This database includes water quality records compiled at the request of the Bureau of Land Management for the Uinta Basin in Utah and Colorado. All data contained within this database are publically available via the United States Geological Survey’s National Water Information System (NWIS) database (available at https://waterdata.usgs.gov/nwis). Data collected and provided by the states of Utah and Colorado were also analyzed, however, this data had also been submitted to, and was available in, NWIS by the time this database was compiled. This database includes all available water-quality data for the Uinta Basin. For groundwater samples this includes data up to October 24, 2014; for surface water samples this includes data up to July 27, 2017.

Groundwater-quality data were collected from 648 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program and are included in this report. Most of the wells (514) were sampled from January through December 2016 and 60 of them were sampled in 2013 and 74 in 2014. The data were collected from seven 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, which are used to evaluate the time scales during which groundwater quality changes; vertical flow-path study networks, which are used to evaluate changes in groundwater quality from shallow to deeper depths; flow path study networks, which are used to evaluate changes in groundwater quality from shallow to deeper depths over a horizontal distance; and modeling support studies, which are used to provide data to support groundwater modeling. Groundwater samples were analyzed for a large number of water-quality indicators and constituents, including major ions, nutrients, trace elements, volatile organic compounds, pesticides, radionuclides, and some special interest constituents (arsenic speciation, chromium [VI] and perchlorate). These groundwater quality data are tabulated in a U.S. Geological Survey Data Series Report DS-1124 which is available at https://dx.doi.org/XXXXXX and in this data release. Some data from environmental samples collected in 2013-14 and quality-control samples collected in 2012-15 also are included in the associated data release. Data from samples collected in 2016 are associated with networks described in this report and have not been published previously; data from samples collected between 2012 and 2015 are associated with networks described in previous reports in this data series (Arnold and others, 2016a,b, 2017a,b, 2018a,b). There are 23 data tables included in this data release and they are referenced as tables 1-13 and appendix tables 4.10-4.19 in the larger work citation. There are 36 tables that are part of the larger work citation; the 13 tables not included in the data release are summary tables derived from some of the other tables (tables 1.1, 2.2-2.3, 3.1, 4.1-4.9). A version of table 1 is included in both the text and data release. This compressed file contains 23 files of groundwater-quality data in ASCII text tab-delimited format and one corresponding metadata in xml format that describes all the tables and attributes.

Groundwater-quality data were collected from 648 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program and are included in this report. Most of the wells (514) were sampled from January through December 2016 and 60 of them were sampled in 2013 and 74 in 2014. The data were collected from seven 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, which are used to evaluate the time scales during which groundwater quality changes; vertical flow-path study networks, which are used to evaluate changes in groundwater quality from shallow to deeper depths; flow path study networks, which are used to evaluate changes in groundwater quality from shallow to deeper depths over a horizontal distance; and modeling support studies, which are used to provide data to support groundwater modeling. Groundwater samples were analyzed for a large number of water-quality indicators and constituents, including major ions, nutrients, trace elements, volatile organic compounds, pesticides, radionuclides, and some special interest constituents (arsenic speciation, chromium [VI] and perchlorate). These groundwater quality data are tabulated in a U.S. Geological Survey Data Series Report DS-1124 which is available at https://dx.doi.org/XXXXXX and in this data release. Some data from environmental samples collected in 2013-14 and quality-control samples collected in 2012-15 also are included in the associated data release. Data from samples collected in 2016 are associated with networks described in this report and have not been published previously; data from samples collected between 2012 and 2015 are associated with networks described in previous reports in this data series (Arnold and others, 2016a,b, 2017a,b, 2018a,b). There are 23 data tables included in this data release and they are referenced as tables 1-13 and appendix tables 4.10-4.19 in the larger work citation. There are 36 tables that are part of the larger work citation; the 13 tables not included in the data release are summary tables derived from some of the other tables (tables 1.1, 2.2-2.3, 3.1, 4.1-4.9). A version of table 1 is included in both the text and data release. This compressed file contains 23 files of groundwater-quality data in ASCII text tab-delimited format and one corresponding metadata in xml format that describes all the tables and attributes.

