Risk Assessment Methods And Applications Study On Dynamic Control Of The Flood Limited Level

China is a country with serious shortage of water resources, and the water resources is uneven spatial and temporal distribution. Dynamic control of the flood limited level can effectively improve the utilization of flood resources, but it will increase the risk of reservoir flood control by the flood water level control static to dynamic control. Dominant floods often occurred during operation period, which has a large space to be used. Relying on the project "Spilling flood limit water level dynamic control risk research of Luhun reservoir", it has important operation significance to research the risk of reservoir region and downstream when the flood for5and20years occurred with different dynamic control scheme of the flood limited level for the reservoir.In this paper, the risk factors of dynamic control of limited water level are simplified into the uncertainty of typical flood-selection flood-forecast error、 flood-operation delay、storage capacity and discharge capacity of the reservoir by fault tree analysis method for the problem of risk evaluation under dynamic control of the flood limited level. The probability distribution of risk factors are estimated based on stochastic simulation and objective or subjective distribution. Typical flood was chosen from flood data generated by one autoregressive model, Copula function constructed flood volume conditional distribution under the peak setting conditions, with these conditionals, the probability distribution of typical flood is determined. The probability distribution of the forecast error is determined by the kernel density estimation, which is one of nonparametric estimation. The probability distribution of flood-operation delay、storage capacity and discharge capacity of reservoir can be taken as triangular distribution or normal distribution. The method combine the Monte Carlo method and the process of reservoir flood, which is used to analyze the risk of dynamic control of limited water level scheme with different factors combination situation. Taking into account the risk of reservoir upstream and downstream, risk evaluation index system is set up, which includes risk rate of upstream and downstream、nundation area of reservoir on average and the maximum、 inundation farmland of reservoir on average and the maximum。Analysis of the Critical risk rate in the different flood frequency, combined with the risk evaluation to search a reasonable domain under dynamic control of limited water level.In this paper,combined with the actual condition of Luhun reservoir, the risk of different dynamic control scheme of the flood limited level for the reservoir is evaluated during pre-flood season and later-flood season. The reasonable program of dynamic control scheme of the flood limited level is recommended, and the rationality and the feasibility of the theoretical approach is verified too.