| As the core project of water resources development and utilization,reservoir plays a key role in flood control,disaster reduction and water supply security.In order to ensure the safety of flood control,the reservoir has to abandon a large amount of water in the flood season,but there is no water to store after the flood season,which intensifies the contradiction between supply and demand of water resources.Using forecast information to carry out reservoir forecast and operation is an effective means to solve the contradiction between flood control and benefit.However,with the development of social economy,the impact of human activities on the underlying surface conditions of the basin is increasing,which makes the original flood forecasting scheme unsuitable for reservoir forecasting and operation.Therefore,this paper takes Gangnan Reservoir and Huangbizhuang Reservoir as the research objects to carry out the research on flood forecasting scheme and cascade reservoir group forecasting operation mode considering the change of underlying surface conditions.The main contents and research results of this paper are as follows:(1)Study on flood forecasting simulation of Gangnan Huangbizhuang section based on multiple models.Firstly,according to the characteristics of the underlying surface and climate of the basin,through the applicability analysis of the main domestic flood forecasting models,three flood forecasting models,namely API model,XAJ model and DHF model,are preliminarily selected to compare and analyze the flood forecasting simulation effects of the basin under different models;Secondly,using 23 floods from 1959 to 2016,the parameters of the above model are calibrated by genetic algorithm combined with manual interaction;Finally,the simulation results of the three flood forecasting models are compared and analyzed according to the characteristics of runoff and its influencing factors.The results show that,due to the change of underlying surface conditions,the simulation results of the three models are not ideal,but the DHF model,which mainly produces seepage,has significantly better simulation results than the other two models,and is more suitable for the preparation and research of flood forecasting scheme in the Gangnan Huangbizhuang section.(2)Study on flood forecasting scheme of Gangnan Huangbizhuang section based on DHF model.Firstly,in view of the influence of the change of the underlying surface conditions of the basin,the reduction coefficient RZ considering the interception of the reservoir in different years and the time infiltration influence coefficient fi considering the rainfall and rainfall frequency are introduced to establish an improved DHF model for in-depth research;Secondly,23 historical floods are used to simulate and calibrate the improved model parameters;Finally,aiming at the problem of poor simulation effect of confluence,the soil water content in the early stage is used as the classification index for classification simulation,and the runoff parameters are re calibrated,and the rationality of the parameters is analyzed.The results show that the simulation effect of DHF model is significantly improved by taking the early soil moisture content as the classification index and considering the influence of the change of underlying surface conditions.Among them,the qualified rate of runoff production has increased from 82.6%to 100%,and the qualified rate of confluence has increased from 39.1%to 87.0%,indicating that the Ganghuang interval prediction scheme developed by using the improved DHF model according to the flood classification is available.(3)Study on flood control forecast and operation scheme of Gangnan Huangbizhuang reservoir group.In view of the problems of more abandoned water in flood season and less water storage after flood season,in order to improve the full storage rate of the reservoir on the premise of ensuring flood control safety,the flood control forecast and operation research of Gangnan～Huangbizhuang reservoir group is carried out.First of all,the necessity and feasibility of carrying out forecast operation are analyzed from the aspects of reservoir storage status over the years,water supply contradiction,flood forecast scheme,automatic measurement and forecast system,information transmission,gate operation,reservoir management level,etc;Secondly,the design net rainfall of different frequencies is calculated by using the inversion simulation prediction method and the same magnification method;Thirdly,taking the forecast net rain as the main index and the measured inflow and reservoir water level as the auxiliary indexes,the design idea of the forecast dispatching scheme is determined;Finally,taking the maximum water level and the maximum discharge of conventional regulation as constraints,the prediction regulation is simulated and determined.The results show that the initial water level of Gangnan Reservoir and Huangbizhuang reservoir can be raised by 0.41m and 0.39m at the same time,and the effective water storage can be increased by 32.28×106m~3。... |
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