Wind and ship wave-induced resuspension in the littoral zone of a large lake

Sediment resuspension in lake littoral zones (nearshore region) is strongly related to the properties of the surface wavefield. The occurrence and characteristics of surface waves, near-bottom current velocities, and related suspended sediment concentrations and properties were measured simultaneously in Lake Constance over 1 year. Wind and ship waves are distinguished on the basis of their typical properties, enabling a detailed investigation of their respective importance for sediment resuspension. In the littoral zone of Lake Constance, resuspension occurred during 25% of the entire observation period. Of those observations, 54% were caused by ship waves, which therefore were as important for resuspension as wind waves. Resuspension induced by wind waves occurs rather sporadically throughout the year, whereas ship wave-induced resuspension occurs regularly during the daytime in summer and is hence associated with pronounced diurnal and seasonal patterns in the suspended sediment concentration.