Qualidade da água do córrego da Formiga associada ao uso e cobertura do solo em Quirinópolis (GO)

Abstract

This study aims to assess the parameters of water quality classification, through water analysis, as well as measure the course flows of Formiga Stream in a hydrological cycle. Using tools from geotechnologies for characterization of Formiga Stream`s watershed and identification of land use and occupation practices and the water quality. The study was developed from research in specific literature on the subjects covered, in water analysis, being collected and assessed the water quality and the flow in five sample points of watercourse (P1 (springs), P2, P3, P4 and P5(outfall)). For the water analysis (quartely analysis), physical, chemical and biological parameters were assessed (temperature, turbidity, apparent color, pH, total alkalinity, total hardness, chloride, total dissolved solids, nitrate, nitrite, electrical conductivity, dissolved oxygen, BOD, total iron, manganese , total coliform and Escherichia coli index), which were carried out by the Goiás Sanitation laboratory. The parameters of water analysis in time scale were submitted to statistical analysis by the F test, and when significant, the Tukey test was applied, for the spatial analysis the PLS-DA multivariate analysis was applied. The use of geotechnologies assisted in the georeferencing of water analysis, thematic mapping, geoprocessing characterization and thematic mapping as maps of erosive susceptibilities, elaborated from the relation between land use and occupation, proximity of roadways, slope, type of soils and others. The water quality parameters were classified in class III according to CONAMA - Resolution n ° 357 / 2005. The water quality in Formiga Stream presented better results in points P2 and P5, while the others presented stability time quality. The flows influenced by the rainfall regime have direct positive correlation for some parameters, while negative for others. Through the multivariate analysis (PLS-DA), it is observed that the points are considered distinct between P1, P2, P3 and P5, and that the parameters with higher SCORES, were: PH, alkalinity, calcium, and hardness. Basin anthropization increased erosive susceptibility classes in the low, middle and very high classes, whereas decreases in the high class.