ASSUNÇÃO ANDRADE DE BARCELOS
Abstract:
The present study aimed to analyze and diagnose the water quality of the Sucuri stream basin, located in Caçu-Goiás. With an area of 74 km², the Sucuri stream basin is typically rural; does not receive urban and industrial effluents. It's inserted in the reservoir basin of Barra do Coqueiros Hydroelectric Power Plant (UHEBC), on the middle course of the Rio Claro. Limnologically, five sampling points were defined in the watercourse in order to diagnose water quality in four distinct periods. The water analysis methodology followed the proposal of the Standard Methods for the Examination of Water and Wastewater, CONAMA Resolution N. 357/2005 and the Water Quality Index (IQA). The mapping of the use and occupation of the watershed was performed by the supervised classification method. From analysis of the use and occupation of the watershed, it was found that about 55.5% of the watershed area is classified as soft undulating, 63% were occupied with pasture for extensive cattle raising. From 2010, sugarcane occupied about 18% of the basin area, while the forest/Cerrado occupies an area around 16.5%. Pedologically, the Dystrophic Red Latosol (LVd) occupies about 72.5% of the basin; geologically, sandstone rocks predominate from the Vale do Rio do Peixe Formation, occupying 90% of the basin. The climate is classified as Aw, with two well-defined seasons - one dry (less rainy) and one wetter (wetter), with average annual rainfall of 1400 to 1600 mm. According to the evaluated data, the non-compliance of the Sucuri stream water to class 1 is verified, the parameters that contributed the most to keep the IQA low were: phosphorus, thermotolerant coliforms and dissolved oxygen, according to CONAMA Resolution N. 357/05, as class 2. According to the IQACETESB classification, the waters were classified as Good Quality; however, for IQA-IGAM water can be classified as Medium and Good quality.
