John G Warden, Ph.D.
John G Warden, Ph.D. - California Water Science Center
Science and Products
Assessing Sediment Nutrient Storage and Release in California's Sacramento-San Joaquin Delta
Sediments represent an important pool of nutrients in the Sacramento-San Joaquin Delta (Delta). The exchange of nutrients between the water column and the benthos impacts water quality and effects phytoplankton, harmful algal blooms, aquatic vegetation, and drinking water quality. To date, there is very limited information about nutrient pools in Delta sediments, nor how these nutrients are...
Produced water disposal at percolation and evaporation ponds in and near oil fields in the southwestern San Joaquin Valley, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board compiled and analyzed data on water production and produced water disposal on land at oil and gas fields in the southwestern San Joaquin Vallley, Kern County, California. Data were compiled from information in state and local agencies’ databases and cover a period of record ranging from the ear
Geophysical, geological, hydrological, and geochemical data for aquifer salinity mapping in the Elk Hills, Buena Vista, and Coles Levee Oil Fields, Kern County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (State Water Board) compiled and analyzed data for mapping groundwater salinity, characterizing aquifer systems, and documenting the effects of oil field water injection in the Elk Hills Elk Hills, Buena Vista, and Coles Levee Oil Fields, San Joaquin Valley, California. Data provided in this da
Multiple-well monitoring site adjacent to the Elk Hills Oil Field, Kern County, California
IntroductionThe Elk Hills Oil Field is one of the many fields selected for regional groundwater mapping and monitoring by the California State Water Resources Control Board as part of the Oil and Gas Regional Monitoring Program (California State Water Resources Control Board, 2015, 2022b; U.S. Geological Survey, 2022a). The U.S. Geological Survey (USGS), in cooperation with the California State Wa
Authors
Rhett R. Everett, Janice M. Gillespie, Mackenzie M. Shepherd, Andrew Y. Morita, Maryanne Bobbitt, Christopher A. Kohel, John G. Warden
Natural and anthropogenic hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California
The Pacific Gas and Electric Company (PG&E) Hinkley compressor station, in the Mojave Desert, 80 miles northeast of Los Angeles, California, is used to compress natural gas as it is transported through a pipeline from Texas to California. Between 1952 and 1964, cooling water was treated with a compound containing hexavalent chromium, Cr(VI), to prevent corrosion of machinery within the compressor
Authors
John A. Izbicki, Krishangi D. Groover, Whitney A. Seymour, David M. Miller, John G. Warden, Laurence G. Miller
Summary and conclusions
Executive SummaryChromium concentrations in rock and aquifer material in Hinkley and Water Valleys in the Mojave Desert, 80 miles northeast of Los Angeles, California, are generally low compared to the average chromium concentration of 185 milligrams per kilogram (mg/kg) in the average bulk continental crust. Chromium concentrations in felsic, coarse-textured “Mojave-type” deposits, composed of Mo
Authors
John A. Izbicki, Krishangi D. Groover, Whitney A. Seymour, David M. Miller, John G. Warden, Laurence G. Miller
Predevelopment water levels, groundwater recharge, and selected hydrologic properties of aquifer materials, Hinkley and Water Valleys, California
Hydrologic and geophysical data were collected to support updates to an existing groundwater-flow model of Hinkley Valley, California, in the Mojave Desert about 80 miles northeast of Los Angeles, California. These data provide information on predevelopment (pre-1930) water levels, groundwater recharge, and selected hydrologic properties of aquifer materials.A predevelopment groundwater-level map,
Authors
Krishangi D. Groover, John A. Izbicki, Whitney A. Seymour, Anthony A. Brown, Randall E. Bayless, Carole D. Johnson, Katherine L. Pappas, Gregory A. Smith, Dennis A. Clark, Joshua Larsen, Meghan C. Dick, Lorraine E. Flint, Christina L. Stamos, John G. Warden
Evaluation of natural and anthropogenic (human-made) hexavalent chromium
Hexavalent chromium, Cr(VI), was released between 1952 and 1964 from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station, in the Mojave Desert about 80 miles northeast of Los Angeles, California. Geologic, geochemical, and hydrologic data from more than 100 wells collected between March 2015 and November 2017 were interpreted using a summative-scale analysis to define the extent
Authors
John A. Izbicki, John G. Warden, Krishangi D. Groover, Whitney A. Seymour
Environmental tracers of groundwater source, age, and geochemical evolution
Hexavalent chromium, Cr(VI), was discharged in cooling wastewater to unlined surface ponds from 1952 to 1964 and reached the underlying unconsolidated aquifer at the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert, 80 miles northeast of Los Angeles, California. A suite of environmental tracers was analyzed in water samples collected from more than 100 wells
Authors
John G. Warden, John A. Izbicki, Jürgen Sültenfuß, Kathleen Scheiderich, John Fitzpatrick
Introduction to study area hydrogeology, chromium sources, site history, and purpose of study
Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert 80 miles (mi) northeast of Los Angeles, California. Remediation began in 1992, and in 2010, site cleanup was projected to require between 10 and 95 years and was expected to cost between $36 and $176 million. A 2007 PG&E
Authors
John A. Izbicki, Krishangi D. Groover, David M. Miller, Whitney A. Seymour, John G. Warden, Laurence G. Miller
Geologic controls on groundwater salinity reversal in North Coles Levee Oil Field, southern San Joaquin Valley, California, USA
This paper documents a reversal in the groundwater salinity depth gradient in the North Coles Levee Oil Field in the San Joaquin Valley, California. Salinity, measured in mg/L, was mapped with water quality data from groundwater and oil and gas wells and salinity estimated from oil and gas well borehole geophysical logs using Archie's equation. The resulting three-dimensional salinity volume shows
Authors
Michael D Flowers, David H. Shimabukuro, Michael J. Stephens, John G. Warden, Janice M. Gillespie, Will Chang
Mapping aquifer salinity gradients and effects of oil field produced water disposal using geophysical logs: Elk Hills, Buena Vista and Coles Levee Oil Fields, San Joaquin Valley, California
The effects of oil and gas production on adjacent groundwater quality are becoming a concern in many areas of the United States. As a result, it has become increasingly important to identify which aquifers require monitoring and protection. In this study, we map the extent of groundwater with less than 10,000 mg/L TDS both laterally and vertically near the Elk Hills, Buena Vista and Coles Levee Oi
Authors
Janice M. Gillespie, Michael J. Stephens, Will Chang, John G. Warden
Evaluating a laboratory flume microbiome as a window into natural riverbed biogeochemistry
Riverbeds are hotspots for microbially-mediated reactions that exhibit pronounced variability in space and time. It is challenging to resolve biogeochemical mechanisms in natural riverbeds, as uncontrolled settings complicate data collection and interpretation. To overcome these challenges, laboratory flumes are often used as proxies for natural riverbed systems. Flumes capture spatiotemporal vari
Authors
Matthew H. Kaufman, John G. Warden, M. Bayani Cardenas, James C. Stegen, Emily B. Graham, Joseph Brown
The importance of groundwater flow to the formation of modern thrombolitic microbialites
Modern microbialites are often located within groundwater discharge zones, yet the role of groundwater in microbialite accretion has yet to be resolved. To understand relationships between groundwater, microbialites, and associated microbial communities, we quantified and characterized groundwater flow and chemistry in active thrombolitic microbialites in Lake Clifton, Western Australia, and compa
Authors
John G. Warden, Lee Coshell, Michael R. Rosen, Daniel O. Breecker, Katinka X. Ruthrof, Christopher R. Omelon
Science and Products
Assessing Sediment Nutrient Storage and Release in California's Sacramento-San Joaquin Delta
Sediments represent an important pool of nutrients in the Sacramento-San Joaquin Delta (Delta). The exchange of nutrients between the water column and the benthos impacts water quality and effects phytoplankton, harmful algal blooms, aquatic vegetation, and drinking water quality. To date, there is very limited information about nutrient pools in Delta sediments, nor how these nutrients are...
Produced water disposal at percolation and evaporation ponds in and near oil fields in the southwestern San Joaquin Valley, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board compiled and analyzed data on water production and produced water disposal on land at oil and gas fields in the southwestern San Joaquin Vallley, Kern County, California. Data were compiled from information in state and local agencies’ databases and cover a period of record ranging from the ear
Geophysical, geological, hydrological, and geochemical data for aquifer salinity mapping in the Elk Hills, Buena Vista, and Coles Levee Oil Fields, Kern County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (State Water Board) compiled and analyzed data for mapping groundwater salinity, characterizing aquifer systems, and documenting the effects of oil field water injection in the Elk Hills Elk Hills, Buena Vista, and Coles Levee Oil Fields, San Joaquin Valley, California. Data provided in this da
Multiple-well monitoring site adjacent to the Elk Hills Oil Field, Kern County, California
IntroductionThe Elk Hills Oil Field is one of the many fields selected for regional groundwater mapping and monitoring by the California State Water Resources Control Board as part of the Oil and Gas Regional Monitoring Program (California State Water Resources Control Board, 2015, 2022b; U.S. Geological Survey, 2022a). The U.S. Geological Survey (USGS), in cooperation with the California State Wa
Authors
Rhett R. Everett, Janice M. Gillespie, Mackenzie M. Shepherd, Andrew Y. Morita, Maryanne Bobbitt, Christopher A. Kohel, John G. Warden
Natural and anthropogenic hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California
The Pacific Gas and Electric Company (PG&E) Hinkley compressor station, in the Mojave Desert, 80 miles northeast of Los Angeles, California, is used to compress natural gas as it is transported through a pipeline from Texas to California. Between 1952 and 1964, cooling water was treated with a compound containing hexavalent chromium, Cr(VI), to prevent corrosion of machinery within the compressor
Authors
John A. Izbicki, Krishangi D. Groover, Whitney A. Seymour, David M. Miller, John G. Warden, Laurence G. Miller
