Two synoptic sampling campaigns were conducted near Breckenridge, Colorado, to quantify metal loading to Illinois Gulch, a tributary of the Blue River. The first campaign, conducted in August 2016, was designed to determine the degree to which Illinois Gulch loses water to the underlying mine workings, and to determine the effect of these losses on observed metal loads. The second campaign, conducted in September 2017, was designed to evaluate metal loading within Iron Springs, a subwatershed that was responsible for the majority of the metal loading observed in 2016. A continuous, instream injection of a sodium bromide (NaBr) tracer was initiated at the head of the respective study reaches several days prior to both synoptic sampling campaigns and maintained throughout the duration of each study. Bromide concentrations were subsequently used to determine streamflow in gaining stream reaches using the tracer-dilution method, and as an indicator of hydrologic connections between the Illinois Gulch and subsurface mine workings. Streamflow losses to the mine workings were quantified using a series of magnesium chloride slug additions conducted in August 2016, wherein specific conductivity readings were used as a surrogate for the tracer concentration. Study results indicate that Illinois Gulch loses water in the vicinity of the Puzzle Extension Shaft, and that water leaving the stream enters the subsurface mine workings. These losses are evidenced by the results of the slug additions and the elevated bromide concentrations observed at a collapsed mine portal in the Iron Springs subwatershed (Willard Adit 1). The primary sources of metal loading to the overall Illinois Gulch study reach include diffuse springs and groundwater near the toe of the Iron Springs mine dump and Willard Adit 1. This data release consists of 8 tables: Table 1, Locations of sampling sites for the 2016 and 2017 campaigns Table 2, Synoptic sampling results, August 18, 2016 Table 3, Synoptic sampling results, September 7, 2017 Table 4, Streamflow measurements, August 2016 Table 5, Bromide time series, August 2016 and September 2017 Table 6, Slug addition conductivity data, August 2016 Table 7, Slug addition results, August 2016 Table 8, Spatial profiles of streamflow and metal load, August 2016 and September 2017

Three synoptic sampling campaigns were conducted on upper Cement Creek, near Gladstone, Colorado, under low-flow conditions. The first campaign, conducted October 2012, was part of a larger campaign to characterize low-flow water quality in the entire Cement Creek watershed. The second campaign, conducted in September 2019, was designed to quantify metal loading and identify sources of contamination along a 2.5-kilometer study reach. The third campaign, conducted in September 2020, was designed to quantify loads and sources along the same 2.5-kilometer study reach during a test closure of a bulkhead on the Red and Bonita Mine, one of the primary sources of metals within the watershed. Streamflow measurements during the 2012 campaign were conducted using Acoustic Doppler Velocimetry. A continuous, instream injection of a sodium bromide tracer was initiated at the head of the study reach two days prior to the 2019 synoptic sampling campaign and maintained throughout the duration of the campaign. Bromide concentrations were subsequently used to determine streamflow using the tracer-dilution method. Streamflow estimates for the 2020 campaign were developed using a series of sodium chloride slug additions, wherein specific conductivity readings were used as a surrogate for chloride concentration. This data release includes concentration data (inorganic cations and anions), estimated streamflow, and calculated loads for the three sampling campaigns. Tracer data for the continuous tracer injection (2019) and slug additions (2020) are also included. Calculated loads may be used to compare low flow conditions with and without contributions from the Gold King Mine (2012 versus 2019) as well as before and after closure of the Red and Bonita bulkhead (2019 versus 2020). The data release consists of a kmz file showing site locations and the following 9 tables: Table 1, Locations of sampling sites Table 2, Synoptic sampling results, October 3, 2012 Table 3, Synoptic sampling results, September 5, 2019 Table 4, Synoptic sampling results, September 19, 2020 Table 5, Iron speciation results, September 7, 2019 Table 6, Bromide timeseries, September 3-5, 2019 Table 7, Slug addition chloride data, September 19, 2020 Table 8, Slug addition results, September 19, 2020 Table 9, Spatial profiles of streamflow and metal load

