Prioritization of sub-watersheds for soil erosion based on morphometric attributes using fuzzy AHP and compound factor in Jainti River basin, Jharkhand, Eastern India

Abstract

Land degradation in the fringe extents of Chotanagpur plateau causes extensive harms to the land and agricultural productivity thereby human sustainability which magnets special provisions. So, this study intends to trace the erodibility nature in sub-basin scale to allocate the sub-watersheds that are very sensitive to soil erosion. Fourteen morphometric attributes which highly related to erosion processes is considered to prioritise the watersheds through the application of fuzzy inference-based analytical hierarchical process and compound factor (CF). A digital elevation model of 30 m spatial resolution along with Survey of India topographical maps and Google earth imagery are considered for extraction of basic, areal, landscape and shape morphometric attributes. Morphometric indices are converted into the unitless 8-bit data format (0–255), and priority weights are assigned to the specified range of control points in fuzzy AHP while consecutive ranks are assigned to indices based on their association with erosion process to get the CF values for each of watershed. The results of prioritisation through both approaches show a quite alike output that is both identifies sub-watershed 6 and 13 as very high erosion prone and CF classifies sub-watershed 4 and 8 as high erosion prone while fuzzy AHP recognises sub-watershed 4, 8, 5, 11, 14 under high-risk category. Therefore, both the results display good efficiency of morphometric indices in the assessment of erodibility priority in sub-basin scale.