Analysis of physical and dynamic variables by Coastal Vulnerability Index (CVI) in Formosa Bay cove, Lagos Fluminense Region - Rio de Janeiro State

Abstract

The coastal segment of Formosa Bay cove, Lagos Fluminense Region - Rio de Janeiro State is in a process of geological risk, resulting from the action of storm waves, intense coastal erosion and high urban occupation recorded in the last 40 years. This study uses the Coastal Vulnerability Index (CVI) in the beach arc delimited by Rio das Ostras headland and Cape Búzios, with the objective of mapping the relative vulnerability of the coast to future mean sea-level rise. The methodology developed by USGS (United States Geological Survey) classifies coastal risk areas calculated numerically, using variables geomorphology, shoreline change rates, coastal slope, mean wave height, mean tidal range and relative sea-level rise. Through GIS (Geographic Information System) techniques, the physical and dynamic variables that integrate the vulnerability model were analyzed. Using as basis the data referring to the mean sea-level rise in IPCC (Intergovernmental Panel of Climate Change) of 4,0 mm/year until 2100, 41.5% of the 40 km long coast segment presents low vulnerability, with predominant in the sector south. In the most pessimistic projection of sea-level rise, at 15,0 mm/year until 2100, the high/very high vulnerability index is registered in 58.5% of the coastal zone, with the northern sector standing out. The Formosa Bay cove CVI Map is expected to be a study material for long-term evaluation and planning by researchers and public administrators.