Dispersion of groundwater age in an alluvial aquifer system

摘要: [1] Interpretation of groundwater ages typically rests on assumptions minimal mixing different water in the samples. The effects three-dimensional, geologic heterogeneity and tracer concentrations, however, have not been evaluated. In this study, we use a series 10 detailed geostatistical realizations along with high-resolution numerical flow contaminant transport simulation to model distributions chlorofluorocarbon (CFC) at wells within heterogeneous stream-dominated alluvial fan aquifer system. Results show that reaching well system consists wide distribution (often spanning >50 years), even over short (<1.5 m) screened intervals. Additionally, simulated arithmetic mean do correspond estimated from CFC concentrations. emphasize potential ambiguity “mean” environmental concentrations systems. significant dispersion also implies ultimate, maximum nonpoint source, anthropogenic contamination may be reached until after many decades or centuries gradual decline quality.