A model study of suspended sand due to surface waves during a storm in the Baltic Proper

During 28 November–5 December 1999 three storms passed the Baltic Sea area. The modelled surface waves in the Baltic Proper during this period have been used to calculate the amount of suspended sand in the water mass. Different parameterisations depending on the flow regimes (rippled bed flow or sheet flow) have been used for the suspended sediment calculations. The study shows that the shallow areas along the eastern and southern sides of the Baltic Proper were most exposed to the wave induced resuspension during this period. The resuspension events lasted for about 6–12 h, thereafter the sediment settled again within an hour. During each low passage, about 2.5 Mton sand were suspended, releasing about 0.5•106 m3 earlier trapped interstitial water. This might have a large effect on the nutrient concentrations in the water mass above these bottoms.