Elevated concentrations of metals including aluminum, arsenic, and lead were identified by Navajo Nation Environmental Protection Agency staff in the San Juan River from below the Navajo Dam, through the Navajo Nation to Mexican Hat, Utah in the Four Corners Region of the United States (Colorado, Arizona, New Mexico, Utah). An interdisciplinary team applied approaches and principles of geology, geochemistry, geomorphology, hydrology, and statistics to gain a better understanding of the tributaries supplying the source(s) of metals to the San Juan River. 15 sites along the San Juan River were sampled by the equal width increment method and composited in a churn during a baseflow synoptic sampling campaign in February 2021 (USGS, 2018). Unfiltered water samples were collected in single-siphon samples and by grab sample at 59 ephemeral and perennial tributaries to the San Juan River in 2021 and 2022. Eighteen surface water sites along the San Juan River were sampled as grab samples in 2021 and 2022. The samples were analyzed for major and trace cations by inductively coupled plasma emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) at the US Geological Survey Analytical Chemistry Laboratory in Denver, Colorado. A total of 765 unfiltered samples were analyzed.

Elevated concentrations of metals including aluminum, arsenic, and lead were identified by Navajo Nation Environmental Protection Agency staff in the San Juan River from below the Navajo Dam, through the Navajo Nation to Mexican Hat, Utah in the Four Corners Region of the United States (Colorado, Arizona, New Mexico, Utah). An interdisciplinary team applied approaches and principles of geology, geochemistry, geomorphology, hydrology, and statistics to gain a better understanding of the tributaries supplying the source(s) of metals to the San Juan River. Water samples that were filtered with 0.45 micron filters were collected in single-siphon samplers and by grab sample at 41 ephemeral and perennial tributaries to the San Juan River in 2021 and 2022. Eighteen surface water sites along the San Juan River were sampled as grab samples in 2021 and 2022. Samples were chosen randomly for filtration to compare to unfiltered sample results. The samples were analyzed for major and trace cations by inductively coupled plasma emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) at the US Geological Survey Analytical Chemistry Laboratory in Denver, Colorado. A sub-set of samples includes data for pH and alkalinity as calcium carbonate. A total of 282 filtered samples were collected.

This study was done because elevated concentrations of metals including aluminum, arsenic, and lead were identified by Navajo Nation EPA staff in the San Juan River from below the Navajo Dam, through the Navajo Nation to Mexican Hat, Utah in the Four Corners Region of the United States (Colorado, Arizona, New Mexico, Utah). An interdisciplinary team applied approaches and principles of geology, geochemistry, geomorphology, hydrology, and statistics to gain a better understanding of the tributaries supplying the source(s) of metals to the San Juan River. Water samples were collected in single-siphon samples and by grab sample at 59 ephemeral and perennial tributaries to the San Juan River in 2021 and 2022. Eighteen surface water sites along the San Juan River were sampled as grab samples in 2021 and 2022 and fifteen sites along the San Juan River were sampled by equal width increment and composited in a churn during a baseflow synoptic sampling campaign in February 2021. A total of 765 unfiltered and 282 filtered samples were analyzed for major and trace cations. All samples were analyzed through the USGS Analytical Chemistry Laboratory in Denver, Colorado (Taggart, 2022; USGS, 2023 Method 37).

As part of the Navajo-Gallup Water Supply Project, the Bureau of Reclamation was tasked with design and construction of infrastructure to treat and deliver potable water to the communities of Navajo Nation, parts of the Jicarilla Apache Nation, and City of Gallup. The Bureau of Reclamation has been evaluating the Public Service Company of New Mexico's (PNM) San Juan Generating Station (SJGS) reservoir as a possible water storage and sediment settling basin for the Navajo-Gallup Water Supply Project. The U.S. Geological Survey (USGS), in cooperation with the Bureau of Reclamation, was tasked with collecting reservoir sediment cores and pore water from SJGS reservoir. This data release contains reservoir sediment organic chemistry results.

