Integration of Large-Scale Electrical Imaging into Geological Framework Development and Refinement

Journal Article · 04 April 2022 · Environmental Processes

DOI: https://doi.org/10.1007/s40710-022-00570-2 · OSTI ID:1887218

Robinson, Judith L. ^[1]; Thomle, Jonathan N. ^[1]; McFarland, Douglas P. ^[1]; Deters, Katherine A. ^[1]; Rockhold, Mark L. ^[1]; Day-Lewis, Frederick D.  ^[1]; Freedman, Vicky L. ^[1]

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1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Geologic framework models (GFMs) are critical to the construction of reliable simulation models of groundwater flow and contaminant transport. To support GFM development, direct information (e.g., core samples, fluid samples, hydraulic testing) tends to be sparse and separated by large distances relative to the spatial scales of aquifer heterogeneity. There are additional challenges associated with highly contaminated legacy waste sites, where drilling is particularly costly, and invasive sampling requires specialized handling and disposal of hazardous materials. At these sites in particular, non-invasive geophysical imaging can play an important role in filling spatial gaps between boreholes and reducing characterization costs by optimizing and minimizing the number of necessary boreholes. Here this paper presents a case study demonstrating the use of large-scale (> 30 km²) electrical mapping to identify hydrostratigraphy and potential paleochannels at the Hanford Site, located in Washington State, USA. In two field campaigns, over 36 line-kilometers of electrical resistivity tomography (ERT) data were collected along 14 transects. ERT surveys were sited and performed to image critical aspects (e.g., paleochannels, stratigraphic contacts) of the subsurface, demonstrating a general workflow for integrating ERT with GFM development. Inconsistencies between the GFM and ERT were catalogued to provide a basis for future site characterization using complementary geophysical methods and (or) direct sampling.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1887218
• Report Number(s): PNNL-SA-166767
• Journal Information: Environmental Processes, Journal Name: Environmental Processes Journal Issue: 2 Vol. 9; ISSN 2198-7491
• Publisher: Springer NatureCopyright Statement
• Country of Publication: United States
• Language: English