Judith C Thomas
Judith Thomas has been with the U.S. Geological Survey for over 25 years with expertise in groundwater and water quality. Judith is currently a Science Supervisory Hydrologist for the Central Midwest Water Science Center.
Judith has a B.S. from Purdue University and a M.S. from Indiana University. Judith started her career with the USGS in July 2000 in Middleton, Wisconsin where she worked on various projects in databases, the USGS Publications Warehouse, groundwater, surface water, and water quality. In 2006, Judith headed west to join the USGS in Grand Junction, Colorado. Some of Judith's Colorado projects included working in northwest Colorado characterizing groundwater resources in areas of significant energy development for the Bureau of Land Management as well as installing and monitoring a groundwater well network in areas of irrigated Mancos Shale in Delta and Montrose, Colorado. After many enjoyable years in Colorado, Judith relocated back to Wisconsin in 2019 to take her current position at the Central Midwest Water Science Center (CMWSC) with her duty station in Dekalb, IL.
In her current role, Judith supervises and oversees a Science Section within the CMWSC, overseeing a diverse portfolio of projects with an emphasis on groundwater and geophysics. Projects include groundwater level monitoring, groundwater modeling, hydrogeologic frameworks, surface water and groundwater quality monitoring, real time water quality monitoring, geophysical investigations, and flood modeling.
Professional Experience
Supervisory Hydrologist, U.S. Geological Survey Central Midwest Water Science Center, Dekalb, IL, 2019-present
Hydrologist, U.S. Geological Survey Colorado Water Science Center, Grand Juntion, CO, 2006-2019
Hydrologist, U.S. Geological Survey Wisconsin Water Science Center, Middleton, WI, 2000-2006
Education and Certifications
2000, M.S. Geological Sciences, Indiana University
1996, B.S., Environmental Geoscience, Purdue University
Science and Products
Filter Total Items: 21
Chemistry and age of groundwater in the Piceance structural basin, Rio Blanco County, Colorado, 2010-12 Chemistry and age of groundwater in the Piceance structural basin, Rio Blanco County, Colorado, 2010-12
Fourteen monitoring wells were sampled by the U.S. Geological Survey, in cooperation with the Bureau of Land Management, to better understand the chemistry and age of groundwater in the Piceance structural basin in Rio Blanco County, Colorado, and how they may relate to the development of underlying natural-gas reservoirs. Natural gas extraction in the area has been ongoing since at...
Authors
Peter B. McMahon, Judith C. Thomas, Andrew G. Hunt
Chemistry and age of groundwater in bedrock aquifers of the Piceance and Yellow Creek watersheds, Rio Blanco County, Colorado, 2010-12 Chemistry and age of groundwater in bedrock aquifers of the Piceance and Yellow Creek watersheds, Rio Blanco County, Colorado, 2010-12
Fourteen monitoring wells completed in the Uinta and Green River Formations in the Piceance Creek and Yellow Creek watersheds in Rio Blanco County, Colorado, were sampled for chemical, isotopic, and groundwater-age tracers to provide information on the overall groundwater quality, the occurrence and distribution of chemicals that could be related to the development of underlying natural...
Authors
P.B. McMahon, J.C. Thomas, A.G. Hunt
Characterization and data-gap analysis of surface-water quality data in the Piceance study area, western Colorado, 1959–2009 Characterization and data-gap analysis of surface-water quality data in the Piceance study area, western Colorado, 1959–2009
The U.S. Geological Survey, in cooperation with Federal, State, county, and industry partners, developed a Web-accessible common data repository to provide access to historical and current (as of August 2009) water-quality information (available on the Internet at http://rmgsc.cr.usgs.gov/cwqdr/Piceance/index.shtml). Surface-water-quality data from public and private sources were...
Authors
Judith C. Thomas, Jennifer L. Moore, Keelin R. Schaffrath, Jean A. Dupree, Cory A. Williams, Kenneth J. Leib
Overview of groundwater quality in the Piceance Basin, western Colorado, 1946--2009 Overview of groundwater quality in the Piceance Basin, western Colorado, 1946--2009
Groundwater-quality data from public and private sources for the period 1946 to 2009 were compiled and put into a common data repository for the Piceance Basin. The data repository is available on the web at http://rmgsc.cr.usgs.gov/cwqdr/Piceance/index.shtml. A subset of groundwater-quality data from the repository was compiled, reviewed, and checked for quality assurance for this...
