Peter B McMahon
Peter is a Research Hydrologist with the USGS Colorado Water Science Center in Lakewood, CO.
Pete McMahon’s current research interests include understanding the effects of hydrocarbon production activities on groundwater quality and identifying natural and human processes that create regional- and national-scale patterns in the chemistry of groundwater. He uses geochemical, isotope, noble-gas, and groundwater-age tracers to understand the origin and fate of chemicals of concern in groundwater.
Education and Certifications
Ph.D., 1990, Geology, University of South Carolina at Columbia
M.A., 1984, Geology, University of Texas at Austin
B.S., 1981, Geology, University of Missouri at Columbia
Science and Products
Filter Total Items: 14
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Methane in aquifers used for public supply in the United States
In 2013 to 2015, 833 public supply wells in 15 Principal aquifers in the U.S. were sampled to identify which aquifers contained high methane concentrations (>1 mg/L) and determine the geologic, hydrologic, and geochemical conditions associated with high concentrations. This study represents the first national assessment of methane in aquifers used for public supply in the U.S. and, as such, advanc
Authors
Peter B. McMahon, Kenneth Belitz, Jeannie R. B. Barlow, Bryant C. Jurgens
Fraction of young water as an indicator of aquifer vulnerability along two regional flow paths in the Mississippi embayment aquifer system, southeastern USA
Wells along two regional flow paths were sampled to characterize changes in water quality and the vulnerability to contamination of the Memphis aquifer across a range of hydrologic and land-use conditions in the southeastern United States. The flow paths begin in the aquifer outcrop area and end at public supply wells in the confined parts of the aquifer at Memphis, Tennessee. Age-date tracer (e.g
Authors
James A. Kingsbury, Jeannie R. B. Barlow, Bryant C. Jurgens, Peter B. McMahon, John K. Carmichael
Methane and benzene in drinking-water wells overlying the Eagle Ford, Fayetteville, and Haynesville Shale hydrocarbon production areas
Water wells (n = 116) overlying the Eagle Ford, Fayetteville, and Haynesville Shale hydrocarbon production areas were sampled for chemical, isotopic, and groundwater-age tracers to investigate the occurrence and sources of selected hydrocarbons in groundwater. Methane isotopes and hydrocarbon gas compositions indicate most of the methane in the wells was biogenic and produced by the CO2 reduction
Authors
Peter B. McMahon, Jeannie R. B. Barlow, Mark A. Engle, Kenneth Belitz, Patricia B. Ging, Andrew G. Hunt, Bryant C. Jurgens, Yousif K. Kharaka, Roland W. Tollett, Timothy M. Kresse
Preliminary results from exploratory sampling of wells for the California oil, gas, and groundwater program, 2014–15
Introduction
In 2014 and 2015, the U.S. Geological Survey (USGS) sampled water wells in the Los Angeles Basin and southern San Joaquin Valley, California, and oil wells in the San Joaquin Valley for analysis of multiple chemical, isotopic, and groundwater-age tracers. The purpose of this reconnaissance sampling was to evaluate the utility of tracers for assessing the effects of oil and gas product
Authors
Peter B. McMahon, Justin T. Kulongoski, Michael T. Wright, Michael T. Land, Matthew K. Landon, Isabelle M. Cozzarelli, Avner Vengosh, George R. Aiken
Response of selenium concentrations in groundwater to seasonal canal leakage, lower Gunnison River Basin, Colorado, 2013
Selenium is a water-quality concern in the lower Gunnison River Basin because irrigation water interacting with seleniferous soils derived from the Mancos Shale Formation has mobilized selenium and increased its concentrations in surface water. Understanding the occurrence of elevated selenium concentrations in groundwater is necessary because groundwater discharge is an important source of seleni
Authors
J.I. Linard, P. B. McMahon, L. R. Arnold, J.C. Thomas
Chemical considerations for an updated National assessment of brackish groundwater resources
Brackish groundwater (BGW) is increasingly used for water supplies where fresh water is scarce, but the distribution and availability of such resources have not been characterized at the national scale in the United States since the 1960s. Apart from its distribution and accessibility, BGW usability is a function of the chemical requirements of the intended use, chemical characteristics of the res
Authors
