Avaliação ambiental de nascentes com o uso de ferramentas de geoprocessamento

Abstract

The Brazil occupation was characterized by the planning lack and consequent destruction of the natural resources, particularly of the forests. Among them the ciliary forests working as filters, retaining sludges and sediments witch would be transported to the water courses, affecting the amount and the quality of the water directly and consequently the aquatic fauna and the human population. This work was accomplished inside fountain areas of the basin of reception water in the barrages of Rodolfo Costa e Silva and Saturnino de Brito of Santa Maria - RS town. It intends to contribute for maintainable development of the area, supplying subsidies to the ordering of the activities, and using Geo processing techniques, among them the sensor remote and the systems of geographical information for characterization and analysis of the environmental data. It began with the assembly of an aero photographic mosaic, where the entrance of data and information were made in SIG IDRISI for Windows, occurring the geo reference and the delimitate area of the study through digitization (in the screen) the following limits of the highways. In the processing of the image a digital classification was accomplished using the algorithm of Maxver, where was obtained the classification of earth use. The selected sub-micro basin of study was measured in 620,58 ha. After it was drawed the drainage net and detected the fountains. It were found 30 starting fountains from in the identification mosaic and chosen 08 for this study, which it enrolled the coordinates UTM (Universal Transversa of Mercator) embracing the whole area of the sub-micro basin. Was observed 3 earth uses: agriculture, forest and scrub. In a general way the fountains are in precarious conservation, because the legislation recommends that total forest protection in a ray of 50m in it spills. It was verified that the agriculture occupies large part of the area of influence of the fountains 48,10%, and the forest occupies 26,68%, and the scrub with 25,22%.