Estimation of soil erosion using revised universal soil loss equation in upper Umiew catchment, East Khasi hills, Meghalaya

Abstract

This study has attempted to estimate soil erosion for four years (2011-2014) in the upper Umiew catchment located in the Central Highland of Shillong plateau by using the Revised Universal Soil Loss Equation (RUSLE) modelled in a GIS environment. The rainfall erosivity factor was calculated seasonally. The slope length factor was obtained from a DEM of 20×20 m pixel size based on the contours of two toposheets of Survey of India at the scale of 1:50,000. The cover management factor that depends on the land use (LU) / land cover (LC) was obtained from Landsat-ETM of 30 m resolution of United States Geological Survey. The soil erodibility factor ranged between <.02 to >.06 t h MJ-1mm-1. The value of conservation practice factor was set at 1 as there were no conservation practices. Further, the results showed that during monsoon the average soil loss falling under the category of high to very severe soil loss (20 to >80 t ha-1) accounted for a total area coverage of about 73.42%. The study also revealed the potential ability of rain-water to erode the undulating landscape that covers about 61.25% of the total area which is mainly associated with forest degradation, agricultural land use and quarrying activities.