The North East 2nd Street Superfund site in Happy, Texas, overlies a groundwater plume of primarily carbon tetrachloride (CT) that is contained within an upper transmissive zone (EA Engineering, Science, and Technology, Inc., 2019) of the Ogallala aquifer. The Ogallala aquifer is contained at the site in Tertiary-age sediments of the Ogallala Formation, which are described by Nordstrom and Fallin (1989, p.10) as "tan, yellow, and reddish-brown, silty to coarse-grained sand mixed or alternating with yellow to red silty clay and variable sized gravel." The plume originated from the application of fire-retardant chemicals to the ground surface during the extinguishing of a fire at a grain storage elevator in 1962. As of 2022, the CT plume was 60 years old and extended approximately two thirds of a mile downgradient (northeast) from the site of the fire along a sloping clay bed. No hydraulic controls or boundaries are evident at the leading edge of the plume to constrain its further transport, and center-pivot irrigated agriculture and concentrated animal feeding operations are immediately downgradient across Interstate Highway 27. Because minimal sampling data have been collected, the question of whether the plume has reached a state of equilibrium is unknown. Slug tests were performed at 14 monitoring wells during February 7–9, 2023, near the North East 2nd Street Superfund site to characterize the range and distribution of hydraulic conductivity values in the upper transmissive zone of the Ogallala aquifer. Estimated hydraulic conductivities ranged from 0.27 to 12.97 ft/day, with the two northernmost wells (MW-27 and MW-28) tested exhibiting the lowest values.

The North East 2nd Street Superfund site in Happy, Texas, overlies a groundwater plume of primarily carbon tetrachloride (CT) that is contained within an upper transmissive zone (EA Engineering, Science, and Technology, Inc., 2019) of the Ogallala aquifer. The Ogallala aquifer is contained at the site in Tertiary-age sediments of the Ogallala Formation, which are described by Nordstrom and Fallin (1989, p.10) as "tan, yellow, and reddish-brown, silty to coarse-grained sand mixed or alternating with yellow to red silty clay and variable sized gravel." The plume originated from the application of fire-retardant chemicals to the ground surface during the extinguishing of a fire at a grain storage elevator in 1962. As of 2022, the CT plume was 60 years old and extended approximately two thirds of a mile downgradient (northeast) from the site of the fire along a sloping clay bed. No hydraulic controls or boundaries are evident at the leading edge of the plume to constrain its further transport, and center-pivot irrigated agriculture and concentrated animal feeding operations are immediately downgradient across Interstate Highway 27. Because minimal sampling data have been collected, the question of whether the plume has reached a state of equilibrium is unknown. Slug tests were performed at 14 monitoring wells during February 7–9, 2023, near the North East 2nd Street Superfund site to characterize the range and distribution of hydraulic conductivity values in the upper transmissive zone of the Ogallala aquifer. Estimated hydraulic conductivities ranged from 0.27 to 12.97 ft/day, with the two northernmost wells (MW-27 and MW-28) tested exhibiting the lowest values.

Water level, water temperature, and specific conductance data were collected during natural gradient tests on six observation wells screened in the upper transmissive zone of the Ogallala aquifer at the North East 2nd Street Superfund site in Happy, Texas, from November 6-13, 2023. Tests involved gravity draining 100-160 gallons of a low-concentration salt-spiked solution with an associated specific conductance of less than 8,000 microsiemens per centimeter (µs/cm) into the wells, measuring water level responses, and recording continuous downhole water temperature and water conductivity (specific conductance). Gravity drainage of the salt-spiked solution into each well took approximately 1 hour at average rates of 2.4 to 5.2 gallons per minute. Depth profiles of water temperature and specific conductance were collected under ambient conditions (prior to draining the salt-spiked solution into each well). Another depth profile was collected after the salt-spiked solution was added to each well (to identify vertical changes in the water column of the well and the degree of vertical mixing of the spiked water). The single well natural gradient tests allow for the analysis of hydraulic responses of the aquifer during gravity drainage and assessment of ambient flow through the well after the emplacement of the salt-spiked solution and subsequent flushing out of the solution back to ambient conditions. Monitoring at each well continued for at least 24 hours after gravity-drainage of the salt-spiked solution into each well was completed to ascertain whether background conditions were achieved. This data release contains information on the well construction of the six wells tested in 2023 for natural gradient tests, the volume and concentration of the dilute salt spike used, profiles of specific conductance and water temperature of the wells pre- and post-spiked, water levels, and continuous monitoring of specific conductance and water temperature.

