Impact of changes in land use and climate on the runoff based on SWAT model in Dawen River Basin, China

Abstract

A distributed hydrological model (SWAT), which is widely used both domestically and internationally, was selected to quantitatively analyze the impact of land use and climate change on runoff in this paper in Dawen River Basin, China. The calibration and validation results obtained at Daicunba and Laiwu hydrological stations yield R2 values of 0.83 and 0.80 and 0.73 and 0.69 and the Ens values of 0.79 and 0.76 and 0.71 and 0.72, respectively. Taking 1980-1990 as the reference period, the annual runoff increased by 288 million m3, which was caused by changes in the land use of basin from 1991 to 2004, whereas the annual runoff decreased by 132 million m3 due to climate change. Land use changed from 2005 to 2015, which resulted in an increase in annual runoff of 13 million m3, and annual changes in climate caused a decrease in annual runoff of 61 million m3. An extreme land use scenario simulation analysis shows that, compared to the current land use simulation in 2000, the runoff of cultivated land scenarios and forest land scenarios was reduced by 38.3% and 19.8%, respectively, and the runoff of grassland scenarios increased by 4.3%. Climate change simulation analysis revealed that there was a positive correlation between runoff changes and precipitation changes in the river basin. The annual total runoff in the basin decreases with rising temperatures and decreases with decreasing temperatures, which showed that the impact of precipitation variability was stronger than that of change in air temperature.