Study on Flood Control Safety Evaluation Based on Composite Risk Model

Abstract. The process of dam design up to the management of dam operation involves many uncertain factors, such as hydrologic, hydraulic and flood control factors, which cause risks for the flood control safety of dams. This study presents an integrated probabilistic framework that combines Monte Carlo Simulation and a flood control risk model. Results show that the highest flood level of 1000-year return periods of the Zhelin Reservoir exceeds the designed flood level. However, the overtopping risk probability is small because super safe elevation is considered in the crest elevation design of the earth dam. Sensitivity analysis indicates that flood peak flow, line type hydrological factors and flood control level are more sensitive than hydraulic factors. When many factors are considered, the comprehensive risk rate is small because of the positive and negative effects of these factors. Numerical experiments indicate that hydrology and flood control level influence the estimated maximum water level more than hydraulics does. Because of these uncertain factors, it is necessary to consider super safe elevation in dam planning and design. And pay attention to the sensitive factor of flood control level in reservoir management and operation.