Quantitative analysis of the effects of climate change and human activities on the runoff in the Shiyang River Basin

Linear regression, inverse distance weighting analyses, and Budyko’s hypothesis were applied to the Shiyang River Basin. The spatial and temporal characteristics of runoff from the main stream and tributaries in the Shiyang River Basin from 1959 to 2017 were analyzed. Furthermore, the contributions of climate change and human activities to runoff in the Shiyang River Basin were quantitatively resolved. The annual runoff showed a decreasing trend (0.06 × 108 m³/10a), with a spatial distribution pattern decreasing from southwest to northeast. Runoff in the Shiyang River Basin accelerated significantly after 1990, and the growth rate was most significant in the main stem. In addition, precipitation and potential evapotranspiration increased at a rate of 7.44 and 8.46 mm/10a, respectively. The areas of farmland and urban land increased to different degrees, whereas the areas of the remaining land types decreased. The construction of hydropower stations was concentrated in the period 2004–2011. Finally, the contributions of climate change and human activity to runoff in the upper reaches were 81.17 and 18.83%, and the main factor of runoff change is climate change. The contributions of climate change and human activity to runoff in the middle and lower reaches were 15.83 and 84.17%, respectively. The main factor affecting runoff change was human activity. Climate change and human activity are the main factors affecting runoff from inland river basins in arid regions. The results provide parameter support for quantifying the impacts of climate change and human activities on inland river basin runoff and for modeling. The findings also provide a scientific basis for the rational allocation, planning, and management of water resources and the sustainable development of arid inland river basins.