Identification of soil erosion vulnerable areas in Chandrabhaga river basin: a multi-criteria decision approach

In this present paper on delineation of soil erosion prone areas in a plateau fringe sub basin river Chandrabhaga (length: 26 km and area: 119 sq km), a tributary of Mayurakshi river, drains over lateritic tract of western Birbhum district of West Bengal. Raster based weighted linear combination (WLC) method considering six soil erosion driving parameters have been done in Arc Gis and ERDAS environments. RUSLE is used to quantify the raster based qualitative spatial erosion vulnerable model produced through WLC. This model is also tallied with pegging operation based measurement of surface lowering rates in different soil erosion vulnerable areas for validating the same. Raster based spatial model reveals that out of total basin area, 19.87 % area is extremely prone to soil erosion with a rate of 21.78 Mg/ha/year and total of 51513.86 Mg/year as derived from RUSLE based estimation of soil loss. Estimated weighted average soil erosion rate of this present basin is 9.12 Mg/ha/year. Pegging operation based measurement of surface lowering rate as well as soil loss validates the spatial scaling of soil erosion. Surface lowering rate is 2.5 mm/year in the extremely vulnerable areas followed by and highly vulnerable areas (1.1 mm/year).