Uncertainty of bivariate design flood estimation and its impact on reservoir flood prevention

The limited sample size would induce quantile estimation uncertainty in bivariate hydrological frequency analysis. A copula-based parametric bootstrap uncertainty (C-PBU) model considering the most likely realization to characterize the uncertainty of bivariate design flood estimation is proposed,and the quantitative uncertainty evaluation indexes are presented. The impacts of joint quantile estimation uncertainty on reservoir operation are explored and such uncertainty of highest reservoir water level derived from different typical flood hydrograph (TFH) schemes were compared. The 95% confidence regions of bivariate quantile estimation in the Geheyan reservoir are derived, and the influences of different sample sizes on uncertainty are investigated. The results demonstrate that the bivariate quantile estimation and TFH selection have large uncertainty. It is suggested to consider the uncertainty of reservoir flood prevention in practice by using of the C-PBU model. © 2018, China Water Power Press. All right reserved.