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High radium (Ra) concentrations in potable portions of the Cambrian-Ordovician (C-O) aquifer system were investigated using water-quality data and environmental tracers ( 3H, 3Hetrit, SF6 , 14C and 4Herad) of groundwater age from 80 public-supply wells (PSWs). Groundwater ages were estimated by calibration of tracers to lumped parameter models and ranged from modern (1 Myr) in the most downgradient, confined portions of the potable system. More than 80 and 40 percent of mean groundwater ages were older than 1000 and 50,000 yr, respectively. Anoxic, Fe-reducing conditions and increased mineralization develop with time in the aquifer system and mobilize Ra into solution resulting in the frequent occurrence of combined...
This data release documents three Microsoft Excel tables (and corresponding comma separated data files) that contain estimates of tritium in precipitation data for the continental United States. Versions of this data release contain additional tritium data for more recent years. The current version has tritium data through 2022. Table 1 contains estimates of tritium in precipitation for precipitation stations located in the continental United States. Measured precipitation data are formatted in regular font while correlated data are italicized. Table 2 contains tritium in precipitation for ninety-six 2-degree latitude by 5-degree longitude quadrangles covering the continental U.S. Latitudes are north of the equator...
Categories: Data,
Data Release - In Progress;
Tags: Tritium,
USGS Science Data Catalog (SDC),
continental United States,
groundwater,
groundwater age,
This data release documents eight Microsoft Excel tables; four which contain data for understanding groundwater ages in the South East Coastal Plain (SECP), Coastal Lowlands (CLOW) and Mississippi Embayment and Texas Coastal Uplands (METX) aquifer systems and four that describe the data fields. Results described include dissolved gas modeling results, environmental tracer concentrations (tritium, tritiogenic helium-3, sulfur hexafluoride, and radiogenic helium-4), mean age and age distribution, and carbon-14 geochmical modeling results Dissolved gas modeling results (DGmodel) contains detailed information on the calibration of dissolved gas models to dissolved gas concentrations (neon, argon, krypton, xenon, and...
We computed mean groundwater ages and age distributions at eight wells by calibrating lumped parameter models (LPMs) to concentrations of tracers (3H, CFCs, SF6) in samples using the computer program TracerLPM (Jurgens and others, 2012). We also measured 14C but all samples contained ancient carbonate from the limestone bedrock, and we were unable to resolve the atmospherically-derived 14C sufficiently to use it as a tracer. Tritium was below the detection level in two of the eight well-water samples, indicating the water was recharged prior to about 1950. Groundwater from the other six wells could be fitted to LPMs that were either piston flow models (PFM), exponential – piston flow models (EPM), or binary mixing...
High radium (Ra) concentrations in potable portions of the Cambrian-Ordovician (C-O) aquifer system were investigated using water-quality data and environmental tracers ( 3H, 3Hetrit, SF6 , 14C and 4Herad) of groundwater age from 80 public-supply wells (PSWs). Groundwater ages were estimated by calibration of tracers to lumped parameter models and ranged from modern (1 Myr) in the most downgradient, confined portions of the potable system. More than 80 and 40 percent of mean groundwater ages were older than 1000 and 50,000 yr, respectively. Anoxic, Fe-reducing conditions and increased mineralization develop with time in the aquifer system and mobilize Ra into solution resulting in the frequent occurrence of combined...
The Captain Jack Superfund site near Ward, Colorado hosts extensive interconnected underground mine workings, which drain via the Big Five Adit. Drainage from the adit has historically been acidic with elevated concentrations of metals. In 2018 the U.S. Environmental Protection Agency (EPA) utilized a subsurface remediation strategy consisting of the installation of a hydraulic bulkhead within the workings to preclude drainage out of the mine. To understand the processes occurring during water impoundment within the mine workings, the U.S. Geological Survey (USGS), in cooperation with EPA, completed water-quality sampling and analysis during 2020 as water was impounded within the mine workings. The USGS sampling...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Boulder County,
Colorado,
Geochemistry,
Hydrology,
USGS Science Data Catalog (SDC),
The U.S. Geological Survey collected groundwater samples from 17 wells in the Indio subbasin (CA basin designation 7-21.01) of the Coachella Valley and surface water samples from two sites representing sources of recharge to the Indio subbasin in 2021. These samples are intended to provide inorganic water quality data, particularly total dissolved solids (TDS), within areas of the Indio subbasin not sampled for the Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project’s assessment of the quality of groundwater used for domestic and small system drinking water supplies in Coachella Valley (CODA). Other areas of special interest for the Indio salinity study were nearby managed aquifer...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
Coachella Valley,
Geochemistry,
Groundwater,
Groundwater age,
Groundwater age is an important indicator of groundwater susceptibility to anthropogenic contamination and a key input to statistical models for forecasting water quality. Numerical models can provide estimates of groundwater age, enabling interpretation of measured age tracers. However, to extend to national-scale groundwater systems where numerical models are not routinely available, a more efficient metamodeling approach can provide a less precise but widely applicable estimate of groundwater age, trained to make forecasts based on predictor variables that can be measured independent of numerical models. We trained gradient-boosted regression tree statistical metamodels to MODFLOW/MODPATH derived groundwater...
