Mapping and Prioritizing Flash-Flood Susceptible Watersheds in the Warana Basin, India: A Morphometric Analysis and Total Ranking Approach for Resilience Planning

The efficiency of flood management is greatly influenced by the physical characteristics of a river basin. Morphometric Analysis is a prominent method used for quantitatively analyzing a river basin. In this study, 22 parameters were selected, some directly and some inversely related to flash floods, from various aspects such as basic, linear, shape, relief, and hypsometric, for the Warana River basin. We delineated 13 sub-watersheds and employed GIS techniques to directly measure basic parameters from the Digital Elevation Model (DEM), while others were calculated using mathematical formulas. The sub-watersheds of the Warana basin were prioritized using the total rank method. The morphometric analysis revealed that the Warana basin was a sixth-order basin with a total area of approximately 2085 km2, a length of 104.75 km, and a perimeter of 460 km. The mean bifurcation ratio of 1.79 indicates a structurally less-disturbed watershed. However, despite the low structural disturbance, 8 out of the 13 sub-watersheds, accounting for 59.5% of the area, were highly susceptible to flooding, ranging from high to very high susceptibility. The findings of this study can be utilized by relevant authorities to implement appropriate measures for reducing losses caused by flash floods and the development of prevention, protection, and mitigation plans.