Risk And Benefit Analysis For Adjustment Schemes Of Limited Water Level In Reservoir

The water resources in the vast north area of china are extremely short. For the rapid development of national economy, the contradiction between the supply and demand of water resources is becoming increasingly acute. The shortage of water resources not only restricts the development of social economy, but brings many serious ecological and environmental problems. For this reason, fully excavating the flood regulation and storage potentialities of existing reservoirs and fitly transforming some flood into available water resources, on the premise of not increasing the flood control risk, are more important for alleviating the water resources crisis and improving the valley ecological environment. But in the flood periods of many reservoirs, for the safety of flood control, the water level must be defined in a lower scope. So a large amount of floodwater is wasted, and the floodwater resources are not comprehensively utilized. To coordinating the contradictions between flood and profiting to reservoirs and further exploiting and utilizing the water resources in flood periods to alleviating the water resources crisis, based on the summary of research results at home and abroad, the risk and benefit rate after the adjustment for limited water level of Panjiakou Reservoir are calculated, and then the optimization for the adjustment schemes of limited water level in the flood period is realized. The major research results are summarized as following:(1) Based on the systematic analysis of definition and calculation methods of risk rate at home and abroad, the concept of limiting risk rate is proposed, the calculation procedures of limiting risk rate are summarized, and then calculation model of the limiting risk rate based on stochastic simulation is established(2) By stochastic simulation methods, the simulated peak flow, the max one-day flood volume and the max three-day flood volume are amplified on the typical flood hydrograph. According to the adjustment schemes of limited water level, the top water levels of each scheme are determined by flood routing, and then the corresponding limited water level is calculated.(3) The average inflow volume of long series is used as the input item, by the SAR(1) and flood routing method, the water supply and power generation benefits corresponding to each adjustment schemes are calculated.(4) Based on the comprehensive analysis for the risk and benefit indexes of adjustment schemes, the multi-objective fuzzy optimal decision-making model for the limited water level schemes based on the maximum entropy principle is established, which provides important decisive information for the reservoir flood operation.