USGS Groundwater Information: Branch of Geophysics
by Kamini Singha(1), F.D. Day-Lewis(2), and J.W. Lane, Jr.(2)
(1) The Pennsylvania State University, 311 Deike Building, University Park, PA 16802
(2) U.S. Geological Survey, Office of Ground Water, Branch of Geophysics, 11 Sherman Place, Unit 5015, Storrs, CT 06269
Bicontinuum models and rate-limited mass transfer (RLMT) explain complex transport behavior (e.g., long tailing and rebound) in heterogeneous geologic media, but experimental verification is problematic because geochemical samples represent the mobile component of the pore space. Here, we present geophysical evidence of RLMT at the field scale during an aquifer-storage and recovery experiment in a fractured limestone aquifer in Charleston, South Carolina. We observe a hysteretic relation between measurements of pore-fluid conductivity and bulk electrical conductivity; this hysteresis contradicts advective-dispersive transport and the standard petrophysical model relating pore-fluid and bulk conductivity, but can be explained by considering bicontinuum transport models that include first-order RLMT. Using a simple numerical model, we demonstrate that geoelectrical measurements are sensitive to bicontinuum transport and RLMT parameters, which are otherwise difficult to infer from direct, hydrologic measurements.
Download complete article (275KB PDF).
Note: Download free Adobe Acrobat Reader to view PDF files at the Adobe web site.
Visit http://access.adobe.com for free tools that allow visually impaired users to read PDF files.
Final copy as submitted to Geophysical Research Letters for publication as: Singha, K., Day-Lewis, F.D., and Lane, J.W., Jr., 2007, Geoelectrical evidence of bicontinuum transport in groundwater: Geophysical Research Letters, 34, L12401, doi:10.1029/2007GL030019.