Bryant C Jurgens
Groundwater is an important source of drinking water in the United States. In order to assess the status and long-term sustainability of this important resource, I use environmental tracers, geochemical modeling, and statistical methods to understand the age structure, geochemical processes, and trends affecting water-quality in aquifers.
Science and Products
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Estimation of aquifer scale proportion using equal area grids: assessment of regional scale groundwater quality
The proportion of an aquifer with constituent concentrations above a specified threshold (high concentrations) is taken as a nondimensional measure of regional scale water quality. If computed on the basis of area, it can be referred to as the aquifer scale proportion. A spatially unbiased estimate of aquifer scale proportion and a confidence interval for that estimate are obtained through the use
Authors
Kenneth Belitz, Bryant C. Jurgens, Matthew K. Landon, Miranda S. Fram, Tyler D. Johnson
Redox Conditions in Selected Principal Aquifers of the United States
Reduction/oxidation (redox) processes affect the quality of groundwater in all aquifer systems. Redox processes can alternately mobilize or immobilize potentially toxic metals associated with naturally occurring aquifer materials, contribute to the degradation or preservation of anthropogenic contami-nants, and generate undesirable byproducts, such as dissolved manganese (Mn2+), ferrous iron (Fe2+
Authors
P. B. McMahon, T.K. Cowdery, F. H. Chapelle, B.C. Jurgens
Assessing the Vulnerability of Public-Supply Wells to Contamination: Central Valley Aquifer System near Modesto, California
This fact sheet highlights findings from the vulnerability study of a public-supply well in Modesto, California. The well selected for study pumps on average about 1,600 gallons per minute from the Central Valley aquifer system during peak summer demand. Water samples were collected at the public-supply well and at monitoring wells installed in the Modesto vicinity. Samples from the public-supply
Authors
Martha L. Jagucki, Bryant C. Jurgens, Karen R. Burow, Sandra M. Eberts
An Excel Workbook for Identifying Redox Processes in Ground Water
The reduction/oxidation (redox) condition of ground water affects the concentration, transport, and fate of many anthropogenic and natural contaminants. The redox state of a ground-water sample is defined by the dominant type of reduction/oxidation reaction, or redox process, occurring in the sample, as inferred from water-quality data. However, because of the difficulty in defining and applying a
Authors
Bryant C. Jurgens, Peter B. McMahon, Francis H. Chapelle, Sandra M. Eberts
Effects of Groundwater Development on Uranium: Central Valley, California, USA
Uranium (U) concentrations in groundwater in several parts of the eastern San Joaquin Valley, California, have exceeded federal and state drinking water standards during the last 20 years. The San Joaquin Valley is located within the Central Valley of California and is one of the most productive agricultural areas in the world. Increased irrigation and pumping associated with agricultural and urba
Authors
Bryant C. Jurgens, Miranda S. Fram, Kenneth Belitz, Karen R. Burow, Matthew K. Landon
Hydrogeology, Water Chemistry, and Factors Affecting the Transport of Contaminants in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California
Ground-water chemistry in the zone of contribution of a public-supply well in Modesto, California, was studied by the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program's topical team for Transport of Anthropogenic and Natural Contaminants (TANC) to supply wells. Twenty-three monitoring wells were installed in Modesto to record baseline hydraulic information and to collect wa
Authors
Bryant C. Jurgens, Karen R. Burow, Barbara A. Dalgish, Jennifer L. Shelton
Simulations of ground-water flow and particle pathline analysis in the zone of contribution of a public-supply well in Modesto, eastern San Joaquin Valley, California
Shallow ground water in the eastern San Joaquin Valley is affected by high nitrate and uranium concentrations and frequent detections of pesticides and volatile organic compounds (VOC), as a result of ground-water development and intensive agricultural and urban land use. A single public-supply well was selected for intensive study to evaluate the dominant processes affecting the vulnerability of
Authors
Karen R. Burow, Bryant C. Jurgens, Leon J. Kauffman, Steven P. Phillips, Barbara A. Dalgish, Jennifer L. Shelton
Framework for a ground-water quality monitoring and assessment program for California
The State of California uses more ground water than any other State in the Nation. With a population of over 30 million people, an agricultural economy based on intensive irrigation, large urban industrial areas, and naturally elevated concentrations of some trace elements, there is a wide range of contaminant sources that have the potential to contaminate ground water and limit its beneficial use
