WATER QUALITY ASSESSMENT IN RELATION TO THE SURROUNDING SOIL MANAGEMENT OF TWO RESERVOIRS IN PINDORAMA/SP - A PRELIMINARY STUDY

Resumo

Water quality monitoring of rural reservoirs is essential to detect the effects of diffuse pollution sources such as agricultural activities on the water quality. This paper describes a preliminary study that uses a multiparameter probe and total phosphorus analysis to characterize and compare two reservoirs in Pindorama/SP surrounded by active plantations, noting that one of them has its surface filled with floating macrophytes. The reservoirs’ areas were characterized, and analysis of physicochemical parameters were made in strategic sampling points. Elevated total phosphorus concentrations were detected in both reservoirs, being hypothesized that the source of this nutrient is the runoff of agricultural byproducts from the surroundings. The reservoir filled with macrophytes had greater phosphorus concentration and was characterized as in a eutrophic state, thus explaining the overpopulation of macrophytes as they can be a consequence of the eutrophication process. Lower levels of phosphorus in the other reservoir may be explained by its morphological characteristics and the presence of a more consolidated riparian forest. To reduce the environmental impacts of the contamination in both reservoirs, it was proposed that practices for adequate soil management in the surroundings, for increasing the reservoirs’ water circulation, and for sustainably retaining the contamination sources, could be implemented to control the effects of eutrophication.