One Dimensional Floodplain Modelling Using Soft Computational Techniques in HEC-RAS - A Case Study on Purna Basin, Navsari District

Abstract

The objective of the research is to use one-dimensional floodplain modeling capabilities of RAS-mapper tools in hydrologic engineering centers River analysis system (HEC-RAS) for floodplain mapping in a downstream side of Purna river without the use of Arc-GIS software. Research demonstrates the utilities of latest version of HEC-RAS 5.0.6, in which high-resolution Digital Elevation Model (DEM) and projection file were used as an input parameter in HEC-RAS as terrain data and peak discharge data of the river, normal slope at downstream side of Purna basin was used for steady flow analysis in this research study area. In the present research, river geometries like river centerline, bank line, flow path line, and cross-section are created in RAS-mapper tools, present in HEC-RAS, which were used to be done in Arc-GIS previously and exported to HEC-RAS for model execution. So, it is a great advantage, that model execution and flood plain mapping can be done simultaneously in HEC-RAS by using computational techniques. The velocity of water, Depth of water and water surface elevation can be found using one-dimensional hydrodynamic unsteady flow analysis. The results from the research investigation could be used by flood management authorities to quantify the flood at different cross-sections.