Parameter identification and uncertainty analysis for variably saturated flow

This study investigates variably saturated groundwater flow in the vicinity of a sanitary landfill. A conjugate gradient method with an objective function that includes both pressure terms and travel time terms is used for parameter identification. The uncertainty in calculated travel time is estimated using both a moment method and a Latin hypercube direct parameter sampling method. The adjoint operator technique is an important component of both the parameter identification procedure and the moment method uncertainty analysis.