Skip to main content
Advanced Search

Filters: Tags: cycle 3 (X)

48 results (53ms)   

View Results as: JSON ATOM CSV
thumbnail
Groundwater quality data were collected in 5,000 wells between 1988-2001 by the National Water-Quality Assessment Project. About 1,500 of these wells were sampled again between 2002-2012 to evaluate decadal changes in groundwater quality. Monitoring wells, domestic supply wells, and some public supply wells were included in this study. All water was collected prior to treatment. Groundwater samples used to evaluate decadal change were collected from networks of wells with similar characteristics. Some networks, consisting of domestic or public supply wells, were used to assess changes in the quality of groundwater used for drinking water supply. Other networks, consisting of monitoring wells, assessed changes in...
thumbnail
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...
thumbnail
This data set includes results for hormone and pharmaceutical compounds analyzed in environmental and quality-control samples collected by the USGS National Water-Quality Assessment Project during 2013 through 2015 for a study of groundwater resources used for drinking-water supply across the United States. Hormone and pharmaceutical results are provided for environmental samples collected at 1,120 wells or springs; selected ancillary data, such as principal aquifer, well depth, and land-use information also are provided for the sampled sites. The types of quality-control samples included in this data set are blanks, matrix spikes, and replicates collected at field sites or field offices. Included in this data...
thumbnail
Water-quality data for groundwater samples collected from 4,824 sites between 1991 through 2018, and ancillary data and information on sampled wells and principal aquifers, were used to assess the occurrence and distribution of strontium in U.S. groundwater from 32 principal aquifers. This data release includes one tab-delimited text file detailing these data. Table: Chemical data from the U.S. Geological Survey National Water Information System and ancillary data considered for assessment of strontium concentration in U.S. groundwater.
thumbnail
Groundwater-quality data were collected from 502 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Project and are included in this data release. Most of the wells (500) were sampled from January through December 2015 and 2 of them were sampled in 2013. The data were collected from five types of well networks: principal aquifer study networks, which are used to assess the quality of groundwater used for public water supply; land-use study networks, which are used to assess land-use effects on shallow groundwater quality; major aquifer study networks, which are used to assess the quality of groundwater used for domestic supply; enhanced trends networks,...
thumbnail
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...
thumbnail
Data provided here describe geochemical correction of carbon-14 in dissolved inorganic carbon (DIC) for groundwater age dating. Datasets include major ion chemistry of groundwater samples, model parameter inputs, and final corrected carbon-14 in DIC. Geochemical correction was completed in two phases: determination of reactive phase mole transfers through an inverse geochemical model (PHREEQC; Parkhurst and Appleo, 1992) and tracking of isotopic mass transfer among phases (NetpathXL; Parkhusrtand Charlton, 2008). Parkhurst, D.L., and Appelo, C.A.J., 2013, Description of input and examples for PHREEQC version 3—A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical...
Tags: Cenozoic, Connecticut, Holocene, Idaho, Illinois, All tags...
thumbnail
This data release documents nine Microsoft Excel tables that contain data for understanding groundwater ages in the Glacial aquifer system. Results for the three sample networks (PAS, principal aquifer study; MSS, modeling support study; FPS, flow path study) are described by three tables each: dissolved gas modeling results, environmental tracer concentrations (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14, and radiogenic helium-4), and results for the mean age and age distribution. Tables are labeled by network and data type (as described below) separated by an underscore (_). For example, dissolved gas modeling results from the PAS network is label ‘PAS_NGmodel’. Dissolved gas modeling results...
thumbnail
This data set includes sample information and results for third-party performance assessment samples analyzed for hormones and pharmaceuticals during the same general time period as environmental samples collected by the National Water-Quality Assessment (NAWQA) Project for a study of groundwater resources used for drinking-water supply across the United States, 2013 through 2015. Hormone and pharmaceutical results are provided for spiked and unspiked samples submitted by the Quality Systems Branch (QSB) Organic Blind Sample Project (OBSP), providing information regarding analyte recovery and occurrence of false positive and false negative results. Included in this data release are the following data tables: Table...
thumbnail
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...
thumbnail
This data release documents three Microsoft Excel tables that contain estimates of tritium in precipitation data for the continental United States. 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 and longitudes are west of the prime meridian. Please see the processing steps below and the main manuscript for additional details on the results presented in this table. Table 3...
thumbnail
Continuous monitoring and discrete water-quality sampling were coupled in a karst aquifer to assess drivers and timescales of water-quality change. Water-quality data included environmental tracers of groundwater age (tritium [3H], tritiogenic helium-3 [3He-trit], sulfur hexafluoride [SF6], carbon-14 [14C], and radiogenic helium-4 [4He-rad]). All water quality data is available from the U.S. Geological Survey NWIS database (U.S. Geological Survey, 2019). Groundwater ages were estimated by calibration of environmental tracers to lumped parameter models of groundwater age for multiple samples collected at six groundwater wells using the program TracerLPM (Jurgens and others, 2012). The final estimates for mean groundwater...
