Flood Modelling of Krishna River at Sangli Using HEC-RAS

Abstract

A flood occurs when water overflows and submerges ordinarily dry terrain. When the flow rate of a river exceeds the capacity of the river channel, particularly near bends or meanders, flooding can occur. As a result, settlements are destroyed, human lives are harmed, and infrastructure and public services are lost. It is necessary to model flood plains in order to determine the flood plain and its extent in advance of taking adequate flood mitigation measures. Decision makers can make better decisions about how to effectively deploy resources to prepare for catastrophes and improve the quality of life by assessing the degree of floods and floodwater inundation. The software created models from the HEC-RAS simulations are extremely useful in a variety of ways, including determining the extent of floods, associating high flood levels with the design and planning of hydraulic structures, and generating flood plain maps that can be used in town planning or estimating the approximate amount of damages. The objective of this study was to map flood inundation areas along the Krishna River. Using the HEC-RAS model, ArcGIS for spatial data processing, and Ras mapper for creating geometry, the flooded areas along the Krishna River were mapped based on peak flows for different return periods. The lands around the Krishna River were simulated to be inundated and results from modelling showed that 7.1 km2, 8.22 km2, 9.2 km2 area is inundated for return period of 25-, 50-, 100-year, respectively. Proper land use management and tree plantations are crucial in reducing the negative effects of floods, especially in low-lying flood-prone areas. The findings of this study will assist the responsible agencies in developing plans based on flood plain mapping and hazard levels in the area.