Authors
J.C. Thomas, P.B. McMahon
Use of diverse geochemical data sets to determine sources and sinks of nitrate and methane in groundwater, Garfield County, Colorado, 2009 Use of diverse geochemical data sets to determine sources and sinks of nitrate and methane in groundwater, Garfield County, Colorado, 2009
Previous water-quality assessments reported elevated concentrations of nitrate and methane in water from domestic wells screened in shallow zones of the Wasatch Formation, Garfield County, Colorado. In 2009, the U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, analyzed samples collected from 26 domestic wells for a diverse set of...
Authors
P.B. McMahon, J.C. Thomas, A.G. Hunt
Analysis of Dissolved Selenium Loading from Surface Water and Groundwater to Sweitzer Lake, Colorado, 2006-07 Analysis of Dissolved Selenium Loading from Surface Water and Groundwater to Sweitzer Lake, Colorado, 2006-07
Elevated selenium concentrations in streams are a water-quality concern in western Colorado. Sweitzer Lake was placed on the State 303(d) list as impaired with respect to dissolved selenium. In Colorado, the Water Quality Control Division of the Colorado Department of Public Health and Environment is required to develop total maximum daily loads of selenium for the 303(d) list segments...
Authors
Judith C. Thomas
Analysis of Dissolved Selenium Loading for Selected Sites in the Lower Gunnison River Basin, Colorado, 1978-2005 Analysis of Dissolved Selenium Loading for Selected Sites in the Lower Gunnison River Basin, Colorado, 1978-2005
Elevated selenium concentrations in streams are a water-quality concern in western Colorado. The U.S. Geologic Survey, in cooperation with the Colorado Department of Public Health and Environment, summarized selenium loading in the Lower Gunnison River Basin to support the development of total maximum daily selenium loads at sites that represent the cumulative contribution to U.S...
Authors
Judith C. Thomas, Kenneth J. Leib, John W. Mayo
Water-quality characteristics for selected sites within the Milwaukee Metropolitan Sewerage District planning area, Wisconsin, February 2004-September 2005 Water-quality characteristics for selected sites within the Milwaukee Metropolitan Sewerage District planning area, Wisconsin, February 2004-September 2005
The Milwaukee Metropolitan Sewerage District (MMSD) Corridor Study is a three-phase project designed to improve the understanding of water resources in the MMSD planning area to assist managers and policy makers in their decisions. Phase I of the Study involved the compilation of existing data from multiple agencies into a single database. These data were analyzed to identify spatial...
Authors
Judith C. Thomas, Michelle A. Lutz, Jennifer L. Bruce, David J. Graczyk, Kevin D. Richards, David P. Krabbenhoft, Stephen M. Westenbroek, Barbara C. Scudder, Daniel J. Sullivan, Amanda H. Bell
Simulation of the shallow aquifer in the vicinity of Silver Lake, Washington County, Wisconsin, using analytic elements Simulation of the shallow aquifer in the vicinity of Silver Lake, Washington County, Wisconsin, using analytic elements
Shallow ground-water flow in the vicinity of Silver Lake, Washington County, Wisconsin, was investigated to develop an understanding of the hydrology of the shallow aquifer, define a water balance for the lake, delineate ground-water recharge areas for the lake, and to estimate solute flux toward the lake. A single-layer, steady-state, analytic-element model was used to simulate shallow...
Authors
C. P. Dunning, Judith Coffman Thomas, Yu-Feng Lin
Non-USGS Publications**
Mills, T.J., Mast, M.A., Thomas, J., Keith, G., 2016, Controls on Selenium Distribution and Mobilization in an Irrigated Shallow Groundwater System Underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA, Science of the Total Environment 566–567 (2016) 1621–1631, http://dx.doi.org/10.1016/j.scitotenv.2016.06.063.
