Impact of operational parameters on turbidity generation in cutter suction dredging: Insights from a numerical model and sensitivity analysis

Abstract

The cutter suction dredger (CSD) is one of the main vessels utilized in the dredging industry. The dynamic actions related to its rotating cutter head are the main trigger for sediment release and turbidity generation by this vessel. The ability to predict the evolution of this turbidity and suspended sediment concentrations is imperative for effective environmental management. This predictive capability allows ecologists to estimate potential damage, enabling environmental managers to propose appropriate mitigation measures. In this study, we conducted a qualitative numerical assessment of the characteristics of turbidity currents generated as a result of cutter suction dredging of densely-packed sand. To this end, we developed a one-dimensional physics-based model, providing the order of magnitude of sediment fluxes and concentration levels. In addition, a quantitative sensitivity analysis is performed to unravel the relative influence of key operational parameters on the generated turbidity currents. The results of this research reveal that breaching (dilative underwater slope failure) is a major source of sediment release by CSDs and should be incorporated in the source-term estimation. It is also found that the cut ratio is the most influential operational parameter on the generated turbidity.