Three synoptic sampling campaigns were conducted on upper Cement Creek, near Gladstone, Colorado, under low-flow conditions. The first campaign, conducted October 2012, was part of a larger campaign to characterize low-flow water quality in the entire Cement Creek watershed. The second campaign, conducted in September 2019, was designed to quantify metal loading and identify sources of contamination along a 2.5-kilometer study reach. The third campaign, conducted in September 2020, was designed to quantify loads and sources along the same 2.5-kilometer study reach during a test closure of a bulkhead on the Red and Bonita Mine, one of the primary sources of metals within the watershed. Streamflow measurements during the 2012 campaign were conducted using Acoustic Doppler Velocimetry. A continuous, instream injection of a sodium bromide tracer was initiated at the head of the study reach two days prior to the 2019 synoptic sampling campaign and maintained throughout the duration of the campaign. Bromide concentrations were subsequently used to determine streamflow using the tracer-dilution method. Streamflow estimates for the 2020 campaign were developed using a series of sodium chloride slug additions, wherein specific conductivity readings were used as a surrogate for chloride concentration. This data release includes concentration data (inorganic cations and anions), estimated streamflow, and calculated loads for the three sampling campaigns. Tracer data for the continuous tracer injection (2019) and slug additions (2020) are also included. Calculated loads may be used to compare low flow conditions with and without contributions from the Gold King Mine (2012 versus 2019) as well as before and after closure of the Red and Bonita bulkhead (2019 versus 2020). The data release consists of a kmz file showing site locations and the following 9 tables: Table 1, Locations of sampling sites Table 2, Synoptic sampling results, October 3, 2012 Table 3, Synoptic sampling results, September 5, 2019 Table 4, Synoptic sampling results, September 19, 2020 Table 5, Iron speciation results, September 7, 2019 Table 6, Bromide timeseries, September 3-5, 2019 Table 7, Slug addition chloride data, September 19, 2020 Table 8, Slug addition results, September 19, 2020 Table 9, Spatial profiles of streamflow and metal load

Researchers at the U.S. Geological Survey (USGS) and their collaborators conducted a study of the geochemical properties of coals currently produced for electric power generation in the Illinois Basin in Illinois and Indiana. The study follows from recommendations by an expert panel for the USGS to investigate the distribution and controls of trace constituents such as mercury (Hg) in Illinois Basin coals and the behavior of these constituents in coal preparation. A total of 72 new samples were collected by USGS collaborators. These samples include raw coals, prepared coals, and waste coals from coal preparation. To understand the geochemistry and cleaning behavior of these coals, these samples were subjected to an integrated series of analyses, including microanalysis of coal constituents and bulk sample chemical analysis. Of the procedures used, whole-sample Hg analysis quantified overall mercury contents and its reduction by coal preparation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of pyrite in coal quantified Hg and other potentially harmful elements contained in pyrite, the most likely host of these constituents. Trace elements investigated include those of environmental interest as well as critical elements such as the rare earths. Results included in this data release include combined output from USGS and non-USGS laboratories.

Researchers at the U.S. Geological Survey (USGS) and their collaborators conducted a study of the geochemical properties of coals currently produced for electric power generation in the Illinois Basin in Illinois and Indiana. The study follows from recommendations by an expert panel for the USGS to investigate the distribution and controls of trace constituents such as mercury (Hg) in Illinois Basin coals and the behavior of these constituents in coal preparation. A total of 72 new samples were collected by USGS collaborators. These samples include raw coals, prepared coals, and waste coals from coal preparation. To understand the geochemistry and cleaning behavior of these coals, these samples were subjected to an integrated series of analyses, including microanalysis of coal constituents and bulk sample chemical analysis. Of the procedures used, whole-sample Hg analysis quantified overall mercury contents and its reduction by coal preparation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of pyrite in coal quantified Hg and other potentially harmful elements contained in pyrite, the most likely host of these constituents. Trace elements investigated include those of environmental interest as well as critical elements such as the rare earths. Results included in this data release include combined output from USGS and non-USGS laboratories.