McMahon, P.B., J.C. Thomas, and A.G. Hunt. 2013b. Groundwater ages and mixing in the Piceance Basin natural gas province, Colorado. Environmental Science & Technology 47, no. 4: 13250–13257.
Olyphant, G.A., Thomas, J.C., Whitman, R. L., Harper, D. Characterization and Statistical Modeling of Bacterial (Escherichia Coli) Outflows from Watersheds that Discharge into Southern Lake Michigan; Environmental Monitoring and Assessment 81: 289–300; 2003
Gotkowitz, M. Zeiler, K.K., Dunning, C.P., Thomas, J.C.; Delineation of zones of Contribution for Municipal Wells in Sauk County, Wisconsin; Wisconsin Open File Report 2002-05; 2002
Thomas, J.C.; Monitoring and Statistical Modeling of Bacterially Contaminated Stream-flow at the Outlet of Burns Ditch, South Shore, Lake Michigan, Indiana; unpublished Master’s Thesis, Indiana University, Bloomington, IN; June 2001
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 21
Chemistry and age of groundwater in the Piceance structural basin, Rio Blanco County, Colorado, 2010-12 Chemistry and age of groundwater in the Piceance structural basin, Rio Blanco County, Colorado, 2010-12
Fourteen monitoring wells were sampled by the U.S. Geological Survey, in cooperation with the Bureau of Land Management, to better understand the chemistry and age of groundwater in the Piceance structural basin in Rio Blanco County, Colorado, and how they may relate to the development of underlying natural-gas reservoirs. Natural gas extraction in the area has been ongoing since at...
Authors
Peter B. McMahon, Judith C. Thomas, Andrew G. Hunt
Chemistry and age of groundwater in bedrock aquifers of the Piceance and Yellow Creek watersheds, Rio Blanco County, Colorado, 2010-12 Chemistry and age of groundwater in bedrock aquifers of the Piceance and Yellow Creek watersheds, Rio Blanco County, Colorado, 2010-12
Fourteen monitoring wells completed in the Uinta and Green River Formations in the Piceance Creek and Yellow Creek watersheds in Rio Blanco County, Colorado, were sampled for chemical, isotopic, and groundwater-age tracers to provide information on the overall groundwater quality, the occurrence and distribution of chemicals that could be related to the development of underlying natural...
Authors
P.B. McMahon, J.C. Thomas, A.G. Hunt
Characterization and data-gap analysis of surface-water quality data in the Piceance study area, western Colorado, 1959–2009 Characterization and data-gap analysis of surface-water quality data in the Piceance study area, western Colorado, 1959–2009
The U.S. Geological Survey, in cooperation with Federal, State, county, and industry partners, developed a Web-accessible common data repository to provide access to historical and current (as of August 2009) water-quality information (available on the Internet at http://rmgsc.cr.usgs.gov/cwqdr/Piceance/index.shtml). Surface-water-quality data from public and private sources were...
Authors
Judith C. Thomas, Jennifer L. Moore, Keelin R. Schaffrath, Jean A. Dupree, Cory A. Williams, Kenneth J. Leib
Overview of groundwater quality in the Piceance Basin, western Colorado, 1946--2009 Overview of groundwater quality in the Piceance Basin, western Colorado, 1946--2009
Groundwater-quality data from public and private sources for the period 1946 to 2009 were compiled and put into a common data repository for the Piceance Basin. The data repository is available on the web at http://rmgsc.cr.usgs.gov/cwqdr/Piceance/index.shtml. A subset of groundwater-quality data from the repository was compiled, reviewed, and checked for quality assurance for this...
Authors
J.C. Thomas, P.B. McMahon
Use of diverse geochemical data sets to determine sources and sinks of nitrate and methane in groundwater, Garfield County, Colorado, 2009 Use of diverse geochemical data sets to determine sources and sinks of nitrate and methane in groundwater, Garfield County, Colorado, 2009
Previous water-quality assessments reported elevated concentrations of nitrate and methane in water from domestic wells screened in shallow zones of the Wasatch Formation, Garfield County, Colorado. In 2009, the U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, analyzed samples collected from 26 domestic wells for a diverse set of...
