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At least 379 records · Page 21Linked to original sources
USGS1972

Emergency ground-water supplies in the Seattle-Tacoma urban complex and adjacent areas, Washington

Urban areas that are supplied from surface-water sources are especially vulnerable to major disruption of their water supplies. Such disruption could result from natural disasters such as earthquakes, floods, or landslides or from such other causes as dam failures fallout of radioactive material or other toxic substance from the atmosphere or other toxic substances from the atmosphere or direct introduction (either accidental or deliberate) of any substance that would render the water unfit for use. Prolonged disruption of public water supplies not only causes personal hardships but also endangers health and safety unless suitable alternative emergency supplies can be provided. The degree of hardship and danger generally increases in direct relation to the population density. Ground water because it occurs beneath protective soil and rock materials is less subject to sudden major contamination than are surface-water bodies. For this reason and also because of its widespread availability in the Puget Sound region ground water is especially desireable as a sources of emergency supplies for drinking or other uses requiring water of good quality. In much of the area existing wells would be suitable as safe sources of emergency supplies.

Washington↗
USGS1975

Ground-water resources and geology of Waukesha County, Wisconsin

Good-quality water is available from the sand-and-gravel, Niagara, and sandstone aquifers in Waukesha County, Wis. As much as 15 gallons per minute (0.95 litres per second) can be obtained from wells almost everywhere in the county. Several hundred gallons per minute are available from aquifers in the glacial drift that fill bedrock valleys to thicknesses of 300 feet (91 metres) or more. Estimated well yields from much of the surficial outwash in western Waukesha County exceed 500 gallons per minute (31 litres per second). Estimated well yields from most of the Niagara aquifer, a dolomite as much as 325 feet (99 metres) thick in the eastern two-thirds of the county, exceed 50 gallons per minute (3.2 litres per second). The sandstone aquifer underlies the entire county and ranges in thickness from about 400 feet (120 metres) in the northwest corner to about 2,400 feet (730 metres) in the southeast corner. This aquifer yields more than 1,000 gallons per minute (63 litres per second) to wells over most of the county and is the principal source for municipal and subdivision water. Ground water in Waukesha County is of good quality and is suitable for most uses. Most of the water is a calcium magnesium bicarbonate type, is very hard [more than 180 mg/l (milligrams per litre) hardness], and requires softening for some uses. The ground water locally contains iron and manganese concentrations that exceed the limits (0.3 and 0.05 mg/l, respectively) recommended by the U.S. Public Health Service (1962, p. 7). Water high in sulfate and dissolved solids (saline water) is present locally in the Niagara and sandstone aquifers. Water from one well contained excessive nitrate (more than 45 mg/l). With one exception, wells sampled at irregular intervals indicated no significant changes in their chemical characteristics with time. About 24.3 million gallons per day (1.06 cubic metres per second) of ground water was pumped in the county in 1970. Sixty-two percent was withdrawn from the sandstone aquifer. More than one-half of the latter amount was for domestic use, and more than one-third was for industrial and commercial uses.

Wisconsin↗
USGS2011

Abbreviated bibliography on energy development—A focus on the Rocky Mountain Region

Energy development of all types continues to grow in the Rocky Mountain Region of the western United States. Federal resource managers increasingly need to balance energy demands, effects on the natural landscape and public perceptions towards these issues. To assist in efficient access to valuable information, this abbreviated bibliography provides citations to relevant information for myriad of issues for which resource managers must contend. The bibliography is organized by seven large topics with various sup-topics: broad energy topics (energy crisis, conservation, supply and demand, etc.); energy sources (fossil fuel, nuclear, renewable, etc.); natural landscape effects (climate change, ecosystem, mitigation, restoration, and reclamation, wildlife, water, etc.); human landscape effects (attitudes and perceptions, economics, community effects, health, Native Americans, etc.); research and technology; international research; and, methods and modeling. A large emphasis is placed on the natural and human landscape effects.

Idaho;Montana;Wyoming;Utah;Colorado;New Mexico;Ari↗
USGS2016

Occurrence and distribution of arsenic and radon in water from private wells in the Rancocas aquifer, southern New Castle and northern Kent Counties, Delaware, 2015

