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USGS2014

Groundwater quality in the Upper Hudson River Basin, New York, 2012

Water samples were collected from 20 production and domestic wells in the Upper Hudson River Basin (north of the Federal Dam at Troy, New York) in New York in August 2012 to characterize groundwater quality in the basin. The samples were collected and processed using standard U.S. Geological Survey procedures and were analyzed for 148 physiochemical properties and constituents, including dissolved gases, major ions, nutrients, trace elements, pesticides, volatile organic compounds (VOCs), radionuclides, and indicator bacteria. The Upper Hudson River Basin covers 4,600 square miles in upstate New York, Vermont, and Massachusetts; the study area encompasses the 4,000 square miles that lie within New York. The basin is underlain by crystalline and sedimentary bedrock, including gneiss, shale, and slate; some sandstone and carbonate rocks are present locally. The bedrock in some areas is overlain by surficial deposits of saturated sand and gravel. Eleven of the wells sampled in the Upper Hudson River Basin are completed in sand and gravel deposits, and nine are completed in bedrock. Groundwater in the Upper Hudson River Basin was typically neutral or slightly basic; the water typically was moderately hard. Bicarbonate, chloride, calcium, and sodium were the major ions with the greatest median concentrations; the dominant nutrient was nitrate. Methane was detected in 7 samples. Strontium, iron, barium, boron, and manganese were the trace elements with the highest median concentrations. Two pesticides, an herbicide degradate and an insecticide degredate, were detected in two samples at trace levels; seven VOCs, including chloroform, four solvents, and the gasoline additive methyl tert-butyl ether (MTBE) were detected in four samples. The greatest radon-222 activity, 2,900 picocuries per liter, was measured in a sample from a bedrock well; the median radon activity was higher in samples from bedrock wells than in samples from sand and gravel wells. Coliform bacteria were detected in one sample with a maximum of 2 colony-forming units per 100 milliliters. Water quality in the Upper Hudson River Basin is generally good, but concentrations of some constituents equaled or exceeded current or proposed Federal or New York State drinking-water standards. The standards exceeded are color (1 sample), pH (3 samples), sodium (3 samples), chloride (1 sample), dissolved solids (1 sample), arsenic (1 sample), iron (2 samples), manganese (2 samples), uranium (1 sample), radon-222 (12 samples), and gross beta activities (3 samples). Total coliform bacteria were each detected in one sample. Concentrations of fluoride, sulfate, nitrate, nitrite, aluminum, antimony, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium, silver, thallium, zinc, and gross alpha activities did not exceed existing drinking-water standards in any of the samples collected. Methane concentration in one sample was greater than 28 milligrams per liter, with a concentration of 35.1 milligrams per liter.

New York↗

USGS2014

Baseline groundwater quality from 34 wells in Wayne County, Pennsylvania, 2011 and 2013

