Stochastic Modeling of Exposure and Risk in a Contaminated Heterogeneous Aquifer. 2: Application of Latin Hypercube Sampling

ABSTRACT

This research has developed a numerical stochastic methodology for analyzing the uncertainty of groundwater flow and transport parameters and their effects on exposure and risk assessment. The Monte Carlo method is commonly used to analyze exposure uncertainty based on the uncertainty of each groundwater parameter measured. If the Monte Carlo method was used for all parameters in this study, it would have required an extremely large number of simulations. Therefore, a stochastic modeling approach based on Latin Hypercube Sampling was used to reduce the number of simulations required and to make uncertainty analysis feasible. This technique was adapted to use samples from both the statistical distributions of nonspatial stochastic parameters and spatial and discrete hydraulic conductivity field simultaneously. The use of Latin Hypercube Sampling proved to be very efficient for modeling uncertainty in exposure and risk assessment related to groundwater contamination.

Key words:

Risk assessment; exposure assessment; Latin Hypercube Sampling; groundwater modeling; stochastic modeling; geographic information systems