Groundwater-quality data were collected from 748 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program from May 2012 through December 2013. The data were collected from four types of well networks: principal aquifer study networks, which assess the quality of groundwater used for public water supply; land-use study networks, which assess land-use effects on shallow groundwater quality; major aquifer study networks, which assess the quality of groundwater used for domestic supply; and enhanced trends networks, which evaluate the time scales during which groundwater quality changes. Groundwater samples were analyzed for a large number of water-quality...
thumbnail
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...
thumbnail
This data release consists of data (in four tables) for assessing the time scales of arsenic variability in three production wells in New Hampshire; tables that describe the data fields in the data tables are also included in the data release. High-frequency (every 5 to 15 minutes) and bi-monthly water-quality monitoring of a bedrock-aquifer domestic well (425651070573701), a bedrock-aquifer public-supply well (425400070545401), and a glacial-aquifer public-supply well (425311070535801) was completed between 2014 and 2018. Concentrations of arsenic and other geochemical constituents and dissolved gases, as tracers of groundwater age, were measured on a bimonthly basis; physicochemical data, including specific conductance,...
thumbnail
Residence time distribution (RTD) is a critically important characteristic of groundwater flow systems; however, it cannot be measured directly. RTD can be inferred from tracer data with analytical models (few parameters) or with numerical models (many parameters). The second approach permits more variation in system properties but is used less frequently than the first because large-scale numerical models can be resource intensive. With the data and computer codes in this data release users can (1) reconstruct and run 115 General Simulation Models (GSMs) of groundwater flow, (2) calculate groundwater age metrics at selected GSM cells, (3) train a boosted regression tree model using the provided data, (4) predict...
thumbnail
Lithium concentrations in untreated groundwater from 1,464 public-supply wells, 1,676 domestic-supply wells, and 1,560 monitoring wells distributed across 33 principal aquifers in the United States were evaluated for spatial variations and possible explanatory factors. For context, lithium concentrations are compared to a drinking-water only threshold (60 micrograms per liter) and a Health-Based Screening Level (HBSL, 10 micrograms per liter). These thresholds were exceeded in 9% and 45% of samples from public-supply wells and in 6% and 37% from domestic-supply wells, respectively. Exceedances were most frequent for arid regions and older groundwater. Groundwater lithium concentrations were highest in unconsolidated...
In 1991, the U.S. Congress established the National Water-Quality Assessment (NAWQA) program within the U.S. Geological Survey (USGS) to develop nationally consistent long-term datasets and provide information about the quality of the Nation’s streams and groundwater. The USGS uses objective and reliable data, water-quality models, and systematic scientific studies to assess current water-quality conditions, to identify changes in water quality over time, and to determine how natural factors and human activities affect the quality of streams and groundwater. NAWQA is the only non-regulatory Federal program to perform these types of studies; participation is voluntary. In the third decade (Cycle 3) of the NAWQA program...
thumbnail
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...


