Geo-hydrological analysis and sub watershed prioritization for flash flood risk using weighted sum model and Snyder's synthetic unit hydrograph

摘要

The present study demonstrates the usefulness of remote sensing data for analyzing the flash flood risk in Uhl River watershed situated in the western Lesser Himalayan region. This is one of the most vulnerable flash flood watersheds in Himachal Pradesh which, suffers heavy damages to man-made features almost every year. In this study different morphometric properties that direct the hydrological response and pertinent to flash flood risk of the watershed have been used to prioritize the sub-watersheds using weighted sum analysis (WSA) model. The result indicates that 12.83 and 16.94 percent of the total area come under very high and high flash flood risk respectively. In addition, the Snyder's synthetic unit hydrograph method was employed to assess the hydrological behavior and prioritization of sub-basins which shows that sub-basins falling under very high and high-risk group have low lag time and high peak discharge per unit of watershed area. This study concludes Watershed 7 and 8 of Uhl River basin in Himachal Pradesh comes under high priority class and is vulnerable to flash floods.