Flood Frequency Analysis of a Sub-watershed in Meenachil River Basin Using Gumbels Extreme Value Distribution

The extreme flood events are always a chapter of concern in all river basins, accompanied by loss of property, lives and economics. Estimation of flood peak discharge for a desired return period is pre-requisite for river basin management, design and execution of structures like bridges, culverts, dams, etc. Hence flood frequency analysis is essential to predict the flood peaks of different return periods. The Gumbels extreme value distribution is one of the best probability distribution model used to model annual maximum flood discharge. This paper presents the results of the flood frequency analysis of Meenachil river basin in Kerala using Gumbels extreme value distribution. The analysis used 34 years of data (1985-2018) to model the annual maximum discharge. The flood peak values of return period 2, 10, 50 and 100 year were computed and further extrapolation could be done to find out the flood discharge of any return period. The R² values of the plots of return period versus stream flow and reduced variate versus flood peak showed that the Gumbels extreme value distribution is suitable for predicting the expected flood flow in Meenachil River.