Study on the techniques of sediment flushing and decreasing sedimentation in Shimen Reservoir

Shimen Reservoir,located in Hanzhong City,Shaan'xi Province,is a large water resources project.After 30 years running,the reservoir is suffered on severe sedimentation.The total silted sediment measured in 2002 reached 38 million m~3.The silted shape was mixed up delta with ribbon and was gradually developing to cone shape.Based on the analysis of the sedimentation development,source of the sediment and the measures to control sediment,the paper has analyzed the feasibility that in flood season discharging by density current and flushing by empty the reservoir can be adopted to decrease sedimentation and recover the storage capacity of the reservoir.The end of September should be the suitable time for flushing by empty the reservoir,and the periodicity should be 4 to 5 years.