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

Abstract

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. Copyright 2011 by the American Geophysical Union.