Water samples were collected and analyzed for arsenic and radon from 36 private, mostly domestic wells that tap the Rancocas aquifer in southern New Castle and northern Kent Counties, Delaware, during the summer of 2015. Both arsenic and radon are from natural mineral sources, in particular glauconitic and other marine-derived sediments, which are important components of the geologic formations comprising the Rancocas aquifer. Routine testing of domestic wells is not required in Delaware; as a result, many homeowners are not aware of potential water-quality problems with these chemicals in their well water. Arsenic has previously been detected at levels of potential concern for human health in this aquifer in adjacent parts of Maryland where it is referred to as the Aquia aquifer. Arsenic and radon also have previously been detected in several Rancocas aquifer wells in Delaware. The Delaware Department of Natural Resources and Environmental Control intends to use the data from this project to better identify areas with potential for levels of concern for domestic well owners. This report includes chemical results and maps showing the distribution of sampled wells and concentrations of arsenic and radon. All data collected for this study also are available in the U.S. Geological Survey’s National Water Information System database. Arsenic was detected above the minimum reporting limit of 0.1 micrograms per liter (µg/L) in 34 of the 36 wells sampled with concentrations ranging from about 0.11 to 27 µg/L. In 15 of the samples, arsenic concentrations were at or above the U.S. Environmental Protection Agency (EPA) Maximum Contaminant Level (MCL) of 10 µg/L for public wells. Most of the higher concentrations are clustered along a band running from the southwest to northeast in the southern part of the study area. Radon, which is an inert gas derived from radium, was detected in all water samples with concentrations ranging from 85 to 1,870 picocuries per liter (pCi/L). Currently, the EPA has not set a MCL for radon in public water systems. There were no samples where radon was detected at a concentration exceeding the proposed alternative MCL of 4,000 pCi/L. Samples from 16 of 36 wells were above the lower proposed MCL of 300 pCi/L. Most of these samples were from wells greater than 200 feet deep located in a similar part of the aquifer as the higher concentrations of arsenic along an east-northeasterly line in the southern part of the study area.

Delaware↗
USGS2022

Comparison of the results of enzyme-linked immunosorbent assay (ELISA) to mass-spectrometry based analytical methods for six unregulated contaminants in source water and finished drinking-water samples

Regulatory entities, such as the Minnesota Department of Health, monitor public water systems for conformance with Federal and State monitoring requirements and water-quality standards. Although some contaminants have Federal and (or) State regulations and guidance values, many contaminants, such as pesticides and pharmaceuticals, are unregulated in that only non-enforceable health-based guidance values have been assigned to them. Furthermore, because these contaminants are not regulated, commonly only limited resources are available to public water systems or regulatory entities to monitor them in drinking water. Focused screening efforts on contaminants that are frequently detected in the environment can provide information to help monitoring entities prioritize their sampling efforts. Here we assess the use of enzyme-linked immunosorbent assay (ELISA) method, a rapid, inexpensive screening method, as an alternative to more expensive methods to analyze source and finished drinking-water samples collected from public water systems throughout Minnesota for three commonly detected pesticides (atrazine, imidacloprid, and pyrethroids) and three commonly detected pharmaceuticals (caffeine, carbamazepine, and sulfamethoxazole). The ELISA results were compared to results provided by more advanced mass-spectrometry analytical methods at the U.S. Geological Survey National Water Quality Laboratory (NWQL) and SGS AXYS Analytical Services Ltd. (AXYS). Overall, these datasets are highly censored (>80 percent) and contain multiple reporting limits within and between laboratories. To discern agreement between paired contaminant group results (target contaminant plus immunologically similar contaminants) by ELISA and the advanced analytical methods at NWQL and AXYS, presence-absence agreement analysis was coupled with false negative and false positive analysis. Analysis of presence-absence agreement shows that ELISA has generally good agreement (77.9 to 100 percent) with both NWQL and AXYS for all unregulated contaminant groups. Imidicloprid, pyrethroids, and caffeine contaminant groups have relatively low false positivity rates (16, 6, and 5 percent, respectively) when analyzed by ELISA, which indicates the ELISA method, for these contaminant groups, could be experiencing low-level interference attributed to the detection of immunologically similar contaminants. Similarly, sulfamethoxazole has a low false positivity rate (0.8 percent), which indicates ELISA is likely not overestimating results for this contaminant group. Analyses for carbamazepine and sulfamethoxazole by ELISA resulted in low false negativity rates (1.6 and 0.8 percent, respectively), which indicates the ELISA method is likely not underestimating the results for this contaminant group. Conversely, the atrazine contaminant group has a high false negativity rate (84 percent), which indicates the method has a strong negative bias and that ELISA underestimates results for this contaminant. These qualitative results indicate that the ELISA method could potentially serve as a reliable and cost-effective screening method to help drinking water monitoring entities prioritize sampling efforts for analyzing carbamazepine and sulfamethoxazole in source and finished drinking-water samples collected from public water systems. At the same time, although ELISA did not prove to be a good screening method for atrazine, evaluation of ELISA results indicated that its use for screening imidacloprid, pyrethroids, and caffeine could be beneficial for water testing.

