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Carole Johnson

Carole Johnson is Acting Chief of the Hydrogeophysics Branch of the USGS Water Resources Mission Area Earth System Processes Division. Carole provides leadership to USGS hydrologists nationally on development and application of hydrogeophysical methods to groundwater studies through applied research, training, and policy development.

Carole Johnson is a hydrologist with the USGS Earth System Processes Division, Hydrogeophysics Branch in Storrs, Connecticut, where she provides leadership to USGS hydrologists nationally on development and application of hydrogeophysical methods to USGS groundwater studies through applied research, training, and policy development. Carole’s research interests include use of borehole- and surface-geophysical methods and hydraulic testing for characterization of fractured-rock aquifers. She has coauthored ~40 USGS publications on use of hydrogeophysical methods for aquifer characterization for water resources and contaminant investigations. An experienced trainer, Carole has taught numerous webinars and more than 20 hands-on workshops for scientists on geophysical field methods, data processing, and data analysis for groundwater investigations, including through USGS courses, U.S. Environmental Protection Agency, National Groundwater Association Fractured Rock Conference workshops, and classes for licensed environmental professionals in New Jersey and around New England.

Carole currently holds a professional geologists license in New Hampshire, and serves on the board of the Environmental and Engineering Geophysics Society. Carole has a B.S. in geology from Bates College and M.S. in hydrology from the University of New Hampshire.

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Photo of a USGS scientist preparing a spectral gamma tool for use.

Spectral Gamma Borehole Logging

Spectral gamma borehole geophysical methods measure natural-gamma energy spectra, which are caused by the decay of uranium, thorium, potassium-40, and anthropogenic radioactive isotopes. Spectral gamma data can be used to identify and quantify the amount of uranium, thorium, and potassium-40 isotopes detected in boreholes.
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Water Resources
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Spectral Gamma Borehole Logging

Spectral gamma borehole geophysical methods measure natural-gamma energy spectra, which are caused by the decay of uranium, thorium, potassium-40, and anthropogenic radioactive isotopes. Spectral gamma data can be used to identify and quantify the amount of uranium, thorium, and potassium-40 isotopes detected in boreholes.
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Scientists hold borehole tool.

Borehole Nuclear Magnetic Resonance (NMR)

Borehole nuclear magnetic resonance (NMR) is an emerging geophysical method being applied to hydrogeology investigations.
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Water Resources
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Borehole Nuclear Magnetic Resonance (NMR)

Borehole nuclear magnetic resonance (NMR) is an emerging geophysical method being applied to hydrogeology investigations.
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Plot of sample gamma energy spectrum.

Understanding Spectral Gamma: Fundamentals of Nuclear Geophysics

The principles essential to the interpretation of gamma, gamma-spectrometry, gamma-gamma, and various types of neutron logs include the nature of subatomic particles and the particles and photons emitted by unstable isotopes.
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Water Resources
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Understanding Spectral Gamma: Fundamentals of Nuclear Geophysics

The principles essential to the interpretation of gamma, gamma-spectrometry, gamma-gamma, and various types of neutron logs include the nature of subatomic particles and the particles and photons emitted by unstable isotopes.
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Selected borehole geophysical logs from three contaminant sites in California, Wisconsin, and New Jersey

Borehole geophysical logs were collected to characterize bedrock aquifers at three contamination sites located in California, Wisconsin, and New Jersey. The data were collected by the U.S. Geological Survey (USGS) and the University of Guelph from 2014 to 2015 as part of the U.S. Department of Defense Strategic Environmental Research and Development Program (SERDP) and Environmental Security Techn

Geophysical Data Collected for an Assessment of a Proposed Landfill Site in Fredericktown, Missouri, June 2018

In June 2018, the U.S. Geological Survey (USGS) in cooperation with the U.S. Environmental Protection Agency (EPA) collected geophysical measurements to help evaluate the suitability of a proposed landfill site for disposing mine-waste materials in Fredericktown, Missouri. Geophysical methods were used to evaluate and characterize the unconsolidated sediment (i.e., regolith) above the crystalline
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Water Resources

Borehole, Surface and Water-Borne Geophysical Surveys at the Callahan Mine Superfund Site in Brooksville, Maine: October 2016 to July 2018

From October 2016 to July 2018, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers and Maine Department of Transportation, collected surface, marine and borehole geophysical surveys to characterize the subsurface materials on land and under the water at a former mine facility in Brooksville, Maine. Three water-based geophysical methods were used to evaluate the geomet
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New England Water Science Center

Surface geophysics investigations at Edwards Air Force Research Laboratory, Antelope Valley, California, 2018

