Qualidade da água da bacia hidrográfica do Rio do Campo: aplicação do modelo matemático QUAL-UFMG

Abstract

Mathematical models allow verify the self-purification capacity of rivers and guide the management of water resources in watershed, both in prevention and control of degradation. This study aimed to develop a mathematical modeling of Rio do Campo watershed through quantitative and qualitative water data. From the QUAL-UFMG program, four different scenarios of Rio do Campo watershed were studied, simulating discharges of liquid treated and raw waste, and medium (Q50) and minimum (Q95) flow conditions of the water bodies. The results were compared with the resolution of the Conselho Nacional do Meio Ambiente - CONAMA 357/2005. Through the graphs of the water quality parameters profiles, it was verified that the biochemical demand of oxygen, total phosphorus and thermotolerant coliforms were the most harmful parameters for the rivers quality. The scenarios with Q95 flow rates were the most critical because they presented concentrations of those parameters more divergent than resolution CONAMA n. 357/2005 allows. The parameters nitrite and nitrate had no complications to attend the resolution, even in launch conditions of raw liquid waste. Finally, four critical points were identified in the watershed, aiming to guide the management of water resources. One of the critical points was the municipal lake, followed by the three other points located downstream of the effluent releases. These results compose the water quality modeling database of Rio do Campo watershed, supporting the development of new research in the area.