Minnesota↗
USGS2019

The landscape of soil carbon data: Emerging questions, synergies and databases

Soil carbon has been measured for over a century in applications ranging from understanding biogeochemical processes in natural ecosystems to quantifying the productivity and health of managed systems. Consolidating diverse soil carbon datasets is increasingly important to maximize their value, particularly with growing anthropogenic and climate change pressures. In this progress report, we describe recent advances in soil carbon data led by the International Soil Carbon Network and other networks. We highlight priority areas of research requiring soil carbon data, including (a) quantifying boreal, arctic and wetland carbon stocks, (b) understanding the timescales of soil carbon persistence using radiocarbon and chronosequence studies, (c) synthesizing long-term and experimental data to inform carbon stock vulnerability to global change, (d) quantifying root influences on soil carbon and (e) identifying gaps in model–data integration. We also describe the landscape of soil datasets currently available, highlighting their strengths, weaknesses and synergies. Now more than ever, integrated soil data are needed to inform climate mitigation, land management and agricultural practices. This report will aid new data users in navigating various soil databases and encourage scientists to make their measurements publicly available and to join forces to find soil-related solutions.

Progress in Physical Geography: Earth and Environm↗
USGS2008

Water-Quality Data Collected from Vallecito Reservoir, Its Inflows and Outflow, Southwestern Colorado, 1999-2002

The Pine River Watershed Stakeholders Group was created in December 1997 to allow local participation in addressing water-quality issues in Los Pi?os River watershed, including Vallecito Reservoir in southwestern Colorado. One water-quality issue identified by the stakeholder group is to increase the understanding of the current water quality of Vallecito Reservoir, its two major inflows, and its outflow. The U.S. Geological Survey (USGS), in cooperation with volunteers from the Pine River Watershed Stakeholders Group and the U.S. Environmental Protection Agency (USEPA), U.S. Bureau of Reclamation (BOR), Colorado Department of Public Health and Environment (CDPHE), Pine River Irrigation District, Southern Ute Tribe, San Juan Basin Health Department, and San Juan Resource Conservation and Development, collected water-quality samples from Vallecito Reservoir, its two major inflows, and its outflow between August 1999 and November 2002 at about monthly intervals from April through November. The water-quality samples were analyzed for total and dissolved metals (aluminum, arsenic, cadmium, copper, chromium, iron, lead, manganese, mercury, nickel, silver, and zinc), dissolved major ions (calcium, magnesium, sodium, potassium, chloride, bicarbonate, and sulfate), dissolved silica, dissolved organic carbon (DOC), ultraviolet (UV) absorbance at 254 and 280 nanometers, nutrients (total organic nitrogen, dissolved organic nitrogen, dissolved ammonia, dissolved nitrate, total phosphorus, dissolved phosphorus, and orthophosphate), chlorophyll-a (reservoir only), and suspended sediment (inlets to the reservoir only). Measurements of field properties (pH, specific conductance, water temperature, and dissolved oxygen) were also made at each sampling site each time a water-quality sample was collected. This report documents (1) sampling sites and times of sample collection, (2) sample-collection methods, (3) laboratory analytical methods, and (4) responsibilities of each agency/group involved in the project. The report also provides the environmental and quality-control data collected during the project and provides an interpretation of the quality-control data (field blanks and field duplicates) to assess the quality of the environmental data. This report provides a baseline data set against which future changes in water quality can be assessed.

Data Series↗
USGS2016

The Water-Quality Partnership for National Parks—U.S. Geological Survey and National Park Service, 1998–2016

The U.S. Geological Survey (USGS) and the National Park Service (NPS) work together through the USGS–NPS Water-Quality Partnership to support a broad range of policy and management needs related to high-priority water-quality issues in national parks. The program was initiated in 1998 as part of the Clean Water Action Plan, a Presidential initiative to commemorate the 25th anniversary of the Clean Water Act. Partnership projects are developed jointly by the USGS and the NPS. Studies are conducted by the USGS and findings are used by the NPS to guide policy and management actions aimed at protecting and improving water quality. The National Park Service manages many of our Nation’s most highly valued aquatic systems across the country, including portions of the Great Lakes, ocean and coastal zones, historic canals, reservoirs, large rivers, high-elevation lakes and streams, geysers, springs, and wetlands. So far, the Water-Quality Partnership has undertaken 217 projects in 119 national parks. In each project, USGS studies and assessments ( http://water.usgs.gov/nps_partnership/pubs.php ) have supported science-based management by the NPS to protect and improve water quality in parks. Some of the current projects are highlighted in the NPS Call to Action Centennial initiative, Crystal Clear, which celebrates national park water-resource efforts to ensure clean water for the next century of park management ( http://www.nature.nps.gov/water/crystalclear/ ). New projects are proposed each year by USGS scientists working in collaboration with NPS staff in specific parks. Project selection is highly competitive, with an average of only eight new projects funded each year out of approximately 75 proposals that are submitted. Since the beginning of the Partnership in 1998, 189 publications detailing project findings have been completed. The 217 studies have been conducted in 119 NPS-administered lands, extending from Denali National Park and Preserve in Alaska to Everglades National Park in Florida, and from Acadia National Park in the Northeast to park lands in Hawaii and Pacific Island territories in the West. Project goals range from periodic stream monitoring, to determining the occurrence and concentrations of contaminants and the potential for them to exceed human health or aquatic life criteria, to conducting interpretive studies to evaluate the effect(s) on or vulnerability of national park resources to visitor usage and other natural and anthropogenic activities.

