Environmental sensitivity mapping for oil spills in the Canhanduba River Basin, Santa Catarina State, Southern Brazil

Abstract

Oil spills may cause serious damage to natural resources and anthropogenic activities. In order to mitigate such adverse impacts, contingency planning based on environmental sensitivity mapping has been developed, encompassing potential areas, where such situation may occur. Recently, an oil distribution company, TRANSPETRO, put into operation a new facility in the Canhanduba River Basin, in Itajaí, Santa Catarina State, Southern Brazil. This facility receives and sends off diverse pipelines containing a great variety of oil products, crossing over the main stretch of the river and its tributaries. Canhanduba River supplies water to part of the city of Itajaí and the oil distribution facility, as well as all pipelines are located up river of water collecting point to supply that town. Therefore, environmental sensitivity maps of Canhanduba drainage were done in order to support decision makers in case of manage any oil spill episode in that area. Firstly, rapid environmental assessment protocols - RAPs to evaluate physical river habitats were conducted to portrait their integrity in distinct stretches along the river basin. Finally, environmental sensitivity maps attributes like ecosystem sensitivity, natural resources, and anthropogenic activities were identified nearby pipelines crossings and graded according to its intensity in each observation site, in order to estimate environmental sensitivity indexes (ESI) and make up the maps. RAPs’ results indicated that in the great majority of river stretches, environmental integrity varies between bad and fair, while ESIs were relatively high, varying from 6 to 9. An environmental sensitivity map (1:50.000 scale) was generated to this area displaying the major attributes and the distinct ESIs along the river basin.