EVALUATION OF COASTAL EROSION VULNERABILITY INDEX (CVI) FOR PIAUI COASTAL ZONE, BRAZIL

The Brazilian coastal zone has undergone geomorphological changes due to the hydrodynamic processes that allied with climate and human induced changes can cause erosion problems. The main goal of the present study was to classify the coastal erosion vulnerability of Piaui State, Brazil, considering three intensities: high, medium or low . The methodology consisted in the CVI (Coastal Vulnerability Index) calculation through an analytical equation obtained by the arithmetical mean of three groups of variables (vulnerability indicators), such as: in loco mapping variables, shoreline changes and NDVI (Normalized Difference Vegetation Index) evaluation. The Piaui coast that has 66 km of extension was divide into four sectors. Among the results, the most in loco observed indicator found were non-structural coastal protection works and destruction of artificial structures. Regarding the NDVI, the sector I obtained a low classification, indicating less presence of vegetation during 10 years. For the shoreline variable, the sector II presented the highest rate of advance, with 65.3%, mainly in the Micas beach; the sector III had the highest retreat rates, with 48% of erosion accentuated in Macapa beach; in sector IV it was identified the most of shoreline stability with 37%. Considering the CVI results, it is highlighted that the coastal erosion vulnerability of Piaui was considered low, in 30.6% of the coastal extension, mainly in sector I; medium in 33.45% and high in 31.44%, located mainly in sector III. Through the presented results, this study could be used to improve integrated coastal zone management.