Peter B. McMahon, John Karl Böhlke, Katharine Dahm, David L. Parkhurst, David W. Anning, Jennifer S. Stanton
The water-energy nexus: an earth science perspective
Water availability and use are closely connected with energy development and use. Water cannot be delivered to homes, businesses, and industries without energy, and most forms of energy development require large amounts of water. The United States faces two significant and sometimes competing challenges: to provide sustainable supplies of freshwater for humans and ecosystems and to ensure adequate
Authors
Richard W. Healy, William M. Alley, Mark A. Engle, Peter B. McMahon, Jerad D. Bales
The quality of our Nation's waters: Water quality in principal aquifers of the United States, 1991-2010
About 130 million people in the United States rely on groundwater for drinking water, and the need for high-quality drinking-water supplies becomes more urgent as our population grows. Although groundwater is a safe, reliable source of drinking water for millions of people nationwide, high concentrations of some chemical constituents can pose potential human-health concerns. Some of these contamin
Authors
Leslie A. DeSimone, Peter B. McMahon, Michael R. Rosen
Quality and age of shallow groundwater in the Bakken Formation production area, Williston Basin, Montana and North Dakota
The quality and age of shallow groundwater in the Bakken Formation production area were characterized using data from 30 randomly distributed domestic wells screened in the upper Fort Union Formation. Comparison of inorganic and organic chemical concentrations to health based drinking-water standards, correlation analysis of concentrations with oil and gas well locations, and isotopic data give no
Authors
Peter B. McMahon, Rodney R. Caldwell, Joel M. Galloway, Joshua F. Valder, Andrew G. Hunt
Groundwater ages and mixing in the Piceance Basin natural gas province, Colorado
Reliably identifying the effects of energy development on groundwater quality can be difficult because baseline assessments of water quality completed before the onset of energy development are rare and because interactions between hydrocarbon reservoirs and aquifers can be complex, involving both natural and human processes. Groundwater age and mixing data can strengthen interpretations of monito
Authors
Peter B. McMahon, Judith C. Thomas, Andrew G. Hunt
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 least the 1950
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
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-gas reserv
Authors
P. B. McMahon, J.C. Thomas, A.G. Hunt
Science and Products
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Filter Total Items: 112
Methane in aquifers used for public supply in the United States
In 2013 to 2015, 833 public supply wells in 15 Principal aquifers in the U.S. were sampled to identify which aquifers contained high methane concentrations (>1 mg/L) and determine the geologic, hydrologic, and geochemical conditions associated with high concentrations. This study represents the first national assessment of methane in aquifers used for public supply in the U.S. and, as such, advancAuthorsPeter B. McMahon, Kenneth Belitz, Jeannie R. B. Barlow, Bryant C. JurgensFraction of young water as an indicator of aquifer vulnerability along two regional flow paths in the Mississippi embayment aquifer system, southeastern USA
Wells along two regional flow paths were sampled to characterize changes in water quality and the vulnerability to contamination of the Memphis aquifer across a range of hydrologic and land-use conditions in the southeastern United States. The flow paths begin in the aquifer outcrop area and end at public supply wells in the confined parts of the aquifer at Memphis, Tennessee. Age-date tracer (e.gAuthorsJames A. Kingsbury, Jeannie R. B. Barlow, Bryant C. Jurgens, Peter B. McMahon, John K. CarmichaelMethane and benzene in drinking-water wells overlying the Eagle Ford, Fayetteville, and Haynesville Shale hydrocarbon production areas
Water wells (n = 116) overlying the Eagle Ford, Fayetteville, and Haynesville Shale hydrocarbon production areas were sampled for chemical, isotopic, and groundwater-age tracers to investigate the occurrence and sources of selected hydrocarbons in groundwater. Methane isotopes and hydrocarbon gas compositions indicate most of the methane in the wells was biogenic and produced by the CO2 reductionAuthorsPeter B. McMahon, Jeannie R. B. Barlow, Mark A. Engle, Kenneth Belitz, Patricia B. Ging, Andrew G. Hunt, Bryant C. Jurgens, Yousif K. Kharaka, Roland W. Tollett, Timothy M. KressePreliminary results from exploratory sampling of wells for the California oil, gas, and groundwater program, 2014–15
