Study On Xinlicheng Reservoir Preflood Limit Level And Operation

Changchun is a northern city lacking in water resources. Xinlicheng reservoir (XLCR) is one of water sources of this city. The original design water utilization factor of XLCR is 0.66, and the annual overflow discharge is about 6772×104m3.The most of surplus water can be utilized by enlarging reservoir available storage. Since XLCR was strengthened, the safety condition of the project has been improved greatly, and the normal water level of XLCR can be raised so that the water volume supplied by XLCR may be increased. At the same time, XLCR has been equipped with the automatic system of hydrologic data collection and transmission, which can carryout forecasting and dispatching on time, and the flood regulating water level may be kept unchanged with raising of preflood limit level and normal water level, while the design flood pass the reservoir in safety. The most important condition is that with the project Carrying Water from Songhua River to Changchun City being put into operation, ChangChun is becoming a modern city with more water sources. The water supplied by XLCR is quite competitive in price, although some extra water supply is of a lower guaranteed probability. The problems with respect to raising preflood limit water level and enlarging reservoir active storage are studied in this paper. The main achievements are as follows:1. Hydrological data of XLCR areas are collected and analyzed systematically, and the rechecked results of the design flood are provided.2. Flood regulation methods of XLCR are improved in this paper. The operation of overflow discharge controlled according to reservoir water level is changed into that controlled according to rainfall and reservoir water level. By use of the automatic system of hydrologic data collection and transmission, the reservoir can be dispatched on flood forecasting and the operation of overflow can raise preflood limit level from 218.83m to 219.70m, while the total reservoir capacity is not changed.3. The normal water level of XLCR can be increased from 218.83m to 220.00m If water supply program in 2 grades of guaranteed probability is adopted, XLCR can provide extra water 1692×104m3 every year with the guaranteed probability of 76%, while the original reservoir design annual water supply 8880×104m3 is still provided with the guaranteed probability of 95%.To sum up,it is a potential and feasible path to increase utilization factor of water resources to optimize the flood control design parameter of the reservoir and the reservoir operation. This is based on the modern flood control concept and the advanced forecast technology of storm rainfall and flood.