Intercomparison of evaluation of low-flow characteristics of streams using statistical modelling approach

Abstract

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Low-flow characteristics of streams are used in planning and design of water supplies, analysing environmental and economic impacts, modelling stream water quality, regulating instream uses, and improving the general level of understanding of natural and regulated stream systems.  Statistical modelling approach involving standard probability distributions of Box-Cox Transformation, Lognormal, Log Pearson Type III and Pearson Type III and Weibull are used to determine low-flow characteristics for different return periods for three different river basins, namely, Mahanadi, Godavari and Narmada.  Chi-square (c²) test is used for comparison of low-flow characteristics of different stream.  The paper presents that Lognormal, Weibull and Pearson Type III distributions are found to be suitable for determination of low-flow characteristics for rivers Narmada, Mahanadi and Godavari respectively.  Low-flow frequency curves are also developed and presented.