Abstract:
The Beira Estuary in Mozambique is a marine system of high importance in terms of biodiversity, and navigation
use at Beira Harbor , the second largest harbor of Mozambique. The intense traffic of large ships implies frequent activities
of maintenance of the port access channel, since it suffers severe siltation. Dredging activities have negative impacts on the
marine environment, and may temporarily affect the abundance and distribution of marine species, also causing change in
estuarine circulation and its bathymetry. This paper focuses on the evaluation of sediment plume dispersion from dredging
activities in the Beira Estuary, and was based on hydrodynamic and sedimentological modeling using Delft3D software.
In general, tidal currents are responsible for sediment transport within the estuary, and dredging activities increase the
concentration of suspended sediments (near the surface) and near the bottom during their execution. River discharges
have an important influence limited to their mouths, transporting sediments towards the estuary. The wind action induces
currents with variable directions in the shallower areas, conditioned by bathymetry (channels and sandbanks) also being
responsible for sediments transport. The dynamics of the dredging plume is mainly conditioned by the hydrodynamics that
depends on the bathymetry characteristics and the tidal action.
