科研之友
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摘要
We applied a recently developed method of aquifer characterization, which combines geophysics and geostatistics to create several heterogeneous realizations of a shallow fluvial aquifer that contain representations of sedimentary bounding surfaces. The influence of such small-scale (several centimeters) features on subsurface transport was investigated using high-resolution groundwater models of each of the subsurface realizations. Flow and transport through the models was simulated parallel, perpendicular, and at an oblique angle to paleoflow. The simulated transport rates showed directionally dependent tendencies and were found to be fastest parallel to paleoflow and slowest perpendicular to paleoflow. Homogeneous and geostatistical realizations with nearly identical mean hydraulic conductivity values were unable to reproduce the directional behavior. Transport was also simulated across three different length scales in the long direction of the model (parallel to paleoflow). The simulated breakthrough of all simulations was fitted using the advection-dispersion equation, but breakthrough was approximated more accurately with a non-Fickian solution. The results of this study show that the rate of transport in heterogeneous sediments depends on the direction of flow relative to bedding and is sensitive to the length scale that transport is simulated across.
- 出版日期2010-2-9
