Coastal Zone Management Tool: A GIS-Based Vulnerability Assessment to Natural Hazards

Abstract

Studies carried out in the State of Para (Brazil) reveal that the northeastern part of the coastal zone has been severely impacted by storm floods and erosion processes in the last 25 years. In response to these impacts, a variety of coastal defense measures and adaptation strategies have been applied in the region, but with only limited success. The work described here intends to support the Coastal Zone Management Program of Para through the identification, assessment and classification of the coastal zone’s overall vulnerability to flood and erosion risks. This is achieved by using a geographic information system (GIS) in order to create a so-called Composite Vulnerability Index (CVI). The CVI includes 16 different variables, describing both the natural and Socio-economic conditions which determine the risk situation in the coastal zone. By means of GIS, these variables are classified, weighted and combined to yield a CVI. This index now provides a reliable, easily applicable tool for the measurement and description of the coastal hazards within and among the 22 municipal districts in the State of Para. The vulnerability index describes five classes, from very low to very high vulnerability. The key results of this study are then presented in three maps, showing the natural, the Socio-economic and the total (=composite) vulnerability for each of the municipal districts. The chapter critically analyzes the confidence levels for the results obtained and the possibilities to update the present variables or to include new ones. Considering the Coastal Zone Management Program of Para, the results are applied to support the spatial distribution of strategies and measures (retreat, protection, accommodation, non-action) against natural hazards for each one of the planning and management units.