Dinâmica da linha de costa do Estado do Ceará, Brasil

Abstract

The coastal zone is a dynamic environment where coastal erosion plays the role of a landscape modeling agent. Natural and anthropic factors cause this erosion, and when its action reaches human constructions, it can cause economic damage. In this coastal environment, there is great population concentration and economic development. In the Brazilian coastal zone, it is possible to observe the scenario mentioned above in some stretches, for example, Fortaleza (Ceará) and adjacent shoreline. This region of Ceará is important under biases environmental, economic and social. Despite this relevance, studies need to understand the dynamics of the Ceará coast better. Therefore, the present study aimed to analyze and specialize the behavior of the shoreline of the State of Ceará through different methodologies implemented in Geographic Information System, with the use of Remote Sensing products, in order to subsidize coastal management. This objective was performed: digital processing of satellite images; calculation of the shoreline variation; determination of erosion sensitivity; determination of urban density; determination of the potential economic damage; and field work. In the coastal zone of Ceará, in the period 1984-2019, there was mathematically a balance between accretion and erosion; however, there are stretches with intense erosion in different sectors. On the stretch of beach between Fortaleza and Paraipaba, there was a predominance of the medium class sensitivity to shoreline erosion with 79.1% (92.1 Km). Despite this predominance, there were significant retreats in Caucaia and Paracuru. Regarding the urban density, the predominant class was the low urban density with 39.7% (46.2 Km). Finally, the very low potential class for economic damage due to shoreline erosion prevailed with 58.1% (67.7 Km). The present research has made improvements in the methodology that determines the potential economic damage due to erosion in two aspects: i) in establishing the erosion sensitivity and ii) in defining the urban density. However, as a recommendation for future work, the previous methodology still needs the insertion of econometric methods and spatialization of its results to be more robust.