Introduction In 2014 and 2015, the U.S. Geological Survey (USGS) sampled water wells in the Los Angeles Basin and southern San Joaquin Valley, California, and oil wells in the San Joaquin Valley for analysis of multiple chemical, isotopic, and groundwater-age tracers. The purpose of this reconnaissance sampling was to evaluate the utility of tracers for assessing the effects of oil and gas productAuthorsPeter B. McMahon, Justin T. Kulongoski, Michael T. Wright, Michael T. Land, Matthew K. Landon, Isabelle M. Cozzarelli, Avner Vengosh, George R. AikenResponse of selenium concentrations in groundwater to seasonal canal leakage, lower Gunnison River Basin, Colorado, 2013
Selenium is a water-quality concern in the lower Gunnison River Basin because irrigation water interacting with seleniferous soils derived from the Mancos Shale Formation has mobilized selenium and increased its concentrations in surface water. Understanding the occurrence of elevated selenium concentrations in groundwater is necessary because groundwater discharge is an important source of seleniAuthorsJ.I. Linard, P. B. McMahon, L. R. Arnold, J.C. ThomasChemical considerations for an updated National assessment of brackish groundwater resources
Brackish groundwater (BGW) is increasingly used for water supplies where fresh water is scarce, but the distribution and availability of such resources have not been characterized at the national scale in the United States since the 1960s. Apart from its distribution and accessibility, BGW usability is a function of the chemical requirements of the intended use, chemical characteristics of the resAuthorsPeter B. McMahon, John Karl Böhlke, Katharine Dahm, David L. Parkhurst, David W. Anning, Jennifer S. StantonThe water-energy nexus: an earth science perspective
Water availability and use are closely connected with energy development and use. Water cannot be delivered to homes, businesses, and industries without energy, and most forms of energy development require large amounts of water. The United States faces two significant and sometimes competing challenges: to provide sustainable supplies of freshwater for humans and ecosystems and to ensure adequateAuthorsRichard W. Healy, William M. Alley, Mark A. Engle, Peter B. McMahon, Jerad D. BalesThe quality of our Nation's waters: Water quality in principal aquifers of the United States, 1991-2010
About 130 million people in the United States rely on groundwater for drinking water, and the need for high-quality drinking-water supplies becomes more urgent as our population grows. Although groundwater is a safe, reliable source of drinking water for millions of people nationwide, high concentrations of some chemical constituents can pose potential human-health concerns. Some of these contaminAuthorsLeslie A. DeSimone, Peter B. McMahon, Michael R. RosenQuality and age of shallow groundwater in the Bakken Formation production area, Williston Basin, Montana and North Dakota
The quality and age of shallow groundwater in the Bakken Formation production area were characterized using data from 30 randomly distributed domestic wells screened in the upper Fort Union Formation. Comparison of inorganic and organic chemical concentrations to health based drinking-water standards, correlation analysis of concentrations with oil and gas well locations, and isotopic data give noAuthorsPeter B. McMahon, Rodney R. Caldwell, Joel M. Galloway, Joshua F. Valder, Andrew G. HuntGroundwater ages and mixing in the Piceance Basin natural gas province, Colorado
Reliably identifying the effects of energy development on groundwater quality can be difficult because baseline assessments of water quality completed before the onset of energy development are rare and because interactions between hydrocarbon reservoirs and aquifers can be complex, involving both natural and human processes. Groundwater age and mixing data can strengthen interpretations of monitoAuthorsPeter B. McMahon, Judith C. Thomas, Andrew G. HuntChemistry 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 least the 1950AuthorsPeter B. McMahon, Judith C. Thomas, Andrew G. HuntChemistry 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-gas reservAuthorsP. B. McMahon, J.C. Thomas, A.G. Hunt - News