Abstract
Estimating effective hydraulic parameters of variably-saturated layered sediments has been extensively studied using deterministic, stochastic or combined approaches and experiments. However, heterogeneity and scale dependence remain as major obstacles for the prediction of water flow and contaminant transport at DOE sites. A physically-based fractal model is introduced in this work to characterize the heterogeneity of layered sediments at different scales and to estimate effective hydraulic parameters with a composite medium approximation approach. Fractal parameters for the Hanford formation are estimated by spectral analysis of a set of gamma ray log data. Numerical simulation results show that the Cantor set composite medium model may work well at small length scale, low gradients or dry conditions. Under unfavorable conditions, the influence of gradient, or pressure or hydraulic conductivity variance on the effective hydraulic conductivity may not be ignored.
