Uncertainty propagation of dam break flow using the stochastic non-intrusive B-splines Bézier elements-based method

Abstract

The non-intrusive B-splines Bézier elements method (BSBEM) is used to perform uncertainty propagation for complex dam break flow models. The predictive efficiency of the BSBEM is first compared to the polynomial chaos expansion (PCE) and Monte Carlo (MC) methods using Stoker’s analytical solution for an idealized dam break flow with discontinuous outputs. The computational efficiency of the proposed methodology is then illustrated by analyzing the uncertainty propagation of a hypothetical failure of an actual dam (Batiscan River) located within the province of Québec (Canada). Three parameters, the input discharge, the Strickler roughness coefficient of the main channel and the average breach width are considered as input random variables from which uncertainties may occur and propagate through the 1D hydraulic numerical model (Mascaret). The obtained results reveal the ability of BSBEM to efficiently predict the statistical moments and probability distributions of the output quantities of interest represented in terms of the downstream discharge, water level and front wave arrival time at different locations of the studied reach, thus yielding useful information for flood risk management with lower computational cost.