Hydrobiogeochemical evaluation in the Ribeirão das Posses basin at the scope of the \Conservador das Águas Project\, Extrema, MG, Brazil

The study of the basins forming the Piracicaba river is a priority in the context of the solution of the water crisis in the southeastern region of Brazil, as they maintain more than 4.5 million inhabitants in the Piracicaba, Capivari and Jundiaí (PCJ) basins and contain the Cantareira dam system, which promotes the water supply of approximately 8 million inhabitants in the metropolitan region of the city of São Paulo. For the guarantee of such water resources, a plan of restoration and conservation of the surroundings of the dams constituting the system, as well as the micro-basins in the headwaters of its tributaries, such as the Jaguari river, is fundamental. In this region, the Conservador das Águas project was started in 2007 in the microbasin of the Posses stream, a tributary of the Jaguari river in the municipality of Extrema - MG, with the purpose of promoting restoration and conservation of springs within private properties, in the Payments for Environmental Services (PSA) model. The objective of this research was to evaluate the spatiotemporal dynamics of qualitative water parameters in water bodies, such as springs in restoration, tributaries and main channel of the Posses stream and its influence on the Jaguari river, considering the use of the soil in the drained area amount of each sampling point. The hydrobiogeochemical parameters evaluated were: flow, temperature, pH, electrical conductivity, BOD, in addition to oxygen, carbon, nitrogen and major dissolved ionic elements and isotopic mass and carbon and nitrogen ratio in suspended particulate matter. The results show that restoration actions have contributed to the reduction in the electrical conductivity (EC) in the springs. Land use has interfered in the quality of the water bodies and that Cl- can be used as an environmental tracer, reflecting the influence of the pasture environment. Finally, erosion processes predominate in the basin, and transport of particulate matter in suspension to the mouth of the Jaguari River was 68 tons km-2 year-1. (AU)