Water renewal in the estuarine lagunar Mundaú-Manguaba complex (Alagoas, Brazil) under different mouth configurations

Abstract

The present work analyzes the morphological changes occurred in the Mundaú-Manguaba Estuarine-Lagoon Complex (MMELC), through geoprocessing techniques and computational modeling. Initially, a multitemporal analysis of the variations of the coastline between the period of 1986 to 2017 was carried out using images from the Landsat 5-TM and Landsat 8-OLI satellites. The images were vectored in a Geographic Information System (GIS) environment for the subsequent calculation of erosion and accretion rates. After that, some simulations were performed with the Hydrodynamic Environmental System (SisBaHiA®) for the residence time and water age parameters, considering three scenarios with different inlet configurations (2006, 2014 and 2017). The results indicated the predominance of deposition of sediments in the inlet region, with the migratory dynamics in the southwest-northeast direction. The residence time indicated possible stagnation areas in the northwest region of the Manguaba lagoon and in the northwest and southeast portions of the Mundaú lagoon. The 2014 scenario showed lower water ages, indicating that the different inlet configurations interfere with the water renewal of the lagoon estuarine complex.