Greg's U.S. Geological Survey experience began working for both the Office of Water Quality and the National Water-Quality Assessment Program (NAWQA). As part of these efforts, he conducted numerous quality-control studies and coordinated national-scale water-quality studies. Greg currently enjoys working with a great staff focused on all aspects of the hydrologic cycle.
Notable highlights of Greg's career include: (1) co-developing recommendations for the development of a modern analytical facility for the Afghan Geological Survey; (2) presenting findings of organic contaminants in source and finished water of community water systems at a Congressional briefing and assisting in a related Congressional briefing; (3) the design, coordination, and reporting of results from a study conducted in cooperation with the American Water Works Association Research Foundation and the Metropolitan Water District of Southern California which monitored source water derived from groundwater, rivers, and reservoirs in 35 states and 120 community water systems; and (4) providing technical leadership, advice, and serving as lead or co-author of about 35 agency reports. Dr. Delzer was also the recipient of the Department of Interior Superior Service Award.
Education and Certifications
Bachelor of Science in Civil Engineering, Master of Science in Civil Engineering, and a Ph.D. in Atmospheric and Environmental Science; all from South Dakota School of Mines and Technology
Science and Products
Water Resources of the Energy Development Area of the Williston Basin in Eastern Montana, Western North Dakota, and Northwest South Dakota
A set of comma-separated value tables containing data for streamflow, water quality, surface-water features, and produced waters in the energy development area of the Williston Basin in eastern Montana, western North Dakota, and northwest South Dakota.
Data to Estimate Water Use Associated with Continuous Oil and Gas Development, Williston Basin, United States, 1980-2017 (ver. 3.0, October 2022)
This U.S. Geological Survey (USGS) Data Release provides data to estimate water use associated with continuous oil and gas development in the Williston Basin during 1980-2017. Data included:
Data records from the national hydraulic fracturing chemical registry, FracFocus, including the state, county, latitude and longitude of each well, and the year and volume of water used for hydraulic fracturi
Delineation of the hydrogeologic framework of the Big Sioux aquifer near Sioux Falls, South Dakota, using airborne electromagnetic data
The U.S. Geological Survey, in cooperation with the City of Sioux Falls, South Dakota, began developing a groundwater-flow model of the Big Sioux aquifer in 2014 that will enable the City to make more informed water management decisions, such as delineation of areas of the greatest specific yield, which is crucial for locating municipal wells. Innovative tools are being evaluated as part of this s
Filter Total Items: 31
Research needs identified for potential effects of energy development activities on environmental resources of the Williston Basin, United States
Unconventional oil and gas development that uses horizontal drilling and hydraulic fracturing is rapidly changing the landscape and exponentially increasing oil production within the Williston Basin, especially in North Dakota and eastern Montana. The activities associated with unconventional oil and gas development are complex and wide reaching and include, in part, road and well-pad construction
Authors
Gregory C. Delzer, Max Post van der Burg
Potential effects of energy development on environmental resources of the Williston Basin in Montana, North Dakota, and South Dakota—Water resources
The Williston Basin has been a leading oil and gas producing area for more than 50 years. While oil production initially peaked within the Williston Basin in the mid-1980s, production rapidly increased in the mid-2000s, largely because of improved horizontal (directional) drilling and hydraulic fracturing methods. In 2012, energy development associated with the Bakken Formation was identified as a
Authors
Timothy T. Bartos, Steven K. Sando, Todd M. Preston, Gregory C. Delzer, Robert F. Lundgren, Rochelle A. Nustad, Rodney R. Caldwell, Zell E. Peterman, Bruce D. Smith, Kathleen M. Macek-Rowland, David A. Bender, Jill D. Frankforter, Joel M. Galloway
Assessment of streamflow trends in the eastern Dakotas, water years 1960–2019
Hydrologic extremes, whether periods of drought or flooding, are occurring more frequently with greater severity and can have substantial economic impacts. Along with flooding, the timing and volume of streamflow also is changing across the United States. The focus of this report is to characterize a unique trend in mean annual streamflow occurring in eastern North and South Dakota, hereafter refe
