Impact of Morphometric Parameters on Flood Susceptibility in the Teesta River Basin, West Bengal

Flooding is one of the most recurrent natural hazards affecting the Teesta River Basin in West Bengal, causing extensive damage to life, property, and infrastructure. The present study examines the impact of morphometric parameters on flood susceptibility within the Teesta River Basin using geospatial techniques. Morphometric characteristics such as drainage density, stream frequency, bifurcation ratio, basin relief, elongation ratio, and form factor play a crucial role in controlling runoff behaviour and flood generation. Using digital elevation models (DEM) and GIS-based spatial analysis, the basin was delineated into sub-watersheds, and linear, areal, and relief morphometric parameters were computed. These parameters were integrated to assess flood susceptibility across different sub-basins. The results indicate that sub-watersheds characterized by high drainage density, high stream frequency, low elongation ratio, and steep relief exhibit greater flood susceptibility. The lower reaches of the Teesta River Basin in West Bengal are particularly vulnerable due to combined effects of morphometry, monsoonal rainfall, and anthropogenic interventions. This study highlights the significance of morphometric analysis as a cost-effective and reliable tool for flood risk assessment and watershed-level planning. The findings can assist planners and policymakers in formulating flood mitigation strategies and sustainable river basin management plans.