ENVIRONMENTAL VULNERABILITY OF THE CARAVELAS (BA) PLAIN – WHALE COAST REGION AS SUBSIDY TO ENVIRONMENTAL PLANNING
ISBN 978-85-88783-11-9
Authors
1Oliveira Souza, S.; 2Câmara do Vale, C.
1UNIVERSITY OF CAMPINAS Email: siriussouza@ige.unicamp.br
2UFES Email: camaravale@gmail.com
Abstract
The planning and management of natural resources nowadays are a necessity to avoid compromising of natural resources and the potentialization or unleashing of morphogenetic processes. In coastal environments the situation becomes alarming, given the fact that these environments have a geology and geomorphology whose nature and evolution favors the intense performance of complex and dynamic processes. The use pressure on coastal zones and their effects on the equilibrium of ecosystems have been a subject often discussed in the scientific literature. This situation takes the planners to look for summarize the scientific information to develop models of integrated coastal studies. Among these integrated models, we adopt in this work the study of environmental vulnerability. Understanding environmental vulnerability as the higher or lower susceptibility of an environment to a potential impact caused by anthropogenic use (TAGLIANI, 2002), it is evident that the evaluation of the carrying capacity of the landscape is, in actuality, a necessity to avoid the impairment of natural resources and the potentialization of negative morphogenetic processes. From these studies, this paper aims to analyze the environmental vulnerability of the Caravelas Plain in Whale Coast Region in the state of Bahia (Brazil) by means of geoprocessing techniques in a Geo-graphic Information System, with the purpose of subsidize the environmental planning. Considering the pro-posal for identification of environmental vulnerability through methodological proposal of Nascimento and Dominguez (2009) that makes use of the variables: Geology, Soils, Slope and Land Use and Occupation. Proceeded to develop routines of Geographic Information System (GIS), such as scanning, georeferencing and digitization of point variables (elevation points). Considering the proposal for identification of environ-mental vulnerability through methodological proposal of Nascimento and Dominguez (2009) that makes use of the variables: Geology, Soils, Slope and Land Use and Occupation. Proceeded to develop routines of Ge-ographic Information System (GIS), such as scanning, georeferencing and digitization of point variables (elevation points), linear (contours, drainage network and main roads) and polygons (boundary municipalities , inundation areas, lakes, rivers, wetlands). Among the available softwares for making maps, we used the ArcGIS 10.1 for presenting the most complete and varied choices of tools applied to spatial data, besides providing an excellent standard the property of exportation of the products generated. Using these variables in raster proceeded to the development of algebraic operation assigning values (from 1 to 5) for each criteri-on, and subsequently adding them together using the Reclassify and Intersect tool. After that for determi-ning the classes of vulnerability the values assigned to each class were added using the raster calculator tool. Assigned values are based on surveys conducted by Nascimento and Dominguez (2009), Tangliani (2002) and Crepani et al., (1996). At the end, the Environmental Vulnerability Index of the Caravelas Coastal Plain result the arithmetic mean found distributed in five classes, with the following ranges: Very Low (4 - | 8), Low (8 | 10), Medium (10 - | 12), High (12- | 15) and Very High (15- | 19). The results indicate wich the classes that have high and very high vulnerability include mangroves, the floodplains and shoreline. In the class that has an average environmental vulnerability is included areas of the coastal plain and the slopes of the trays. The classes of low and very low vulnerability include the trays located at the northwest portion of the study area. The results obtained allowed understand the different degrees of vulnerability of each unit front of some human pressures, can be used as a tool for local and regional environmental planning.