Authors
Parker A. Norton, Gregory C. Delzer, Joshua F. Valder, Wyatt S. Tatge, Karen R. Ryberg
Estimates of water use associated with continuous oil and gas development in the Williston Basin, North Dakota and Montana, 2007–17
This study of water use associated with development of continuous oil and gas resources in the Williston Basin is intended to provide a preliminary model-based analysis of water use in major regions of production of continuous oil and gas resources in the United States. Direct, indirect, and ancillary water use associated with development of continuous oil and gas resources in the Williston Basin
Authors
Ryan R. McShane, Theodore B. Barnhart, Joshua F. Valder, Seth S. Haines, Kathleen M. Macek-Rowland, Janet M. Carter, Gregory C. Delzer, Joanna N. Thamke
Analytical framework to estimate water use associated with continuous oil and gas development
An analytical framework was designed to estimate water use associated with continuous oil and gas (COG) development in support of the U.S. Geological Survey Water Availability and Use Science Program. This framework was developed to better understand the relation between the production of COG resources for energy and the amount of water needed to sustain this type of energy development in the Unit
Authors
Joshua F. Valder, Ryan R. McShane, Theodore B. Barnhart, Spencer L. Wheeling, Janet M. Carter, Kathleen M. Macek-Rowland, Gregory C. Delzer, Joanna N. Thamke
Construction of a groundwater-flow model for the Big Sioux Aquifer using airborne electromagnetic methods, Sioux Falls, South Dakota
The city of Sioux Falls is the fastest growing community in South Dakota. In response to this continued growth and planning for future development, Sioux Falls requires a sustainable supply of municipal water. Planning and managing sustainable groundwater supplies requires a thorough understanding of local groundwater resources. The Big Sioux aquifer consists of glacial outwash sands and gravels a
Authors
Joshua F. Valder, Gregory C. Delzer, Janet M. Carter, Bruce D. Smith, David V. Smith
Estimating national water use associated with unconventional oil and gas development
The U.S. Geological Survey’s (USGS) Water Availability and Use Science Program (WAUSP) goals are to provide a more accurate assessment of the status of the water resources of the United States and assist in the determination of the quantity and quality of water that is available for beneficial uses. These assessments would identify long-term trends or changes in water availability since the 1950s
Authors
Janet M. Carter, Kathleen M. Macek-Rowland, Joanna N. Thamke, Gregory C. Delzer
Anthropogenic organic compounds in source water of select community water systems in the United States, 2002-10
Drinking water delivered by community water systems (CWSs) comes from one or both of two sources: surface water and groundwater. Source water is raw, untreated water used by CWSs and is usually treated before distribution to consumers. Beginning in 2002, the U.S. Geological Survey’s (USGS) National Water-Quality Assessment Program initiated Source Water-Quality Assessments (SWQAs) at select CWSs a
Authors
Joshua F. Valder, Gregory C. Delzer, James A. Kingsbury, Jessica A. Hopple, Curtis V. Price, David A. Bender
Percent recoveries of anthropogenic organic compounds with and without the addition of ascorbic acid to preserve finished-water samples containing free chlorine, 2004-10
This report presents finished-water matrix-spike recoveries of 270 anthropogenic organic compounds with and without the addition of ascorbic acid to preserve water samples containing free chlorine. Percent recoveries were calculated using analytical results from a study conducted during 2004-10 for the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). The stud
Authors
Joshua F. Valder, Gregory C. Delzer, David A. Bender, Curtis V. Price
Concentration data for anthropogenic organic compounds in groundwater, surface water, and finished water of selected community water systems in the United States, 2002-10
The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States. As used in SWQA studies, source water is the raw (ambient) water collected at
Authors
Janet M. Carter, James A. Kingsbury, Jessica A. Hopple, Gregory C. Delzer
Occurrence of volatile organic compounds in selected urban streams in the United States, 1995-2003
As part of the U.S. Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) Program, urban indicator sites were monitored to (1) characterize the stream quality from drainage basins with predominantly residential and commercial land use, and (2) determine which selected natural and anthropogenic factors affect stream quality. A total of 869 water samples were collected from 37 urban s