The Wilcox Oil Company Superfund site (hereinafter referred to as “the site”) was formerly an oil refinery in northeast of Bristow in Creek County, Oklahoma. Historical refinery operations contaminated the soil, surface water, streambed sediments, alluvium, and groundwater with refined and stored products at the site. The Wilcox and Lorraine process areas are where the highest concentrations of volatile organic compounds, semivolatile organic compounds, polycyclic aromatic hydrocarbons, and trace elements (including metals) (collectively hereinafter referred to as “contaminants”) were measured in a local shallow perched groundwater system within the alluvium (hereinafter referred to as the “alluvial aquifer”) at the site during previous site assessments. In order to understand the potential migration of contaminants through the soil and groundwater in these areas, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, investigated aquifer characteristics of the alluvial aquifer in the Wilcox and Lorraine process areas of the site to (1) document hydraulic conductivity and other aquifer characteristics of the alluvial aquifer that govern contaminant fate and transport, (2) describe the geospatial extent and concentration of the contaminants in the alluvial aquifer in the Wilcox and Lorraine process areas, and (3) describe the geochemical controls pertaining to oxidation and reduction governing the fate and transport and the degradation potential of contaminants in the groundwater. This data release documents the data that were collected and briefly describes how they were used to characterize the hydrogeologic framework, groundwater-flow system, geochemistry, and aquifer hydraulic properties of the shallow groundwater system. Refer to the companion larger work citation (Teeple and others, 2025) for the complete description and data analyses. In November and December 2022, following groundwater monitoring well development and groundwater-quality sampling, slug tests were completed on each of the groundwater monitoring wells installed in 2022 to (1) determine if the wells were in good hydraulic connection with the aquifer and (2) estimate the hydraulic conductivity of the aquifer at each well. This dataset includes the pressure transducer data from the slug tests and the hydraulic conductivity values estimated by using the Bouwer-Rice method of analysis.

Short-term aquifer tests were conducted to estimate hydraulic properties in an alluvial aquifer. Tests included eight single-hole pumping and recovery tests and three slug tests (in a single well). These investigations were conducted in the Wet Mountain Valley, in Custer and Fremont Counties, Colorado. The U.S. Geological Survey (USGS) conducted aquifer tests in May, 2019. These aquifer tests inform the conceptual understanding of the valley-fill aquifer and serve as primary inputs to the numerical groundwater-flow model. Testing was completed in cooperation with the Upper Arkansas Water Conservancy District. This data release contains raw data from aquifer tests, water-level and pumping discharge rate measurements, well logs, graphs of the testing data, and plots of analytical solutions.

Well and aquifer data were collected from field measurements and drillers’ logs. Multiple slug tests were completed at each well with a transducer to record the change in water level and a U.S. Geological Survey standard mechanical slug to displace the well’s water column. A Solinst Levelogger LT F30/M10 electronic transducer (unvented) was used to record water-level changes during each slug test. Water-level changes for each trial were analyzed in AQTESOLV Pro version 4.50.002 using the Springer and Gelhar method of curve fitting.

Well and aquifer data were collected from field measurements and drillers’ logs. Multiple slug tests were completed at each well with a transducer to record the change in water level and a U.S. Geological Survey standard mechanical slug to displace the well’s water column. A Solinst Levelogger LT F30/M10 electronic transducer (unvented) was used to record water-level changes during each slug test. Water-level changes for each trial were analyzed in AQTESOLV Pro version 4.50.002 using the Springer and Gelhar method of curve fitting.

The Ogallala aquifer is contained in the Tertiary-age Ogallala Formation in the Texas Panhandle and is the primary water-bearing hydrogeologic unit of the High Plains aquifer system. The Ogallala aquifer is the primary source of water used for agricultural and municipal purposes in the Texas Panhandle. The Dockum aquifer is contained in the formations that compose the Triassic-age Dockum Group and serves as an additional source of water in the Texas Panhandle. Depth to groundwater measurements and water-quality samples were collected from 32 monitoring wells in the North Plains Groundwater Conservation District management area within the northern part of the Texas Panhandle as part of two synoptic sampling efforts, one during 2012–13 and the other during 2019–20. Groundwater-quality samples were collected for analysis of dissolved solids, major ions, nutrients, and trace elements. Selected organic compounds were analyzed in samples collected from a subset of 6 wells. Sample results for selected constituents were compared to drinking-water standards and between the two synoptic sampling times in an interpretative report. A previously published report by Baldys and others (2014) discusses the results from the 2012–13 sampling event.

The Ogallala aquifer is contained in the Tertiary-age Ogallala Formation in the Texas Panhandle and is the primary water-bearing hydrogeologic unit of the High Plains aquifer system. The Ogallala aquifer is the primary source of water used for agricultural and municipal purposes in the Texas Panhandle. The Dockum aquifer is contained in the formations that compose the Triassic-age Dockum Group and serves as an additional source of water in the Texas Panhandle. Depth to groundwater measurements and water-quality samples were collected from 32 monitoring wells in the North Plains Groundwater Conservation District management area within the northern part of the Texas Panhandle as part of two synoptic sampling efforts, one during 2012–13 and the other during 2019–20. Groundwater-quality samples were collected for analysis of dissolved solids, major ions, nutrients, and trace elements. Selected organic compounds were analyzed in samples collected from a subset of 6 wells. Sample results for selected constituents were compared to drinking-water standards and between the two synoptic sampling times in an interpretative report. A previously published report by Baldys and others (2014) discusses the results from the 2012–13 sampling event.

More than 11,500 well records, such as geophysical logs, drilling descriptions, and published hydrogeologic framework information, were evaluated to help characterize the framework of hydrogeologic units in and near Gaines, Terry, and Yoakum Counties, Texas. Additional geophysical data were collected to improve the spatial coverage across the study area and to reduce uncertainty with regard to hydrogeologic unit extents. The evaluation of existing data plus the collection of new geophysical data provided that basis for developoing a refined understanding of how the saturated thickness of the Ogallala and Edwards-Trinity aquifers vary throughout the study area.