Evaluation of the tropic state of the Piracicaba River and its relationship with the UHE-SÁ Carvalho, MG – Brazil

Abstract

The Piracicaba River, Minas Gerais, presents corresponding extension to 241 km from its source in the Serra do Caraça to its mouth on the Doce River, totaling an area of 6,000 km² with several tributaries leading to the River Watershed Piracicaba (RWP). Among the localities of RWP highlights the metropolitan area of the Vale do Aço, which has high level of human pressure on water body according to their production profile (mining, steel, reforestation with eucalyptus, etc.) affecting ecosystem health. In this study prioritized examine the issue of surface water quality with emphasis on the process of eutrophication based on the measurement of the phosphorus and nitrogen concentration in different stations, and P₁ (Fonseca), P₂ (Rio Piracicaba), P₃ (Nova Era), P₄ (Coronel Fabriciano) and P₅ (Ipatinga) located around the Sá Carvalho hydroelectric power plant (HPP- Sá Carvalho). Surface water samples were collected on quarterly basis in the period from July / 2007 to July / 2012, paying attention separates the relevant seasonality of rainfall, compared with changes in physical and chemical parameters and analyzing the influence of hydropower in quality water. The data were worked by analyzing the relationship between nitrogen and phosphorus (N: P), Trophic Status Index (TSI) for total phosphorus and the Trophic State Index (TSI) for chlorophyll a showing an increase of nutrients being identified eutrophied conditions in several campaigns possibly related to the discharge of sewage, agricultural activities and industrial wastewater. This approach is finalized explaining the need for enforcement actions to contain the disturbances aimed at sustainable development and preservation of that water body.