Paper Details

A significant deficiency of most computer models used for stream floodplain analysis, is that the locations ofstructures impacted by floodwaters, such as bridges, roads, and buildings, cannot be effectively compared to thefloodplain location. This research presents a straightforward approach for processing output of the HEC-RAS hydraulicmodel, to enable two- and three-dimensional floodplain mapping and analysis in HEC-RAS using ArcView geographicinformation system. The methodology is applied to a lower Narmada reach, located between Sardar Sarovar Dam andproposed Garudeshwar weir. Because Garudeshwar weir has been proposed to construct at the downstream of damwhich will create tail storage for running RBPH turbine a thought year. Because of that it will lead to increase waterlevel due to back water flow in flood situation will arise between Garudeshwar weir and SSD. Conventional floodfrequency analysis, involving log-normal, Gumbel’s, and log-Pearson type III (LP3) distributions, was used to calculateextreme flows with different return periods. The peak floods from frequency analysis were input into HEC-RAS model tofind the corresponding flood levels expected along river reaches extending through SSD dam to proposed Garudeshwarweir. Results obtained with HEC-RAS model were used in combination with ArcGIS to prepare floodplain maps fordifferent return periods. Through floodplain maps, areas that are vulnerable to flooding hazards have been identified.

Munjal Patel, Dr. Suvarna Shah, Er. Rajendra Shah, “MAPPING INUNDATION DUE TO MAXIMUM PROBABLE FLOOD USING GIS AND HEC-RAS”, International Journal of Advance Engineering and Research Development (IJAERD), Vol. 4, Issue 14, pp. -, January 2017.