Three-dimensional hydrodynamic modeling of the Santos-São Vicente-Bertioga estuarine system, Brazil

Abstract

Composed of three channels, a bay and an extensive mangrove area, the Santos-São Vicente-Bertioga estuarine complex, which is located in São Paulo, Brazil, is one of the most important water resources for the region. It hosts the activities of the largest Brazilian port and is used for recreational and subsistence activities. Due to its complexity and different forms of use, the study of its hydrodynamics is of extreme importance and an ongoing concern for researchers and decision makers. Generally, hydrodynamic studies are performed through field monitoring, which is a limited approach because it is discrete in space and time. In view of these limitations, it is necessary to apply field data in conjunction with other tools that allow the integrated assessment of the environment; one of these tools is numerical modeling. Based on this background, this paper presents a hydrodynamic study of the estuarine complex through the application of three-dimensional numerical modeling. Our objective was to improve the representativeness of water level and currents in the water column through time and space, thereby building a background model for future studies involving the understanding of the water circulation in the system. The modeling results showed a high degree of agreement with the in situ measurements. Concerning the water circulation of the complex, the results indicated that the three channels that make up the complex had distinct behaviors; flood currents were dominant in the Santos channel, while ebb currents were dominant in the São Vicente and Bertioga channels. The strongest currents were observed in the Santos channel. We also show that the influence of river discharge and channel morphology creates subregions with different hydrodynamic behaviors within the same estuarine channel.