Wayne County, Pennsylvania, is underlain by the Marcellus Shale, which currently (2014) is being developed elsewhere in Pennsylvania for natural gas. All residents of largely rural Wayne County rely on groundwater for water supply, primarily from bedrock aquifers (shales and sandstones). This study, conducted by the U.S. Geological Survey in cooperation with the Pennsylvania Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey (Pennsylvania Geological Survey), provides a groundwater-quality baseline for Wayne County prior to development of the natural gas resource in the Marcellus Shale. Selected wells completed in the Devonian-age Catskill Formation, undifferentiated; the Poplar Gap and Packerton Members of the Catskill Formation, undivided; and the Long Run and Walcksville Members of the Catskill Formation, undivided, were sampled. Water samples were collected once from 34 domestic wells during August 2011 and August and September 2013 and analyzed to characterize their physical and chemical quality. Samples were analyzed for 45 constituents and properties, including nutrients, major ions, metals and trace elements, radioactivity, and dissolved gases, including methane and radon-222. The quality of the sampled groundwater was generally within U.S. Environmental Protection Agency (USEPA) drinking-water standards, although in some samples, the concentrations of a few constituents exceeded USEPA drinking-water standards and health advisories. The pH of water samples ranged from 5.5 to 9.3 with a median of 7.0. The pH was outside the USEPA secondary maximum contaminant level (SMCL) range of 6.5 to 8.5 in water samples from 14 of the 34 wells (41 percent). Eleven samples had a pH less than 6.5, and three samples had a pH greater than 8.5. Dissolved oxygen concentrations ranged from 0.2 to 11.5 milligrams per liter (mg/L) with a median of 4.7 mg/L. The dissolved oxygen concentration was less than 1 mg/L in water samples from 6 wells; 5 of these 6 water samples had a pH greater than 7.7. Concentrations of dissolved methane ranged from less than 0.00006 to 3.3 mg/L. Methane was detectable in 22 of the 34 wells sampled (65 percent). Methane concentrations were greatest in the 5 samples with pH of 7.8 or higher, ranging from 0.040 to 3.3 mg/L. These samples also had among the lowest concentrations of dissolved oxygen. Three water samples, which had sufficient dissolved methane concentrations (greater than 0.9 mg/L), were analyzed for isotopes of carbon and hydrogen in the methane. The isotopic ratio values fell within (two samples) or close to (one sample) the range for a thermogenic natural gas source. The total dissolved solids concentration ranged from 33 to 346 mg/L; the median concentration was 126 mg/L. Sodium concentrations ranged from 1.07 to 116 mg/L; the median concentration was 9.42 mg/L. The sodium concentration exceeded the USEPA health advisory for sodium of 20 mg/L in water samples from 7 of the 34 wells (21 percent). Concentrations of dissolved arsenic ranged from less than 0.06 to 21.8 micrograms per liter (µg/L); the median concentration was 0.59 µg/L. Water samples from 2 of the 34 wells (6 percent) exceeded the USEPA maximum contaminant level (MCL) of 10 µg/L for arsenic. Concentrations of dissolved manganese ranged from less than 0.15 to 61.5 µg/L; the median concentration was 0.42 µg/L. A water sample from 1 of the 34 wells (3 percent) exceeded the USEPA SMCL of 50 µg/L for manganese; the concentration was less than the USEPA lifetime health advisory of 300 µg/L for manganese. Activities of radon-222 in water from the 34 sampled wells ranged from 110 to 7,180 picocuries per liter (pCi/L); the median activity was 2,105 pCi/L. Water samples from 33 of the 34 wells (97 percent) exceeded the proposed USEPA MCL of 300 pCi/L, and 4 water samples (12 percent) exceeded the USEPA proposed alternative MCL of 4,000 pCi/L for radon-222. Differences in groundwater chemistry were related to pH. Water with a pH greater than 7.6 generally had low dissolved oxygen concentrations, indicating reducing conditions in the aquifer. These high pH waters also had relatively elevated concentrations of methane, arsenic, boron, bromide, fluoride, lithium, and sodium but low concentrations of copper, nickel, and zinc. Water samples with a pH greater than 7.8 had methane concentrations equal to or greater than 0.04 mg/L.

Pennsylvania↗

USGS2014

Quality of surface-water supplies in the Triangle area of North Carolina, water year 2009

Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of governments have tracked water-quality conditions and trends in several of the area’s water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, during October 2008 through September 2009. Major findings for this period include: - Annual precipitation was approximately 20 percent below the long-term mean (average) annual precipitation. - Streamflow was below the long-term mean at the 10 project streamgages during most of the year. - More than 7,000 individual measurements of water quality were made at a total of 26 sites—15 in the Neuse River Basin and 11 in the Cape Fear River Basin. Forty-seven water-quality properties and constituents were measured. - All observations met North Carolina water-quality standards for water temperature, pH, hardness, chloride, fluoride, sulfate, nitrate, arsenic, cadmium, chromium, lead, nickel, and selenium. - North Carolina water-quality standards were exceeded one or more times for dissolved oxygen, dissolved oxygen percent saturation, chlorophyll a, mercury, copper, iron, manganese, silver, and zinc. Exceedances occurred at 23 sites—13 in the Neuse River Basin and 10 in the Cape Fear River Basin. - Stream samples collected during storm events contained elevated concentrations of 18 water-quality constituents compared to samples collected during non-storm events. - Concentrations of nitrogen and phosphorus were within ranges observed during previous years. - Five reservoirs had chlorophyll a concentrations in excess of 40 micrograms per liter at least once during 2009: Little River Reservoir, Falls Lake, Cane Creek Reservoir, University Lake, and Jordan Lake.

