Comparing statistical models of physical heterogeneity in buried‐valley aquifers

摘要: The hypothesis that physical heterogeneity has similarities in separate aquifers created by similar depositional environments is tested comparing statistical characteristics of facies assemblages. comparisons are made for a number data-rich sites two buried-valley the North American midcontinent: White River aquifer Indiana and Miami Valley Ohio. These were proglacial valleys directed drainage away from Quaternary ice margins filled with glaciofluvial sediments: predominantly sand gravel (s) lithofacies, interbedded mud diamicton (m) lithofacies. At scales encompassing assemblages both lithofacies m s, permeability strongly bimodal. We find it useful to compare statistics characterize proportions, geometry, spatial distribution each facies. results give rise general model valley-fill sediments along sluiceway aquifers. proportion ∼15%. mean thickness 3.5 order 10 s. coefficient variation either 1, ranging over orders magnitude. Correspondingly, vertical autotransition probabilities exponential, they relatively symmetric effective range m. lateral lengths indicated vary magnitude be multimodally distributed, 102 m, correlation structure 103 anisotropy ratio <2. There some how vertically embedded within areas have proportions stationary elevation. In other Miami, there near-horizontal zones having higher or lower proportions. However, such variations on mass transport context relevant remediation problem thus would lead conclusion decision. Thus one applicable this context. broader sense, we illustrated method which examples developed can compared.