Fact Sheet↗
USGS1993

The United States Geological Survey: A vision for the 21st century

Leadership in Earth science for sustained global health, welfare, and prosperity. We envision a U.S. Geological Survey that is a global leader in relevant, innovative, and interdisciplinary Earth science. We shall conduct collaborative, impartial, multi-scale scientific investigations into the Earth's systems and conditions through a spectrum of basic to applied research on the environment, hazards, resources, and information management, all in support of present and future societal needs. We envision an organization that serves the public by sharing Earthscience data and information and by promoting its dissemination, understanding, and application. We shall be a flexible organization that values its employees and works in concert with them for attainment of both institutional and individual goals.

Report↗
USGS2025

Estimated hydrogeologic, spatial, and temporal distribution of self-supplied domestic groundwater withdrawals for aquifers of the Virginia Coastal Plain

Water use from private-domestic wells accounts for nearly 40 percent of total groundwater withdrawals in the Virginia Coastal Plain Physiographic Province (henceforth called the Virginia Coastal Plain). However, because self-supplied domestic water use generally falls below the Virginia Department of Environmental Quality (VDEQ) reporting and management threshold of 300,000 gallons per month, quantifying these withdrawals is challenging. This report builds upon the foundation of previous U.S. Geological Survey investigations by providing revised techniques to improve estimates of the aquifer source, spatial distribution, and monthly magnitude of these groundwater withdrawals. The aquifer sources of private-domestic wells in the Virginia Coastal Plain were estimated by cross-referencing 8,264 well records from the VDEQ and the Virginia Department of Health to a digital model of the Virginia Coastal Plain hydrogeologic framework. This analysis highlights the regional importance of the Yorktown-Eastover, Potomac, and surficial aquifers. Collectively, these three aquifers account for 80 percent of self-supplied domestic groundwater withdrawals. The population using self-supplied domestic water was estimated using census blocks, well-use ratios, building footprints, and land-use and land-cover data to produce a high-resolution, disaggregated, raster-based dataset. This approach improves upon previous models at the census-block or road-network scale by reducing the low-density spread of the self-supplied domestic population across undeveloped areas and concentrating the population and its corresponding water use in the areas where it is most likely to occur. Results show that an estimated 475,332 people comprise the 2020 self-supplied domestic population of the Virginia Coastal Plain, an increase of 5.7 percent since 2010, and the greatest concentrations of self-supplied domestic population surround large cities. Estimates could be further refined with the addition of current and complete spatial data on public water-system service areas. The quantity of water used by the self-supplied domestic population was estimated by modifying published state per-capita water-use coefficients with the corresponding monthly variability assessed from Virginia Coastal Plain public water-system withdrawal data. This analysis estimates an average increase of 12 percent from June through August and an average decrease of 8 percent from December through March from the baseline annual average of 80 gallons per day per capita, which generally matches similar studies in the eastern United States. The application of these revised methodologies for the estimation of private-domestic wells and the self-supplied domestic population improves understanding of domestic groundwater use in the Virginia Coastal Plain across hydrogeologic, spatial, and temporal scales. These revisions help better inform water-resource managers and decision makers and support higher resolution groundwater modeling. Furthermore, these methods are transferrable to other areas where self-supplied domestic water withdrawals are important to the overall water budget.

