NUMERICAL SIMULATION OF CURRENT INDUCED COHESIVE SEDIMENT TRANSPORT IN MINAMATA BAY

Cohesive sediment has been identified as an important carrier for heavy metal transport in coastal and offshore areas. Minamata Bay was heavily polluted by wastewater discharge contained mercury in 1950s and pollution research around this area has been carrying out. To further understand the distribution and transport of mercury contaminants in Minamata Bay, a current induced cohesive sediment transport model was developed, considering the process of resuspension, deposition, settling, etc. Hydrodynamic environment was provided by the Princeton Ocean Model. Wind and river discharge impacts on bottom shear stress were analyzed and the density current caused by the Komenotsu River had significant effect on the sediment transport in research areas. Simulation results on bottom ocean layer showed good agreement with measured data of three observation stations. Relation between flow field and bottom cohesive sediment concentration was also discussed.