Morphometry-Based Subwatershed Prioritization for Flood Potentiality Analysis of the Gumani River Basin (India) Using TOPSIS

Abstract

AbstractFlood is an extreme environmental threat amongst the natural hazards that affects the livelihood of millions of people across the world, especially in the flood plains and deltas. The conservation measures should be implemented to prevent the unlikely loss based on the physical, socio-economic, and cultural characteristics of a region. The present paper aims to analyze the morphometric parameters, and therefore, to find out the prioritization of the sub-watersheds of the Gumani River Basin (GRB) to induce flood hazards in the study area. The study area having an area of ~1307 km2 is divided into 34 sub-watersheds. The Shuttle Radar Topographic Mission (SRTM) Digital Elevation Model (DEM) (30 m) and Survey of India (SoI) topographical maps (1:50,000) have been used to delineate the sub-watersheds and assess the morphometric parameters. The two linear (stream order and mean bifurcation ratio), seven areal (form factor, elongation ratio, circularity index, drainage texture, stream frequency, drainage density, and compactness coefficient), and five relief (basin relief, relief ratio, ruggedness number, slope, and hypsometric integral) aspects have been measured in this study. The relative weights of the sub-watersheds have been calculated using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) which ranks the alternative based on the closest distance to the ideal solution and the farthest distance to the negative ideal solution. The produced performance score of the sub-watersheds has been categorized into five classes such as very low (0.36–0.39), low (0.39–0.44), moderate (0.44–0.49), high (0.49–0.55), and very high (0.55–0.73). The very low class includes the five sub-basins, while the very high class consists of the three sub-basins. The low priority class is confined to the twelve sub-basins, while the high class encompasses the five sub-basins. The medium class includes the ten sub-basins of GRB. The present study would address the micro-level planning and development activity of the study area.KeywordsMicro-level planningSub-watershedsFlood hazardsRelative weightsBasin morphometry