Dinâmica costeira e vulnerabilidade à erosão do litoral dos municípios de Caucaia e Aquiraz, Ceará

Abstract

The coastal plains are one of the most fragile ecosystems known, however, have the highest rate of use, occupation, urbanization and population density in the world. This fact demonstrates the need to require specific studies in this area so that your planning is done sustainably. Thus, the present thesis held in the coastal municipalities of Caucaia and Aquiraz, Ceará, located in the metropolitan region of Fortaleza, aimed to analyze the socio-environmental dynamics of the coastal zone, assessing the levels of vulnerability to erosion of the site. The methodology was performed by monitoring the 12 points marked, in which they were made, field work with the realization of profiles transverse, measurements of height, period and direction of waves and sediment samples collected in the beach zone, dunes and frontal dunes to back morphoscopy and analysis granulometric, and survey data such as winds, rainfall, currents, temperature and tidal fluctuations. According to the results given that the coastal area studied had almost entirely, urbanization and occupation by tourist activities, and this in some specific environments have lower intensity due to unattractive and/or speculation has yet to be inserted so active on the beach. The evolution of the urban city of Caucaia occurred more intensely compared to the occupation of Aquiraz, even the latter has a history older than the first city, a fact proven by the characteristics social and economic. In the oceanographic aspects there was tidal amplitudes monthly maximum 3.1 minimum 2,3 m. In Caucaia the wave height ranged from 0,60 m to 2,10 m Aquiraz a variation of 1,5 m and 0,50 m wave predominance of type sea. The morphoscopy identified in dune environments and beach sediments matte and shiny, which demonstrate the existence of interaction between environments underwater and wind transport. As the modal states, the coast of Caucaia characterized by beaches with a tendency to intermediate stages, resulting in certain periods of the year in the reflective beach stages in Iparana and dissipative stages in Pacheco and Icaraí. Already in Aquiraz modal stages were also characterized by beaches tend to intermediate stages, only in getting internships reflective stages in Iguape. It was confirmed the retreat of the shoreline around the coastline studied based on the program DSAS 4.2, with rates ranging from -4,10 m/year to 0,35 m/year in Caucaia and -1,4 m/year to -0,25 m/year in Aquiraz. In view of the foregoing it was found that the coast of Caucaia showed average to high vulnerability to erosion taking place as a major problem in the forms of use and occupancy of interaction between environments of the coastal zone, while in Aquiraz was low to high along its entire length, with the most problematic areas of real estate speculation should be preserved. These implications may clarify why the erosion processes are more intense in coastal Caucaia in relation to coastal Aquiraz, mainly because of the position of the coastline, that is, how the elements studied oceanographic reached the coast, in the case, in coastal Caucaia these are much more intenseIt is concluded that, in comparative diagnosis of the two cities through the methodologies, the erosion indicators, the categories and morphodynamics that, the vulnerability to coastal together with conditions receding coast line and reduced sediment supply, is related mainly with the evolution of the occupation, the use and the forms of dynamic coastal area