Geospatial Assessment of Flash Floods Susceptibility Using El-Shamy’s Approach: A Study of District Khyber, Pakistan

Abstract

The Study area District Khyber is situated in the Khyber Pakhtunkhwa, Pakistan. Flash flooding is a recurring phenomenon in District Khyber, Pakistan and cause widespread damages to life and property in the district. The remotely sensed open-source ASTER GDEM dataset is used for this purpose. The DEM was processed using the Arc Hydro Tool in ArcMap 10.8 environment and three morphometric parameters were derived. Subsequently, El-Shamy's approach was employed to analyze the flash flood susceptibility based on the derived parameters i.e. drainage density (D_d), stream frequency (F_s), and bifurcation ratio (R_b). The flash flood susceptibility was assessed for 15 Sub-Watersheds by Plotting of D_d vs R_b and F_s vs R_b. The D_d vs R_b analysis reveals SW-8 has the highest flash flood susceptibility (FFS). While the remaining fourteen SW-1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, and SW-15 has the moderate FFS. Plotting F_s vs R_b reveals that SW-6, 8 and SW-I2 are highly susceptible while SW-1, 2, 3, 4, 5, 7, 9, 10, 11, 13, 14, and SW-15 are moderately susceptible to flash flooding. The current study is expected to assist the relevant government agencies and the local communities in developing policies for environmental sustainability that effectively mitigate flash flooding.