Three dimensional numerical modelling of circulation patterns in Manila Bay, Philippines

Abstract

Flow processes found in Manila Bay, Philippines are dominated by complex wind driven currents. Flow circulation within the bay has a significant impact upon the water quality and sediment transport processes occurring in the bay. This paper presents the outcomes of a study, funded by the International Atomic Energy Agency, which used a combination of field data collection and numerical modelling techniques to assess the distribution of Red Tide algal blooms within Manila Bay. This paper presents the model verification against nuclear tracer experiments and the three dimensional hydrodynamics of Manila Bay. Field experiments were undertaken using radioactive isotope tracers to track flow currents at selected locations in the bay. The data from the field experiments were used to validate a threedimensional hydrodynamic (RMA-10) model of the bay. The methods of presenting the radioactive isotope tracers results and comparison of model results and experimental data are presented in this paper. The outcomes of the field data collection and numerical modelling work clearly demonstrate the importance of representing three-dimensional flow processes in defining the hydrodynamic behaviour of the bay. The significance of wind generated currents and the resulting three-dimensional flow patterns is indicated by both field data and model results. A comparison against model results obtained using a two-dimensional depth-averaged flow approximation is presented to further highlight this point. © 2021 Institution of Engineers, Australia