Influence of the different inlet configurations on the water quality of the Mundaú-Manguaba Estuarine-Lagoon Complex
Coastal lagoons; Water quality; TRIX; Model; SisBaHiA®.
The Mundaú-Manguaba Estuarine-Lagoon Complex (MMELC) is a system composed of two coastal lagoons, Mundaú and Manguaba, which are connected by narrow channels and share an oceanic inlet that shifts position dynamically. The MMELC has great economic importance for the municipalities located in its surroundings, which include the capital Maceió. However, many environmental problems resulting from industrialization, urbanization and the discharge of domestic and industrial effluents, contribute to the reduction of water quality. In this context, hydrodynamic and water quality models emerge as a tool to support coastal planning and management. Therefore, the aim of this work is to evaluate the spatiotemporal behavior of the water quality parameters and to analyze the trophic state through the TRIX index (Trophic Index) in the lagoon complex, considering the morphological changes that occur at the ocean inlet. The water quality modeling was performed with the Hydrodynamic Environmental System (SisBaHiA®). Three different simulations were carried out, corresponding to the years 2006, 2014 and 2017, which have different inlet configurations. The results indicated that the variations in the concentrations of the quality parameters inside the Mundaú and Manguaba lagoons are highly influenced by the fluvial contribution of the Mundaú and Paraíba do Meio rivers, respectively. The highest values of the TRIX index in the Manguaba lagoon were found near the mouth of the Paraíba do Meio river, during peak flows; in the Mundaú lagoon, it was observed that during the peak flows of the Mundaú river, there was a reduction in the values of the TRIX index in the areas near its mouth.