Authors
David A. Bender, Gregory C. Delzer, Curtis V. Price, John S. Zogorski
Anthropogenic organic compounds in source water of selected community water systems that use groundwater, 2002-05
Source water, defined as groundwater collected from a community water system well prior to water treatment, was sampled from 221 wells during October 2002 to July 2005 and analyzed for 258 anthropogenic organic compounds. Most of these compounds are unregulated in drinking water and include pesticides and pesticide degradates, gasoline hydrocarbons, personal-care and domestic-use products, and sol
Authors
Jessica A. Hopple, Gregory C. Delzer, James A. Kingsbury
Science and Products
- Data
Water Resources of the Energy Development Area of the Williston Basin in Eastern Montana, Western North Dakota, and Northwest South Dakota
A set of comma-separated value tables containing data for streamflow, water quality, surface-water features, and produced waters in the energy development area of the Williston Basin in eastern Montana, western North Dakota, and northwest South Dakota.Data to Estimate Water Use Associated with Continuous Oil and Gas Development, Williston Basin, United States, 1980-2017 (ver. 3.0, October 2022)
This U.S. Geological Survey (USGS) Data Release provides data to estimate water use associated with continuous oil and gas development in the Williston Basin during 1980-2017. Data included: Data records from the national hydraulic fracturing chemical registry, FracFocus, including the state, county, latitude and longitude of each well, and the year and volume of water used for hydraulic fracturi - Maps
Delineation of the hydrogeologic framework of the Big Sioux aquifer near Sioux Falls, South Dakota, using airborne electromagnetic data
The U.S. Geological Survey, in cooperation with the City of Sioux Falls, South Dakota, began developing a groundwater-flow model of the Big Sioux aquifer in 2014 that will enable the City to make more informed water management decisions, such as delineation of areas of the greatest specific yield, which is crucial for locating municipal wells. Innovative tools are being evaluated as part of this s - Multimedia
- Publications
Filter Total Items: 31
Research needs identified for potential effects of energy development activities on environmental resources of the Williston Basin, United States
Unconventional oil and gas development that uses horizontal drilling and hydraulic fracturing is rapidly changing the landscape and exponentially increasing oil production within the Williston Basin, especially in North Dakota and eastern Montana. The activities associated with unconventional oil and gas development are complex and wide reaching and include, in part, road and well-pad constructionAuthorsGregory C. Delzer, Max Post van der BurgPotential effects of energy development on environmental resources of the Williston Basin in Montana, North Dakota, and South Dakota—Water resources
The Williston Basin has been a leading oil and gas producing area for more than 50 years. While oil production initially peaked within the Williston Basin in the mid-1980s, production rapidly increased in the mid-2000s, largely because of improved horizontal (directional) drilling and hydraulic fracturing methods. In 2012, energy development associated with the Bakken Formation was identified as aAuthorsTimothy T. Bartos, Steven K. Sando, Todd M. Preston, Gregory C. Delzer, Robert F. Lundgren, Rochelle A. Nustad, Rodney R. Caldwell, Zell E. Peterman, Bruce D. Smith, Kathleen M. Macek-Rowland, David A. Bender, Jill D. Frankforter, Joel M. GallowayAssessment of streamflow trends in the eastern Dakotas, water years 1960–2019
Hydrologic extremes, whether periods of drought or flooding, are occurring more frequently with greater severity and can have substantial economic impacts. Along with flooding, the timing and volume of streamflow also is changing across the United States. The focus of this report is to characterize a unique trend in mean annual streamflow occurring in eastern North and South Dakota, hereafter refeAuthorsParker A. Norton, Gregory C. Delzer, Joshua F. Valder, Wyatt S. Tatge, Karen R. RybergEstimates of water use associated with continuous oil and gas development in the Williston Basin, North Dakota and Montana, 2007–17
This study of water use associated with development of continuous oil and gas resources in the Williston Basin is intended to provide a preliminary model-based analysis of water use in major regions of production of continuous oil and gas resources in the United States. Direct, indirect, and ancillary water use associated with development of continuous oil and gas resources in the Williston BasinAuthorsRyan R. McShane, Theodore B. Barnhart, Joshua F. Valder, Seth S. Haines, Kathleen M. Macek-Rowland, Janet M. Carter, Gregory C. Delzer, Joanna N. ThamkeAnalytical framework to estimate water use associated with continuous oil and gas development
