Soil Erosion Assessment and Its Effect on Sustainability for a Mountainous Watershed using Remote Sensing and GIS

Abstract

Soil erosion is an important social and economic problem, and an essential factor in assessing health and function of ecosystem. Soil-erosion control requires a quantitative evaluation of potential soil erosion on a specific location. The revised universal soil loss equation (RUSLE), remote sensing, and GIS were used to model the soil-erosion intensity for soil conservation and vegetative rehabilitation in an Uttarakhand watershed, which is located 45 km north of Dehradun, a city in India. Data used in this study to generate the potential soil loss were: IRS satellite image, digitized elevation model (DEM), soil erodibility, rainfall erosivity, and inventory data. The linear spectral unmixing-analysis (LSMA) method was used for fraction vegetation cover. With this, cover management factor (C factor) has been created. Five raster maps such as soil erodibility, rainfall erosivity, slope length and steepness, cover management factor and conservation management practice factor have been created for soil erosion potential. The result can be beneficial to erosion-control measures, monitoring ecological restoration in the degraded mountainous watershed. The study shows the average soil loss in the entire watershed has been estimated as 19.201 Mg ha⁻¹ year⁻¹ with < 36.30 Mg ha⁻¹ year⁻¹ in the paddy cultivated areas and > 43.82 Mg ha⁻¹ year⁻¹ in some of the denuded mountainous areas (barren land/exposed rocks). The denuded slopes that are devoid of forest cover are predicted as the high potential area of soil erosion. The well-stocked forests on the same slopes show lower potential for soil loss due to dense forest cover, i.e., broad leaf. The spatial information of the potential soil loss in the study area would provide crucial inputs to the planners and resource manager for taking informed decisions and help in developing conservation plan for the watershed.

Keywords: soil erosion, RUSLE, DEM, LSMA, soil loss