SENSIBILIDADE DE CARACTERÍSTICAS MORFOLÓGICAS NO COMPORTAMENTO DE PARÂMETROS DE QUALIDADE DA ÁGUA EM RIO DE PORTE MÉDIO

Due to the lack of historical water quality data in the country, many technical papers about the river self-cleaning capacity in lotic ambients estimate the biochemical reaction coefficients from empirical equations, which depend on morphological and hydraulic characteristics of the river channel, the quality of the watercourse and the quality of the effluent released in the river. This paper analyzes the sensitivity of some morphological and hydraulic characteristics such as longitudinal slope, cross-section geometry and roughness of the side walls and bottom of the channel, in the concentration change of DO and BOD in a medium-sized river in Minas Gerais Brazil. A reach of 33 km of the Uberabinha River in Triângulo Mineiro has been chosen because its surface water availability and quality are critical for Uberlândia’s water suply system. The simulations showed that (i) the variation of the channel cross-section causes the lowest sensitivity in the OD profile; (ii) the sensitivity in the OD profile is larger for the longitudinal slope and Manning roughness coefficient, which shows the importance of field work and not use of inaccurate techniques for the determination of these two characteristics; (iii) there were not significant BOD differences for the three morphological characteristics analysed. Keywords: Sensitivity analysis, morphological characteristics, self-purification, medium-sized river.