Authors
P.B. McMahon, J.C. Thomas, A.G. Hunt
Analysis of Dissolved Selenium Loading from Surface Water and Groundwater to Sweitzer Lake, Colorado, 2006-07 Analysis of Dissolved Selenium Loading from Surface Water and Groundwater to Sweitzer Lake, Colorado, 2006-07
Elevated selenium concentrations in streams are a water-quality concern in western Colorado. Sweitzer Lake was placed on the State 303(d) list as impaired with respect to dissolved selenium. In Colorado, the Water Quality Control Division of the Colorado Department of Public Health and Environment is required to develop total maximum daily loads of selenium for the 303(d) list segments...
Authors
Judith C. Thomas
Analysis of Dissolved Selenium Loading for Selected Sites in the Lower Gunnison River Basin, Colorado, 1978-2005 Analysis of Dissolved Selenium Loading for Selected Sites in the Lower Gunnison River Basin, Colorado, 1978-2005
Elevated selenium concentrations in streams are a water-quality concern in western Colorado. The U.S. Geologic Survey, in cooperation with the Colorado Department of Public Health and Environment, summarized selenium loading in the Lower Gunnison River Basin to support the development of total maximum daily selenium loads at sites that represent the cumulative contribution to U.S...
Authors
Judith C. Thomas, Kenneth J. Leib, John W. Mayo
Water-quality characteristics for selected sites within the Milwaukee Metropolitan Sewerage District planning area, Wisconsin, February 2004-September 2005 Water-quality characteristics for selected sites within the Milwaukee Metropolitan Sewerage District planning area, Wisconsin, February 2004-September 2005
The Milwaukee Metropolitan Sewerage District (MMSD) Corridor Study is a three-phase project designed to improve the understanding of water resources in the MMSD planning area to assist managers and policy makers in their decisions. Phase I of the Study involved the compilation of existing data from multiple agencies into a single database. These data were analyzed to identify spatial...
Authors
Judith C. Thomas, Michelle A. Lutz, Jennifer L. Bruce, David J. Graczyk, Kevin D. Richards, David P. Krabbenhoft, Stephen M. Westenbroek, Barbara C. Scudder, Daniel J. Sullivan, Amanda H. Bell
Simulation of the shallow aquifer in the vicinity of Silver Lake, Washington County, Wisconsin, using analytic elements Simulation of the shallow aquifer in the vicinity of Silver Lake, Washington County, Wisconsin, using analytic elements
Shallow ground-water flow in the vicinity of Silver Lake, Washington County, Wisconsin, was investigated to develop an understanding of the hydrology of the shallow aquifer, define a water balance for the lake, delineate ground-water recharge areas for the lake, and to estimate solute flux toward the lake. A single-layer, steady-state, analytic-element model was used to simulate shallow...
Authors
C. P. Dunning, Judith Coffman Thomas, Yu-Feng Lin
Non-USGS Publications**
Mills, T.J., Mast, M.A., Thomas, J., Keith, G., 2016, Controls on Selenium Distribution and Mobilization in an Irrigated Shallow Groundwater System Underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA, Science of the Total Environment 566–567 (2016) 1621–1631, http://dx.doi.org/10.1016/j.scitotenv.2016.06.063.
McMahon, P.B., J.C. Thomas, and A.G. Hunt. 2013b. Groundwater ages and mixing in the Piceance Basin natural gas province, Colorado. Environmental Science & Technology 47, no. 4: 13250–13257.
Olyphant, G.A., Thomas, J.C., Whitman, R. L., Harper, D. Characterization and Statistical Modeling of Bacterial (Escherichia Coli) Outflows from Watersheds that Discharge into Southern Lake Michigan; Environmental Monitoring and Assessment 81: 289–300; 2003
Gotkowitz, M. Zeiler, K.K., Dunning, C.P., Thomas, J.C.; Delineation of zones of Contribution for Municipal Wells in Sauk County, Wisconsin; Wisconsin Open File Report 2002-05; 2002
Thomas, J.C.; Monitoring and Statistical Modeling of Bacterially Contaminated Stream-flow at the Outlet of Burns Ditch, South Shore, Lake Michigan, Indiana; unpublished Master’s Thesis, Indiana University, Bloomington, IN; June 2001
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.