USGS Groundwater Information: Hydrogeophysics Branch
The USGS Office of Groundwater, Branch of Geophysics (OGW BG) has collaborated on multi-year applied research to develop and demonstrate geophysical strategies to measure mass-transfer parameters over a range of spatial scales and to provide geophysical estimates of mass-transfer parameters for Hanford 300 Area materials.
Multi-scale (also called multi-rate) mass transfer (fig. 1) is recognized as a principal control on the efficiency of remediation and natural attenuation of legacy contamination at numerous contaminated sites around the Nation. Evidence of this multi-scale mass transfer includes long "tailing" behavior and concentration rebound observed during pump-and-treat remediation of groundwater.
Figure 1. Schematic diagram of the conceptual model for rate-limited mass transfer (RLMT), where the porous medium is represented by a bicontinuum. Diagram presents a porous medium representative elementary volume (REV), separated into the mobile and immobile domains.
The lack of experimental methods to verify and measure mass transfer in-situ or independently of tracer breakthrough results in substantial uncertainties in estimates of controlling parameters. These uncertainties can affect the effectiveness, efficiency, duration, and costs of remediation activities at federal facilities and at other contaminated sites.
The goal of this applied research project has been to develop and demonstrate geoelectrical characterization of mass-transfer parameters at multiple spatial scales, including at the U.S. Department of Energy's Hanford Site Hanford 300 Area and with Hanford sediments.
Key project components included:
The combination of time-lapse direct-current (DC) resistivity measurements and conventional fluid sampling provides insight into exchange of mass between mobile and immobile domains, whereas CR measurements provide insight into the distribution of length scales associated with the architecture and internal surface area of a porous medium. NMR measurements have provided insight into length-/pore-scale distribution.
To date, work has focused on
Figure 2. Setup of the infiltration/tracer experiment conducted at the Hanford 300 Area Hanford Integrated Field Research Challenge well field, Hanford Site, Washington.
This research was conducted in collaboration with
This work was supported by U.S. Department of Energy Subsurface Biogeochemical Research Program Grant #DE-SC0001773. Additional support was provided by the USGS Toxic Substances Hydrology Program and USGS Groundwater Resources Program.
Day-Lewis, F.D., Haggerty, R., Singha, K., Binley, A.M., Swanson, R.D., Clifford, J., Lane, J.W., Jr., Ward, A., and Johnson, T.C., 2011, Pore network simulation to develop electrical petrophysical relations in the presence of mass transfer [abs.], in AGU fall meeting, San Francisco, California, 5-9 December 2011: American Geophysical Union, Washington, D.C.
Keery, J., Binley, A., Elshenawy, A., Clifford, J. 2012, Markov chain Monte Carlo estimation of distributed Debye relaxations in spectral induced polarization, Geophysics, v. 77, no. 2, p. E159-E170.
Singha, K., Li, L., Day-Lewis, F.D., and Regberg, A.B., 2011, Quantifying transport processes: Are chemically conservative tracers geophysically conservative?, Geophysics., v. 76, no. 1, doi: 10.1190/1.3511356.
Swanson, R. D., Singha, Kamini, Day-Lewis, F.D., Binley, Andrew, Keating,K., and Haggerty, R., 2012, Direct geoelectrical evidence of mass transfer at the laboratory scale: Water Resources Research, v. 48, W10543, doi:10.1029/2012WR012431.
Swanson, R., Singha, Kamini, Day-Lewis, F.D., Haggerty, R., Keating, K., Binley, A., and Clifford, J., 2011, Direct geoelectrical evidence of mass transfer at the lab scale [abs.], in AGU fall meeting, San Francisco, California, 5-9 December 2011: American Geophysical Union, Washington, D.C.
Figure 3. Hydrologist Fred Day-Lewis (USGS Office of Groundwater, Branch of Geophysics) monitors tracer experiment at Hanford 300 Area, Hanford Site, Washington, July 2012. Image credit: U.S. Geological Survey.
Figure 4. Close-up view of tracer experiment infiltration equipment. Hanford 300 Area, Hanford Site, Washington, July 2012. Image credit: U.S. Geological Survey.
Figure 5. Hydrologists prepare electrical resistivity cables for geophysical monitoring of tracer experiment at Hanford 300 Area, Hanford Site, Washington, July 2012. Image credit: U.S. Geological Survey.
Figure 6. Project study area at Hanford 300 Area, Hanford Site, Washington, July 2012. Image credit: U.S. Geological Survey.
For more information on this project, please contact Fred Day-Lewis (Research Hydrologist, USGS OGW Branch of Geophysics), or call the Branch of Geophysics at (860) 487-7402.
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