This data release documents four Microsoft Excel tables; one contains data for understanding water ages, one contains noble gas model data, two that describe the data fields. Results described include environmental tracer concentrations (tritium, tritiogenic helium-3, choloroflourocarbons, and radiogenic helium-4), mean age and age distribution, noble gas concentrations, and groundwater recharge conditions. Mean age and age distribution results (LPM) contain final models of groundwater age by calibration of lumped parameter models to tracer concentrations (Jurgens and others, 2012). Please see the main manuscript for additional details on the results presented in this table. Noble gas model results (CEmodel) contain...
High radium (Ra) concentrations in potable portions of the Cambrian-Ordovician (C-O) aquifer system were investigated using water-quality data and environmental tracers ( 3H, 3Hetrit, SF6 , 14C and 4Herad) of groundwater age from 80 public-supply wells (PSWs). Groundwater ages were estimated by calibration of tracers to lumped parameter models and ranged from modern (1 Myr) in the most downgradient, confined portions of the potable system. More than 80 and 40 percent of mean groundwater ages were older than 1000 and 50,000 yr, respectively. Anoxic, Fe-reducing conditions and increased mineralization develop with time in the aquifer system and mobilize Ra into solution resulting in the frequent occurrence of combined...
Categorical classification of groundwater age based on concentrations of tritium (3H) in groundwater can provide useful information for the assessment and understanding of groundwater resources. These data present a three-part groundwater age classification system for the continental United States based on tritium thresholds that vary in space and time: modern (recharged after 1952), if the measured value is larger than an upper threshold; premodern (recharged prior to 1953) if the measured value is smaller than a lower threshold; or mixed if the measured value is between the two thresholds. Inclusion of spatially-varying that vary geographically on the basis of the location of the sample rather than a single threshold...
This data release contains environmental tracer model inputs, outputs, and model results. Dataset includes environmental tracer concentrations, simulated recharge conditions (water temperature, excess air), and estimated groundwater residence times. This dataset supports an integrated hydrologic investigation of groundwater recharge processes and groundwater flow in the Wet Mountain Valley alluvial aquifer, Custer and Fremont Counties, Colorado. Data were collected by the U.S. Geological Survey in cooperation with the Upper Arkansas Water Conservancy District.
Groundwater age distribution and susceptibility to natural and anthropogenic contaminants were assessed for selected principal aquifers of the Western United States: the Central Valley aquifer system (CVAL), the Basin and Range basin-fill aquifers (BNRF), the Rio Grande aquifer system (RIOG), the High Plains aquifer (HPAQ), the Columbia Plateau basaltic-rock aquifers (CLPT), and the Colorado Plateaus aquifers (COPL). Groundwater ages were estimated by calibration of environmental tracers (tritium, tritiogenic helium-3, chlorofluorocarbons, sulfur hexafluoride, carbon-14 and radiogenic helium-4) to lumped parameter models (LPMs) for 1,353 samples from 1,182 sample locations. Groundwater samples were collected from...
Categories: Data;
Tags: Arizona,
Basin and Range Aquifers,
California,
Central Valley Aquifer,
Colorado,
This data release documents two Microsoft Excel tables that contain data for understanding tracer concentrations and groundwater age in the Columbia Plateau aquifer system. Results for geochemical correction of carbon-14, and lumped parameter modeling of groundwater age for the sample network (VPFS, vertical flow path study) are described. Geochemical carbon-14 correction results (RFG) describe geochemical correction of carbon-14 in dissolved inorganic carbon (DIC) for groundwater age dating. Datasets includes measured water parameters and chemistry, model parameter inputs, and final corrected carbon-14 in DIC. Geochemical correction was completed using the revised Fontes and Granier model of Han and Plummer (2013)....