Virginia↗
USGS2020

Simulation of the probabilistic plume extent for a potential replacement wastewater-infiltration lagoon, and probabilistic contributing areas for supply wells for the Town of Lac du Flambeau, Vilas County, Wisconsin

An existing two-dimensional, steady-state groundwater-flow model of the shallow groundwater-flow system of the Lac du Flambeau Reservation in Vilas County, Wisconsin, originally developed by the U.S. Geological Survey, was used to simulate the potential for wastewater from a proposed relocation of a wastewater lagoon to contaminate the Lac du Flambeau Band of Lake Superior Chippewa’s drinking-water-supply wells. This simulation was completed by the U.S. Geological Survey in cooperation with the Lac du Flambeau Band of Lake Superior Chippewa and Indian Health Service. The simulated scenarios consisted of removing wastewater infiltration from existing lagoons and re-applying that infiltration at the proposed location. Two analyses were performed for the scenarios. First, the probable extent of the plume discharging from the proposed infiltration lagoons was mapped with a Monte Carlo algorithm that used uncertainty identified during the calibration process to simulate thousands of possible outcomes. Second, the Monte Carlo method was again used to simulate a probabilistic contributing area for the Tribe’s nearby “Main Pumphouse” supply wells. The purpose of the simulations was to evaluate the potential for infiltrated wastewater to be captured by the public-supply wells. Most features of the previously developed model remained unchanged, including calibrated parameters such as hydraulic conductivity and recharge. Thus, the same covariance distributions that were generated during calibration of the regional model (Juckem and others, 2014) remained unchanged and were used to inform the Monte Carlo simulations for the scenario simulations described in this report. The reader is encouraged to read the full report by Juckem and others (available at https://doi.org/10.3133/sir20145020 ) for a detailed description of the model design and calibration, as well as a description of the Monte Carlo method, its limitations, and the original results. Results for these new scenarios indicate that the probabilistic plume extent for the proposed infiltration lagoons does not reach the Main Pumphouse wells using pumping rates and wastewater volumes estimated for 2010. Similarly, the contributing area for the Main Pumphouse wells does not capture water from within the proposed infiltration lagoon footprint. However, at higher pumping rates and wastewater volumes, as projected by the Tribe for about 2035, the contributing area for the Main Pumphouse wells do include particles that originated within the proposed lagoon footprint, albeit at low probabilities. That is, for a few of the thousands of simulations that represented a range of calibration-informed parameter covariances, some amount of infiltrated wastewater was captured by the Main Pumphouse wells under projected 2035 conditions.

Wisconsin↗
USGS2010

Quality of Source Water from Public-Supply Wells in the United States, 1993-2007

More than one-third of the Nation's population receives their drinking water from public water systems that use groundwater as their source. The U.S. Geological Survey (USGS) sampled untreated source water from 932 public-supply wells, hereafter referred to as public wells, as part of multiple groundwater assessments conducted across the Nation during 1993-2007. The objectives of this study were to evaluate (1) contaminant occurrence in source water from public wells and the potential significance of contaminant concentrations to human health, (2) national and regional distributions of groundwater quality, and (3) the occurrence and characteristics of contaminant mixtures. Treated finished water was not sampled. The 932 public wells are widely distributed nationally and include wells in selected parts of 41 states and withdraw water from parts of 30 regionally extensive aquifers used for public water supply. These wells are distributed among 629 unique public water systems-less than 1 percent of all groundwater-supplied public water systems in the United States-but the wells were randomly selected within the sampled hydrogeologic settings to represent typical aquifer conditions. Samples from the 629 systems represent source water used by one-quarter of the U.S. population served by groundwater-supplied public water systems, or about 9 percent of the entire U.S. population in 2008. One groundwater sample was collected prior to treatment or blending from each of the 932 public wells and analyzed for as many as six water-quality properties and 215 contaminants. Consistent with the terminology used in the Safe Drinking Water Act (SDWA), all constituents analyzed in water samples in this study are referred to as 'contaminants'. More contaminant groups were assessed in this study than in any previous national study of public wells and included major ions, nutrients, radionuclides, trace elements, pesticide compounds, volatile organic compounds (VOCs), and fecal-indicator microorganisms. Contaminant mixtures were assessed in subsets of samples in which most contaminants were analyzed. Contaminant concentrations were compared to human-health benchmarks-regulatory U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Levels (MCLs) for contaminants regulated in drinking water under the SDWA or non-regulatory USGS Health-Based Screening Levels (HBSLs) for unregulated contaminants, when available. Nearly three-quarters of the contaminants assessed in this study are unregulated in drinking water, and the USEPA uses USGS data on the occurrence of unregulated contaminants in water resources to fulfill part of the SDWA requirements for determining whether specific contaminants should be regulated in drinking water in the future. More than one in five (22 percent) source-water samples from public wells contained one or more naturally occurring or man-made contaminants at concentrations greater than human-health benchmarks, and 80 percent of samples contained one or more contaminants at concentrations greater than one-tenth of benchmarks. Most individual contaminant detections, however, were less than one-tenth of human-health benchmarks. Public wells yielding water with contaminant concentrations greater than benchmarks, as well as those with concentrations greater than one-tenth of benchmarks, were distributed throughout the United States and included wells that withdraw water from all principal aquifer rock types included in this study. Ten contaminants individually were detected at concentrations greater than human-health benchmarks in at least 1 percent of source-water samples and collectively accounted for most concentrations greater than benchmarks. Seven of these 10 contaminants occur naturally, including three radionuclides (radon, radium, and gross alpha-particle radioactivity) and four trace elements (arsenic, manganese, strontium, and boron); three of these 10 contaminants (dieldrin, nitrate, and perchl

