Research On Distributed Flood Forecasting In Miyun Reservoir Basin

Miyun Reservoir is the most important source of drinking water of Beijing. Thepresence of Miyun Reservoir greatly reduces the possibility of downstreamdevastating floods. As south-to-north water transfers gradually put into operation,Miyun Reservoir is facing with flood control, water supply and water security-relatedchallenges. So doing Miyun Reservoir flood forecasting research work well has a veryimportant significance for the protection of the downstream flood control security inBeijing, Tianjin, Hebei and water safety of Beijing and other aspects. Flood forecastmodel was establised based on the EasyDHM model and by using the runoffgeneration model of EasyDHM, the Muskingum method,the parameter sensitivityanalysis method LH-OAT and the parameter optimization methodSCE-UA,parameters were calibrated and flood events are simulated to solve thisproblem. the model was also validated through the session flood.The results show thatthe modelhas good applicability in the Miyun Reservoir basin. And on this basis, thepaper carried out a systematic analysis on the factors that impacts Miyun reservoirflood forecast accuracy, in order to provide a scientific basis for the Miyun ReservoirBasin Water Resources Development and Management.(1)According to the geography, hydrological and meteorological characteristics ofMiyun Reservoir watershed, basing on EasyDHM hydrological model, MiyunReservoir watershed hydrological model was constructed.The parameter calibrationand validation of each parameter partitions is also completed. The results show thatthe modelhas good applicability in the Miyun Reservoir basin. Miyun Reservoirwatershed distributed flood forecasting model can quite accurately predict futureflood process.It can be used for application of practical problems.(2)The paper regionally analyses the runoff and converge parameters of MiyunWatershed. Overall, the watershed runoff and converge parameters value uniformlydistributed. However, they exist a certain degree of difference between the upstreamand downstream of the river and the different branches.(3)The paper analyses the Miyun reservoir flood forecast accuracy errorfactors.The data sources are the First factor.The consistency of the hydrologicalyearbooks, hydrological data and telemetry rainfall data and the data integrity andmultiplicity has a direct impact on forecast accuracy. Secondly, whether the algorithm in the data integration process is close to the actual runoff and rainfall has an impacton forecast accuracy, especially in the present time of the floodpeak. Distribution ofrainfall stations set congenital conditions on forecast accuracy from the geographicaldimension. In addition, water conservancy and other human activities is also animportant reason. Overall, these factors cause the flood forecasting accuracy variousdifficulties.