Investigation of ship-induced hydrodynamics and sediment resuspension in a restricted waterway

Abstract

The movement of the ship-generated waves on restricted shallow waterways creates complex river dynamics. The irregular bathymetry increases the bed shear stress in the waterway, causing significant sediment resuspension. In order to investigate the impact of the ship-generated waves on the sediment resuspension, field measurements were performed at the Falta stretch of the Hooghly river, India (National Waterway 1). The present study applied the acoustic backscattering intensity of a horizontally-looking ADCP to quantify the sediment resuspension generated by ship waves. Based on the low-pass filter, the primary and secondary waves were separated. Based on the analysis, the low-frequency primary waves are less significant compared to the high-frequency secondary waves. The correlation study suggested that the ship-induced sediment resuspension is highly influenced by irregular bathymetry, river geometry, depth Froude number and ship speed. Finally, two new empirical models were proposed to estimate the sediment resuspension due to ship-generated waves by using correlation study and regression analysis.