You are here:
Using SWAT to Simulate Streamflow and Evaluate Sediment Yield in Xinjiang River Basin
Citation:
Yuan, L., H. Singh, J. Wilhelm, Bart Faulkner, AND Ken Forshay. Using SWAT to Simulate Streamflow and Evaluate Sediment Yield in Xinjiang River Basin. AWRA 2019 Spring Specialty Conference, Omaha, Nebraska, March 23 - 27, 2019.
Impact/Purpose:
It is significant to simulate and predict sediment yield by hydrology model, especially when we research the relationship between a lake and surrounding its watershed. Sediment coming from a watershed flow into a lake, then result in deteriorating water quality and shrinking a capacity of a lake. A calibrated-well hydrology model can relative accurately predict annual sediment yield in a watershed, which help decision maker make a correct plan of a watershed management.
Description:
Soil erosion and lake sediment loading are critical concerns of watershed managers throughout the world. In the Xinjiang River Basin, severe soil erosion results in sediment flows into Poyang lake, causing lake water quality deterioration. In this work the SWAT model was applied to predict streamflow, sediment yield, and identify sediment source area. It was set up with 25 years (1985-2009) weather data series using ArcSWAT 2012. Sensitivity analyses show streamflow simulation is governed by both surface runoff and base flow. The SWAT Calibration Uncertainty Procedure (SWAT-CUP) and Sequential Uncertainty Fitting-2 (SUFI-2) algorithm were applied to conduct calibration, validation, and uncertainty analysis of the model. Monthly and daily streamflow (1985-2009) and monthly sediment data (1985-2001) at Meigang station were used to calibrate and validate the model. The calibration period of streamflow and sediment is 1990-1999; the validation period is 2000-2009 and 2000-2001. The coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS) and root mean square error observation standard deviation ratio (RSR) were used to evaluate model performance. The results show the study area experienced severe soil erosion during 1990-2001 since 99.9% of total land use where sediment yield rate was larger than 5 t/ha/year and suffers from soil loss. Varying annual sediment yield within subbasins from 3 t/ha/year in lowlands to 33 t/ha/year in highlands were from 103 contributing subbasins, with an average rate of 19 t/ha/year. Spatially, highland soil erosion was a more important source of sediment than the lowland soil erosion. Most of sediment yield happened at the south bank highlands of the Xinjiang main river channel. Based on the results of this modeling exercise, focus should be given to orchards and barren lands because these land use classifications tend to be disproportionately large contributors to sediment loads. It is necessary to improve land use management in lowlands while practicing soil conservation methods in highlands, and change inappropriate tillage practices on the areas with >25° slope that are main sediment sources to decrease sediment loading. This study has potential for others watershed with hydrological and geographical characteristics similar to the Xinjiang River Basin.