map background search result map search result map Data from Decadal Change in Groundwater Quality Web Site, 1988-2012 Geochemical Correction of Carbon-14 in Dissolved Inorganic Carbon used for Groundwater Age Dating in the Glacial Aquifer System, Conterminous United States Datasets from Groundwater-Quality and Select Quality-Control Data from the National Water-Quality Assessment Project, January through December 2015 and Previously Unpublished Data from 2013-2014 Data for Radium Mobility and the Age of Groundwater in Public-drinking-water Supplies from the Cambrian-Ordovician Aquifer System, North-Central USA: Table 1. Dissolved gas modeling results, environmental tracer concentrations (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14, and radiogenic helium-4), and results for the mean age of groundwater by calibration of lumped parameter models to tracer concentrations. Data for Radium Mobility and the Age of Groundwater in Public-drinking-water Supplies from the Cambrian-Ordovician Aquifer System, North-Central USA: Table 2. Detailed information on the calibration of dissolved gas models to dissolved gas concentrations (neon, argon, krypton, xenon, and nitrogen). Data for Radium Mobility and the Age of Groundwater in Public-drinking-water Supplies from the Cambrian-Ordovician Aquifer System, North-Central USA: Table 3. Detailed information on calculations of environmental tracer data. Dissolved Gas, Environmental Tracer Concentrations, and Lumped Parameter Modeling Results for Groundwater Age Dating in the Glacial Aquifer System, Conterminous United States Environmental and Quality-Control Data Collected by the USGS National Water-Quality Assessment Project for Hormones and Pharmaceuticals in Groundwater Used as a Source of Drinking Water Across the United States, 2013-15 Third-party performance assessment data encompassing the time period of analysis of groundwater samples collected for hormones and pharmaceuticals by the National Water-Quality Assessment Project in 2013-15 Data for Tritium deposition in precipitation in the United States, 1953 - 2012 Data for Groundwater Age and Susceptibility of Poorly Consolidated Sedimentary Aquifers of the United States Gulf Coast: Results from the Southeast Coastal Plain (SECP), Coastal Lowland (CLOW), Mississippi Embayment and Texas Coastal Upland (METX) Principal Aquifer Networks Data for Tritium as an Indicator of Modern, Mixed and Premodern Groundwater Age Data for timescales of water-quality change in a karst aquifer, south-central Texas Data for Time Scales of Arsenic Variability and the Role of High-Frequency Monitoring at Three Water-Supply Wells in New Hampshire, USA Data for three-dimensional distribution of groundwater residence time metrics in the glaciated United States using metamodels trained on general numerical simulation models Data for the occurrence and distribution of strontium in U.S. groundwater Inorganic Constituent and Ancillary Data for Evaluation of Lithium in Groundwater in the United States, 1991-2018 Data for Time Scales of Arsenic Variability and the Role of High-Frequency Monitoring at Three Water-Supply Wells in New Hampshire, USA Data for timescales of water-quality change in a karst aquifer, south-central Texas Data for Radium Mobility and the Age of Groundwater in Public-drinking-water Supplies from the Cambrian-Ordovician Aquifer System, North-Central USA: Table 1. Dissolved gas modeling results, environmental tracer concentrations (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14, and radiogenic helium-4), and results for the mean age of groundwater by calibration of lumped parameter models to tracer concentrations. Data for Radium Mobility and the Age of Groundwater in Public-drinking-water Supplies from the Cambrian-Ordovician Aquifer System, North-Central USA: Table 2. Detailed information on the calibration of dissolved gas models to dissolved gas concentrations (neon, argon, krypton, xenon, and nitrogen). Data for Radium Mobility and the Age of Groundwater in Public-drinking-water Supplies from the Cambrian-Ordovician Aquifer System, North-Central USA: Table 3. Detailed information on calculations of environmental tracer data. Data for Groundwater Age and Susceptibility of Poorly Consolidated Sedimentary Aquifers of the United States Gulf Coast: Results from the Southeast Coastal Plain (SECP), Coastal Lowland (CLOW), Mississippi Embayment and Texas Coastal Upland (METX) Principal Aquifer Networks Dissolved Gas, Environmental Tracer Concentrations, and Lumped Parameter Modeling Results for Groundwater Age Dating in the Glacial Aquifer System, Conterminous United States Geochemical Correction of Carbon-14 in Dissolved Inorganic Carbon used for Groundwater Age Dating in the Glacial Aquifer System, Conterminous United States Data for three-dimensional distribution of groundwater residence time metrics in the glaciated United States using metamodels trained on general numerical simulation models Datasets from Groundwater-Quality and Select Quality-Control Data from the National Water-Quality Assessment Project, January through December 2015 and Previously Unpublished Data from 2013-2014 Data for Tritium deposition in precipitation in the United States, 1953 - 2012 Data for Tritium as an Indicator of Modern, Mixed and Premodern Groundwater Age Environmental and Quality-Control Data Collected by the USGS National Water-Quality Assessment Project for Hormones and Pharmaceuticals in Groundwater Used as a Source of Drinking Water Across the United States, 2013-15 Third-party performance assessment data encompassing the time period of analysis of groundwater samples collected for hormones and pharmaceuticals by the National Water-Quality Assessment Project in 2013-15 Data from Decadal Change in Groundwater Quality Web Site, 1988-2012 Inorganic Constituent and Ancillary Data for Evaluation of Lithium in Groundwater in the United States, 1991-2018 Data for the occurrence and distribution of strontium in U.S. groundwater