North Carolina↗

USGS2014

Groundwater quality in central New York, 2012

Water samples were collected from 14 production wells and 15 private wells in central New York from August through December 2012 in a study conducted by the U.S. Geological Survey in cooperation with the New York State Department of Environmental Conservation. The samples were analyzed to characterize the groundwater quality in unconsolidated and bedrock aquifers in this area. Fifteen of the wells are finished in sand-and-gravel aquifers, and 14 are finished in bedrock aquifers. Six of the 29 wells were sampled in a previous central New York study, which was conducted in 2007. Water samples from the 2012 study were analyzed for 147 physiochemical properties and constituents, including major ions, nutrients, trace elements, radionuclides, pesticides, volatile organic compounds, dissolved gases (argon, carbon dioxide, methane, nitrogen, oxygen), and indicator bacteria. Results of the water-quality analyses are presented in tabular form for individual wells, and summary statistics for specific constituents are presented by aquifer type. The results are compared with Federal and New York State drinking-water standards, which typically are identical. The results indicate that the groundwater generally is of acceptable quality, although for all of the wells sampled, at least one of the following constituents was detected at a concentration that exceeded current or proposed Federal or New York State drinking-water standards: color (2 samples), pH (7 samples), sodium (9 samples), chloride (2 samples), fluoride (2 samples), sulfate (2 samples), dissolved solids (8 samples), aluminum (4 samples), arsenic (1 sample), iron (9 samples), manganese (13 samples), radon-222 (13 samples), total coliform bacteria (6 samples), and heterotrophic bacteria (2 samples). Drinking-water standards for nitrate, nitrite, antimony, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium, silver, thallium, zinc, gross alpha radioactivity, uranium, fecal coliform, and Escherichia coli were not exceeded in any of the samples collected. None of the pesticides or volatile organic compounds analyzed exceeded drinking-water standards. Methane was detected in 11 sand-and-gravel wells and 9 bedrock wells. Five of the 14 bedrock wells had water with methane concentrations approaching 10 mg/L; water in one bedrock well had 37 mg/L of methane.

New York↗

USGS2015

Groundwater quality in the Chemung River, Eastern Lake Ontario, and Lower Hudson River Basins, New York, 2013

In a study conducted by the U.S. Geological Survey (USGS) in cooperation with the New York State Department of Environmental Conservation, water samples were collected from 4 production wells and 4 domestic wells in the Chemung River Basin, 8 production wells and 7 domestic wells in the Eastern Lake Ontario Basin, and 12 production wells and 13 domestic wells in the Lower Hudson River Basin (south of the Federal Lock and Dam at Troy) in New York. All samples were collected in June, July, and August 2013 to characterize groundwater quality in these basins. The samples were collected and processed using standard USGS procedures and were analyzed for 148 physiochemical properties and constituents, including dissolved gases, major ions, nutrients, trace elements, pesticides, volatile organic compounds, radionuclides, and indicator bacteria. The Chemung River Basin study area covers 1,744 square miles in south-central New York and encompasses the part of the Chemung River Basin that lies within New York. Two of the wells sampled in the Chemung River Basin are completed in sand and gravel, and 6 are completed in bedrock. Groundwater in the Chemung River Basin was generally of good quality, although properties and concentrations of some constituents—sodium, arsenic, aluminum, iron, manganese, radon-222, total coliform bacteria, and Escherichia coli bacteria—equaled or exceeded primary, secondary, or proposed drinking-water standards. The constituent most frequently detected in concentrations exceeding drinking-water standards (six of eight samples) was radon-222. The Eastern Lake Ontario Basin study area covers 3,225 square miles in north-central New York. The Eastern Lake Ontario Basin (between the Oswego River Basin and the St. Lawrence River Basin) includes the Mid-Northern Lake Ontario Basin, the Black River Basin, and the Chaumont River-Perch River Basin. Five of the wells sampled in the Eastern Lake Ontario Basin are completed in sand and gravel, and 10 are completed in bedrock. Groundwater in the Eastern Lake Ontario Basin was generally of good quality, although properties and concentrations of some constituents—color, pH, sodium, dissolved solids, fluoride, iron, manganese, uranium, gross-α radioactivity, radon-222, total coliform bacteria, and fecal coliform bacteria—equaled or exceeded primary, secondary, or proposed drinking-water standards. The constituent most frequently detected in concentrations exceeding drinking-water standards (10 of 15 samples) was radon-222. The Lower Hudson River Basin study area covers 5,607 square miles and encompasses the part of the Lower Hudson River Basin that lies within New York plus the parts of the Housatonic, Hackensack, Bronx, and Saugatuck River Basins that are in New York. Twelve of the wells sampled in the Lower Hudson River Basin are completed in sand-and-gravel deposits, and 13 are completed in bedrock. Groundwater in the Lower Hudson River Basin was generally of good quality, although properties and concentrations of some constituents—pH, sodium, chloride, dissolved solids, arsenic, aluminum, iron, manganese, radon-222, total coliform bacteria, fecal coliform bacteria, Escherichia coli bacteria, and heterotrophic plate count—equaled or exceeded primary, secondary, or proposed drinking-water standards. The constituent most frequently detected in concentrations exceeding drinking-water standards (20 of 25 samples) was radon-222.

