Análise da relação entre a qualidade da água, o uso e ocupação do solo e a densidade demográfica na bacia hidrográfica do Rio Passaúna

Abstract

The designated areas of environment protection (APA) created in the Metropolitan Region of Curitiba, are intended to protect river basins that feed into the dams providing water supply now and for future generations. Between those dams are the APA of Passauna, with a delimited hydrographic of the Passauna basin, it is an important channel for public water supply. The objective of this work is to evaluate how the use and occupation of soil and demographic density influence the quality of water in the hydrographic basin. This study made use of historical data used to determine the water quality in the sample stations of the IAP available during the spring months between 1991 to 2016. This study is based on samples collected the AIQA (Integrated evaluation of water quality) located in the water station sample collection and their respective sewage area. The data was collected over the years of 2000, 2010, 2016, and the results assessed the demographic density, use of soil and the sewage collection system near the sub-basins. In addition, the results verified the parameters to accordance with the limits established by the Class 2 qualification of the water quality as defined at the resolution CONAMA 357/2005. In general, the restrictions for use and soil occupation in urban and industrial areas established by the APA of Passauna contributed to the maintenance of water quality. In the sub-basin SB 28, where it wasn’t detected urbanized areas, it was identified a huge area of arboreal vegetation and a better preservation of Riparian Vegetation, therefore a better water quality in relation to the others. In the sub-basins upstream the dam (SB 30, SB 31, SB 33 e SB 35), the degradation of water quality is associated to the presence of Fecal Coliforms and Escherichia Coli. In the sub-basins SB 11, outside the Passaúna APA perimeter, downstream the dam, there is a significant decrease of water quality, that is related to an increase of soil use, urbanization and population density. In some sub-basins despite increased urbanization and population density in these areas, it was observed that increased sewage collection contributes to improve or maintain the water quality based on the date provided in the past years. The results indicate the need to implement mitigating measures to reduce water pollution, increase awareness, and improve regulation to support through inspection in these areas, as well as increase the sewage collection system in these areas.