Flood Management in Mahanadi Basin using HEC-RAS and Gumbel’s Extreme Value Distribution

Abstract

Using Gumbel’s extreme value distribution and HEC-RAS hydrodynamic model, the levels of peak floods at different locations of Mahanadi River reach between Hirakud dam and Naraj (delta head of Mahanadi) for 10, 25, 50 and 100 years return period are estimated. Based on the simulation study carried out considering 36 cross sections for 310 km length of river, it is observed that the heightening of embankment system for almost all the existing bank stations both in the left and right embankments are required. In the present study, the analysis has been carried out considering 25 years return period floods (45067 cumecs), as this flood is considered as most significant and under changed climatic conditions. The results of the study show that out 36 cross sections, at 23 sections, heightening of embankment spanning from a minimum of 0.11 m to a maximum of 10.63 m in the left bank should be carried out. Similarly for right bank embankment heightening is needed from 0.09 m to a maximum of 9.94 m. This can very effectively minimize the flood hazard of the Mahanadi River system.