Assessing the influence of watershed characteristics on the flood vulnerability of Jhelum basin in Kashmir Himalaya

Abstract

In Himalayan region, it is very important to generate detailed terrain information for identifying the causes of natural hazards such as debris flows, debris floods, and flash floods, so that appropriate corrective measures are initiated for reducing the risk of the people and property to these disasters. Basic watershed morphometrics coupled with the land-cover and slope information are useful for assessing the hazard vulnerability. The terrain characteristics govern the surface hydrology and have profound influence on the incidence and magnitude of natural hazards, particularly floods. The present work is a comparative study of two watersheds of Jhelum basin (upper Indus basin in Kashmir). In this research, we make an integrated use of the Linear Imaging Self-Scanner satellite data and Advanced Spaceborne Thermal Emission and Reflection Radiometer digital elevation model, supported with extensive field information, in a GIS environment for assessing the surface hydrological behavior of Lidder and Rembiara watersheds of the Jhelum basin. Knowledge-driven modelling approach has been used to evaluate the runoff potential of the watersheds to assess the flood vulnerability downstream. The results revealed that Lidder watershed exhibits lesser basin lag time compared to Rembiara watershed for a storm event. Further, due to higher population density in the Lidder downstream, this watershed is also socially more vulnerable to flooding than Rembiara. The methodology and results of this study shall help in formulating better flood mitigation strategies in this part of the Himalayan region, where the observation network of hydrometeorological and other land surface parameters is either missing or very scanty.