The goal of this study was to develop a suite of inter-related water quality monitoring approaches capable of modeling and estimating the spatial and temporal gradients of particulate and dissolved total mercury (THg) concentration, and particulate and dissolved methyl mercury (MeHg), concentration, in surface waters across the Sacramento / San Joaquin River Delta (SSJRD). This suite of monitoring approaches included: a) data collection at fixed continuous monitoring stations (CMS) outfitted with in-situ sensors, b) spatial mapping using boat-mounted flow-through sensors, and c) satellite-based remote sensing. The focus of this specific Child Page is to present laboratory measured spectral data associated with discrete surface water samples collected as part of both the CMS and boat mapping sampling efforts. All laboratory-based measurement presented herein were conducted by the U.S. Geological Survey (USGS) Organic Matter Research Laboratory (OMRL) in Sacramento, Calif. The machine-readable (comma separated value, *.csv) files presented herein include spectral data collected using two different instruments: 1) Laboratory-based absorbance and fluorescence measurements on filtered water using an Aqualog (Hansen and others, 2018) and 2) Laboratory-based absorption measurements using a Varian Cary spectrophotometer on particulate samples collected on glass fiber filters (Kishino and others, 1985; Roesler, 1998). The reported spectral data includes: 1) fluorescence intensities across a wide range of excitation (240 to 800 nm) and emission (250 to 800 nm) wavelengths expressed as an excitation-emission matrix (EEM), 2) absorbance of light (from 239 nm to 800 nm) due to dissolved and colloidal substances, and 3) absorption coefficients (from 350 nm to 715 nm) for particulates using the quantitative filter technique (QFT).

The California State Water Resources Control Board (State Water Board) initiated the Oil and Gas Regional Monitoring Program (RMP) to assess effects of oil and gas development on groundwater designated for any beneficial use. The U.S. Geological Survey (USGS) is the technical lead in conducting the RMP through the California Oil, Gas, and Groundwater (COGG) Program, working in cooperation with the State Water Board, and in partnership with other State and local agencies. The USGS collected and analyzed groundwater (GW) and surface water (SW) for the San Ardo Oil Field study area, the area within the San Ardo Oil Field administrative boundary and the surrounding five-kilometer buffer zone, in Monterey County, California. Eighteen groundwater, two stream, and two spring samples were collected from March 2019 through May 2021. Groundwater samples were collected from one public-supply well, five monitoring wells, two irrigation wells, one livestock well, five oil-field water supply wells, and four domestic wells. Samples were collected using established water data-collection protocols and procedures and analyzed for (1) water-quality indicators, (2) major and minor ions, (3) nutrients, (4) trace elements, (5) volatile organic compounds (VOCs), (6) naturally-occurring radioactive material (radium isotopes), (7) geochemical and age-dating tracers, (8) dissolved organic carbon (DOC), (9) dissolved standard and hydrocarbon gases (methane through hexane), and (10) dissolved noble gases and atmospheric gases. In total, 185 constituents, water-quality indicators, or properties are included in this data release. Quality-control (QC) samples were used to assess the quality of laboratory results.

The goal of this study was to develop a suite of inter-related water quality monitoring approaches capable of modeling and estimating the spatial and temporal gradients of particulate and dissolved total mercury (THg) concentration, and particulate and dissolved methyl mercury (MeHg), concentration, in surface waters across the Sacramento / San Joaquin River Delta (SSJRD). This suite of monitoring approaches included: a) data collection at fixed continuous monitoring stations (CMS) outfitted with in-situ sensors, b) spatial mapping using boat-mounted flow-through sensors, and c) satellite-based remote sensing. The focus of this specific Child Page is to present all field and laboratory-based data associated with discrete surface water samples collected as part of the CMS and boat mapping components of the study. The data provided in the table herein constitute a collection of field-based and laboratory-based measurements that coincide with the timestamps of samples collected at 33 sites across the Delta. Laboratory-based measurements presented herein were conducted by the U.S. Geological Survey (USGS) Organic Matter Research Laboratory (OMRL) in Sacramento, CA, the USGS Earths System Processes Division (ESPD) microbial biogeochemistry laboratory in Menlo Park, CA, the USGS Reston Stable Isotope Laboratory (RSIL) in Reston, VA and the USGS National Water Quality Laboratory (NWQL) in Denver, CO. The machine-readable (comma separated value, *.csv) file presented herein includes laboratory-based measurements for discrete samples collected from 33 established field sites (sampled repeatedly). In addition, field-based sensor data from continuous measurement platforms (CMS locations or as part of the mapping boat flow-through system) are also included in this discrete sample dataset by ensuring that the field sensor measurements were both spatially and temporally coincident with the physically discrete water sample collected for laboratory analysis.