Scientific Investigations Report↗
USGS2010

Mercury in Indiana watersheds: Retrospective for 2001–2006

Information about total mercury and methylmercury concentrations in water samples and mercury concentrations in fish-tissue samples was summarized for 26 watersheds in Indiana that drain most of the land area of the State. Mercury levels were interpreted with information on streamflow, atmospheric mercury deposition, mercury emissions to the atmosphere, mercury in wastewater, and landscape characteristics. Unfiltered total mercury concentrations in 411 water samples from streams in the 26 watersheds had a median of 2.32 nanograms per liter (ng/L) and a maximum of 28.2 ng/L. When these concentrations were compared to Indiana water-quality criteria for mercury, 5.4 percent exceeded the 12-ng/L chronic-aquatic criterion, 59 percent exceeded the 1.8-ng/L Great Lakes human-health criterion, and 72.5 percent exceeded the 1.3-ng/L Great Lakes wildlife criterion. Mercury concentrations in water were related to streamflow, and the highest mercury concentrations were associated with the highest streamflows. On average, 67 percent of total mercury in streams was in a particulate form, and particulate mercury concentrations were significantly lower downstream from dams than at monitoring stations not affected by dams. Methylmercury is the organic fraction of total mercury and is the form of mercury that accumulates and magnifies in food chains. It is made from inorganic mercury by natural processes under specific conditions. Unfiltered methylmercury concentrations in 411 water samples had a median of 0.10 ng/L and a maximum of 0.66 ng/L. Methylmercury was a median 3.7 percent and maximum 64.8 percent of the total mercury in 252 samples for which methylmercury was reported. The percentages of methylmercury in water samples were significantly higher downstream from dams than at other monitoring stations. Nearly all of the total mercury detected in fish tissue was assumed to be methylmercury. Fish-tissue samples from the 26 watersheds had wet-weight mercury concentrations that exceeded the 0.3 milligram per kilogram (mg/kg) U.S. Environmental Protection Agency (USEPA) methylmercury criterion in 12.4 percent of the 1,731 samples. The median wet-weight concentration in the fish-tissue samples was 0.13 mg/kg, and the maximum was 1.07 mg/kg. A coarse-scale analysis of all fish-tissue data in each watershed and a fine-scale analysis of data within 5 kilometers (km) of the downstream end of each watershed showed similar results overall. Mercury concentrations in fish-tissue samples were highest in the White River watershed in southern Indiana and the Fall Creek watershed in central Indiana. In fish-tissue samples within 5 km of the downstream end of a watershed, the USEPA methylmercury criterion was exceeded by 45 percent of mercury concentrations from the White River watershed and 40 percent of the mercury concentration from the Fall Creek watershed. A clear relation between mercury concentrations in fish-tissue samples and methylmercury concentrations in water was not observed in the data from watersheds in Indiana. Average annual atmospheric mercury wet-deposition rates were mapped with data at 156 locations in Indiana and four surrounding states for 2001–2006. These maps revealed an area in southeastern Indiana with high mercury wet-deposition rates—from 15 to 19 micrograms per square meter per year (µg/m 2 /yr). Annual atmospheric mercury dry-deposition rates were estimated with an inferential method by using concentrations of mercury species in air samples at three locations in Indiana. Mercury dry deposition-rates were 5.6 to 13.6 µg/m 2 /yr and were 0.49 to 1.4 times mercury wet-deposition rates. Total mercury concentrations were detected in 96 percent of 402 samples of wastewater effluent from 50 publicly owned treatment works in the watersheds; the median concentration was 3.0 ng/L, and the maximum was 88 ng/L. When these concentrations were compared to Indiana water-quality criteria for mercury, 12 percent exceeded the 12-ng/L chronic-aquatic criterion, 68 percent exceeded the 1.8-ng/L Great Lakes human-health criterion, and 81 percent exceeded the 1.3-ng/L Great Lakes wildlife criterion. Annual stream mercury yields were calculated with a model by using the mercury concentrations in water samples and daily average streamflows for 2002–2006, normalized to the watershed drainage areas. The average annual total mercury stream yields ranged from 0.73 to 45.2 µg/m 2 /yr and were highest in two White River watersheds in central Indiana. Median methylmercury stream yield was 1.9 percent of the median total mercury stream yield. In most watersheds, average annual stream yields of total mercury were a fraction of the combined average annual atmospheric mercury wet-deposition and estimated annual dry-deposition loading rates, indicating that much of the stream mercury was attributable to atmospheric deposition. In two watersheds, average annual stream yields of total mercury were approximately twice the atmospheric mercury loading, indicating that some of the stream mercury apparently was not attributable to atmospheric deposition. Rather, some of the stream mercury yield potentially was contributed by mercury in wastewater discharges. Land-cover type corresponded with the mercury levels in three watersheds: (1) A watershed of the White River in central Indiana with a high percentage of urban land cover had some of the highest total mercury concentrations and stream mercury yields. The urban land cover and numerous permitted wastewater outfalls with mercury in treated effluent potentially contributed mercury to this watershed. (2) A monitoring station on the Maumee River in northeastern Indiana, downstream from a large area of urban land cover, recorded the highest stream mercury concentrations. The urban land cover and mercury detected in treated effluent potentially contributed to the high mercury concentrations at this station. (3) A watershed of the Patoka River in southern Indiana with a high percentage of forest land cover had the highest atmospheric mercury dry-deposition rate. The high dry-deposition rate from the forest land cover potentially contributed to the high mercury concentrations in this watershed. From a retrospective view, mercury concentrations in Indiana watersheds routinely exceeded criteria protective of humans and commonly exceeded criteria protective of wildlife. Atmospheric mercury wet deposition was a predominant factor, but not the single factor, affecting mercury in Indiana watersheds. Mercury in wastewater discharges and atmospheric mercury dry deposition apparently contributed a substantial part of the mercury yield from some watersheds. Dams and impoundments increased the percentage of methylmercury in downstream waters. Long-term monitoring of mercury in wet and dry atmospheric deposition, and in streams and reservoirs, coordinated with monitoring of mercury in fish, will be needed to detect whether mercury levels in Indiana watersheds change in the future.

