Abstract
Geophysical measurements, and electrical resistivity tomography (ERT) data in particular, are sensitive to properties that are related (directly or indirectly) to hydrological processes. The challenge is in extracting information from geophysical data at a relevant scale that can be used quantitatively to refine hydrological models and interpret plume behavior. We consider the use of ERT data for examining the impact of recharge on subsurface contamination at the southern-most corner of the S-3 ponds at the Oak Ridge Integrated Field Research Challenge (IFRC) site, TN. The approach we have developed involves the coupled inverse modeling of time-lapse borehole ERT data and hydrogeochemical data, including water level and solute concentration data. The time variations in resistivity are due to changes in total dissolved solids (primarily nitrate), saturation, pH, and temperature. The current approach is to use our understanding of the borehole ERT response to recharge-related processes at the local scale to aid in interpretation of more spatially extensive surface ERT data. We consider a large dataset of time-lapse borehole and surface ERT data collected at the site in 2008 and 2009. We find that the system response to short-term heavy rainstorms is different from the response to seasonal and annual fluctuations and that there is a very good agreement between resistivity structures recovered from borehole and surface ERT data. These results suggest that we can transfer derived insights about petrophysical models and plume behavior across scales, thus permitting remote quantification of recharge-induced processes (such as nitrate dilution) over field-relevant scales.
Original language | English |
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Title of host publication | Society of Exploration Geophysicists International Exposition and 80th Annual Meeting 2010, SEG 2010 |
Publisher | Society of Exploration Geophysicists |
Pages | 3930-3934 |
Number of pages | 5 |
ISBN (Print) | 9781617389801 |
DOIs | |
State | Published - 2010 |
Externally published | Yes |
Event | Society of Exploration Geophysicists International Exposition and 80th Annual Meeting 2010, SEG 2010 - Denver, United States Duration: Oct 17 2010 → Oct 22 2010 |
Publication series
Name | Society of Exploration Geophysicists International Exposition and 80th Annual Meeting 2010, SEG 2010 |
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Conference
Conference | Society of Exploration Geophysicists International Exposition and 80th Annual Meeting 2010, SEG 2010 |
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Country/Territory | United States |
City | Denver |
Period | 10/17/10 → 10/22/10 |
Funding
This work was supported by the U.S. Department of Energy, Contract No. DE-AC02-05CH11231 and by the Environmental Remediation Program of the U.S. DOE Office of Biological and Environmental Research as part of the Oak Ridge National Laboratory IFRC Study. The authors would like to thank Marcella Mueller (ORNL) for assistance with the hydrogeochemical data.