Estudo da morfodinãmica e morfologia de fundo da desembocadura do estuário do Rio Coreaú, Camocim, Ceará

Abstract

The study of estuarine systems, have been employed on a large scale throughout Ceará's coast in the last years, the influence of the semi-arid regime on the drainage basins of rivers, allied with the construction of dams and shrimp farms, among other forms of anthropogenic interventions alter their natural river flow, making the estuaries become dominated by waves and tides, becoming sediment importers, altering their natural dynamic. The present study aimed to understand what changes have occurred in the last 70 years in the bottom morphology and the morphodynamics of the mouth of the estuary of the river Coreaú, in the county of Camocim, extreme west of Ceará's coast. By compiling historical nautical charts, from the years of 1945 and 1967, and the bathymetry performed in the field, in the year of 2012, it was possible to characterize the evolution of bottom morphology of the mouth of the estuary. Furthermore, using seismic of reflection and side scan sonar was possible to characterize the bottom stratigraphy and how occur the sediment transport of the region, respectively, correlating with the sediment sampling, which was conducted throughout the study area, which were sampled 72 points, thus enabling to understand the local morphodynamic. This way was possible to observe that the estuary is undergoing a continuing process of siltation, but even with this evidence the average depth of the estuary remained very close over the years, around 4 m, demonstrating that even if the estuary is being silted the local dynamics enables the remobilization of the sediment. The sonographic study, along with the seismic enabled to understand that even thought the tides have a major influence on the local hydrodynamics, the river flow is still present in sediment transport, being also observed in the sedimentological study demonstrating a large presence of sediments fine and muddy, from the continent through river flow.