Geotecnologias aplicadas à área ambiental: estudo de caso nas microbacias hidrográficas da Sanga da Taquara e do Arroio Inhamandá no município de São Pedro do Sul - RS

Abstract

The environmental degradation, through the incorrect and indiscriminate natural resources use, is demanding a deep revision of the relationship between man and nature. In the last times the development of the farming and the intense urbanization provoked serious unbalances to the nature elements with its physiochemical and biological properties alterations. Considering that problem, this present research has as objective applies geotechnologies to the environmental area, seeking to know the impacts of the antropic action in the Taquara and Inhamandá stream catchments, located in the Municipal District of São Pedro do Sul Rio Grande do Sul State. They were used pre existent data, field research and computational techniques for the execution of the study. Among the computational techniques, it stands out the use of Spring 4.2 Software in the elaboration of the base map and thematic maps as: clinographic, permanent preservation areas (PPA) and earth use. The earth use rising took into account the LANDSAT-7 ETM+ (1999) and CBERS-2 (2005) satellites images. Starting from the crossing of PPA with the earth use was noticed that of 1999 to 2005 the urban area passed from 17.51 to 23.38ha; the area with cultures obtained growth, passing from 574.35 to 1,027.07ha; in compensation, the fields that were occupied 500.15ha, they presented, in 2005, only 120.07ha.The forests had a smaller fall, passing from 757.54 to 742.22ha. The water, as well as in the whole study area, it showed a significant reduction; in 1999, it occupied 74.23ha and in 2005, 11.04ha. Therefore, the chosen area possesses environmental problems, especially in the urban district, where the deposition of residues was evidenced in inadequate places, and the location of residences in risk areas, besides the sewer thrown at the two streams that permeate the city. Those problems interfere in the population s life quality and also in the surface and underground water quality in the micro basins. Its suggests that must have a larger concern in managing in a maintainable way the natural resources of the area, especially the hydrics resources, avoiding larger environmental damages.