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 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.

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 of the High Plains aquifer system (hereinafter referred to as the "Ogallala aquifer"). The Ogallala aquifer is contained in Tertiary-age sediments of the Ogallala Formation in the study area, 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 (including CT) onto the ground surface during the extinguishing of a fire at a grain storage elevator in 1962. As of 2022, the plume was 60 years old and extended approximately two-thirds of a mile downgradient (northeast) from the site of the fire. 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 in cooperation with the U.S. Environmental Protection Agency at 10 monitoring wells during January 7–8, 2025, including some of the newly-drilled wells in addition to some preexisting wells that had not been tested previously. Estimated hydraulic conductivities ranged from 0.05 to 410 feet per day (ft/day) in the 10 wells tested in 2025.

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.

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.

The U.S. Geological Survey in cooperation with the Harris‐Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, and Lone Star Groundwater Conservation District has produced this dataset of water‐level altitudes and water‐level changes in the Chicot, Evangeline, and Jasper aquifers in the Houston‐Galveston region, Texas.This dataset shows current‐year (2015-2016) water‐level altitudes for each aquifer, 5‐year (2011‐16) water‐level changes for each aquifer, long‐term (1990‐2016 and 1977‐2016) water‐level changes for the Chicot and Evangeline aquifers, and long‐term (2000‐2016) water‐level change for the Jasper aquifer. For the 1‐year (2015-16) water‐level changes, data were computed as the difference in water‐level altitude at each point (well) for which a water‐level measurement was made in 2015 and 2016. Five‐year (2011‐16) water‐level changes were computed the same as for the 1‐year water-level changes; the difference in water‐level altitude at each point for which a water‐level measurement was made in 2011 and 2016. The water‐level measurements in the dataset are built upon and stored in the National Water Information System: Web Interface, groundwater information, field measurements website located here: http://dx.doi.org/10.5066/F7P55KJN This site is a publicly available, searchable, online database of water information.

The U.S. Geological Survey in cooperation with the Harris‐Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, and Lone Star Groundwater Conservation District has produced this dataset of water‐level altitudes and water‐level changes in the Chicot, Evangeline, and Jasper aquifers in the Houston‐Galveston region, Texas.This dataset shows current‐year (2015-2016) water‐level altitudes for each aquifer, 5‐year (2011‐16) water‐level changes for each aquifer, long‐term (1990‐2016 and 1977‐2016) water‐level changes for the Chicot and Evangeline aquifers, and long‐term (2000‐2016) water‐level change for the Jasper aquifer. For the 1‐year (2015-16) water‐level changes, data were computed as the difference in water‐level altitude at each point (well) for which a water‐level measurement was made in 2015 and 2016. Five‐year (2011‐16) water‐level changes were computed the same as for the 1‐year water-level changes; the difference in water‐level altitude at each point for which a water‐level measurement was made in 2011 and 2016. The water‐level measurements in the dataset are built upon and stored in the National Water Information System: Web Interface, groundwater information, field measurements website located here: http://dx.doi.org/10.5066/F7P55KJN This site is a publicly available, searchable, online database of water information.

Water levels in 93 wells completed in the Wood River Valley aquifer system were measured during October 22–24, 2012; these wells are part of a network established by the U.S. Geological Survey in 2006. Maps of the October 2012 water-table altitude in the unconfined aquifer and the potentiometric- surface altitude of the confined aquifer have similar topology to those on maps of October 2006 conditions. Between October 2006 and October 2012, water-table altitude in the unconfined aquifer rose by as much as 1.86 feet in 6 wells and declined by as much as 14.28 feet in 77 wells; average decline was 2.9 feet. From October 2006 to October 2012, the potentiometric-surface altitude in 10 wells completed in the confined aquifer declined between 0.12 and 20.50 feet; average decline was 6.8 feet.