Analysis of changes and trend of water and sediment load at Huayuankou station on Yellow River

The Huayuankou station is the most important hydrological monitoring station on the Lower Yellow River.Its response is very sensitive to the changes on the underlying surface of the upper and middle reaches of the Yellow River.Therefore,through analyzing the changing characteristics of water and sediment load at Huayuankou station the profound changes in the Yellow River Basin induced by long-term natural and human activities can be revealed to some extents.The runoff and sediment data at Huayuankou station during 1953-2002 are used to analyze the changing characteristics,future trend of water and sediment load,and evolution of water and sediment load relationship in different times in the past nearly 60 years by quantitative analysis methods.The results show that the runoff and sediment load at Huayuankou station showed significantly decreasing tendency,and will further decline in the predictable future.The runoff and sediment load appeared four change periods and had the similar rich-poor variation characteristics.The evolution of runoff and sediment load relationship could be divided into four periods in which the turning years were 1960,1980 and 1999,respectively.The response level of sediment load to runoff became weaken gradually,and the human-induced land surface changes had growing impacts.