Climate Change Effect on Streamflow and Sediment Yield for Watershed Prioritization and Identification of Best Management Practices in a River Basin

Abstract

newlineThe study was undertaken to prioritize sub-catchments for implementing best newlinemanagement practices under present and future climate scenarios. Streamflow and newlinesediment yield simulations for sub-catchment prioritization were conducted based on newlinecurrent and future scenarios using SWAT model. For that SWAT model was calibrated newlineand validated using stream discharge and sediment yield data from 2000 to 2016 and newline2017 to 2020. Model performance was evaluated using NSE, R2, and PBIAS values. The newlineMann-Kendall test was used to identify trends in historical climatic variables. The study newlineanalyzed mid-century (2021-2060) and end-century (2061-2099) rainfall and temperature newlineunder two climate change representative concentration pathways (RCPs), RCP 4.5 and newlineRCP 8.5. The trend analysis of maximum and minimum temperatures indicates a newlinesignificant increasing trend observed in all seasons. In terms of precipitation, a newlinedecreasing trend was observed in all seasons except for the post-monsoon season. The newlineresults suggest that the analysis of minimum and maximum temperatures predicts a newlinefuture increase, with peaks of 4.1°C and 3.8°C under the RCP 8.5 scenario, respectively. newlineAdditionally, annual rainfall is projected to increase significantly from the baseline newlineperiod, with a 33.3% rise observed by the end of the century under the RCP8.5 scenario. newlineCalibration and validation of the SWAT model simulated streamflow and sediment yield newlinesatisfactory results with NSE, R2, and PBIAS values of 0.91, 0.86, -2.4 and 0.7, 0.52, - newline5.2 for the calibration period and 0.72, 0.6, -3.2 and 0.49, 0.7, -4.2 for the validation newlineperiod, respectively. The SWAT model predictions indicated that average annual newlinestreamflow and sediment yield will increase significantly under both RCP scenarios with newlinehighest rates of 73.5% and 36.5% during end-century under the RCP8.5 scenario. newlineFurthermore, the study revealed that the average annual sediment yield of the basin newlineduring the baseline period was 4.1t/ha/yr, which is expected to increase to 4.3t/ha/yr, newline5.2t/ha/yr, 4.4t/