Local‐ and field‐scale stochastic‐advective vertical solute transport in horizontally heterogeneous unsaturated soils

摘要: Description of field-scale solute transport in unsaturated soils is essential for assessing the degree contamination, estimating fluxes past a control plane and designing remedial measures. The flow field usually described by numerical solution Richards equation followed advection-dispersion to describe contaminant movement. These solutions are highly complex, do not provide insights that possible from simpler analytical representations. In this study, at local scale developed purely advective vertical conservative along principle characteristic field. Local-scale model development simplified using sharp-front approximation water then upscaled adopting lognormally distributed horizontal hydraulic conductivity represent natural heterogeneity observed soils. Analytical expressions mean behavior scale. Comparisons with experimental observations find trends reasonably reproduced model. accuracy proposed improves increasing spatial variability as revealed further comparisons results equation-based some cases, may lead anomalous depending on role pre postponded conditions field, limitation discussed. method shows promise describing movement loamy sand sandy loam