Risk Assessment of Lake Flooding Considering Propagation of Uncertainty from Rainfall

Risk assessment of lake flooding is studied through uncertainty propagation of the rainstorm control model. The failure risks of insufficient drainage capacity are assessed using the classic reliability approach and time-dependent reliability approach separately. The rainstorm control model consists of three submodels: a design rainstorm model to determine design storm hyetograph, a rainfall-runoff model to generate inFLow hydrograph of the lake, and a lake operation model to simulate the storage volume of lake. Monte Carlo simulation with stochastic rainfall is implemented to provide random input for the combined model. The effect of uncertainty propagation on the three submodels is examined. The developed methodology is demonstrated with a case study, and results reveal that it offers an appropriate technique to assess flooding risks and consider the effect of uncertainty propagation on urban storm water modeling in designing a new drainage plan. (C) 2013 American Society of Civil Engineers.