基于关键闸坝优选的区域水网水量调控

Water quantity regulation of regional water network based on optimal selection of key gate dam

为实现区域水网水量的高效调控,从水量、水生态、水质和闸坝管理等4个方面构建包含10个指标的闸坝优选评价指标体系,以廊坊市凤河-永定河区域水网为研究对象,计算区域内32座闸坝的综合关键指数并给出影响程度排序,采用水动力数学模型验证关键闸坝选取的合理性。结果表明:优选出的永丰闸和东张务闸是区域水网的关键闸坝,通过调节这两座闸坝的开度即可满足区域水网的生态需水和防洪排涝调度目标,保持区域水网较优的水力连通能力,提高区域水网水量调控效率。

Uneven distribution of water quantity in regional water network results in cut-off and difficulty in satisfying ecological water demand.Therefore,it is necessary to scientifically formulate a scheme to regulate regional water network.Regulating water quantity by operating gate dams is a critical way,but the selection of different numbers and scales of gate dams will have different effects on the efficiency and effect of regulation results.How to select the key dams that may have a greater influence on the regional water network under different objective conditions and realize the efficient regulation of the water quantity.A gate dam evaluation index system is established which includes 10 indices from the aspect of water quantity,water quality,water ecology,and gate dam management.Taking the regional water network of Fenghe-Yongding River in Langfang as the research object,the AHP-entropy weight method is used to determine the index weight.To select the key gate dams under multi-objective water quantity regulation,the influence ability of each gate dam on the regional water network quantity regulation is evaluated.Considering the gate dams need to adjust the opening to achieve the water regulation target,a hydrodynamic mathematical model is built,and the opening of each key gate dam is set at five grades of 0%,25%,50%,75%,and 100%,and combined into 25 groups of simulation working conditions.Based on the simulation calculation of each working condition,the opening degree of each key dam and the range of water level is determined under the objective of satisfying the regional ecological water demand and flood control safety,and the judgment of the priority of the dam operation by the gate dam evaluation index system is verified.The composite key index of Yongfeng and Dongzhangwu are the highest,and they are the key gate dams in the regional multi-objective water quantity regulation.The differences between the single key and the composite key index are obvious for some gate dams.In practical application,the operating dam can be selected according to the regulation target.The composite key index can play a good reference role in water quantity regulation under the condition of multi-objective.For operating requirements,the gate and dam whose objective corresponds to a higher key index can be selected more accurately,and the composite key index can be considered at the same time.The opening of two key gate dams is set and combined into 25 working conditions to calculate the hydrodynamic model.Only four of the 25 working conditions meet the requirements of regional water network ecological water demand and flood control safety,and the index of hydraulic connectivity capacity under these four working conditions is relatively high,which is between 0.837 and 0.839.In conclusion,Yongfeng and Dongzhangwu gate dams are the keys in the target area,and their critical water quantity and composite indices are the highest in the gate dam evaluation index system.When the opening degree of Yongfeng gate dam is 50%to 75%,the opening degree of Dongzhangwu gate dam is 75%to 100%,and the corresponding water level range is 11.30 to 11.95 m and 10.55 to 11.65 m,respectively.It can ensure that each river reach and wetland in the target area and may meet the demand of ecological water level and give consideration to flood control safety.The evaluation index system has a directivity effect on operating gate dams under multi-objective regulation of water.It can reflect the influence degree of gate dams in a single aspect or comprehensive aspect.This method is used to determine the scheduling priority of gate dams.It is of significance reference to reasonably reduce the number of gate dams and improve the efficiency of water regulation.