Application of InVEST SDR model to assess soil erosion and sediment export: A case study from Deduru Oya River Basin, Sri Lanka Abeysingha N.S.1,*, Muthunayaka C. H.2, Nirmanee K. G. S.3, Amarasekara M. G. T. S.4, Ray L.5 1Professor, Faculty of Agriculture, Rajarata University of Sri Lanka, Puliyankulama, Anuradhapura 2U.G. Student, Faculty of Agriculture, Rajarata University of Sri Lanka, Puliyankulama, Anuradhapura 3Lecturer, Faculty of Agriculture, Rajarata University of Sri Lanka, Puliyankulama, Anuradhapura 4Professor, Faculty of Agriculture, Rajarata University of Sri Lanka, Puliyankulama, Anuradhapura 5Professor, College of Agriculture, Food and Natural Resources, Prairie View A&M University, Prairie View, TX, USA *Corresponding author e-mail address: nabeysingha@gmail.com, nsabey@agri.rjt.ac.lk
Online Published on 20 January, 2024. Abstract Quantification of soil loss and sediment load is an essential step to prioritise erosion prone areas for watershed management. Soil erosion in the Deduru Oya River basin in Sri Lanka was assessed using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) Sediment Delivery Ratio (SDR) model. The InVEST-SDR model uses the Revised Universal Soil Loss Equation (RUSLE) embedded in it to compute soil loss and sediment yield. This study used a 30 m x 30 m Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) digital elevation model (DEM), 20-year rainfall data measured at six rain gauge stations across the basin; land use - land cover and soil maps of the basin data as input to the model. The average annual soil loss in Deduru Oya River basin varied from 0 to 277.25 t.ha-1. yr-1. About 5.6% of the basin (145.9 km2 area) was identified as having high rate of soil erosion (> 12 t.ha-1.yr-1), and those areas were mainly found at the upstream of the river basin. The mean annual sediment export from the Deduru Oya basin was estimated to be 0.18 t.ha-1. yr-1, while Kiribathgalla and Bambaragahakanda areas showed highest (>18 t.ha-1. yr-1) sediment export values. The result of this study would be helpful for basin managers to prioritise soil erosion prone areas and planning watershed management interventions in the Deduru Oya River basin. Top Keywords Deduru Oya basin Sri Lanka, InVEST SDR model, Soil erosion. Top |