IMPACTS OF CLIMATE CHANGE AND HUMAN ACTIVITY ON SEDIMENT DISCHARGE IN THE MIDDLE REACH OF THE YELLOW RIVER

Based on the hydrological study and correlation analysis, yearly/monthly datasets of precipitation, water discharge and sediment load from the main gauging stations of the Yellow River during the period of 1951-2011 are collected. Data suggests that the sediment load during the flood seasons (May to October) of the four phases of 1951-1968, 1969-1986, 1987-1999 and 2000-2011 is 88.46%, 88.79%, 90.41%, 95.94% respectively. And a statistical model denoting the relationship between precipitation and sediment load is built for the base phase and the first phase. According to the estimation of the model, the contribution of anthropogenic activities to the sediment load increases with time. During the latest period (2000-2011), the sediment load was basically contributed by human activities (e. g., the Xiaolangdi Reservoir), and the contribution of climate change (especially the rainfall) was less than 1%. It designates that the Yellow River drainage system has been severely reversed in the past 61 years. Now the sediment budget of the Yellow River is mainly controlled by human activities instead of the nature and it will bring great impact onto the development of the Yellow River delta.