We developed a methodology to estimate maximum brine injection rates in subsurface formations across wide geographic areas using inverse modeling-based optimization techniques. We first defined geographic areas where groundwater was too saline to meet the standard for drinking water and where sufficient confining units existed above and below the injection layers. We then assumed concurrent brine injection into a system of wells on a consistent 25 km x 25 km spacing across the entire modeled area. Taking advantage of symmetry, we represented each 25 km x 25 km injection area as a 12.5 km-long one-dimensional radial model, divided into 100 logarithmically-sized grid blocks. A single layer of grid blocks was used because homogenous porous media were assumed. Brine injection was simulated into the leftmost (innner) grid block, and the injection rate was automatically adjusted to meet a maximum pressure buildup to 80% of the fracturing pressure, estimated as the least principal stress, at the injection location. A secondary constraint of 1 bar maximum pressure increase at the right-most (far-field boundary) grid block after 50 years of injection was applied. We demonstrated this method on three stratigraphic layers that overlie the Mt. Simon Sandstone (MSS) in the Illinois Basin, as well as in the MSS itself, because the MSS is a well-known CO2 injection target with a large estimated CO2 storage capacity. CO2 storage in the MSS could be optimized by extracting brine from that formation and injecting it elsewhere, so the brine injection rates estimated with the models contained herein could help to refine CO2 storage capacity estimates.

A collection of analysis-ready datasets for the U.S. Geological Survey - Idaho National Laboratory (USGS-INL) groundwater and surface-water monitoring networks, administered by the USGS-INL Project Office in cooperation with the U.S. Department of Energy. The data collected from wells and surface-water stations at the Idaho National Laboratory and surrounding areas have been used to describe the effects of waste disposal on water contained in the eastern Snake River Plain aquifer, located in the southeastern part of Idaho, and the availability of water for long-term consumptive and industrial use. The datasets include long-term monitoring records dating back to measurements from 1922. Geospatial data describing the areas from which samples were collected or observations were made are also included.

In 2019, the U.S. Geological Survey (USGS), in cooperation with the National Park Service, initiated a study using surrogate technology to predict real-time metallic-contaminant concentrations (MCCs) in the Clark Fork at two USGS streamgages that bracket Grant-Kohrs Ranch National Historic Site (GRKO) near Deer Lodge, Montana. Clark Fork at Deer Lodge(streamgage 12324200), Mont., about one mile upstream from GRKO, and Clark Fork above Little Blackfoot River near Garrison (streamgage 12324400), Mont., about 12 miles downstream from GRKO property were instrumented with turbidity and acoustic sensors for monitoring the Clark Fork during National Park Service Superfund remediation activities. Time-series data from backscatter signals from fixed-point turbidity and acoustic sensors were correlated with discrete MCC samples collected from the Clark Fork and were used as surrogates for estimating real-time cadmium, copper, iron, lead, manganese, zinc, and the metalloid trace element arsenic. A stepwise regression approach was used to develop statistical models to predict MCCs based on instantaneous values of turbidity and acoustic backscatter. Simple linear regression models using turbidity as the sole explanatory variable produced the best models with R-squared values exceeding 0.90 in 9 of 12 models. Nash-Sutcliffe Efficiency values were used to evaluate the effectiveness of predictive models to approximate measured MCCs, and model biases were calculated as an additional check on model accuracy. The R-LOADEST statistical package was used to compute annual and daily metallic-contaminant loads along with 95-percent prediction intervals. R-LOADEST loads were compared to time-series computed loads to evaluate the applicability of time-series data for calculating daily and annual metallic-contaminant loads. Results from annual load estimates indicated an increase in loads for all metallic contaminants between the two monitoring sites. These results provided real-time information to National Park Service management for evaluating variation in water quality during Superfund remediation, comparing MCC values relative to aquatic life standards, and will help quantify benefits from Superfund remediation activities.