Summary and conclusions
Executive SummaryChromium concentrations in rock and aquifer material in Hinkley and Water Valleys in the Mojave Desert, 80 miles northeast of Los Angeles, California, are generally low compared to the average chromium concentration of 185 milligrams per kilogram (mg/kg) in the average bulk continental crust. Chromium concentrations in felsic, coarse-textured “Mojave-type” deposits, composed of Mo
Authors
John A. Izbicki, Krishangi D. Groover, Whitney A. Seymour, David M. Miller, John G. Warden, Laurence G. Miller
Predevelopment water levels, groundwater recharge, and selected hydrologic properties of aquifer materials, Hinkley and Water Valleys, California
Hydrologic and geophysical data were collected to support updates to an existing groundwater-flow model of Hinkley Valley, California, in the Mojave Desert about 80 miles northeast of Los Angeles, California. These data provide information on predevelopment (pre-1930) water levels, groundwater recharge, and selected hydrologic properties of aquifer materials.A predevelopment groundwater-level map,
Authors
Krishangi D. Groover, John A. Izbicki, Whitney A. Seymour, Anthony A. Brown, Randall E. Bayless, Carole D. Johnson, Katherine L. Pappas, Gregory A. Smith, Dennis A. Clark, Joshua Larsen, Meghan C. Dick, Lorraine E. Flint, Christina L. Stamos, John G. Warden
Evaluation of natural and anthropogenic (human-made) hexavalent chromium
Hexavalent chromium, Cr(VI), was released between 1952 and 1964 from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station, in the Mojave Desert about 80 miles northeast of Los Angeles, California. Geologic, geochemical, and hydrologic data from more than 100 wells collected between March 2015 and November 2017 were interpreted using a summative-scale analysis to define the extent
Authors
John A. Izbicki, John G. Warden, Krishangi D. Groover, Whitney A. Seymour
Environmental tracers of groundwater source, age, and geochemical evolution
Hexavalent chromium, Cr(VI), was discharged in cooling wastewater to unlined surface ponds from 1952 to 1964 and reached the underlying unconsolidated aquifer at the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert, 80 miles northeast of Los Angeles, California. A suite of environmental tracers was analyzed in water samples collected from more than 100 wells
Authors
John G. Warden, John A. Izbicki, Jürgen Sültenfuß, Kathleen Scheiderich, John Fitzpatrick
Introduction to study area hydrogeology, chromium sources, site history, and purpose of study
Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert 80 miles (mi) northeast of Los Angeles, California. Remediation began in 1992, and in 2010, site cleanup was projected to require between 10 and 95 years and was expected to cost between $36 and $176 million. A 2007 PG&E
Authors
John A. Izbicki, Krishangi D. Groover, David M. Miller, Whitney A. Seymour, John G. Warden, Laurence G. Miller
Geologic controls on groundwater salinity reversal in North Coles Levee Oil Field, southern San Joaquin Valley, California, USA
This paper documents a reversal in the groundwater salinity depth gradient in the North Coles Levee Oil Field in the San Joaquin Valley, California. Salinity, measured in mg/L, was mapped with water quality data from groundwater and oil and gas wells and salinity estimated from oil and gas well borehole geophysical logs using Archie's equation. The resulting three-dimensional salinity volume shows
Authors
Michael D Flowers, David H. Shimabukuro, Michael J. Stephens, John G. Warden, Janice M. Gillespie, Will Chang
Mapping aquifer salinity gradients and effects of oil field produced water disposal using geophysical logs: Elk Hills, Buena Vista and Coles Levee Oil Fields, San Joaquin Valley, California
The effects of oil and gas production on adjacent groundwater quality are becoming a concern in many areas of the United States. As a result, it has become increasingly important to identify which aquifers require monitoring and protection. In this study, we map the extent of groundwater with less than 10,000 mg/L TDS both laterally and vertically near the Elk Hills, Buena Vista and Coles Levee Oi
Authors
Janice M. Gillespie, Michael J. Stephens, Will Chang, John G. Warden
Evaluating a laboratory flume microbiome as a window into natural riverbed biogeochemistry
Riverbeds are hotspots for microbially-mediated reactions that exhibit pronounced variability in space and time. It is challenging to resolve biogeochemical mechanisms in natural riverbeds, as uncontrolled settings complicate data collection and interpretation. To overcome these challenges, laboratory flumes are often used as proxies for natural riverbed systems. Flumes capture spatiotemporal vari
Authors
Matthew H. Kaufman, John G. Warden, M. Bayani Cardenas, James C. Stegen, Emily B. Graham, Joseph Brown
The importance of groundwater flow to the formation of modern thrombolitic microbialites
Modern microbialites are often located within groundwater discharge zones, yet the role of groundwater in microbialite accretion has yet to be resolved. To understand relationships between groundwater, microbialites, and associated microbial communities, we quantified and characterized groundwater flow and chemistry in active thrombolitic microbialites in Lake Clifton, Western Australia, and compa
Authors
John G. Warden, Lee Coshell, Michael R. Rosen, Daniel O. Breecker, Katinka X. Ruthrof, Christopher R. Omelon