An analytical framework was designed to estimate water use associated with continuous oil and gas (COG) development in support of the U.S. Geological Survey Water Availability and Use Science Program. This framework was developed to better understand the relation between the production of COG resources for energy and the amount of water needed to sustain this type of energy development in the UnitAuthorsJoshua F. Valder, Ryan R. McShane, Theodore B. Barnhart, Spencer L. Wheeling, Janet M. Carter, Kathleen M. Macek-Rowland, Gregory C. Delzer, Joanna N. ThamkeConstruction of a groundwater-flow model for the Big Sioux Aquifer using airborne electromagnetic methods, Sioux Falls, South Dakota
The city of Sioux Falls is the fastest growing community in South Dakota. In response to this continued growth and planning for future development, Sioux Falls requires a sustainable supply of municipal water. Planning and managing sustainable groundwater supplies requires a thorough understanding of local groundwater resources. The Big Sioux aquifer consists of glacial outwash sands and gravels aAuthorsJoshua F. Valder, Gregory C. Delzer, Janet M. Carter, Bruce D. Smith, David V. SmithEstimating national water use associated with unconventional oil and gas development
The U.S. Geological Survey’s (USGS) Water Availability and Use Science Program (WAUSP) goals are to provide a more accurate assessment of the status of the water resources of the United States and assist in the determination of the quantity and quality of water that is available for beneficial uses. These assessments would identify long-term trends or changes in water availability since the 1950sAuthorsJanet M. Carter, Kathleen M. Macek-Rowland, Joanna N. Thamke, Gregory C. DelzerAnthropogenic organic compounds in source water of select community water systems in the United States, 2002-10
Drinking water delivered by community water systems (CWSs) comes from one or both of two sources: surface water and groundwater. Source water is raw, untreated water used by CWSs and is usually treated before distribution to consumers. Beginning in 2002, the U.S. Geological Survey’s (USGS) National Water-Quality Assessment Program initiated Source Water-Quality Assessments (SWQAs) at select CWSs aAuthorsJoshua F. Valder, Gregory C. Delzer, James A. Kingsbury, Jessica A. Hopple, Curtis V. Price, David A. BenderPercent recoveries of anthropogenic organic compounds with and without the addition of ascorbic acid to preserve finished-water samples containing free chlorine, 2004-10
This report presents finished-water matrix-spike recoveries of 270 anthropogenic organic compounds with and without the addition of ascorbic acid to preserve water samples containing free chlorine. Percent recoveries were calculated using analytical results from a study conducted during 2004-10 for the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). The studAuthorsJoshua F. Valder, Gregory C. Delzer, David A. Bender, Curtis V. PriceConcentration data for anthropogenic organic compounds in groundwater, surface water, and finished water of selected community water systems in the United States, 2002-10
The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States. As used in SWQA studies, source water is the raw (ambient) water collected atAuthorsJanet M. Carter, James A. Kingsbury, Jessica A. Hopple, Gregory C. DelzerOccurrence of volatile organic compounds in selected urban streams in the United States, 1995-2003
As part of the U.S. Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) Program, urban indicator sites were monitored to (1) characterize the stream quality from drainage basins with predominantly residential and commercial land use, and (2) determine which selected natural and anthropogenic factors affect stream quality. A total of 869 water samples were collected from 37 urban sAuthorsDavid A. Bender, Gregory C. Delzer, Curtis V. Price, John S. ZogorskiAnthropogenic organic compounds in source water of selected community water systems that use groundwater, 2002-05
Source water, defined as groundwater collected from a community water system well prior to water treatment, was sampled from 221 wells during October 2002 to July 2005 and analyzed for 258 anthropogenic organic compounds. Most of these compounds are unregulated in drinking water and include pesticides and pesticide degradates, gasoline hydrocarbons, personal-care and domestic-use products, and solAuthorsJessica A. Hopple, Gregory C. Delzer, James A. Kingsbury