Attribution of runoff and hydrological drought changes in an ecologically vulnerable basin in semi‐arid regions of China

Abstract

AbstractClimate change and human activities have been widely recognized as two major factors that deeply influence hydrological processes. Evaluating and identifying the contribution between different drivers contributes to better regional water management regulation. In this study, we used the variable infiltration capacity (VIC) model to quantify the contributions of different climatic variables and human activities to runoff in the Hunhe basin, which has a semiarid climate, in northern China. Through trend analysis, the study period is divided into the ‘baseline period’ (1982–1999) and the ‘change period’ (2000–2020). The results indicated that compared with climate change, human activities were the major factors decreasing runoff, contributing more than 86.3% to the runoff reduction in the change period. Climate change increased winter runoff but decreased summer and autumn runoff, resulting in an overall decrease in runoff. There is a trend of increasing severity of hydrological drought in the Hunhe basin, where climate change accounted for 28.2% of the total impact and human activities accounted for 72.8%. The change in runoff and hydrological drought was mainly due to human activities, including changing farmland to grassland and forest. These results would be helpful for policy‐makers and researchers to better understand the responses of runoff and hydrological drought to these changing environmental conditions and offering references for future water resource planning and management at the basin scale.