The Air Force Research Laboratory (AFRL) is about 7 kilometers southwest of Boron, California, and covers 320 square kilometers of Edwards Air Force Base. The AFRL consists of 12 facilities for testing full-size rocket engines, engine components, and liquid and solid propellants. The historical release of contaminants from rocket test stands, evaporation ponds, burn pits, catch basins, and leaking
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California Water Science Center

Transient Electromagnetics, Passive Seismic, and Borehole Electromagnetics, Gamma, and Nuclear Magnetic Resonance Methods to Characterize an Unconsolidated Aquifer on Cape Cod, Massachusetts

Reserved for CDJ. Transient Electromagnetics, Passive Seismic, and Borehole Electromagnetics, Gamma, and Nuclear Magnetic Resonance Methods to Characterize an Unconsolidated Aquifer on Cape Cod, Massachusetts Johnson, White, Phillips, Pappas, Hull, LeBlanc, and Lane
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Water Resources

Geophysical Data Collected in the Cedar River Floodplain, Cedar Rapids, Iowa, 2015-2017

A suite of geophysical methods was used along the Cedar River in Cedar Rapids, Iowa to support the hydrogeologic characterization of the alluvial aquifer associated with the river and to assess the area for suitability for larger-scale airborne geophysics. The aquifer is comprised of sand and gravel, interbedded with finer sediments, and underlain by carbonate-dominated bedrock. The aquifer is the
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Central Midwest Water Science Center

Temperature and seepage data from a lake-bottom permeable reactive barrier, Ashumet Pond, Falmouth, MA, 2004-2015.

These data were collected to evaluate groundwater/surface-water exchange in the area of a lake-bottom permeable reactive barrier and to assess changes in groundwater seepage over the period between 2004 and 2015. This data release includes geospatial datasets, comma separated values (.csv) files, and associated FGDC-compliant metadata representing data collected between 2004 and 2015 as part of a
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New England Water Science Center

Transient Electromagnetic Surveys Collected for Delineation of Saline Groundwater in the Genesee Valley New York: October-November 2016

In late October and early November 2016, transient electromagnetic (TEM) data were acquired at two locations in Livingston County, in western New York, in order to characterize the subsurface resistivity structure in support of a U.S. Geological Survey groundwater investigation. The TEM data were collected as part of a pilot project to evaluate geophysical methods to characterize the valley-fill s
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Water Resources, Groundwater and Streamflow Information Program
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Application of frequency- and time-domain electromagnetic surveys to characterize hydrostratigraphy and landfill construction at the Amargosa Desert Research Site, Beatty, Nevada

In 2014 and 2015, the U.S. Geological Survey (USGS), conducted frequency-domain electromagnetic (FDEM) surveys at the USGS Amargosa Desert Research Site (ADRS), approximately 17 kilometers (km) south of Beatty, Nevada. The FDEM surveys were conducted within and adjacent to a closed low-level radioactive waste disposal site located at the ADRS. FDEM surveys were conducted on a grid of north-south a
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Ecosystems, Toxic Substances Hydrology, Environmental Health Program

Statistical comparison of methods for estimating sediment thickness from Horizontal-to-Vertical Spectral Ratio (HVSR) seismic methods: An example from Tylerville, Connecticut, USA

Determining sediment thickness and delineating bedrock topography are important for assessing groundwater availability and characterizing contamination sites. In recent years, the horizontal-to-vertical spectral ratio (HVSR) seismic method has emerged as a non-invasive, cost-effective approach for estimating the thickness of unconsolidated sediments above bedrock. Using a three-component seismomet
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Ecosystems, Toxic Substances Hydrology, Environmental Health Program

Characterization of fractures and flow zones in a contaminated crystalline-rock aquifer in the Tylerville section of Haddam, Connecticut

The U.S. Geological Survey, in cooperation with the Connecticut Department of Energy and Environmental Protection, investigated the characteristics of the bedrock aquifer in the Tylerville section of Haddam, Connecticut, from June to August 2014. As part of this investigation, geophysical logs were collected from six water-supply wells and were analyzed to (1) identify well construction, (2) deter

Imaging pathways in fractured rock using three-dimensional electrical resistivity tomography

Major challenges exist in delineating bedrock fracture zones because these cause abrupt changes in geological and hydrogeological properties over small distances. Borehole observations cannot sufficiently capture heterogeneity in these systems. Geophysical techniques offer the potential to image properties and processes in between boreholes. We used three-dimensional cross borehole electrical resi
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Water Resources, Ecosystems, Toxic Substances Hydrology, Environmental Health Program, New Jersey Water Science Center

Flow and sorption controls of groundwater arsenic in individual boreholes from bedrock aquifers in central Maine, USA

