Comparison of EV1 and LP3 Distributions using Goodness-of-Fit and Diagnostic Tests for Estimation of Design Flood

Estimation of design flood at a desired location on a river is important for planning, design and management of hydraulic structures. This can be carried out through frequency analysis by fitting of probability distribution to the series of recorded annual Peak Flood Discharge (PFD) data. In this paper, Extreme Value Type-1 (EV1) and Log Pearson Type-3 distributions are adopted for frequency analysis of annual PFD data of Giri and Jalal rivers. Maximum likelihood method is used for determination of parameters of the distributions. Goodness-of-Fit tests viz., Anderson-Darling and Chi-square are applied for checking the adequacy of fitting of probability distributions to the recorded data. Diagnostic test, viz., D-index is used for the selection of most suitable distribution for estimation of PFD. The GoF test results and D-index values show the estimated PFD from LP3 distribution could be used for design of hydraulic structures in Giri and Jalal rivers and design of flood in river protection works of Yamuna river basin.