Analysing flood history and simulating the nature of future floods using Gumbel method and Log-Pearson Type III: the case of the Mayurakshi River Basin, India

Abstract

Floods of the Mayurakshi River Basin (MRB) have been historically documented since 1860. The high magnitude, low-frequency flood events have drastically changed to low magnitude, high-frequency flood events in the post-dam period, especially after the 1950s, when the major civil structure (Massanjore dam, Tilpara barrage, Brahmani barrage, Deucha barrage, and Bakreshwar dam) were constructed in the MRB. The present study intends to find out the nature flood frequency using the extreme value method of Gumbel and Log-Person type III (LP-III). The results show that the highest flood magnitude (11,327 m³ s^˗1) was observed during 1957–2009 for the Tilpara barrage with a return probability of 1.85% and the lowest (708 m³ s^˗1) recorded by the Bakreshwar weir during 1956–77 with a return probability of 4.55%. In the present endeavour, we have computed the predicted discharge for the different return periods like 2, 5, 10, 25, 50,100, and 200 years. The quantile-quantile plot shows that the expected discharge calculated using LP-III is more normally distributed than that of Gumbel. Moreover, Kolmogorov–Smirnov (KS) test, Anderson–Darling (AD), x² distribution show that LP-III distribution is more normally distributed than the Gumbel at 0.01 significance level, implying its greater reliability and acceptance in the flood simulation of the MRB.