High Resolution Remote Sensing Data Evaluation for Integrative Vulnerability Assessment in the Coastal Region of Rio de Janeiro (Brazil)

The coastal region Região dos Lagos of the Brazilian State Rio de Janeiro can be characterized by an increasing population pressure resulting from a strong seasonal tourist fluctuation. This causes an infrastructural overload and increases the environmental pollution and degradation of the ecosystems of this sensitive region. Problems in water supply and wastewater treatment intensify and illegal land-grabs become more prominent. Furthermore, coastal erosion of the beach areas puts the urban structures at risk.

The aim of this work is a GIS and remote sensing supported Vulnerability Assessment of the coastal region using objective indicators to identify, classify and compare the different kinds of bad conditions. This objective evaluation basis can be used by local policy makers to improve their urban and regional planning strategies in order to pursuit a sustainable Coastal Zone Management.

Remote sensing data facilitates a quick area-covering spatial data gathering which is fundamental for a broad integrative assessment. Furthermore it is possible to assess the current situation, possible trends and future prospects by using this spatial information gained. This demonstrates an important basis in terms of an Integrative Vulnerability Assessment. By using a multi-temporal analysis certain changes can be detected: urban structures and dynamics can be determined and the resulting pressure on the investigation unit caused by these forces can be identified. Regional urban expansion triggers the occupation of ecologically protected areas and a removal of natural vegetation. As a consequence of coastal erosion caused by southern storms, a displacement of the coastline can be detected. Combining this fact with the knowledge about fast growing urban areas, several endangered regions can be designated. The database for this high resolution remote sensing data evaluation consists of aerial photographs of 1976 (resolution 1,9m*1,9m) on the one hand, and of an IKONOS-image of 2007 on the other hand. A supervised land use classification was generated for a Landsat 7 image taken in the year 2000.

The Pressure - State - Response- Model (P-S-R-Model) which was developed from the OECD (1993) will be applied as the methodical framework for this vulnerability evaluation. The advantage of this framework can be found in the possibility of integrating indicators of different origins which can be summarized in categories and combined to several indices (CENDRERO et al. 2003). Factors with physical geographical as well as socio-economic origin will express the degree of vulnerability of individual communities, their susceptibility and their strategies of coping with or reducing risks.

In order to realize this goal, several indices are constructed: one index in function of urbanity, one index in function of seasonality and one index in function of natural risks combined with the coastal dynamic. The necessary data are obtained through the integrative high resolution remote sensing data evaluation, spatial modelling, data from statistical agencies and surveys. The presented multi-temporal results show the potential of multi-sensorial remote sensing data evaluation for integrated vulnerability assessment in coastal zone management.