ASR - A Global Partner for the Sustainable Management of Coastal and Marine Resources

Straits Of Malacca

Location: Straits of Malacca, Malaysia

Type of Project: Numerical Modelling

Client: Asia Pacific Environmental Consultants (APEC)

ASR Projects- Straits Of Malacca

The cross-shore currents along a cross-shore transect. Noteworthy is the surface boundary layer pushing water shorewards (positive velocities) and the downwelling flows at the coast which leads to offshore (negative) currents at depth near the seabed.

Project Overview:

ASR Ltd performed a numerical hydrodynamic and sediment dispersal modelling study to depict the movement and concentration of plumes arising from a proposed dredging operation in the Straits of Malacca.

Project Outcomes:

The sediment plume dispersion study determined the dispersal directions of suspended sediment plumes under the influence of the Southeast and Northwest Monsoons in the Straits of Malacca. The study also determined the spatial distribution of suspended sediment plume concentrations (mg/L) at different intervals. The modelling showed the settlement location and thickness of the depositing sediment along the plume route as well as an integrated number indicator showing the likely areas that would be impacted by the plume.

The modelling revealed that the plume would remain in the water column for up to 48 hours. However, the coarsest sediments settled quickly (within a few hours) and close to the dredge. The finest sediments travelled up to 30 km from the dredge before settling. The concentrations decayed to around 0.01 kg.m-3 after 24 hours due to settling and mixing (a concentration decay factor of 10-5) and were totally settled after 48 hours.

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