Environmental Advances (Jul 2021)
Geospatial modelling of soil erosion and risk assessment in Indian Himalayan region—A study of Uttarakhand state
Abstract
Soil erosion is the major cause of land degradation, which has become a worldwide environmental problem that degrades soil productivity and water quality. Assessing soil erosion in hilly and mountainous terrain always pose a great challenge to researchers and policy makers due to the inaccessible terrain as well as the scarcity of detailed information of soil erosion factors. The study was carried out to estimate the average annual soil erosion and risk area in the Uttarakhand State of Indian Himalayan region using various high-resolution geospatial data layers such as Global rainfall erosivity database, SOILGRIDS, CartoDEM as well as LULC data by employing Revised universal soil loss equation (RUSLE) model in a GIS environment. These data layers provided spatially distributed reliable information of erosion factors. The average annual soil erosion rate was estimated as 27.45 t ha−1 yr−1, totaling to an amount of 119Mt yr−1 as potential soil loss from the state. Among the various physiographic regions, total soil loss amounts were estimated to be 2.94, 5.08, 5.35, 7.48, 15.55 and 82.88 Mt yr−1 from Tarai, Trans Himalaya, Bhabhar (foothills), Shivalik, Greater Himalaya and Middle Himalaya respectively. Mean erosion rates estimated for major river basins were found to be 14.64, 22.22, 31.23, 33.24, 36.86 and 38.00 t ha−1yr−1 for Ramganga, Ganga, Alaknanda, Kali, Bhagirathi and Yamuna basins respectively. Among the different slope classes, very steep slopes (>60%) showed the highest mean soil loss rates of 40.11 t ha−1yr−1 amounting to total soil loss of 50.28Mt yr−1. Study revealed that 20.34% of the area is classified as very severe erosion class (>40 t ha−1 yr−1). Vital information regarding regional assessment of soil erosion rate and risk area in the State highlighted the need for policy makers and planners in devising various strategies aimed at conservation and sustainable use of land resources.
