Title: Probabilistic flood risk assessment using coupled hydrologic and 2D-hydraulic model in the Jhelum River, Northwest Himalayas

Authors: Saika Manzoor; Manzoor Ahmad Ahanger

Addresses: Department of Civil Engineering, National Institute of Technology, Srinagar, India ' Department of Civil Engineering, National Institute of Technology, Srinagar, India

Abstract: Keeping in mind the susceptibility to flooding-related disasters in the past, the need was identified for flood risk assessment using recent modelling techniques in the data-scarce River Jhelum, India. This study conducted a preliminary rainfall frequency analysis to find the best fit statistical model for calculating peak flow rates for multiple return periods. A framework was followed for the spatio-temporal delineation of flood-prone areas by integrating the watershed modelling system (WMS), Hydrologic Engineering Center-Hydrologic Modelling system (HEC-HMS), and two-dimensional Hydrologic Engineering Center-River Analysis System (2-D HEC-RAS) for different return period design floods. The 2-D unsteady state flood modelling in HEC-RAS showed the river overflowing its flow path for all the return periods, with 55% of the Srinagar city inundated in the 100-year event. The simulated flood depths and velocity maps for every design flood scenario are shown. The 2-D simulations yielded encouraging results compared to the most recent flood event.

Keywords: hydrologic modelling; 2D hydraulic modelling; floodplain delineation; 2D HEC-RAS; River Jhelum.

DOI: 10.1504/IJHST.2024.135133

International Journal of Hydrology Science and Technology, 2024 Vol.17 No.1, pp.46 - 74

Received: 25 Apr 2022
Accepted: 01 Aug 2022
Published online: 01 Dec 2023 *