| Abstract: | The Three Gorges Project is one of the largest hydro-projects in the world and has drawn many debates inside China and abroad.The major concern is that sediment load from the river basin may eventually fail the functions of the project for flood control and power generation.To reduce sedimentation in the reservoir,watershed management has been adopted.However,there is limited information regarding the effectiveness of various control measures such as terracing and afforestation on a watershed scale.The Jialing River,a main tributary of the Yangtze River,contributes approximately 25% of the total sediment load in the main river but only represents 8% of the whole basin area.There have been various land use patterns and extensive human activities for thousands of years in the Jialing River watershed.Based on analysis of the major factors affecting erosion in the Jialing River watershed,the main watershed management strategies (afforestation,farming and engineering practice) are illustrated,and their effects on the reduction of sediment and runoff are studied in detail.The sediment budget of the watershed shows that 1/3 of the sediment yield is trapped by the erosion control measures (afforestation and farming) on the slope,1/3 is trapped by the reservoirs,ponds and dams within the watershed,and only about 1/3 is transported into the Yangtze River,which will affect the Three Gorges Project. |
