Identification of the most important parameters influencing flood occurrence and flooding priority in Kakareza watershed using Shannon entropy and TOPSIS method

Flood is one of the natural disasters that causes various property and life damages worldwide every year. The main purpose of the present study was to identify the sub-basins with the most potential for flooding and to prioritize them for flood control measures in Kakareza watershed in Lorestan province, and to determine the most effective factors in flood generation using Shannon and TOPSIS entropy techniques, and also watershed morphometric analysis in the framework of GIS. For this purpose, in this study, 15 effective parameters including precipitation, daily maximum precipitation, curve number, drainage density, slope, stream frequency, stream retention constant, drainage texture, relief number, circularity coefficient, compaction coefficient, relief ratio, form factor, elongation coefficient was used. Shannon entropy method was used to determine the weight of the parameters. The results of the parameters weighting showed that Annual average precipitation factor, maximum daily precipitation, curve number, and compression coefficient had the highest effect on flooding of Kakareza watershed. While the lowest weights were related to the Concentration time, form factor, drainage texture and roughness ratio parameters. Moreover, the TOPSIS decision making method was used to prioritize 23 sub-basins of Kakareza watershed. The results showed that sub-basin O in the first rank (0.91), sub-basin M (0.89) in the second and sub-basin Q (0.85) in the third rank had the highest flood potential. So, these sub-basins have the highest priority for conservation measures, while sub-basins B and W had the least flood potential.