Title : Current and future soil loss under changing climate and land use in the lake tana basin
Soil erosion in the Lake Tana basin poses a critical economic and environmental crisis due to its impacts of agriculture productivity, food security and reservoir sedimentations. This study assessed soil erosion hazards considering change of land use climate change in the basin. Simulation of land use change was carried out by applying CA_Markov chain model while climate was downscaling using statistical techniques from CanESM2 model. Thus, effects of changing climate, changing land use and, combined changing climate and land use on loss of soil was assessed. The revised universal soil loss equation (RUSLE) was integrated with a geographic information system and remote sensing. To quantify soil loss, six RUSLE model parameters were used: rainfall erosivity (R), soil erodibility (K), topography (LS), cover and management (C), support and conservation practices (P). The average loss of soil annually in the basin is projected to be 7.9, 7.8 and 8.2 tons per hectare per year under changing land use, combined changing of land use and climate, and changing of climate, respectively. Furthermore, by the end of 21st century loss of soil in the basin tends to increase by 10.8%, 3.4% and 2.2% by considering changing land use, combined changing of land use and climate, and changing of climate, respectively. Accordingly, the effects of climate change on soil erosion are greater than the combined effects of climate change and land use. Consequently. integration of RUSLE model with spatial data and analysis techniques was effective to project soil loss in the basin. Furthermore, future watershed management in basin should considered climate change in addition to land degradation for effective conservation practices.