Research On Reservoir Operation Considering Ecological Water Demand Analysis

The natural runoff process is the important technology driver to river ecosystem. On the one hand, the construction and operation of reservoirs relieves the supplying demanding contradiction of water resources, which are mal-distributed in space and time; On the other hand, it also changes the natural runoff of downstream river, thus producing negative influence to river ecosystem. For the ecological problems brought by reservoir operation, reasonable reservoir regulation mode can make up the adverse effect to ecological environment. According to that ecological water demand of downstream river is hardly considered by existing reservoir regulation mode, changing reservoir regulation mode is studied in this paper for combining reservoir regulation mode with ecological factors. By this method, ecological recharge is supplied by reservoir, thereby ensuring that original water supply demand is fulfilled, and the negative influence to river ecosystem is relieved. The main contents are as follows:(1) According to that the construction and operation of reservoirs changes the natural runoff of downstream river, the degree of its alteration is evaluated using RVA method. Considering the index in RVA method as ecological evaluation index, it can be controlled by changing reservoir regulation mode, thereby leading the runoff which is released from reservoir close to the state of natural runoff in magnitude and variation.(2) Focusing in the ecological water demand of downstream river, minimum ecological water demand is calculate using minimum ecological runoff calculation method, and suitable ecological water demand is calculated using month-by-month frequency calculation method. The minimum ecological water demand calculated in this paper is barely enough to maintain biological survival, and it cannot be sustained for long. The suitable ecological water demand calculated in this paper can make the ecological system to achieve stability and health. The study can provide valuable reference for mitigating the negative influence which reservoir brings to downstream river.(3) It increases reservoir operation goal that combining reservoir regulation mode with ecological factors. According to the problem that how to coordinate multi-objective, the result of multi-objective reservoir operation is analyzed in different weight group of multi-objective. By creating optimal operation model, it is calculated that the optimal water shortage rate and the recommend ecological water supply order in different weight group of multi-objective, thereby seeking the position of ecological water demand in various water supply target. The study can provide valuable reference for making scheduling rules of reservoir next.(4) According to the problem that how to change reservoir regulation mode with ecological water supply target, the method of reservoir operation is designed. After making clear the ecological water supply target and ecological evaluation index, ecological scheduling rules of reservoir are calculated by optimal operation model. In accordance with the rules calculated in this paper, the reservoir can improve ecological index, satisfying the original water supply task at the same time. The method can provide valuable reference for mitigating ecological stress which reservoir operation mode brings to downstream river.Finally, a summary is given for this paper, and some problems that need to be further studied are discussed.