Categories: Data;
Tags: Columbia Plateau Aquifer,
Environmental tracers,
Geochemistry,
Hydrology,
USGS Science Data Catalog (SDC),
A multivariate regression model was developed to predict zero-order oxygen reduction rates (mg/L/yr) in aquifers across the State of Wisconsin. The model used a combination of dissolved oxygen concentrations and mean groundwater ages estimated with sampled age tracers from wells in the U.S. Geological Survey National Water Information System and previously published project reports from state agencies and universities. The multivariate regression model was solved using the Microsoft Excel solver, with 461 wells used for training and 46 wells held-out for validation. A total of 31 predictor variables were used for model development (56 were tested), including basic well characteristics, soil properties, aquifer properties,...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: USGS Science Data Catalog (SDC),
Wisconsin,
environment,
geoscientificInformation,
groundwater,
Thirty water-supply drinking-water wells were sampled during fall 2018 for a set of constituents including PFAS. Groundwater samples were sent to Maxxam Laboratories (RTI Laboratory contract) to be analyzed for eighteen PFAS using USEPA 537m method. Groundwater age data were collected and analyzed as well in the USGS Reston, Va. laboratory. Quality-control samples including equipment and field blanks, sequential replicate samples, and laboratory spikes, were collected to evaluate and estimate potential contamination bias and measure variability from water-quality data-collection processes. No PFAS were detected in equipment or field blanks indicating that selected equipment, cleaning, sampling, and handling procedures...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Coastal Plain,
Delaware,
Emergent contaminants,
Groundwater age,
Groundwater quality,
Groundwater salinity presents a challenge to the management of water quality in the Indio subbasin of the Coachella Valley where a growing population is dependent primarily on groundwater for drinking water. The U.S. Geological survey, along with the Colorado River Basin regional water quality control board, are working to provide an assessment of salinity trends and sources in the Indio subbasin (California (CA) basin designation 7-21.01; California Department of Water Resources (2020)). As part of this work, salinity data and other selected inorganic water quality data, along with well construction information, for wells with available total dissolved solids (TDS) or conductance data were compiled from published...
This data release provides additional data collected since the original publication of: Busenberg, Eurybiades, Plummer, L.N., Coplen, T.B., Doughten, M.W., Widman, P.K., Casile, G.C., Wayland, J.E., and Nelms, D.L., 2014, A 19-year record of chemical and isotopic composition of water from springs of the Shenandoah National Park, Virginia, 1995–2014: U.S. Geological Survey Data Series 893, 11 p., http://dx.doi.org/10.3133/ds893. ISSN 2327-638X (online) This data release represents to original 2014 U.S. Geological Survey Data Series along with additional data collected in Shenandoah National Park up to April 18, 2017. The data release consists of two files: a spreadsheet consisting of multiple worksheets, and a data...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Groundwater,
Groundwater Age,
Hydrology,
USGS Science Data Catalog (SDC),
Water Chemistry
In 2013, water-quality and age-date tracer samples were collected at wells located along two flow paths in the Memphis aquifer, southwest Tennessee, as part of the National Water Quality Assessment (NAWQA) Project of the National Water-Quality Program to better understand the vulnerability of the aquifer to contamination.. Each flow path began in the aquifer outcrop area (shallow well depths) and ended at public supply wells (deep well depths) in Memphis, TN in the confined parts of the aquifer. This data release includes results for samples collected as part of this study and information for additional wells that provided supplemental data near the end of each flow path to support the findings in "Fraction of young...
Categories: Data;
Types: Citation;
Tags: Memphis, Tennessee,
USGS Science Data Catalog (SDC),
groundwater age,
groundwater flow path,
vulnerability,
High radium (Ra) concentrations in potable portions of the Cambrian-Ordovician (C-O) aquifer system were investigated using water-quality data and environmental tracers ( 3H, 3Hetrit, SF6 , 14C and 4Herad) of groundwater age from 80 public-supply wells (PSWs). Groundwater ages were estimated by calibration of tracers to lumped parameter models and ranged from modern (1 Myr) in the most downgradient, confined portions of the potable system. More than 80 and 40 percent of mean groundwater ages were older than 1000 and 50,000 yr, respectively. Anoxic, Fe-reducing conditions and increased mineralization develop with time in the aquifer system and mobilize Ra into solution resulting in the frequent occurrence of combined...
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