Authors
Kenneth Belitz, Neil M. Dubrovsky, Karen Burow, Bryant C. Jurgens, Tyler John
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 56
Estimation of aquifer scale proportion using equal area grids: assessment of regional scale groundwater quality
The proportion of an aquifer with constituent concentrations above a specified threshold (high concentrations) is taken as a nondimensional measure of regional scale water quality. If computed on the basis of area, it can be referred to as the aquifer scale proportion. A spatially unbiased estimate of aquifer scale proportion and a confidence interval for that estimate are obtained through the use
Authors
Kenneth Belitz, Bryant C. Jurgens, Matthew K. Landon, Miranda S. Fram, Tyler D. Johnson
Redox Conditions in Selected Principal Aquifers of the United States
Reduction/oxidation (redox) processes affect the quality of groundwater in all aquifer systems. Redox processes can alternately mobilize or immobilize potentially toxic metals associated with naturally occurring aquifer materials, contribute to the degradation or preservation of anthropogenic contami-nants, and generate undesirable byproducts, such as dissolved manganese (Mn2+), ferrous iron (Fe2+
Authors
P. B. McMahon, T.K. Cowdery, F. H. Chapelle, B.C. Jurgens
Assessing the Vulnerability of Public-Supply Wells to Contamination: Central Valley Aquifer System near Modesto, California
This fact sheet highlights findings from the vulnerability study of a public-supply well in Modesto, California. The well selected for study pumps on average about 1,600 gallons per minute from the Central Valley aquifer system during peak summer demand. Water samples were collected at the public-supply well and at monitoring wells installed in the Modesto vicinity. Samples from the public-supply
Authors
Martha L. Jagucki, Bryant C. Jurgens, Karen R. Burow, Sandra M. Eberts
An Excel Workbook for Identifying Redox Processes in Ground Water
The reduction/oxidation (redox) condition of ground water affects the concentration, transport, and fate of many anthropogenic and natural contaminants. The redox state of a ground-water sample is defined by the dominant type of reduction/oxidation reaction, or redox process, occurring in the sample, as inferred from water-quality data. However, because of the difficulty in defining and applying a
Authors
Bryant C. Jurgens, Peter B. McMahon, Francis H. Chapelle, Sandra M. Eberts
Effects of Groundwater Development on Uranium: Central Valley, California, USA
Uranium (U) concentrations in groundwater in several parts of the eastern San Joaquin Valley, California, have exceeded federal and state drinking water standards during the last 20 years. The San Joaquin Valley is located within the Central Valley of California and is one of the most productive agricultural areas in the world. Increased irrigation and pumping associated with agricultural and urba
Authors
Bryant C. Jurgens, Miranda S. Fram, Kenneth Belitz, Karen R. Burow, Matthew K. Landon
Hydrogeology, Water Chemistry, and Factors Affecting the Transport of Contaminants in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California
Ground-water chemistry in the zone of contribution of a public-supply well in Modesto, California, was studied by the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program's topical team for Transport of Anthropogenic and Natural Contaminants (TANC) to supply wells. Twenty-three monitoring wells were installed in Modesto to record baseline hydraulic information and to collect wa
Authors
Bryant C. Jurgens, Karen R. Burow, Barbara A. Dalgish, Jennifer L. Shelton
Simulations of ground-water flow and particle pathline analysis in the zone of contribution of a public-supply well in Modesto, eastern San Joaquin Valley, California
Shallow ground water in the eastern San Joaquin Valley is affected by high nitrate and uranium concentrations and frequent detections of pesticides and volatile organic compounds (VOC), as a result of ground-water development and intensive agricultural and urban land use. A single public-supply well was selected for intensive study to evaluate the dominant processes affecting the vulnerability of
Authors
Karen R. Burow, Bryant C. Jurgens, Leon J. Kauffman, Steven P. Phillips, Barbara A. Dalgish, Jennifer L. Shelton
Framework for a ground-water quality monitoring and assessment program for California
The State of California uses more ground water than any other State in the Nation. With a population of over 30 million people, an agricultural economy based on intensive irrigation, large urban industrial areas, and naturally elevated concentrations of some trace elements, there is a wide range of contaminant sources that have the potential to contaminate ground water and limit its beneficial use
Authors
Kenneth Belitz, Neil M. Dubrovsky, Karen Burow, Bryant C. Jurgens, Tyler John