Evolução geomorfológica do Canal Estuarino do Rio Coreaú, Ceará, Brasil

Abstract

Studied in different ways and in different fields of science, estuaries are strategic and high sensitivity anthropogenic activities environments. The overall objective of the study developed in the estuary of Coreaú river on the west coast of Ceará-Brazil, 350 km from the capital Fortaleza was to understand and identify geomorphological changes correlating the natural causes and/or anthropogenic over time generating useful information to environmental management. In order todo this were mapped and quantified the land use and land cover in the last 37 years, the interference in erosion and sedimentation resulting in the modification of the channel and estuarine bed, the influences of climatological and oceanographic events in morphology and sedimentation and identification of the impact of anthropogenic processes in mobility channels. The results were obtained by integrating data generated in GIS mapping with satellite images of the last 37 years, historical and updated bathymetry (data collection were made in 2012 and 2013) and sediment analysis in the field from the mouth to near the first dam built. We observed that sectors with higher channel mobility are located in the central and lower estuary. Despite the intensity of tidal currents and migration of the spit, the structure of Camocim´s rocks formation at the mouth exercises control in the flow, wiping out the silting process in this sector. Sedimentation is controlled by marine influence, with the predominance of quartz sands of medium particle size. The sedimentation of silt and clay is concentrated in the first ten kilometers from the dam, indicating the limit of maximum influence of fluvial contribution. The results generated in this study are extremely important for coastal environmental management of the city of Camocim situated on the banks of Coreaú. The development of a management plan is needed to prevent the suspension of river flow due to channel obstruction by sandy banks for Coreaú´s estuarine basin, which could affect the ecological flows with answers in the economy and local sustainability.