Indiana↗
USGS2011

Geologic map of Big Bend National Park, Texas

The purpose of this map is to provide the National Park Service and the public with an updated digital geologic map of Big Bend National Park (BBNP). The geologic map report of Maxwell and others (1967) provides a fully comprehensive account of the important volcanic, structural, geomorphological, and paleontological features that define BBNP. However, the map is on a geographically distorted planimetric base and lacks topography, which has caused difficulty in conducting GIS-based data analyses and georeferencing the many geologic features investigated and depicted on the map. In addition, the map is outdated, excluding significant data from numerous studies that have been carried out since its publication more than 40 years ago. This report includes a modern digital geologic map that can be utilized with standard GIS applications to aid BBNP researchers in geologic data analysis, natural resource and ecosystem management, monitoring, assessment, inventory activities, and educational and recreational uses. The digital map incorporates new data, many revisions, and greater detail than the original map. Although some geologic issues remain unresolved for BBNP, the updated map serves as a foundation for addressing those issues. Funding for the Big Bend National Park geologic map was provided by the United States Geological Survey (USGS) National Cooperative Geologic Mapping Program and the National Park Service. The Big Bend mapping project was administered by staff in the USGS Geology and Environmental Change Science Center, Denver, Colo. Members of the USGS Mineral and Environmental Resources Science Center completed investigations in parallel with the geologic mapping project. Results of these investigations addressed some significant current issues in BBNP and the U.S.-Mexico border region, including contaminants and human health, ecosystems, and water resources. Funding for the high-resolution aeromagnetic survey in BBNP, and associated data analyses and interpretation, was from the USGS Crustal Geophysics and Geochemistry Science Center. Mapping contributed from university professors and students was mostly funded by independent sources, including academic institutions, private industry, and other agencies.

Texas↗
USGS2013

Challenge theme 2: assuring water availability and quality in the 21st century: Chapter 4 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Along the United States–Mexican border, the health of communities, economies, and ecosystems is inextricably intertwined with the availability and quality of water, but effective water management in the Borderlands is complicated. Water users compete for resources, and their needs are increasing. Managers are faced with issues such as finding a balance between agriculture and rapidly growing cities or maintaining public supplies while ensuring sufficient resources for aquatic ecosystems. In addition to human factors, the dry climate of the Borderlands, as compared to more temperate regions, also increases the challenge of balancing water supplies between humans and ecosystems. Warmer, drier, and more variable conditions across the southwestern United States—the projected results of climate change (Seager and others, 2007)—would further stress water supplies.

