Quantitative evaluation of the impact of climate change and human activities on Jialing river runoff changes in the past 60 years, China

Abstract

Abstract Runoff is one of the key driving forces of watershed hydrological cycle processes. Quantifying the relative impacts of climate change and human activities on runoff change is critical to clarify the mechanisms of watershed hydrological responses. This study analyses the characteristics of hydrological changes in the Jialing River Basin based on observational data from 1957 to 2017. The degree of runoff change was then quantified with the aid of Indicators of hydrologic alterations and Range of variability approach (IHA-RVA) method. By establishing the Budyko model and comparing the Slope change ratio of accumulative quantity (SCRAQ), the influencing factors of runoff change are quantified. The result: (1) Except for Qu River Basin, the average annual runoff of other basins showed a significant downward trend. 1985 was chosen as the abrupt change year. (2) The overall flow alteration in the basin is 50.87%, which is close to the height change. (3) The effects of climate change and human activities on runoff have some spatial variation. Human activities are the main influence factors, of which the contribution rates to the Fu River Basin, the mainstream of Jialing River, Bailong River Basin, and Qu River Basin are 64.57, 66.31, and 74.17% respectively.