Caracterização fisiográfica e determinação de indicadores de qualidade da água na bacia hidrográfica do rio Tumurupará, Campina das Missões-RS

Abstract

Currently, the scenario of water bodies degradation has been compromising the water quality that is used for multiple uses, such as public supply, recreation and agriculture. The main cause is the lack of basic sanitation and the development of anthropic activities without adequate planning. In this context, water quality indexes are used to assess and inform the population of water quality, as well as to relate the main sources of pollution that are changing the physical, chemical and microbiological parameters. Thus, the objective of this work is to perform the physiographic characterization and determine the Water Quality Index (WQI), the Trophic State Index (TSI) and the Balneability Index (BI) of Tumurupará River, located in Campina das Missões / RS. In addition, it seeks to analyze the chemical parameters in accordance with CONAMA Resolution 357/2005. The collections were taken in four strategic points of the river, from august to September in 2016. In order to determine BI, it was used thermotolerant coliforms as biological parameter in a sample period of five weeks, the other indexes and parameters were determined through a single collection. The methodology used in the physiographic characterization of the basin was the QGIS software, for calculating WQI uses pH, biochemical oxygen demand (BOD), dissolved oxygen (DO), temperature, total solids, thermotolerant coliforms, turbidity, nitrogen and total phosphorus. The total phosphorus was used for the TSI analysis. The results for physiographic characterization indicate an elongated basin and not susceptible to flood, with Kc 1.36 and Kf equal to 0.36. It also presents regular drainage density (Dd) with 1.43 km / km² and low sinuosity with branching in order 4. The IQA classified the river as reasonable and poor, the TSI was classifies at the mesotrophic level throughout the analyzed section, with no implications for water quality, and according to IB, the river was considered inappropriate for primary contact in all samples. As for the chemical elements, the ones that presented nonconformity with legislation stand out the aluminum, the iron, the chlorine and the copper. These results compromise the water quality that is used for public supply and recreation of primary contact by the population of Campina das Missões / RS. Therefore, it is recommended that measures be taken by the government in order to improve the quality of the water body.