Erosão costeira da praia do Iguape: desafios e perspectivas

Abstract

The growth of the occupation of coastal areas causes several problems that are reflected in the own environment, as for example the coastal erosion. The control of the urban expansion to preserve this environment is essential, since this region is included among the most dynamic of the planet. The State of Ceará has an extension of 573 km of coastline that has undergone extensive erosive processes. Due to this great extension some of the main economic activities are directed to the use of the coast, as in Iguape beach, located 30 km from Fortaleza in the municipality of Aquiraz, east coast of the State of Ceará. The occupation and urbanization through tourism and the construction of summer houses caused changes in the dynamics of sediment transport coming from the dune field and the beach strip. In view of this, the present work has the objective of analyzing the stretches of coastline retreat and characterizing the coastal erosion of Iguape Beach, metropolitan region of Fortaleza and associated impacts. The methodology consisted of the bibliographical survey and field exits. The acquisition of satellite imagery of Google Earth Pro was performed to analyze the space-time variation of the coastline through the extension DSAS 3.2 in the interval of 2011 to 2018. While the short-term monitoring occurred in the month of October 2018, whe re data from the position of the coast line of 2018 were collected through RTK trawling, sediment samples and 12 beach profiles were made using RTK. From the analysis of the variation of the coastline, it was possible to determine the rates of variation inmeters per year in the Iguape beach, in addition it was possible to perform the sedimentological characterization through morphoscopy and granulometric analysis. The study site was divided into two sectors, sector 1, located at the mouth of the mouth of the Iguape Creek, integrating part of the cove formed from the promontory; and sector 2 located to the west of the mouth. In the period from 2011 to 2018 an erosion of -26.53 m was observed in 7 years in sector 1 and -52.08 m in 7 years in sector 2 located west of the Iguape Creek. Furthermore, from the sedimentological analysis it was possible to verify that the sediments that compose the beach come mainly from the wind transport and the underwater region. Based on the analysis of the use and occupation of the area, it was possible to observe a decrease in the occupied area associated with the destruction of the residences, 28 houses in total were lost in the post-beach region during the years 2011 to 2017. From the results obtained was it is possible to verify that the coastline retreat is not only associated with sea level rise but also with the increase in undue occupation that has a direct influence on the coastal dynamics of the site.