New York↗

USGS2016

Quality of surface-water supplies in the Triangle area of North Carolina, water years 2010-11

Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of local governments have tracked water-quality conditions and trends in several of the area’s water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, during October 2009 through September 2010 (water year 2010) and October 2010 through September 2011 (water year 2011). Major findings for this data-collection effort include Annual precipitation was approximately 4 percent above the long-term mean (average) annual precipitation in 2010 and approximately 6 percent below the long-term mean in 2011. In water year 2010, streamflow was near the long-term mean for most of the period for the 10 project streamflow gaging stations. Streamflow was near or below the long-term mean at the same streamflow gaging stations during the 2011 water year. More than 13,000 individual measurements of water quality were made at a total of 28 sites—17 in the Neuse River Basin and 11 in the Cape Fear River Basin. Forty-three water-quality properties or constituents were measured; North Carolina water-quality standards exist for 21 of these. All observations met State water-quality standards for water temperature, hardness, chloride, fluoride, sulfate, nitrate plus nitrite, arsenic, cadmium, chromium, lead, nickel, and selenium. State water-quality standards were exceeded one or more times for dissolved oxygen, dissolved oxygen percent saturation, pH, copper, iron, manganese, mercury, silver, and zinc. Exceedances occurred at 27 sites—17 in the Neuse River Basin and 10 in the Cape Fear River Basin. Stream samples collected during storm events contained elevated concentrations of 25 water-quality constituents relative to non-storm events.

North Carolina↗

USGS2016

Quality of surface-water supplies in the Triangle Area of North Carolina, water years 2012–13

Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of local governments have tracked water-quality conditions and trends in several of the area’s water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, during October 2011 through September 2012 (water year 2012) and October 2012 through September 2013 (water year 2013). Major findings for this period include: Annual precipitation was approximately 2 percent above the long-term mean (average) annual precipitation in 2012 and approximately 3 percent below the long-term mean in 2013. In water year 2012, streamflow was generally below the long-term mean during most of the period for the 10 project streamflow gaging stations. Streamflow was near or above the long-term mean at the same streamflow gaging stations during the 2013 water year. More than 7,000 individual measurements of water quality were made at a total of 17 sites—6 in the Neuse River Basin and 11 in the Cape Fear River Basin. Forty-three water-quality properties or constituents were measured; State water-quality standards exist for 23 of these. All observations met State water-quality standards for pH, temperature, hardness, chloride, fluoride, sulfate, nitrate, arsenic, cadmium, chromium, lead, nickel, and selenium. North Carolina water-quality standards were exceeded one or more times for dissolved oxygen, dissolved-oxygen percent saturation, turbidity, chlorophyll a , copper, iron, manganese, mercury, silver, and zinc. Exceedances occurred at all 17 sites. Stream samples collected during storm events contained elevated concentrations of 19 water-quality constituents relative to non-storm events.

