Sediment bank contribution to form a vortex and a deep scour hole on tidal channel meander

Based on bathymetric, currents, and sediment data collected through oceanographic surveys, we hypothesize that a sediment bank within the channel can modify the tidal current pattern contributing to the formation and maintenance of a deep hole in the meander curvature.

Based on our data, we found that the formation and maintenance of the scour hole are possible because of a vortex forced by the presence of an elongated sandy bank connected to the tidal channel bank that acts as a barrier to the currents, inducing the modification of the typical meander current pattern. The currents curvature favoring the establishment of the scour hole in the thalweg on the north channel bank, and the presence of a countermeander causes an attenuation of the current velocities mainly during the flood.