HR: 1340h
AN: H33D-1605    [Abstracts]
TI: Does small variance of ln K (~0.3) represent less geologic heterogeneity? A recent lithofacies study at the Borden aquifer
AU: * Lee, S
EM: sylee6@buffalo.edu
AF: State University of New York, Department of Geology, Buffalo, NY 14260, United States
AU: Polmanteer, R T
EM: rpolmanteer@gmail.com
AF: State University of New York, Department of Geology, Buffalo, NY 14260, United States
AU: McGrane, S T
EM: smcgrane@buffalo.edu
AF: State University of New York, Department of Geology, Buffalo, NY 14260, United States
AU: Allen-King, R M
EM: richelle@geology.buffalo.edu
AF: State University of New York, Department of Geology, Buffalo, NY 14260, United States
AU: Dominic, D F
EM: david.dominic@wright.edu
AF: Wright State University, Department of Earth and Environmental Sciences, Dayton, OH 45435, United States
AU: Ritzi, R W
EM: robert.ritzi@wright.edu
AF: Wright State University, Department of Earth and Environmental Sciences, Dayton, OH 45435, United States
AB: The variance of ln K has been commonly used to indicate the degree of spatial variability of the hydraulic conductivity (K) distribution in a geologic system. For example, the sandy Borden aquifer with its small ln K variance (= 0.29, Sudicky, 1986), has been considered to be relatively homogeneous. Recently, we collected core samples and mapped lithofacies in the Borden aquifer as part of a collaborative research project to determine spatial cross-correlation between the properties of the aquifer that control reactive transport. A horizontal transect of seventy-two densely-spaced (0.25-1.0m) cores, including those previously collected by Allen-King et al. (2006), allowed us to determine the spatial distribution and lateral dimensions of lithofacies units, which were not clearly discernible in previous studies. Our lithofacies mapping shows the following sedimentary features: dipping strata, channel-like structures, gradational transition among facies units, erosional discontinuities in the low-K materials, and isolated occurrences of silt materials. Geostatistical analysis of the horizontal cross-transition probabilities at two hierarchical levels reveals the contribution of stratal architecture to the sample semivariogram. The lithofacies structures identified in the Borden aquifer imply a potentially important role in groundwater flow and transport processes even with this low variance of ln K. This suggests that the characterization of spatial variability based solely on statistical abstractions without consideration of geologic structure may neglect important and useful information.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2007 Fall Meeting