Ship-generated wave-induced sediment dynamics in upper St. Lawrence River: analysis of field data

Abstract This study examines the effects of combined ship-generated waves and wind-driven waves on sediment dynamics in the upper St. Lawrence River, focusing on two sites at Mariatown and Jacobs Island in Ontario, Canada. Six loggers installed at the two study sites recorded wave and turbidity data over a period of 300 days to distinguish the influences of natural versus ship-induced waves on sediment resuspension. The findings indicate that wind-driven waves regularly resuspend sediment, establishing a baseline turbidity level, while ship-generated waves cause short-lived but intense turbidity spikes, particularly in shallow zones with fine sediment. Spectral signal analyses, including synthetic natural wave modeling and frequency-based filtering, are used to isolate the frequency characteristics of primary and secondary ship-generated waves from those of natural wind waves, enabling a focused assessment of each wave type’s impact on sediment dynamics. Wavelet analysis is applied as a validation tool to confirm the spectral localization of separated wave components. The study demonstrates that factors such as water depth, sediment type, and proximity to the navigation channel strongly influence local turbidity responses. While historical shoreline imagery is used to provide spatial context, shoreline change was not formally analyzed in this study. Overall, the results offer a replicable framework for isolating wave contributions to sediment resuspension and support future efforts in sustainable sediment and shoreline management in modified river environments.