Correlacionando a qualidade da água com o uso e a cobertura da terra: um estudo da Bacia de Contribuição da Represa Doutor João Penido, Juiz de Fora (MG)

Abstract

This research presents a study of water quality in the basin of one of the most important public supply water source of Juiz de Fora, Minas Gerais. The main objective of this study was to analyze the behavior of limnological parameters in space and in the dry and rainy seasons, as well as the correlation with usage and land cover of the contribution basin of the Doutor João Penido dam (BCRJP). The methodology was based on the analysis of water quality parameters, relative to water samples taken from 2012 to 2015 and from 2019 to 2020. Six sampling points chosen from different locations: spring, medium course, main tributaries in the dam and the dam catchment. The parameters analyzed were turbidity, total solids (ST), oxygen consumed (OC), dissolved oxygen (OD), electrical conductivity, total nitrogen (NT), total phosphorus (FT), E. Coli, temperature, pH and total dissolved solids (SDT). The Kruskal-Wallis test was used to compare the measured results between sampling points and stations. The Kendall¶s tau test was used to analyze the correlations between parameters of water quality, land use, and land cover in the BCRJP. The results of each parameter were compared with the limits established by the current legislation Conama Resolution 357/2005 for Class 1 waters. The OD, OC and NT parameters differed by location; the turbidity, ST and OD varied by season. Final results shown that 80.11% of the OD readings were in disagreement with the Resolution. In general, measured parameters showed better results in spring and in dam catchment, showing a worse quality of the water along the tributaries and the dilution power of the dam. The correlations pointed to the need of protection and preservation of forests in strategic locations to ensure good quality water.