Application And Method Of Dynamic Control Of The Wucheng Reservoir’s Flood Control Limited Level(FCLL)

Water, especially floods, can promote the beneficial and the harmful. In the past, people view floods as wild beasts, and fear its harm side, but they ignore the other side that is they can increase the amount of available fresh water resources. Today in the condition of extreme shortage of water resources and drought disasters, making the most effective uses of flood resources has become an important open method. Using flood resources as a new concept of water control, it changes the past mind of leaving floods alone, while they are running into the sea. Now we increase the investment and make full use of existing water conservancy facilities, take non-engineering measures as the main means to co-ordinate flood protection and flood control. We not only protect the safety of flood, but retain flood resources.The flood dynamic control of limited level based on the flood control and flood resources utilization is an important filed of reservoir regulation. It changes the traditional reservoir static water level control pattern. On the premise of not increasing the risks of flood control, trying the best to raise the flood control level, and increase the volume of water can improve the performance of reservoirs.The flood dynamic control of limited level relies on the flood into reservoirs and how precise the rain forecast is. Taking into the full consideration of downstream channel flood control standard and reservoirs’safety discharge, we research on WuCheng reservoir’s flood dynamic control of limited level and then get the actual flood dynamic control range of limited level, and then propose the reservoir scheduling scheme. The primary tasks of this thesis are as follows:1. The feasibility study of rainfall forecasting applying to reservoir flood limit level dynamic control. According to the meteorological department rainfall level, make sure these years’forecast accuracy rate of WuCheng reservoir. The result shows that the accuracy of the forecast can meet the reservoir flood limited water dynamic control applications requirements. WuCheng reservoir flood season has three periods:pre-flood period, main flood period and late flood period. The main task of pre-flood period and main period is preventing flood while the late period is preventing flood and saving water. So the late flood period is the key period of rainfall forecast. Regardless of the forecast with no rain, light rain or moderate rain, the possibility of the actual rainfall greater than100mm is only0.12%,which is far less than the50year’s flood of the reservoir design flood.That means standard’s rainfall forecast can be used in the research of flood limited water level dynamic control. 2. Determining the flood dynamic control range of limited level and scheduling scheme. Firstly, make use of relation between rainfall and flood derives stage design flood indirectly. In Pre-flood period and the main flood period the maximum design flood is used and in the late flood period Stage design flood is adopted. Secondly, determine the flood dynamic control range of limited level. Combining the main tasks of the different stages of the reservoir、 the reservoir upstream、downstream safety and the result of flood calculation,the thesis draw the conclusion that the FCLL of the flood period is1022m; While based on the rainfall and safety forecast and adopting pre-discharge capacity constraint method,the upper limit of the flood limit level dynamic control of is1027m. Finally, according to the flood dynamic control range of limited level, using pre-storage and pre-discharge method determines reservoir scheduling program by flood regulating calculation.3. Performance analysis.The performance of flood limit level of dynamic control is described by the method deducting years of more rainfall after flood season. After the date was calculated, WuCheng reservoir using dynamic control flood limited level can offer more2454thousands cubic meter each year.4. Risk analysis.Based on that the rainfall omission is independent with occurred design flood, the risk can be calculated by the probabilistic method of independent events occuring simultaneously. According to calculations, regardless of the forecast with no-rain、light rain or moderate rain,the risk rate is less than0.1%of the reservoir checked standard. By inference, the flood limited level is safe and reasonable in dynamic control range.