Abstract:In order to explore the effects of human activities and climate changes on the runoff and sediment yield in the Yellow River, a typical watershed in the middle reaches of the Yellow River——Xinshui River watershed, was selected as the research area to analyze the annual variation of hydrometeorological factors from 1958 to 2015. The Mann-Kendall test and Pettitt test were used to analyze the trend and mutation of runoff, sediment discharge and sediment concentration. In addition, double cumulative curve method, regression analysis method and elastic coefficient method were used to evaluate the attribution of runoff and sediment yield. Results show that: (1) The annual average runoff, sediment discharge and sediment concentration were 32.0 mm, 1 289.1 t/km2 and 33.7 kg/m3, respectively. They all exhibited a significant decreasing trend on the annual scale. The results of mutation test showed that the abrupt change in annual runoff, sediment discharge and sediment concentration all occurred in 1980. (2) Before 2002, the relationship between annual runoff and sediment yield showed a good linear relationship. However, the correlation between annual runoff and sediment yield was significantly weakened during 2003—2015, which was difficult to be represented by a definite regression equation. The main reason was that the implementation of soil and water conservation engineering measures, especially the construction of check-dam, weakened the runoff-sediment relationship. (3) The results of double cumulative curve method, regression analysis method and elastic coefficient method were relatively close. Human activities were the main driving factors of runoff and sediment variations in the Xinshui River watershed. The traditional empirical statistical method does have certain reliability and applicability. This study can provide scientific basis for ecological restoration and regulation of runoff and sediment in the Yellow River watershed.