North Carolina↗

USGS2016

Groundwater quality in the Lake Champlain and Susquehanna River basins, New York, 2014

In a study conducted by the U.S. Geological Survey in cooperation with the New York State Department of Environmental Conservation, groundwater samples were collected from 6 production wells and 7 domestic wells in the Lake Champlain Basin and from 11 production wells and 9 domestic wells in the Susquehanna River Basin in New York. All samples were collected from June through December 2014 to characterize groundwater quality in these basins. The samples were collected and processed using standard procedures of the U.S. Geological Survey and were analyzed for 148 physiochemical properties and constituents, including dissolved gases, major ions, nutrients, trace elements, pesticides, volatile organic compounds, radionuclides, and indicator bacteria. The Lake Champlain Basin study area covers the 3,050 square miles of the basin in northeastern New York; the remaining part of the basin is in Vermont and Canada. Of the 13 wells sampled in the Lake Champlain Basin, 6 are completed in sand and gravel, and 7 are completed in bedrock. Groundwater in the Lake Champlain Basin was generally of good quality, although properties and concentrations of some constituents— fluoride, iron, manganese, dissolved solids, sodium, radon-222, total coliform bacteria, fecal coliform bacteria, and Escherichia coli bacteria—sometimes equaled or exceeded primary, secondary, or proposed drinking-water standards. The constituent most frequently detected in concentrations exceeding drinking-water standards (5 of 13 samples) was radon-222. The Susquehanna River Basin study area covers the entire 4,522 square miles of the basin in south-central New York; the remaining part of the basin is in Pennsylvania. Of the 20 wells sampled in the Susquehanna River Basin, 11 are completed in sand and gravel, and 9 are completed in bedrock. Groundwater in the Susquehanna River Basin was generally of good quality, although properties and concentrations of some constituents—pH, chloride, sodium, dissolved solids, iron, manganese, aluminum, arsenic, barium, gross-alpha radioactivity, radon-222, methane, total coliform bacteria, and fecal coliform bacteria—sometimes equaled or exceeded primary, secondary, or proposed drinking-water standards. As in the Lake Champlain Basin, the constituent most frequently detected in concentrations exceeding drinking-water standards (13 of 20 samples) was radon-222.

New York↗

USGS2017

Triangle Area Water Supply Monitoring Project, North Carolina—Summary of monitoring activities, quality assurance, and data, October 2013–September 2015

North Carolina↗

USGS2019

Triangle area water supply monitoring project, North Carolina-Summary of monitoring activities, quality assurance, and data, October 2015–September 2017

North Carolina↗

USGS2021

Triangle Area Water Supply Monitoring Project, North Carolina—Summary of monitoring activities, quality assurance, and data, October 2017–September 2019

Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of local governments have tracked water-quality conditions and trends in several of the area’s water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, from October 2017 through September 2018 (water year 2018) and from October 2018 through September 2019 (water year 2019). Major findings for this period include the following: More than 7,500 individual measurements of water quality were made at 20 sites—7 in the Neuse River Basin and 13 in the Cape Fear River Basin. For the lake sites, only measurements from the photic zone and 1 meter below the water surface are documented in this report. Thirty-six water-quality properties or constituents are presented in this report; the State of North Carolina water-quality thresholds are presented for 11 of these. All observations met the State of North Carolina water-quality thresholds for water temperature, hardness, chloride, fluoride, sulfate, and nitrate plus nitrite. The State of North Carolina water-quality thresholds were exceeded one or more times for dissolved oxygen, dissolved-oxygen percent saturation, pH, turbidity, and chlorophyll a .

