Abstract

ESCALANTE-SANDOVAL, C.A.. Mixed Distributions in Low-Flow Frequency Analysis. Ing. invest. y tecnol. [online]. 2009, vol.10, n.3, pp.247-253. ISSN 2594-0732.

Low-flow characteristics are required to solve several water-engineering problems. In this paper, the Mixed Gumbel and the Two Component Extreme Value distributions are presented toward their applications in low-flow frequency analysis. A region in southern Mexico, with 39 gauging stations was selected to analyze the lowest 1 day flows. Additionally, in order to calculate the stream design flow ( ₇Q₁₀) for water quality standards down stream of the Hydroelectric project La Parota, the lowest 7 day average flows were used. Results produced by fitting the mixed distribution were compared with those obtained by the Weibull-3, Gumbel, Lognormal-3 and General Extreme Value distributions. Results suggest that mixed distributions are a suitable option to be considered when analyzing minimum flows.

Keywords : Minimum flow frequency analysis; maximum likelihood; heterogeneous samples; water quality.