Record amounts of precipitation fell across the Colorado Front Range from September 9 to 16, 2013, resulting in extensive flooding in the South Platte River and its major mountain tributaries. In this study, the effects of the flood on the City of Boulder, Colorado urban hydrology system were assessed using weekly time-series sampling of 3 source waters (Boulder tap water, Boulder wastewater treatment facility effluent, and Boulder Creek water) conducted from September 20 to October 16, 2012 (n=5) and August 13 to September 30, 2013 (n=8). The effect of the flood on the South Platte River was assessed using a single basin-wide sampling of 5 main stem and 7 tributary sites from September 18 to 22, 2013. Filtered water samples were analyzed at the Boulder sites, and filtered and unfiltered samples were analyzed at the South Platte River sites. Major elements were measured by inductively coupled plasma-optical emission spectrometry and trace elements were measured by inductively coupled plasma-mass spectrometry. Each sample was measured in triplicate and the averages and standard deviations are reported. The results from analyses of associated quality assurance samples (field blanks and field duplicates) also are presented.

Sediment traps were deployed in tributaries to the San Juan River during 2021 and 2022. These traps collected sediment during storm events that typically occur as monsoonal convective storms from June to September. Because of the rural nature of the watershed, sediment traps were collected every 3 weeks so the sediment collected is a composite of that time period. The date listed is the date the trap was collected. This dataset includes the chemical concentrations of the sediment samples. Major ions are reported in weight percentage, while all other elements are reported in parts per million. Sediment samples in this dataset are digested using a mixture of hydrochloric, nitric, perchloric, and hydrofluoric acids at low temperature. The resulting solution is analyzed by ICP-OES and ICP-MS. The 49 element dataset includes aluminum, calcium, iron, potassium, magnesium, sodium, sulfur, silicon, titanium, silver, arsenic, barium, beryllium, bismuth, cadmium, cerium, cobalt, chromium, cesium, copper, gallium, hafnium, indium, lanthanum, lithium, lutetium, manganese, molybdenum, niobium, nickel, phosphorous, lead, rubidium, antimony, scandium, selenium, tin, strontium, tantalum, terbium, tellurium, thorium, thallium, thulium, uranium, vanadium, tungsten, yttrium, ytterbium, zinc, and zircon.

An investigation was done by the U.S. Geological Survey, in cooperation with the California State Water Resources Control Board's Program of Regional Groundwater Monitoring of Water Quality in Areas of Oil and Gas Production, to assess the effects of oil and gas production activities on nearby groundwater resources. During November 2016–September 2017, 30 samples were collected at groundwater wells and 1 sample was collected at a surface-water site. This dataset contains site information and water chemistry results for samples collected near the Lost Hills and North and South Belridge oil fields, Kern County, California. Samples were analyzed for water-quality indicators, major and minor ions, nutrients, trace elements, volatile organic compounds, naturally occurring radioactive material, geochemical and age-dating tracers, dissolved organic carbon, low molecular weight organic acids, dissolved standard and hydrocarbon gases, and dissolved noble and atmospheric gases. Quality-control samples including replicates; source-solution, equipment, and field blanks; laboratory spikes; and split samples for interlab comparisons were collected and summarized in this data release.