Assessment of Morphology and Soil Erosion Risk in Agrarian Watershed of Jharkhand India Using RUSLE, GIS and MCDA-AHP

Abstract

Water induced surface erosion is one of the major factors for causing land degradation leading to massive food insecurity. Therefore, the estimation of water induced erosion risk becomes important mainly in an agrarian watershed. In this 2021 study, water erosion is holistically assessed using erosion models, while the role of topography was analysed through hydro-geomorphometric parameters. Qualitative erosion analysis is performed using the multi-criteria decision-making Analytical Hierarchical Process (MCDM-AHP) tool, while sediment yield is calculated using the RUSLE model. As the empirical formulas are data driven lack of data for smaller region does not provide quite accurate results hence in this experiment a more holistic approach is taken in addressing the erosion through both qualitative and quantitative approach. The morphometric study using a Geographical information system (GIS) showed that the Jumar watershed has rolling and slightly undulating terrain, with mild slope. The hydrological parameters indicated low infiltration capacity of soil and high surface runoff potential indicated that the watershed is at increasing risk (from low to moderate) of gully formation in the lowlands. The analysis of land use land cover (LULC) revealed a significant rise in urbanization, and barren land. Limited vegetation cover was observed during the summer and winter seasons. The RUSLE model showed about 26% of the total geographic area faced erosion between 100–2500 t/ha/year in the watershed. The MCDM-AHP model showed 27.25% of the total geographic area was under moderate to high susceptibility erosion. Both the models showed aggregable results in comparison to each other. It is suggested to plant cover crops during the fallow period and use of biopolymer mulches for land covering. Use of agricultural waste biochar as organic fertilizer is suggested to control erosion and nutrient pollution. This will also improve crop productivity.