Numerical assessment of the dispersion of overspilled sediment from a dredge barge and its sensitivity to various parameters

- Two numerical models are used to simulate fine sediment dispersion from a barge.
- Different hydrodynamic scenarios, particle sizes and dredging tracks are considered.
- In this area, particle size seems to be secondary to the final sediment transport.
- Tidal currents are the main responsible for the seabed final sediment distribution.
- Wind and waves play a secondary role in the transport pattern.

Marine dredging operations are not uncommon in coastal waters since they are necessary for several beneficial uses, such as harbour maintenance, beach nourishment or removal/capping of pollutants, amongst others. They also constitute a significant risk for the environment, changing its physical, chemical and biological characteristics, as evidenced by many authors. In this study, two numerical models are used to simulate the dispersion pattern of fine suspended sediment spilled from a dredge barge, considering different hydrodynamic scenarios, particle sizes and dredging tracks in a mesotidal environment. The results show that, in this particular case, the currents (largely induced by the tide) are the main responsible for the final disposition of the settled particles, being the other variables of secondary importance.