This data release supports the following publication: Mast, M. A., 2018, Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah: U.S. Geological Survey Scientific Investigations Report 2018-5116. The U.S. Geological Survey (USGS), in cooperation with the U. S. Environmental Protection Agency (EPA), developed site-specific regression models to estimate concentrations of selected metals at nine USGS streamflow-gaging stations along the Animas and San Juan Rivers. Multiple linear-regression models were developed by relating metal concentrations in discrete water-quality samples to continuously monitored streamflow and surrogate parameters including specific conductance, pH, turbidity, and water temperature. Models were developed for dissolved and total concentrations of aluminum, arsenic, cadmium, iron, lead, manganese, and zinc using water-quality samples collected during 2005–17 by several agencies, using different collection methods and analytical laboratories. Calibration datasets in comma-separated format (CSV) include the variables of sampling date and time, metal concentrations (in micrograms per liter), stream discharge (in cubic feet per second), specific conductance (in microsiemens per centimeter at 25 degrees Celsius), pH, water temperature (in degrees Celsius), turbidity (in nephelometric turbidity units), and calculated seasonal terms based on Julian day. Surrogate parameters and discrete water-quality samples were used from nine sites including Cement Creek at Silverton, Colo. (USGS station 09358550); Animas River below Silverton, Colo. (USGS station 09359020); Animas River at Durango, Colo. (USGS station 09361500); Animas River Near Cedar Hill, N. Mex. (USGS station 09363500); Animas River below Aztec, N. Mex. (USGS station 09364010); San Juan River at Farmington, N. Mex. (USGS station 09365000); San Juan River at Shiprock, N. Mex (USGS Station 09368000); San Juan River at Four Corners, Colo. (USGS station 09371010); and San Juan River near Bluff, Utah (USGS station 09379500). Model archive summaries in pdf format include model statistics, data, and plots and were generated using a R script developed by USGS Kansas Water Science Center available at https://patrickeslick.github.io/ModelArchiveSummary/. A description of each USGS streamflow gaging station along with information about the calibration datasets also are provided.

These data are comprised of measurements of elements (e.g., uranium, cobalt, nickel, copper, zinc, cadmium, lead, etc.), major anions (chloride, nitrite+nitrate as nitrogen, sulfate, etc.), dissolved organic carbon, and general water quality characteristics in Canyon Mine containment pond water, sediment, vegetaiton and invertebrate samples collected in calendar year 2019.

These data are comprised of measurements of elements (e.g., uranium, cobalt, nickel, copper, zinc, cadmium, lead, etc.), major anions (chloride, nitrite+nitrate as nitrogen, sulfate, etc.), dissolved organic carbon, and general water quality characteristics in Canyon Mine containment pond water, sediment, vegetaiton and invertebrate samples collected in calendar year 2019.

The U.S. Environmental Protection Agency characterized sediments and seeps/springs in the San Juan watershed located in southwestern Colorado and the four corners region of Colorado, New Mexico, Arizona, and Utah (western United States). The Datasets contain field and laboratory data that resulted from that sampling. Samples for this project were collected from 2018 to 2021. Results of new Pb isotope ratio measurements are provided for sediments (n = 96) collected from across the watershed and seeps/springs (n = 73) from the mineralized headwaters region of the watershed. The Microsoft Excel spreadsheets contain sample data and Quality Control data, including results of primary standards, second source standards, and sample duplicate analyses.

