HR: 13:40h
AN: H13H-01 INVITED     [Abstracts]
TI: The Hydrofacies Approach and Why ln K $\sigma$$^{2}$ $<$5-10 is Unlikely
AU: * Fogg, G E
EM: gefogg@ucdavis.edu
AF: University of California, Hydrologic Sciences, Davis, CA 95616 United States
AB: When heterogeneity of geologic systems is characterized in terms of hydrofacies rather than solely based on K measurements, the resulting flow and transport models typically contain not only aquifer materials but also significant volumes (10-70%) of aquitard materials. This leads to clear, heuristic rationale for the ln K $\sigma$$^{2}$ commonly exceeding 5 to 10, contradicting published data on ln K $\sigma$$^{2}$. I will explain the inconsistencies between commonly held assumptions of low ($<$1-2) ln K $\sigma$$^{2}$ and abundant geologic and hydrologic field data that indicate substantially larger values. The K data commonly cited in support of the low ln K $\sigma$$^{2}$ assumption have been misinterpreted because of unintentional, biased sampling. Geologic fundamentals and field data indicate that ln K $\sigma$$^{2}$ is commonly $>$10 and can easily exceed 20 in typical sedimentary deposits (not surficial soils) at spatial scales on the order of 10$^{1}$ to 10$^{2}$ m. Presence of large ln K $\sigma$$^{2}$ can be paramount in transport models and is often requisite for modeling observed transport phenomena such as preferential flow, extreme tailing, difficult remediation including frequent pump-and-treat failure, and significant, unanticipated mixing of groundwater ages.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1869 Stochastic processes
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting