Variabilidade espacial da qualidade da água do Canal São Gonçalo em períodos de alta e baixa pluviosidade: avaliação de dados pretéritos utilizando estatística multivariada.

The São Gonçalo Channel is located in southern Rio Grande do Sul and connects Mirim Lagoon to Patos Lagoon. It is a water body of great importance to the region, used for urban water supply, navigation, irrigation, and environmental balance. Giving its importance and the growing demand for its water, understand and monitoring its water quality is essential. Whitin this context, the aim of this research was access the water quality of the São Gonçalo Channel. Water samples were collected in 22 sites in two different periods, in rainy season and in dry season. The water samples were analyzed for 24 different surface water parameters.The principal component analysis techniques were applied for the results. The analysis showed that the water quality of the São Gonçalo Channel is different to each site and to each season. Different tributaries were identified that pollute the São Gonçalo Channel. Moreover, the water quality is low downstream the dam. The water quality parameters that are related with dissolved solids are the most significant in dry season. In rainy season there are increases in the parameters that are related with suspended solids.