North Carolina↗

USGS2023

Quality of groundwater used for domestic drinking-water supply in the Coachella Valley, 2020

Groundwater is the primary source of drinking water in the Coachella Valley in the desert region of southern California. Although most people in Coachella Valley are served by public drinking-water systems, about 20,000 people rely on private domestic or small-system wells (referred to herein as domestic wells). Recently, the U.S. Geological Survey (USGS) found that 39 percent of the groundwater resources used by domestic wells in Coachella Valley contained arsenic, fluoride, or both constituents at concentrations greater than the maximum contaminant levels established for public drinking-water systems. Uranium, chromium, nitrate, and perchlorate were detected at moderate concentrations below maximum contaminant levels. Elevated (above background) perchlorate concentrations in some areas indicate that domestic wells may receive recharge from Colorado River water used for irrigation or aquifer replenishment. Moderate total dissolved solids (TDS) concentrations throughout the study area and the co-occurrence of high concentrations of TDS and perchlorate indicates that Colorado River water is a source of recharge in the southeastern Indio groundwater subbasin. Four volatile organic compounds were detected at low concentrations, and pesticides and per- and polyfluoroalkyl substances were not detected.

California↗

USGS1951

Geology and ground-water resources of the northern part of the Ranegras Plain area, Yuma County, Arizona

The Ranegras Plain area is part of the Basin and Range province in west-central Arizona. The report discusses rocks of pre-Cambrian, pre-Cambrian (?), Paleozoic (?), Mesozoic (?), Cretaceous (?), Cretaceous and Tertiary, Tertiary (?), Quaternary (?), and Quaternary age. All the Paleozoic (?) and Cretaceous (?) rocks and parts of the Mesozoic (?),Cretaceous and Tertiary, and Tertiary (?) rocks have been mapped as a unit because they are so intensely faulted that detailed mapping was not practical. Rocks older than Quaternary form the mountain ranges bordering the Ranegras Plain. Quaternary alluvium underlies the broad, gently sloping valley floor to depths of generally a few hundred feet, locally more. Well logs indicate that the underlying Tertiary (?) alluvium exceeds 1,100 feet in thickness. The structure of the area is controlled by faulting typical of the Basin and Range province, but the major faults are covered by alluvium and are inferred from topographic features. Ground water occurs in Quaternary and Tertiary (?) alluvium and the best aquifers are in sand and gravel of the Quaternary alluvium. Ground-water movement is, in general, to the northwest. Recharge to the aquifers is predominantly from stream flow resulting from heavy rains. There is also minor or unevaluated recharge from underflow from Butler Valley to the east, andsince 1948seepage from irrigation. Discharge is by pumping and by natural processes of underflow and evapotranspiration. In addition to small domestic and stock wells, only two irrigation wells, in the vicinity of Utting, are in use. No accurate data on pumpage are available. The safe yield from the ground-water reservoir may be less than 5,000 acre-feet and probably does not exceed 10,000 to 15,000 acre-feet per year. The quality of ground water ranges from permissible to unsuitable for irrigation purposes. The fluoride content is generally too high for the water to be considered satisfactory for use by young children.

Open-File Report↗

USGS1971

Geology, hydrology, and water quality of the Tracy-Dos Palos area, San Joaquin Valley, California

The Tracy-Dos Palos area includes about 1,800 square miles on the northwest side of the San Joaquin Valley. The Tulare Formation of Pliocene and Pleistocene age, terrace deposits of Pleistocene age, and alluvium and flood-basin deposits of Pleistocene and Holocene age constitute the fresh ground-water reservoir Pre-Tertiary and Tertiary sedimentary and crystalline rocks, undifferentiated, underlie the valley and yield saline water. Hydrologically most important, the Tulare Formation is divided into a lower water-bearing zone confined by the Corcoran Clay Member and an upper zone that is confined, semiconfined, and unconfined in different parts of the area. Alluvium and flood-basin deposits are included in the upper zone. Surficial alluvium and flood-basin deposits contain a shallow water-bearing zone. Lower zone wells were flowing in 1908, but subsequent irrigation development caused head declines and land subsidence. Overdraft in both zones ended in 1951 with import of surface water. Bicarbonate water flows into the area from the Sierra Nevada and Diablo Range. Diablo Range water is higher in sulfate, chloride, and dissolved solids. Upper zone water averages between 400 and 1,200 mg/l (milligrams per liter) dissolved solids and water hardness generally exceeds 180 mg/l as calcium carbonate. Nitrate, fluoride, iron, and boron occur in excessive concentrations in water from some wells. Dissolved constituents in lower zone water generally are sodium chloride and sodium sulfate with higher dissolved solids concentration than water from the upper zone. The foothills of the Diablo Range provide favorable conditions for artificial recharge, but shallow water problems plague about 50 percent of the area and artificial recharge is undesirable at this time.