A synoptic sampling campaign was conducted on the Animas River near Silverton, Colorado, under low flow conditions in September 2021. The sampling campaign was designed to quantify constituent loading and identify sources of contamination along a 3.8-kilometer study reach. The study reach began approximately 170 meters upstream of Arrastra Creek and extended downstream to U.S. Geological Survey (USGS) gage 09358000 within the city of Silverton, Colorado. A continuous, instream injection of a sodium bromide tracer was initiated at the head of the study reach three days prior to the start of the sampling campaign and maintained until the completion of main stem sampling. Bromide concentrations were subsequently used to determine streamflow using the tracer-dilution method. Water quality samples were collected at 23 sites along the Animas River main stem, and 28 inflow sites including springs, seeps, small tributaries, and ponded water. Main stem sites were sampled using three sampling approaches. Under the first approach, a subset of 8 main stem sites were sampled "simultaneously" (in less than 20 minutes) to assess the effects of diel variation in constituent concentration. Under the second approach, all main stem sites were sampled with the sampling team working in the downstream-to-upstream direction, a protocol typically used during synoptic sampling. A subset of 5 main stem sites were also sampled using an Equal Discharge Increment approach that was designed to indicate which side of the stream was responsible for the observed constituent loads. This data release includes field parameters (water temperature, pH, and specific conductivity), concentration data (inorganic cations and anions), estimated streamflow, and calculated loads for the sampling campaign. Calculated loads may be used to identify and rank sources of contamination to the Animas River. The data release consists of a kmz file showing site locations and the following 3 tables: Table 1, Locations of sampling sites Table 2, Synoptic sampling results, September 20-21, 2021 Table 3, Spatial profiles of streamflow and constituent load

A synoptic sampling campaign was conducted on the Animas River near Silverton, Colorado, under low flow conditions in September 2021. The sampling campaign was designed to quantify constituent loading and identify sources of contamination along a 3.8-kilometer study reach. The study reach began approximately 170 meters upstream of Arrastra Creek and extended downstream to U.S. Geological Survey (USGS) gage 09358000 within the city of Silverton, Colorado. A continuous, instream injection of a sodium bromide tracer was initiated at the head of the study reach three days prior to the start of the sampling campaign and maintained until the completion of main stem sampling. Bromide concentrations were subsequently used to determine streamflow using the tracer-dilution method. Water quality samples were collected at 23 sites along the Animas River main stem, and 28 inflow sites including springs, seeps, small tributaries, and ponded water. Main stem sites were sampled using three sampling approaches. Under the first approach, a subset of 8 main stem sites were sampled "simultaneously" (in less than 20 minutes) to assess the effects of diel variation in constituent concentration. Under the second approach, all main stem sites were sampled with the sampling team working in the downstream-to-upstream direction, a protocol typically used during synoptic sampling. A subset of 5 main stem sites were also sampled using an Equal Discharge Increment approach that was designed to indicate which side of the stream was responsible for the observed constituent loads. This data release includes field parameters (water temperature, pH, and specific conductivity), concentration data (inorganic cations and anions), estimated streamflow, and calculated loads for the sampling campaign. Calculated loads may be used to identify and rank sources of contamination to the Animas River. The data release consists of a kmz file showing site locations and the following 3 tables: Table 1, Locations of sampling sites Table 2, Synoptic sampling results, September 20-21, 2021 Table 3, Spatial profiles of streamflow and constituent load

The San Juan basin is a significant physical and structural element in the southeastern part of the Colorado Plateau physiographic province. The San Juan basin is in New Mexico, Colorado, Arizona, and Utah and has an area of about 21,600 square miles. The basin is about 140 miles wide and about 200 miles long. In the 1980’s and 1990’s, the San Juan basin was the focus of the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) study. Investigation of the San Juan structural basin began in October 1984 with an objective, among others, to define and evaluate the aquifer system. As part of this analysis, a multi-publication series of reports were produced as Hydrologic Atlas 720 (HA-720) that described on 1:1,000,000-scale maps the subsurface configuration and hydrogeology of the San Jose, Nacimiento, and Animas Formations (Levings and others, 1990; HA-720-A), the Ojo Alamo Sandstone (Thorn and others, 1990; HA-720-B), the Kirtland Shale and Fruitland Formation (Kernodle and others, 1990; HA-720-C), the Pictured Cliffs Sandstone (Dam and others, 1990; HA-720-D), the Cliff House Sandstone (Thorn and others, 1990; HA-720-E), the Menefee Formation (Levings and others, 1990; HA-720-F), the Point Lookout Sandstone (Craigg and others, 1990; HA-720-G), the Gallup Sandstone (Kernodle and others, 1990; HA-720-H), the Dakota Sandstone (Craigg and others, 1990; HA-720-I), and the Morrison Formation (Dam and others, 1990; HA-720-J). This digital dataset contains spatial datasets corresponding to the contoured subsurface maps produced by the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) San Juan basin study. The data define the elevation, thickness, and extent of principal stratigraphic units of the basin. The digital data describe the following stratigraphic units: the San Jose Formation, the Ojo Alamo Sandstone, the Kirtland Shale and Fruitland Formation, the Pictured Cliffs Sandstone, the Cliff House Sandstone, the Menefee Formation, the Point Lookout Sandstone, the Gallup Sandstone, the Dakota Sandstone, and the Morrison Formation. Digital data for each unit are contained in individual features classes within a geodatabase (also saved as individual shapefiles). Feature classes have a single attribute, either elevation or thickness, that represents the contoured value. Contoured values are given in feet, to maintain consistency with the original publication, and in meters.

