Evolution of the precipitation–stream runoff relationship in different precipitation scenarios in the Yellow River Basin

Environmental change can lead to differences in the magnitude of change for the precipitation and stream runoff, which in turn affects the precipitation–stream runoff relationship. However, little is known about the evolution of this relationship at present. Here, a systematic framework is proposed to identify the stream runoff responses to graded precipitations under the changing hydrological cycle process over time based on the changes in runoff coefficients across the Yellow River Basin (YRB). From this, the variations in precipitation and stream runoff from control areas of eight main hydrometric stations on the main stream are analyzed. Then, fluctuations in the runoff coefficients among them to reflect the evolution of precipitation–stream runoff relationship are compared in five precipitation scenarios. Results indicated the unsynchronized evolution of precipitation and stream runoff has changed the stream runoff response to graded precipitation, and the corresponding runoff coefficient decreased by 0.003 to 0.110, thus proving the influence of changing environment on the runoff generation and concentration is intensified. Generally, this study can effectively improve the understanding on the relationship between precipitation and stream runoff in a changing environment and thus have implications for the water resource management in the YRB.