In 2019, the U.S. Geological Survey (USGS), in cooperation with the National Park Service, initiated a study using surrogate technology to predict real-time metallic-contaminant concentrations (MCCs) in the Clark Fork at two USGS streamgages that bracket Grant-Kohrs Ranch National Historic Site (GRKO) near Deer Lodge, Montana. Clark Fork at Deer Lodge(streamgage 12324200), Mont., about one mile upstream from GRKO, and Clark Fork above Little Blackfoot River near Garrison (streamgage 12324400), Mont., about 12 miles downstream from GRKO property were instrumented with turbidity and acoustic sensors for monitoring the Clark Fork during National Park Service Superfund remediation activities. Time-series data from backscatter signals from fixed-point turbidity and acoustic sensors were correlated with discrete MCC samples collected from the Clark Fork and were used as surrogates for estimating real-time cadmium, copper, iron, lead, manganese, zinc, and the metalloid trace element arsenic. A stepwise regression approach was used to develop statistical models to predict MCCs based on instantaneous values of turbidity and acoustic backscatter. Simple linear regression models using turbidity as the sole explanatory variable produced the best models with R-squared values exceeding 0.90 in 9 of 12 models. Nash-Sutcliffe Efficiency values were used to evaluate the effectiveness of predictive models to approximate measured MCCs, and model biases were calculated as an additional check on model accuracy. The R-LOADEST statistical package was used to compute annual and daily metallic-contaminant loads along with 95-percent prediction intervals. R-LOADEST loads were compared to time-series computed loads to evaluate the applicability of time-series data for calculating daily and annual metallic-contaminant loads. Results from annual load estimates indicated an increase in loads for all metallic contaminants between the two monitoring sites. These results provided real-time information to National Park Service management for evaluating variation in water quality during Superfund remediation, comparing MCC values relative to aquatic life standards, and will help quantify benefits from Superfund remediation activities.

Biogeochemical processes are key drivers of chemical solubility and mobilization. Understanding these processes will lead to improved predictive capabilities and may aid with watershed management decisions. This data release presents results from the Boulder Creek, Colorado watershed, including analyses of water and sediment. From April to August 2019, water samples were collected weekly at 2 sites along Boulder Creek and 4 tributary sites draining into Boulder Creek. In August 2022, water samples were collected every 2 hours for 34 hours at 2 sites on Boulder Creek (upstream and downstream of the city of Boulder). Samples for both studies were analyzed for major cations and anions, dissolved organic carbon, UV absorbance, total dissolved nitrogen, ammonium, nitrate, alkalinity, trace metals, water isotopes, and field parameters including dissolved oxygen, pH, water temperature, and specific conductance. In August 2022, bed sediment (0-3 cm depth) samples were collected at 8 sites along Boulder Creek. The sediment was dried, sieved, pulverized, digested, and then analyzed for metals, total carbon, sulfur, and carbonate. In 2021 and 2022, laboratory incubations of sediment and stream water were conducted to assess how different oxidation-reduction conditions affect metal and nutrient concentrations. Sediment cores (0-5 cm and 5-10 cm depth) and surface water were collected from Boulder Creek at three sites upstream, within, and downstream of the city of Boulder. Samples were collected from incubation reactors over time and analyzed for major cations and anions, dissolved organic carbon, UV absorbance, total dissolved nitrogen, ammonium, nitrate, trace metals, total arsenic, pH, and specific conductance. Sediments used for the incubations were further characterized by sequential extractions with hydroxylamine and dithionite and analyzed for major cations and trace metals. Site information, soil characterization details, incubation preparation and biogeochemical nutrient data, sediment sequential extraction data, and water-quality data are presented in this data release as ten comma-separated values (.csv) formatted tables. A data dictionary file describes the data found in the .csv files. Method details and references are located in the metadata file “Boulder Creek Watershed Data (2019-2023).xml.”