DETERMINING THE CAUSES AND THRESHOLD OF SEDIMENT RESUSPENSION IN THE LAFAYETTE RIVER
We define a resuspension event as a period of time during which the backscatter intensity exceeds 65 dB. Based on this definition, 8 different resuspension events were observed during the research period, seven of which occurred in association with increased wave orbital velocity of above 0.15 m/s. Peaks in the current speed, representing a tidal cycle at its maximum velocity, were also found to coincide with resuspension events. All but one resuspension event occurred when winds were from the SW; winds from this direction occurred most frequently.
The study revealed that prolonged stretches of consistent direction and constantly strong winds can generate wave-orbital velocities above 0.15 m/s. When these conditions are coincident with the maximum tidally induced current speeds, the optimal conditions for sediment resuspension exist. It was revealed that the synchronization of the wave orbital velocity and maximum current speed is more effective at resuspending sediment than either factor alone. Since no HAB occurred during the research period, it is still unknown for certain what effect this resuspension has on the initiation of blooms, still, this conclusion gives further insight into the dynamics of the river and can be applied to future research done on the initiation of HABs.