The Contribution of Climate Change and Human Activities to the Sediment Discharge Changes of Xiangxi River Watershed in the Gorges Reservior Region

摘要

Based on the meteorological and hydrological data collected from in Xiangxi River watershed during 1974 -2010, the mutation point of the sediment yield and precipitation were detected with the help of Pettitt test, accumulative anomaly analysis and double mass curve analysis. Meanwhile, the proportion of contribution of climate and human activities to the sediment yield change were researched by the method of slope change ratio of cumulative quantity. The result showed that the sediment yield change altered abruptly in 1978 and 1989, annual precipitation in 1989, respectively; Using the double accumulative curve based on rainfall VS sediment, the whole period was divided into three phases: 1974-1978, 1979-1989 and 1989-2010; The contribution rates of the human intervention were 100% during 1979-1989 and 155.35% during 1990-2010, compared to that during 1974-1978. The contribution rates of the human intervention were 79.11% during 1990-2010 compared to that during 1979-1989. This research indicates the trend of sediment load change and rainfall in Xiangxi River watershed during 1974-2010, and also the contributions of precipitation and human activity. It is not only important to the soil and water conservation and assessment, but also provides theoretical support to the sharp decline of sediment discharge in Three Gorges Reservoir Area.