Qualidade da água de um ecossistema lótico urbano

Abstract

Water quality is strongly influenced by the use and management of soils in a watershed and the rainfall. During the rainy season there is surface runoff and during the dry season, increased concentrations of pollutants from releases, because of reduced flow. This work aimed to evaluate the spatial and temporal variation of water quality and trophic characteristics of the main watercourses in the watershed of Ribeirão Vermelho in Lavras - MG. The Water Quality Index (IQA) and the Trophic State Index (IET) during the rainy season (summer) and the dry season (winter ) were determined.. IQA values were obtained in three samples during the rainy period and three in the dry season. They were between 31 and 64 during the summer and 33 and 67 in the winter. Results obtained showed that the Ribeirão Vermelho and its tributaries are strongly influenced by forms of land use and occupation found by the input of organic matter and nutrients into the water systems from discharging untreated sewage and by agriculture in the watershed drainage system.