As part of a larger groundwater research study conducted at the U.S. Army Fort Irwin National Training Center (NTC), located approximately 35 miles north-northeast of Barstow, California, the U.S. Environmental Protection Agency (EPA), the U.S. Army, and the U.S. Geological Survey (USGS) have cooperated to evaluate unsaturated zone soil property data of cores from the borehole for a newly drilled monitoring well (ESW2B). Specific horizons of interest were identified and selected for detailed grain-size distribution analysis using the Fritsch Analysette A28 Image Sizer (particle analyzer) located at the USGS California Water Science Center (CAWSC) in San Diego, CA. The particle analyzer identified circularity and grain size (feret diameter) for individual grains in each subsample. Ten core subsamples from the ESW2B site were analyzed with the particle analyzer. Quality-assurance data collected as part of this task included measurements of National Institute of Standards and Technology (NIST) standard 8010, and custom reference materials (including a sample of alluvium from the Mojave River, and a combination of round silica beads and plastic bugle beads) created in the USGS San Diego office. A sieve analysis was done on one core subsample using ASTM International method D6913 (method A; 2017) as additional quality assurance method.

As part of a research study in cooperation with the U.S. Environmental Protection Agency (EPA) and the U.S. Army at Fort Irwin National Training Center, the U.S. Geological Survey (USGS) evaluated unsaturated zone soil property data of cores from a borehole for a newly drilled monitoring well near a dry well and Four-plex baseball field. Cores were continuous from land surface down to 240 feet below land surface and were drilled by consultants to EPA using sonic rotary–a fluidless drilling technique. Data on this page consist of: 1) field drilling notes from USGS and consultants to EPA (GeoSystems Analysis, Inc., Tucson, Arizona); 2) field descriptions of core lithology–including grain size, sorting, color, mineralogy, moisture content and other distinguishing characteristics–done on site by USGS personnel; and 3) photos of the cores taken by USGS personnel–consisting of bagged cores in original core liners, and subsampled cores in plastic core boxes.

As part of a research study in cooperation with the U.S. Environmental Protection Agency (EPA) and the U.S. Army at Fort Irwin National Training Center, the U.S. Geological Survey (USGS) evaluated unsaturated zone soil property data of cores from a borehole for a newly drilled monitoring well near a dry well and Four-plex baseball field. Cores were continuous from land surface down to 240 feet below land surface and were drilled by consultants to EPA using sonic rotary–a fluidless drilling technique. Data on this page consist of: 1) field drilling notes from USGS and consultants to EPA (GeoSystems Analysis, Inc., Tucson, Arizona); 2) field descriptions of core lithology–including grain size, sorting, color, mineralogy, moisture content and other distinguishing characteristics–done on site by USGS personnel; and 3) photos of the cores taken by USGS personnel–consisting of bagged cores in original core liners, and subsampled cores in plastic core boxes.

As part of a research study in cooperation with the U.S. Environmental Protection Agency (EPA) and the U.S. Army at Fort Irwin National Training Center, the U.S. Geological Survey (USGS) evaluated unsaturated zone soil property data of cores from a newly drilled monitoring well site near a dry well and Four-plex baseball field. Measurements and observations are presented for cores from an initial drilling attempt (site ESW2A), which stopped at 85 feet below land surface due to equipment issues, and data are presented for cores from the successful drilling attempt (ESW2B) down to 240 feet below land surface. The two core sites are located approximately 6 feet from each other. Data measured on core material included gravimetric measurements of bulk water content, matric potential, and specific conductance of soil leachate samples.

As part of a research study in cooperation with the U.S. Environmental Protection Agency (EPA) and the U.S. Army at Fort Irwin National Training Center, the U.S. Geological Survey (USGS) evaluated unsaturated zone soil property data of cores from a newly drilled monitoring well site near a dry well and Four-plex baseball field. Measurements and observations are presented for cores from an initial drilling attempt (site ESW2A), which stopped at 85 feet below land surface due to equipment issues, and data are presented for cores from the successful drilling attempt (ESW2B) down to 240 feet below land surface. The two core sites are located approximately 6 feet from each other. Data measured on core material included gravimetric measurements of bulk water content, matric potential, and specific conductance of soil leachate samples.

