U.S. Geological Survey (USGS) in cooperation with the U.S. Air Force Civil Engineering Center conducted short-term aquifer tests at 11 wells to estimate hydraulic properties in the Fountain Creek alluvial aquifer, in El Paso County, Colorado. Data were collected in July 2019 over three days. Single-hole pumping and recovery tests were completed at five wells, and multiple single-hole displacement (solid slug) tests were conducted at all 11 wells. This data release contains water-level data collected at various time intervals (0.25 seconds, 0.5 seconds, and variable during a manual test with a stopwatch) and well-discharge rates for the aquifer tests in comma separated value (CSV) files for the 34 tests analyzed. All water-level displacement data for a given well are provided in a single CSV file for the well. Data are further categorized by the type of aquifer test used for data collection (slug or pumping). Well logs, graphs of the test data, and plots of analytical solutions are included in file, “FCAA_aquifer_testing_description_plots_vFINAL.pdf.”

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.

This dataset presents tabular data and Excel workbooks used to analyze single-well aquifer tests in pumping wells and slug tests in monitoring wells near Long Canyon. The data also include pdf outputs from the analysis program, Aqtesolv (Duffield, 2007). The data are presented in two zipped files, (1) single-well aquifer tests in pumping wells and (2) slug tests in monitoring wells. The slug-test data were supplied by Newmont Mining Corporation and collected by Golder and Associates in 2011. Reference Cited: Duffield, G.M., 2007, AQTESOLV for windows: Version 4.5 User’s Guide, HydroSOLV, Inc. Reston, VA, p. 530, at, http://www.aqtesolv.com/download/aqtw20070719.pdf.

This dataset presents tabular data and Excel workbooks used to analyze single-well aquifer tests in pumping wells and slug tests in monitoring wells near Long Canyon. The data also include pdf outputs from the analysis program, Aqtesolv (Duffield, 2007). The data are presented in two zipped files, (1) single-well aquifer tests in pumping wells and (2) slug tests in monitoring wells. The slug-test data were supplied by Newmont Mining Corporation and collected by Golder and Associates in 2011. Reference Cited: Duffield, G.M., 2007, AQTESOLV for windows: Version 4.5 User’s Guide, HydroSOLV, Inc. Reston, VA, p. 530, at, http://www.aqtesolv.com/download/aqtw20070719.pdf.

To determine aquifer properties in the San Antonio Creek Valley watershed (SACVW) single well air and physical slug aquifer tests were conducted on seventeen monitoring wells at nine sites beginning on August 7 2017 and ending on August 13, 2017 . For all tests either a physical or air slug was used based on the distance of the groundwater level from the perforated interval of the well. A physical slug was used if the distance from the groundwater level to the top of the perforated interval was less than seven feet (ft); otherwise an air slug was used. above the screened interval than a physical slug was used. Physical slug tests were used in order to produce enough change in groundwater levels to adequately characterize the hydraulic conductivity, but without losing air to the aquifer which would significantly affect the outcome and interpretation of the test. Aquifer slug tests were conducted in order to estimate the hydraulic conductivity of aquifer units within the SACVW. The perforation intervals of the 17 monitoring wells in which aquifer slug tests were conducted varied between 45 ft below land surface and 940 ft below land surface providing a range of aquifer zones to study.

To determine aquifer properties in the San Antonio Creek Valley watershed (SACVW) single well air and physical slug aquifer tests were conducted on seventeen monitoring wells at nine sites beginning on August 7 2017 and ending on August 13, 2017 . For all tests either a physical or air slug was used based on the distance of the groundwater level from the perforated interval of the well. A physical slug was used if the distance from the groundwater level to the top of the perforated interval was less than seven feet (ft); otherwise an air slug was used. above the screened interval than a physical slug was used. Physical slug tests were used in order to produce enough change in groundwater levels to adequately characterize the hydraulic conductivity, but without losing air to the aquifer which would significantly affect the outcome and interpretation of the test. Aquifer slug tests were conducted in order to estimate the hydraulic conductivity of aquifer units within the SACVW. The perforation intervals of the 17 monitoring wells in which aquifer slug tests were conducted varied between 45 ft below land surface and 940 ft below land surface providing a range of aquifer zones to study.

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 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,

This data release contains environmental tracer concentrations, modeled recharge conditions (water temperature, excess air), and resulting estimated groundwater residence times. This dataset supports an integrated hydrogeochemical investigation of solute sources, groundwater recharge processes, and groundwater flow in the Fountain Creek alluvial aquifer. The data release contains five comma separated value (CSV) files. The CSV files contain the model inputs (gas and tracer concentrations) and the model outputs (simulated recharge temperature, excess air, apparent groundwater age, and mean groundwater residence time). Data were collected in cooperation with the U.S. Air Force Civil Engineering Center.