Groundwater-quality data were collected from 983 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program and are included in this report. The data were collected from six 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, which are used to evaluate the time scales during which groundwater quality changes; vertical flow-path study networks, which are used to evaluate changes in groundwater quality from shallow to deeper depths; and modeling support studies, which are used to provide data to support groundwater modeling. Groundwater samples were analyzed for a large number of water-quality indicators and constituents, including major ions, nutrients, trace elements, volatile organic compounds, pesticides, radionuclides, microbiological indicators, and some special interest constituents (arsenic speciation, chromium [VI] and perchlorate). Most of the data included were collected from wells that were sampled between January 2017 and December 2019. Microbiological indicator data for networks sampled in 2016 are included in this data release. These groundwater quality networks are described in a U.S. Geological Survey Data Series report DS####, which is available at https://dx.doi.org/XXXXXX, and the results are in this data release. Data for quality-control samples collected in 2017 through 2019 also are included in this data release. Data from samples collected between 2012 and 2016 are associated with networks described in previous reports in this data series (Arnold and others, 2016a and b; 2017a and b; 2018a and b; and 2020a and b). There are 24 data tables included in this data release and they are referenced as tables 1 through 14 and appendix tables 5-11 through 5-20 in the larger work citation (see supplemental information for descriptions). Two tables summarizing well depth and open interval are included in the data series report and were derived from table 1 in this data release. A separate table named DSR_2017-19_Description_of_Data_Fields.txt describes the 405 unique fields contained in the 24 data tables.

Groundwater-quality data were collected from 983 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program and are included in this report. The data were collected from six 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, which are used to evaluate the time scales during which groundwater quality changes; vertical flow-path study networks, which are used to evaluate changes in groundwater quality from shallow to deeper depths; and modeling support studies, which are used to provide data to support groundwater modeling. Groundwater samples were analyzed for a large number of water-quality indicators and constituents, including major ions, nutrients, trace elements, volatile organic compounds, pesticides, radionuclides, microbiological indicators, and some special interest constituents (arsenic speciation, chromium [VI] and perchlorate). Most of the data included were collected from wells that were sampled between January 2017 and December 2019. Microbiological indicator data for networks sampled in 2016 are included in this data release. These groundwater quality networks are described in a U.S. Geological Survey Data Series report DS####, which is available at https://dx.doi.org/XXXXXX, and the results are in this data release. Data for quality-control samples collected in 2017 through 2019 also are included in this data release. Data from samples collected between 2012 and 2016 are associated with networks described in previous reports in this data series (Arnold and others, 2016a and b; 2017a and b; 2018a and b; and 2020a and b). There are 24 data tables included in this data release and they are referenced as tables 1 through 14 and appendix tables 5-11 through 5-20 in the larger work citation (see supplemental information for descriptions). Two tables summarizing well depth and open interval are included in the data series report and were derived from table 1 in this data release. A separate table named DSR_2017-19_Description_of_Data_Fields.txt describes the 405 unique fields contained in the 24 data tables.

This dataset is a compilation of data obtained from the Idaho Department of Water Quality, the Idaho Department of Water Resources, and the Water Quality Portal. The 'SiteID' table catalogues organization-specific identification numbers assigned to each monitoring location.

Groundwater samples were collected from 60 public supply wells in the Colorado Plateaus principal aquifer. Water quality evaluations of groundwater for drinking water at public supply depths were made with the purpose of summarizing the current quality of source water (that is, untreated water) from public supply wells using two types of assessments; (1) status: an assessment that describes the current quality of the groundwater resource, and (2) understanding: an evaluation of the natural and human factors affecting the quality of groundwater, including an explanation of statistically significant associations between water quality and selected explanatory factors. To provide context for water-quality data, constituent concentrations of untreated groundwater are compared with available water-quality benchmarks Federal regulatory benchmarks for protecting human health (maximum contaminant levels [MCLs]; U.S. Environmental Protection Agency [USEPA] primary drinking water regulations; U.S. Environmental Protection Agency, 2018a) are used for this evaluation. Additionally, non-regulatory human-health benchmarks (health-based screening levels [HBSLs]; Norman and others, 2018; U.S. Geological Survey, 2018); and federal non-regulatory benchmarks for nuisance chemicals (USEPA secondary maximum contaminant levels [SMCLs]; U.S. Environmental Protection Agency, 2018b) are used. This report considers benchmarks in the context of health-based (MCLs and HBSLs) and non-health based (SMCLs) benchmarks. This sampling approach uses an equal-area grid design (Belitz and others, 2010) which allows for the estimation of the proportion of high, moderate, or low concentrations relative to federal water-quality benchmarks of selected constituents over the entire area of the aquifer. Tables included in this data release: Table 1. Identification, location, and construction information for wells sampled for the U.S. Geological Survey National Water-Quality Assessment Project, Colorado Plateaus principal aquifer, June 2013 through December 2017. Table 2. Constituent primary uses and sources; analytical schedules and sampling period; USGS parameter codes; comparison thresholds and reporting levels wells sampled for the for the U.S. Geological Survey National Water-Quality Assessment Project, Colorado Plateaus principal aquifer, June 2013 through December 2017. Table 3. Water-quality indicators in groundwater samples collected by the for the U.S. Geological Survey National Water-Quality Assessment Project, Colorado Plateaus principal aquifer, June 2013 through December 2017. [Table code definitions: NC, not collected; <, less than] Table 4. Nutrients and dissolved organic carbon in groundwater samples collected by the U.S. Geological Survey National Water-Quality Assessment Project, Colorado Plateaus principal aquifer, June 2013 through December 2017. [Table code definitions: --, less than minimum laboratory reporting level] Table 5. Major and minor ions in groundwater samples collected by the U.S. Geological Survey National Water-Quality Assessment Project, Colorado Plateaus principal aquifer, June 2013 through December 2017. [Table code definitions: --, less than minimum laboratory reporting level; E, estimated] Table 6. Trace elements in groundwater samples collected by the U.S. Geological Survey National Water-Quality Assessment Project, Colorado Plateaus principal aquifer, June 2013 through December 2017. [Table code definitions: NC, not collected; --, less than minimum laboratory reporting level] Table 7. Radionuclides in groundwater samples collected by the U.S. Geological Survey National Water-Quality Assessment Project, Colorado Plateaus principal aquifer, June 2013 through December 2017. [Table code definitions: --, less than minimum laboratory reporting level] Table 8. Volatile organic compounds (VOCs) in groundwater samples collected by the U.S. Geological Survey National Water-Quality Assessment Project, Colorado Plateaus principal aquifer,

