences in local depths between the study site and the coarse grid model are possible causes for the discrepancies. The model predicted correctly some erosion and accumulation areas.