The Coordinated Flood Control Operation Rules at the Upper and Lower Jinhu Reservoirs

The concerted flood control operation rules at the upper and lower Jinhu reservoirs on the Bijiasha River in Shenzhen, China were discussed in this study. The upper and lower Jinhu reservoirs play an important role in the flood control in Shenzhen City. The upstream flood forecast and downstream hydrological information were not considered in the present operation modes. In order to improve the reservoir operation modes, the concerted real-time operation rules for the two reservoirs were developed in consideration of the hydrological information of the inflows, and the water level of the downstream river channel. In the new operation rules, the releasing discharges from the two reservoirs were determined according to their regulating capacities, and the downstream water level in the channel from the dams to the Nigang gaging station where the real-time water level and discharge data are available. The uncertainty of the flood forecast and the downstream discharge forecast data is taken into account during the process of determining the releasing discharges. In actual operation, the floodgate opening are adjusted in a define time because of the floodgate mechanical performance. The influence of the downstream water level on the reservoir releases was considered from the safety view of point. The effects of the newly developed operation rules were verified by a 50-year flood. The retention effects performed by the new operation rules are better than those by the present modes. The new operation rules are operated easier than the present ones, and provide higher safety to the reservoirs and the downstream river channel.