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 Program and are included in this report. 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, which are used to evaluate the time scales during which groundwater quality changes; and vertical flow-path study networks, which are used to evaluate changes in groundwater quality from shallower to deeper depths. Groundwater samples were analyzed for a large number of water-quality indicators and constituents, including major ions, nutrients, trace elements, volatile organic compounds, pesticides, radionuclides, and some special interest constituents (arsenic speciation, chromium [VI] and perchlorate). These groundwater quality data are tabulated in a U.S. Geological Survey Data Series Report DS-XXXX which is available at https://dx.doi.org/XXXXXX and in this data release. Data from the environmental and QC samples from the 2012-2013 sampling period were presented in Arnold and others (2016a,b) and those from the 2014 sampling period were presented in Arnold and others (2017a,b). There are 20 data tables included in this data release and they are referenced as tables 1-12 and appendix tables 3.3-3.10 in the larger work citation. There are 25 tables that are part of the larger work citation; the 5 tables not included in the data release are summary tables derived from some of the other 20 tables. A version of table 1 is included in both the text and data release. This compressed file contains 20 files of groundwater-quality data in ASCII text tab-delimited format and 20 corresponding metadata in xml format for wells sampled for the U.S. Geological Survey National Water-Quality Assessment Project.

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 Program and are included in this report. 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, which are used to evaluate the time scales during which groundwater quality changes; and vertical flow-path study networks, which are used to evaluate changes in groundwater quality from shallower to deeper depths. Groundwater samples were analyzed for a large number of water-quality indicators and constituents, including major ions, nutrients, trace elements, volatile organic compounds, pesticides, radionuclides, and some special interest constituents (arsenic speciation, chromium [VI] and perchlorate). These groundwater quality data are tabulated in a U.S. Geological Survey Data Series Report DS-XXXX which is available at https://dx.doi.org/XXXXXX and in this data release. Data from the environmental and QC samples from the 2012-2013 sampling period were presented in Arnold and others (2016a,b) and those from the 2014 sampling period were presented in Arnold and others (2017a,b). There are 20 data tables included in this data release and they are referenced as tables 1-12 and appendix tables 3.3-3.10 in the larger work citation. There are 25 tables that are part of the larger work citation; the 5 tables not included in the data release are summary tables derived from some of the other 20 tables. A version of table 1 is included in both the text and data release. This compressed file contains 20 files of groundwater-quality data in ASCII text tab-delimited format and 20 corresponding metadata in xml format for wells sampled for the U.S. Geological Survey National Water-Quality Assessment Project.

This dataset and the accompanying Data Series report was created to assist in analysis and interpretation of water-quality data provided by the U.S. Geological Survey, National Stream Quality Accounting Network (NASQAN) and the National Monitoring Network (NMN). The report describes the methods used to develop the geospatial data which was primarily derived from the National Watershed Boundary Dataset (WBD12). The geospatial data contains polygon shapefiles of basin boundaries for 33 NASQAN and 5 NMN stations. In addition, 30 polygon shapefiles of the closed and noncontributing basins contained within the NASQAN or NMN boundaries where applicable are included. Also included is a point shapefile of the NASQAN and NMN gaging stations and associated basin and station attributes. The basin boundaries included in this dataset are for those sites implemented under the October 2007 design for the 5-years from 2008-2013 (http://water.usgs.gov/nasqan/).