Results of three meter‐scale outcrop studies suggest a quantifiable relationship between fluvial bounding surfaces and the permeability correlation structure. Mapping of bounding surfaces and in situ measurements of permeability were obtained in three types of deposits: a low‐energy channel deposit, a paleosol, and a high‐energy channel deposit. For the low‐energy channel deposit only second‐order surfaces separating lithofacies were mapped. The variogram exhibits anisotropic exponential behavior, and an analysis of variance (ANOVA) suggests that the within‐facies variation dominates over between‐facies variation. The paleosol contained no internal bounding surfaces and exhibited a “bellshaped” variogram consistent with a smoothly varying style of heterogeneity. Both firstand second‐order bounding surfaces were mapped in the high‐energy channel deposit. Results of the ANOVA suggest that the between‐facies variation dominates over the within‐facies variation. A model of spatial correlation using superposition of independent processes acting over different scales provides a good fit to the data. These three studies suggest that fluvial bounding surfaces provide a geological basis for conceptualizing and modeling heterogeneity in alluvial deposits.