United States-Mexico Borderlands↗
USGS2003

Hazards, Disasters, and The National Map

Governments depend on base geographic information that describes the Earth's surface and locates features. They use this information for economic and community development, land and natural resource management, delivery of health services, and ensuring public safety. It is also the foundation for studying and solving geographically based problems. Geographic information underpins an increasingly large part of the Nation's economy. It is an important part of our national infrastructure in the same way that the Interstate Highway System is an essential element of our transportation network. Federal, State, and local response and management personnel must have current, reliable, and easily accessible geographic information and maps to prepare for, respond to, or recover from emergency situations. In life-threatening events, such as earthquakes, floods, or wildland fires, geographic information is essential for locating critical infrastructure and carrying out evacuation and rescue operations.

Fact Sheet↗
USGS1990

Geohydrology and water quality of Kalamazoo County, Michigan, 1986-88

Thick, glacial sand and gravel deposits provide most ground-water supplies in Kalamazoo County. These deposits range in thickness from 50 to about 600 feet in areas that overlie buried bedrock valleys. Most domestic wells completed at depths of less than 75 feet in the sands and gravels yield adequate water supplies. Most industry, public supply, and irrigation wells completed at depths of 100 to 200 feet yield 1,000 gallons per minute or more. The outwash plains include the most productive of the glacial aquifers in the county. The Coldwater Shale of Mississippian age, which underlies the glacial deposits in most of the county, usually yields only small amounts of largely mineralized water. Ground-water levels in Kalamazoo County reflect short- and long-term changes in precipitation and local pumpage. Ground-water levels increase in the spring and decline in the fall. Ground-water recharge rates, for different geologic settings, were estimated from ground-water runoff to the streams. Recharge rates ranged from 10.86 to 5.87 inches per year. A countywide-average ground-water recharge rate is estimated to be 9.32 inches per year. Chemical quality of precipitation and dry fallout at two locations in Kalamazoo County were similar to that of other areas in the State. Total deposition of dissolved sulfate is 30.7 pounds per acre per year, of total nitrogen is 13.2 pounds per acre per year, and of total phosphorus is 0.3 pounds per acre per year. Rainfall and snow data indicated that the pH of precipitation is inversely proportional to its specific conductance. Water of streams and rivers of Kalamazoo County is predominately of the calcium bicarbonate type, although dissolved sulfate concentrations are slightly larger in streams in the southeastern and northwestern parts of the county. The water in most streams is hard to very hard. Concentrations of dissolved chloride in streams draining urban-industrial areas are slightly larger than at other locations. Concentrations of total nitrogen and total phosphorus in streams are directly proportional to streamflow. Except for elevated concentrations of iron, none of the trace elements in streams exceeded maximum contaminant levels for drinking water established by the U.S. Environmental Protection Agency. Pesticides were detected in some streams. Ground water in the surficial aquifers is of the calcium bicarbonate type, although sodium, sulfate, and chloride ions predominate at some locations. Specific conductance and hardness and concentrations of total dissolved-solids slightly exceed statewide averages. Concentrations of dissolved sodium and dissolved chloride in 6 wells were greater than most natural ground waters in the State, indicating possible contamination from road salts. Water samples from 6 of the 46 wells sampled contained concentrations of total nitrate as nitrogen greater than 10.0 milligrams per liter. Elevated concentrations of total nitrate as nitrogen in water from wells in rural-agricultural areas probably are related to fertilizer applications. Results of partial chemical analyses by the Michigan Department of Public Health indicates specific conductance, and concentrations of hardness, dissolved fluoride, and total iron are fairly uniform throughout the county. Concentrations of dissolved sodium, dissolved chloride, and total nitrate as nitrogen differed among townships. Pesticides were detected in water from only one well. Water from five wells contained volatile organics. A map of susceptibility of ground water to contamination in Kalamazoo County was developed using a system created by the U.S. Environmental Protection Agency. Seven geohydrologic factors that affect and control ground-water movement are mapped and composited onto a countywide map. All seven factors have some effect on countywide susceptibility, but the most important factors are depth to water and composition of the materials above the aquifer.

Michigan↗
USGS2014

The quality of our Nation's waters: Water quality in the Denver Basin aquifer system, Colorado, 2003-05

Availability and sustainability of groundwater in the Denver Basin aquifer system depend on water quantity and water quality. The Denver Basin aquifer system underlies about 7,000 square miles of the Great Plains in eastern Colorado and is the primary or sole source of water for domestic and public supply in many areas of the basin. Use of groundwater from the Denver Basin sandstone aquifers has been instrumental for development of the south Denver metropolitan area and other areas, but has resulted in a decline in water levels in some parts of the system. Human activities in many areas have adversely affected the quality of water in the aquifer system, especially the shallow parts. Groundwater in deeper parts of the system used for drinking water, once considered isolated from the effects of overlying land use, is increasingly vulnerable to contamination from human activities and geologic materials. Availability and sustainability of high-quality groundwater are vital to the economic health of the Denver Basin area.

Colorado↗