Open-File Report↗

USGS1976

Water-quality data for the Southern Ute Indian Reservation, southwestern Colorado

Water-quality data from a study by the U.S. Geological Survey on the Southern Ute Indian Reservation in southwestern Colorado are presented in two tables. The data were collected during 1973-76 from 338 ground-water and surface-water samples. All samples were analyzed for major catons and anions, and selenium and arsenic. Data in the tables are keyed by numbers to maps showing the locations of sampling sites. Many of the samples contained arsenic, chloride, dissolved solids, fluoride, iron, magnesium, manganese, nitrate, nitrite-plus-nitrate as nitrogen, selenium, and sulfate in concentrations exceeding recommended or mandatory standards for drinking water established by the Colorado Department of Health and U.S. Public Health Service. (Woodard-USGS)

Open-File Report↗

USGS1976

Chemical characteristics of the major thermal springs of Montana

Twenty-one thermal springs in western Montana were sampled for chemical, isotope, and gas compositions. Most of the springs issue dilute to slightly saline sodium-bicarbonate waters of neutral to slightly alkaline pH. A few of the springs issue sodium-mixed anion waters of near neutral pH. Fluoride concentrations are high in most of the thermal waters, up to 18 milligramsper litre, while F/Cl ratios range from 3/1 in the dilute waters to 1/10 in the slightly saline waters. Most of the springs are theoretically in thermodynamic equilibrium with respect to calcite and fluorite. Nitrogen is the major gas escaping from most of the hot springs; however, Hunters Hot Springs issue principally methane. The deuterium content of the hot spring waters is typical of meteoric water in western Montana. Geothermal calculations based on silica concentrations and Na-K-Ca ratios indicate that most of the springs are associated with low temperature aquifers (less than 100?C). Chalcedony may be controlling the silica concentrations in these low temperature aquifers even in 'granitic' terranes.

Open-File Report↗

USGS1977

Chemical, isotopic, and gas compositions of selected thermal springs in Arizona, New Mexico, and Utah

Twenty-seven thermal springs in Arizona, New Mexico, and Utah were sampled for detailed chemical and isotopic analysis. The springs issue sodium chloride, sodium bicarbonate, or sodium mixed-anion waters of near neutral (6.2) to alkaline (9.2) pH. High concentrations of fluoride, more than 8 milligrams per liter, occur in Arizona in waters from Gillard Hot Springs, Castle Hot Springs, and the unnamed spring of Eagle Creek, and in New Mexico from springs along the Gila River. Deuterium compositions of the thermal waters cover the same range as those expected for meteoric waters in the respective areas. The chemical compositions of the thermal waters indicate that Thermo Hot Springs in Utah and Gillard Hot Springs in Arizona represent hydrothermal systems which are at temperatures higher than 125 deg C. Estimates of subsurface temperature based on the quartz and Na-K-Ca geothermometer differ by up to 60 deg C for Monroe, Joseph, Red Hill, and Crater hot springs in Utah. Similar conflicting estimates of aquifer temperature occur for Verde Hot Springs, the springs near Clifton and Coolidge Dam, in Arizona; and the warm springs near San Ysidro, Radium Hot Springs, and San Francisco Hot Springs, in New Mexico. Such disparities could result from mixing, precipitation of calcium carbonate, or perhaps appreciable concentrations of magnesium. (Woodard-USGS)

Open-File Report↗

USGS1978

Analytical results for 89 water samples from the Papago Indian Reservation, Arizona

Eighty-nine water samples were collected from the Papago Indian Reservation during 1977 and 1978 as a part of a mineral resource study. Each sample was analyzed for copper, zinc, molybdenum, arsenic, uranium, sodium, potassium, calcium, magnesium, bicarbonate, sulfate, chloride, fluoride, and silica. Temperature, pH, and specific conductance were also measured. The data are presented in accompanying tables. Also, included are the location and a description of each sample site.

Arizona↗