Abstract: The Zhexi Reservoir was impounded from Feb. 15 1961 by closinggate. Up to March of 1995 it was operating 34 years. Because of bar sedimentation the water level rises in the upstream in flood season and hence the losses from inundation in its surroundings and tail of thereservoir increase and the transport is influenced. Thus it must betreated in time. From geological investigation and observation data of the bar sedimentation, an analysis of the source for silt is made audits controlling measures are discussed in the paper.