The collection of borehole geophysical logs and images and continuous water-level data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. The study purpose was part of a continued effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved similar data collection, in addition to surface geologic mapping and passive diffusion bag sampling within monitoring wells (Chapman and others, 2013). The continued data compilation efforts included the delineation of more than 900 subsurface features (primarily fracture orientations) in 10 open borehole wells. Geophysical logs, borehole imagery, pumping data, and heat-pulse flow measurements were collected and are presented within this data release. The data on this page consists of .csv and .xlsx files with water-level information collected from a pressure transducer within the borehole during pumping conditions for the "stressed" heat-pulse flow measurements. The water-levels were used for drawdown calculations.

The collection of borehole geophysical logs and images and continuous water-level data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. The study purpose was part of a continued effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved similar data collection, in addition to surface geologic mapping and passive diffusion bag sampling within monitoring wells (Chapman and others, 2013). The continued data compilation efforts included the delineation of more than 900 subsurface features (primarily fracture orientations) in 10 open borehole wells. Geophysical logs, borehole imagery, pumping data, and heat-pulse flow measurements were collected and are presented within this data release. The data on this page consists of .csv and .xlsx files with water-level information collected from a pressure transducer within the borehole during pumping conditions for the "stressed" heat-pulse flow measurements. The water-levels were used for drawdown calculations.

The collection of borehole geophysical logs and images and continuous water-level data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. The study purpose was part of a continued effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved similar data collection, in addition to surface geologic mapping and passive diffusion bag sampling within monitoring wells (Chapman and others, 2013). The continued data compilation efforts included the delineation of more than 900 subsurface features (primarily fracture orientations) in 10 open borehole wells. Geophysical logs, borehole imagery, pumping data, and heat-pulse flow measurements were collected and are presented within this data release. The data on this page consists of .csv files that contain vertical flow measurements within the borehole and the associated depth below land surface. Measurements recorded under both ambient and stressed conditions are contained in each file.

The collection of borehole geophysical logs and images and continuous water-level data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. The study purpose was part of a continued effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved similar data collection, in addition to surface geologic mapping and passive diffusion bag sampling within monitoring wells (Chapman and others, 2013). The continued data compilation efforts included the delineation of more than 900 subsurface features (primarily fracture orientations) in 10 open borehole wells. Geophysical logs, borehole imagery, pumping data, and heat-pulse flow measurements were collected and are presented within this data release. The data on this page consists of .csv files that contain vertical flow measurements within the borehole and the associated depth below land surface. Measurements recorded under both ambient and stressed conditions are contained in each file.

The U.S. Army Fort Irwin National Training Center (NTC), approximately 35 miles north-northeast of Barstow, California, obtains all of its potable water supply from three groundwater basins (Irwin, Langford, and Bicycle Basins) within the NTC boundaries. In these basins, groundwater withdrawals exceed natural recharge, resulting in water-level declines. However, managed aquifer recharge using treated wastewater has offset water-level declines in Irwin Basin. Additionally, localized water-quality changes have occurred in some parts of Irwin Basin as a result of human activities (for example, wastewater disposal practices, landscape irrigation, and (or) leaking pipes). As part of a research study in cooperation with the U.S. Environmental Protection Agency (EPA), the U.S. Geological Survey (USGS) collected geophysical data to do a site characterization of an irrigated field (Four-plex baseball field) in the Irwin Basin. To aid in the understanding of the subsurface near the Four-plex baseball fields the USGS collected borehole geophysical data during 2018–2020. Natural gamma and neutron geophysical logs were collected in two monitoring wells that were installed by the EPA during 2018–19. Fluid resistivity, natural gamma, and electromagnetic induction logs were repeated in one of the EPA monitoring wells in February 2020; these types of geophysical logs also were collected at a nearby monitoring well on the eastern side of the Four-plex baseball field.