First-Order Reliability Analysis of Groundwater Flow

A method for stochastic analysis of groundwater flow based on the first-order reliability approach is presented. The method is well suited for problems in which statistical information is limited to second moments and marginal distributions, as is commonly the case for groundwater flow analyses. A stochastic finite element model is described which utilizes the first-order reliability approach to estimate probabilities associated with a particular performance criterion for confined or unconfined saturated groundwater flow in porous media. Element hydraulic conductivities and boundary conditions are assumed to be random variables with known second moments and marginal distributions. The model estimates the probability of exceeding a specified target fluid flux or nodal fluid head, and provides sensitivity information