The San Juan basin is a significant physical and structural element in the southeastern part of the Colorado Plateau physiographic province. The San Juan basin is in New Mexico, Colorado, Arizona, and Utah and has an area of about 21,600 square miles. The basin is about 140 miles wide and about 200 miles long. In the 1980’s and 1990’s, the San Juan basin was the focus of the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) study. Investigation of the San Juan structural basin began in October 1984 with an objective, among others, to define and evaluate the aquifer system. As part of this analysis, a multi-publication series of reports were produced as Hydrologic Atlas 720 (HA-720) that described on 1:1,000,000-scale maps the subsurface configuration and hydrogeology of the San Jose, Nacimiento, and Animas Formations (Levings and others, 1990; HA-720-A), the Ojo Alamo Sandstone (Thorn and others, 1990; HA-720-B), the Kirtland Shale and Fruitland Formation (Kernodle and others, 1990; HA-720-C), the Pictured Cliffs Sandstone (Dam and others, 1990; HA-720-D), the Cliff House Sandstone (Thorn and others, 1990; HA-720-E), the Menefee Formation (Levings and others, 1990; HA-720-F), the Point Lookout Sandstone (Craigg and others, 1990; HA-720-G), the Gallup Sandstone (Kernodle and others, 1990; HA-720-H), the Dakota Sandstone (Craigg and others, 1990; HA-720-I), and the Morrison Formation (Dam and others, 1990; HA-720-J). This digital dataset contains spatial datasets corresponding to the contoured subsurface maps produced by the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) San Juan basin study. The data define the elevation, thickness, and extent of principal stratigraphic units of the basin. The digital data describe the following stratigraphic units: the San Jose Formation, the Ojo Alamo Sandstone, the Kirtland Shale and Fruitland Formation, the Pictured Cliffs Sandstone, the Cliff House Sandstone, the Menefee Formation, the Point Lookout Sandstone, the Gallup Sandstone, the Dakota Sandstone, and the Morrison Formation. Digital data for each unit are contained in individual features classes within a geodatabase (also saved as individual shapefiles). Feature classes have a single attribute, either elevation or thickness, that represents the contoured value. Contoured values are given in feet, to maintain consistency with the original publication, and in meters.

Acid mine drainage (AMD) can cause ecological harm throughout the state of Colorado, including in the Upper Animas River watershed near Silverton. In the Upper Animas River watershed, a technique that includes the emplacement of hydraulic bulkheads within draining mines has been used to remediate AMD. Data for major ions and trace metal concentrations, isotopic compositions, and discharge from streams, draining mines, and springs were compiled for a period of approximately 30 years to better understand the processes occurring during the impoundment of water within underground mine workings and to define spatial extent of groundwater connectivity. These datasets were evaluated using statistical and geochemical modeling approaches.

Acid mine drainage (AMD) can cause ecological harm throughout the state of Colorado, including in the Upper Animas River watershed near Silverton. In the Upper Animas River watershed, a technique that includes the emplacement of hydraulic bulkheads within draining mines has been used to remediate AMD. Data for major ions and trace metal concentrations, isotopic compositions, and discharge from streams, draining mines, and springs were compiled for a period of approximately 30 years to better understand the processes occurring during the impoundment of water within underground mine workings and to define spatial extent of groundwater connectivity. These datasets were evaluated using statistical and geochemical modeling approaches.