Aplicação de modelo hidrodinâmico bidimensional para o estudo da dispersão de poluentes na baía de Maputo

Abstract

In this work, the phenomenon of the dispersion of passive particles emitted from the selected areas of Maputo Bay was analyzed, simultaneously considering the forcing action of the prevailing winds, river flows and tides recorded in the Bay, with the aim of contributing to the knowledge of the trajectory and destination of the particles deposited along the Bay. The work consisted of the application of a two-dimensional hydrodynamic developed by J.J. Leenderise and E. C. Grifton (1971), and a Lagrangian particle transport module was attached to the model. The simulation was carried out by using the model in two phases, considering the summer and winter seasons, in a period of 15 days of simulations for each phase. Flow, wind and water level data for 2002 were used. February was considered to represent the summer season, where the forcers were considered for this period, and June as representatives of the summer season. Winter. The trajectory of the particles was determined from five zones selected for the emission of such particles, and the behavior of the evolution of their trajectory was analyzed. The results indicate that, in the tidal cycle of approximately 12 hours, almost all the particles still remain inside the Bay, assuming that during the ebb the particles are transported outside the Bay and in the flood to the interior of the Bay. It was observed that for a time scale greater than the tidal cycle, the phenomenon of dispersion is more significant in the center of the Bay, in the Espírito Santo estuary area and in the areas near the mouth of the rivers.