SPATIAL DISTRIBUTION OF SOIL EROSION USING GIS- BASED RUSLE MODELLING

Abstract

Soil erosion is a major environmental problem that leads to land degradation, loss of soil fertility, reduced agricultural productivity and deterioration of water resources. Accurate assessment of soil erosion is essential for sustainable watershed management and the implementation of effective conservation measures. This study evaluates the spatial distribution of soil erosion in the Kalpathy Puzha sub-basin of the Bharathapuzha River Basin, Kerala, using the Revised Universal Soil Loss Equation (RUSLE) integrated with Geographic Information System (GIS) and Remote Sensing (RS) techniques. The RUSLE model estimates average annual soil loss by integrating five factors: rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C) and conservation practice (P). Spatial data sets including Digital Elevation Model (DEM), rainfall data, soil maps and land use/land cover information were processed in a GIS environment to generate individual factor maps and estimate soil erosion across the study area. The estimated annual soil loss ranged from 0 to 28.99 t ha⁻¹ yr⁻¹, indicating considerable spatial variation in erosion intensity. Most parts of the basin were classified under low to moderate erosion risk, while high erosion was concentrated in the northern and north-eastern regions, mainly due to steep slopes, higher runoff potential and sparse vegetation cover. The study highlights the significant influence of topography and vegetation on soil erosion and identifies erosion-prone areas requiring priority conservation measures. The integration of RUSLE with GIS proved to be an effective and reliable approach for soil erosion assessment and mapping. The results provide valuable information for watershed planning and support the implementation of suitable soil and water conservation practices to promote sustainable land and water resource management in the Kalpathy Puzha sub-basin.