The main tasks of the Guanting Reservoir on the Yongding River were flood control and water supply to Beijing. However, it is not able to supply water due to the serious sedimentation and water pollution in recent years. Of the total original reservoir storage capacity of 2.27109 m3 (after rebuilt), 0.651109 m3 in the Yongding Zone is lost due to sedimentation and 0.252109 m3 in the Guishui Zone cannot be used due to the sand bar at the mouth of the Guishui River. Dredging is performed to deal with the sedimentation of Guanting Reservoir. A dredged channel on the mouth bar between the two parts of the reservoir, i.e. Yongding Zone and Guishui Zone, to resume their connection and a dike to guide most sediment from upstream of the Yongding River to the Guishui Zone are suggested. The main tasks of the Guanting Reservoir on the Yongding River were flood control and water supply to Beijing. However, it is not able to supply water due to the serious sedimentation and water pollution in recent years. Of the total original reservoir storage capacity of 2.27109 m3 (after rebuilt), 0.651109 m3 in the Yongding Zone is lost due to sedimentation and 0.252109 m3 in the Guishui Zone can not be used due to the sand bar at the mouth of the Guishui River. Dredging is performed to deal with the sedimentation of Guanting Reservoir. A dredged channel on the mouth bar between the two parts of the reservoir, ie Yongding Zone and Guishui Zone, to resume their connection and a dike to guide most sediment from upstream of the Yongding River to the Guishui Zone are suggested.