EVALUATION OF METHODOLOGIES OF REGIONALIZATION OF MINIMUM STREAM FLOWS OF REFERENCE FOR THE SÃO FRANCISCO RIVER WATERSHED

Abstract

In the present study, was made the evaluation of three methodologies of regionalization of minimum stream flows of reference (Q7,10, Q90 and Q95) applied in São Francisco river watershed, upstream of the Três Marias reservoir, to know: a) Eletrobrás (1985), based on regional equations of regression; b) Chaves et al. (2002), that applies automatic interpolation and extrapolation techniques; e c) specific stream flow. The minimum stream flows of reference esteemed by the three methodologies were compared with those observed in each one of the 28 used fluviometric stations in the study. The method that presented greater precision was the proposed by Eletrobrás (1985), resulting in three equations of flow regionalization, with average relative error of 26,8%. Amongst the used physical and climatic characteristics in the regionalization, the draining area was the one that better explained the behavior of the minimum stream flows. The other methodologies didn’t present satisfactory results when the difference in the drainage area of the place of known flow and the place where the stream flow have been estimated, was large.