Geoenvironmental analysis of a small watershed in municipality of Lençóis, Chapada Diamantina (Bahia), Brazil

Abstract

This study aimed at surveying the physiography and land use in the small watershed of Lençóis River, in order to constitute an instrument for the management of natural resources. This small watershed is located in the municipality of Lençóis, Chapada Diamantina, state of Bahia, Brazilian Northeast. The waters drained by this small watershed are destined to the water supply of the city. The methodology used they based on geosystemic theories and methods and on the use of geoprocessing and remote sensing. The results indicated that the small watershed of Lençóis River is elongated, with a low branched and sparse hydrography. The climatic typology is tropical at altitude, and lithology is predominantly metasedimentary, with a structural geology defined by transcurrent fault, which controls the main fluvial channel. Sierras, valleys and river terraces, with an average slope of 27.5%, compose the geomorphology. The predominant vegetation cover class is the rupestrian fields. The levels of preservation of the vegetation cover, detected in the mapping, provide ensure of protection to the fluvial system, thus protecting the good natural condition of the predominant geoenvironmental units. At the geosystemic interface, the small watershed Lençóis River presents physical-environmental characteristics that suggest a management that values conservation, in order to ensure the balanced use of natural resources that promote socio-economic resources.