To understand the hydrogeochemical processes regulating well water arsenic (As) evolution in fractured bedrock aquifers, three domestic wells with [As] up to 478 μg/L are investigated in central Maine. Geophysical logging reveals that fractures near the borehole bottom contribute 70-100% of flow. Borehole and fracture water samples from various depths show significant proportions of As (up to 69%)
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Water Resources, New England Water Science Center

A small-diameter NMR logging tool for groundwater investigations

A small-diameter nuclear magnetic resonance (NMR) logging tool has been developed and field tested at various sites in the United States and Australia. A novel design approach has produced relatively inexpensive, small-diameter probes that can be run in open or PVC-cased boreholes as small as 2 inches in diameter. The complete system, including surface electronics and various downhole probes, has
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Water Resources

Physical, chemical, and isotopic data from groundwater in the watershed of Mirror Lake, and in the vicinity of Hubbard Brook, near West Thornton, New Hampshire, 1983 to 1997

Research on the hydrogeologic setting of Mirror Lake near West Thornton, New Hampshire (43° 56.5’ N, 71° 41.5’ W), includes the study of the physical, chemical, and isotopic characteristics of groundwater in the vicinity of the lake and nearby Hubbard Brook. Presented here are those physical, chemical, and isotopic data for the period 1983 to 1997. Data were collected from observation wells instal
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Groundwater and Streamflow Information Program, New England Water Science Center, Pennsylvania Water Science Center

Well network installation and hydrogeologic data collection, Assateague Island National Seashore, Worcester County, Maryland, 2010

The U.S. Geological Survey, as part of its Climate and Land Use Change Research and Development Program, is conducting a multi-year investigation to assess potential impacts on the natural resources of Assateague Island National Seashore, Maryland that may result from changes in the hydrologic system in response to projected sea-level rise. As part of this effort, 26 monitoring wells were installe
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Water Resources, Ecosystems, Toxic Substances Hydrology, Environmental Health Program, Maryland-Delaware-D.C. Water Science Center, New England Water Science Center

Spatially variable stage-driven groundwater-surface water interaction inferred from time-frequency analysis of distributed temperature sensing data

Characterization of groundwater-surface water exchange is essential for improving understanding of contaminant transport between aquifers and rivers. Fiber-optic distributed temperature sensing (FODTS) provides rich spatiotemporal datasets for quantitative and qualitative analysis of groundwater-surface water exchange. We demonstrate how time-frequency analysis of FODTS and synchronous river stage

Collection, processing, and interpretation of ground-penetrating radar data to determine sediment thickness at selected locations in Deep Creek Lake, Garrett County, Maryland, 2007

The U.S. Geological Survey collected geophysical data in Deep Creek Lake in Garrett County, Maryland, between September 17 through October 4, 2007 to assist the Maryland Department of Natural Resources to better manage resources of the Lake. The objectives of the geophysical surveys were to provide estimates of sediment thickness in shallow areas around the Lake and to test the usefulness of three
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Water Resources, Maryland-Delaware-D.C. Water Science Center

Borehole geophysical investigation of a formerly used defense site, Machiasport, Maine, 2003-2006

The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, collected borehole geophysical logs in 18 boreholes and interpreted the data along with logs from 19 additional boreholes as part of an ongoing, collaborative investigation at three environmental restoration sites in Machiasport, Maine. These sites, located on hilltops overlooking the seacoast, formerly were used for
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Water Resources, Ecosystems, Toxic Substances Hydrology, Groundwater and Streamflow Information Program, Environmental Health Program, New York Water Science Center

Use of electrical imaging and distributed temperature sensing methods to characterize surface water–groundwater exchange regulating uranium transport at the Hanford 300 Area, Washington

We explored the use of continuous waterborne electrical imaging (CWEI), in conjunction with fiber‐optic distributed temperature sensor (FO‐DTS) monitoring, to improve the conceptual model for uranium transport within the Columbia River corridor at the Hanford 300 Area, Washington. We first inverted resistivity and induced polarization CWEI data sets for distributions of electrical resistivity and
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Ecosystems, Toxic Substances Hydrology, Groundwater and Streamflow Information Program, Environmental Health Program

Fractured Rock Geophysical Toolbox Method Selection Tool (FRGT-MST)

The Fractured Rock Geophysical Toolbox Method Selection Tool (FRGT-MST) is an Excel-based tool for identification of geophysical methods most likely to be appropriate for project goals and site conditions.

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Water Resources

FLASH: A Computer Program for Flow-Log Analysis of Single Holes

FLASH (Flow-Log Analysis of Single Holes) is a computer program for the analysis of borehole vertical flow logs.

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Water Resources, Groundwater and Streamflow Information Program, Nevada Water Science Center

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