Approach to the Operational Mode of Four Reservoirs Joint Operation for Flood Control Adopted by Xiaolang di Reservoir

The storage capacity of the Xiaolangdi Reservoir at early stage is relatively big. In order to give full play to the storage capacity superiority of the reservoir and reduce sedimentation in the Sanmenxia Reservoir and operational probability, it is a better opportunity to put into operation when the reservoir water level reaches to 273 m as a major flood happened in the upper stream of the Sanmenxia Reservoir. It is a better opportunity to put into operation when the reservoir water level reaches to 270 m after storage as a major flood happened in the down stream of the Sanmenxia Reservoir. Through analysis and comparison of several scenarios, it puts forward that it should try to reduce dominant discharge of medium and small sized floods at the beginning stage of operation of the Xiaolangdi Reservoir and under the conditions of no effect to the dam safety. 5,000 m 3/s for the dominant discharge of medium-sized flood and 245 m decided as the maximum water level in flood season are better. In addition, it also has put forward a joint operation plan of four reservoirs of Sanmenxia, Xiaolangdi, Luhun and Guxian.