Runoff simulation and attribution analysis under the comprehensive influences of climate, land use, check-dams and coal mining in the Sanchuan River Basin of the Loess Plateau China

In the context of global climate change, runoff simulation accuracy is greatly affected by various human activities and must be enhanced. In this study, we divide different periods according to the influence of human activities, add check-dams to the Soil and Water Assessment Tool (SWAT) model in the form of reservoirs and ponds, and construct a SWAT-MODFLOW model to consider the impacts of coal mining. Eventually, the SWAT model of the historical baseline period (HBP) and SWAT-MODFLOW model of the comprehensive impact period (CIP) were constructed, and an attribution analysis based on different scenarios was conducted to elucidate the influences of climate and various human activities on changes in runoff. The results showed that: (1) The SWAT model had good accuracy during HBP, which indicated good performance under relatively natural conditions. (2) The SWAT-MODFLOW model used during the CIP comprehensively considered the influences of climate, land use, check-dams, and coal mining. The simulation results verified the efficiency of the proposed method via consideration of the influences of check-dams and coal mining on runoff. (3) Six simulation scenarios were set up for attribution analysis. Climate and human activity were found to positively and negatively affect runoff, respectively. Human activities were the predominant drivers, accounting for 54.0%. Among these, coal mining and check-dam construction accounted for a large proportion of 39.76%. The results of this study emphasise the impacts of coal mining and check-dam construction on the hydrological cycle of the Loess Plateau and provide a theoretical basis for water resource management.