The temporal variations in runoff-generation parameters of the Xinanjiang model due to human activities: A case study in the upper Yangtze River Basin, China

Study region: Upper Yangtze River Basin, China. Study focus: The intensification of climate change and human activities leads to non-stationarity of hydrological processes. Previous studies mainly focus on monthly hydrological or Budyko models. However, it is a challenge that catchment hydrological responses to human activities for daily hydrological models. This study aims to evaluate anthropogenic impacts on water yield of the upper Yangtze River Basin by representing the Xinanjiang model parameters as functions of socio-economic factors. New hydrological insights: The hydrological parameters WM (soil water storage capacity) and KE (ratio of potential evaporation to pan evaporation) increased in 1976–2000, while the parameter B (non-homogeneity of the soil water storage capacity) declined. It is further demonstrated that the population and the drainage area of reservoirs have the greatest impact on B and WM, respectively. Their linear functional form is validated to be effective for improving streamflow simulation. These findings can help understand the non-stationarity of the rainfall-runoff relationship due to increasing human development and contribute to adaptive development strategies for future water resource management.