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At least 271 records · Page 15Linked to original sources
USGS2024

Assessment of water levels, nitrate, and arsenic in the Carson Valley Alluvial Aquifer and the development of a data visualization tool for the Carson River Basin, Nevada

Residents of Carson Valley, Douglas County, Nevada, rely on the basin-fill alluvial aquifer underlying the valley for drinking water. Since the 1980s, groundwater levels and water-quality data have been collected to monitor the status of the aquifer system and to assist in planning efforts to address current (2024) and future demand. The U.S. Geological Survey (USGS), in cooperation with Douglas County, Nevada, evaluated trends in water levels, nitrate, and arsenic concentrations from a network of monitoring and domestic wells in Carson Valley. This work also assessed the monitoring well network to determine the suitability of wells for characterizing the occurrence of arsenic in the groundwater. Monitoring of constituents, such as nitrate and arsenic concentrations, is needed to assess changes in contaminant distribution and to evaluate the effect that changing land use and groundwater pumping has on their occurrence and transport. Results of the trend analysis indicate water levels are declining ( p <0.05) in 17 of 26 selected monitoring wells (65 percent). Areas with the largest change in water levels, with more than 20 feet of declines, were within the community areas of Johnson Lane, Ruhenstroth, South Agricultural, East Valley, and Fish Springs. Variations in water levels measured in wells from the Central Agricultural, Minden, Foothill, Alpine County (one well), and Gardnerville Ranchos areas show periods of increase and decrease over time, but they also maintain long-term declining trends ( p <0.05). Increases in nitrate concentrations in groundwater samples collected from 9 out of 14 selected monitoring wells (64 percent) are statistically significant ( p <0.05) within the Ruhenstroth, Gardnerville Ranchos, East Valley, Genoa, and Johnson Lane community areas. Samples collected from a well in Indian Hills/Jacks Valley indicated a decreasing trend in nitrate concentration over time. Nitrate concentrations in samples collected from wells in East Valley, Genoa, Johnson Lane, and Indian Hills/Jack Valley were consistently low (less than 3 milligrams per liter [mg/L]) and stable. Nitrate concentrations from selected wells in Johnson Lane and Garnerville Ranchos exceeded the U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10 mg/L (as nitrogen) and have trends that are increasing over time. In 2022, a sample collected from Johnson Lane had a concentration (7.3 mg/L) below the MCL with an increasing trend over time. Temporal trend analyses for groundwater arsenic concentrations in Carson Valley could not be done because of a lack of temporal data. However, using available historical data, arsenic concentrations seem to be greater in groundwater from wells located on the eastern and northern areas of the valley than in wells located on the western or southern areas. Groundwater arsenic concentrations exceed 5 micrograms per liter (μg/L) in most samples collected from wells in Johnson Lane, Airport, Central Agricultural, and East Valley areas and in many cases exceed the U.S. Environmental Protection Agency (EPA) MCL of 10 μg/L. Data indicate that groundwater from domestic wells screened at deeper intervals are likely more vulnerable to elevated arsenic concentrations than shallower wells. A groundwater network evaluation for Carson Valley identified potential modifications in the sampling locations and frequency to better understand the effect of groundwater pumping in communities where municipal and domestic demand are greatest, potentially enhancing understanding of contaminant transport in these areas. Potential modifications to the active well network include reducing the frequency of sample collection from existing network wells (6 out of 11) that have consistently shown low and stable nitrate concentrations, adding wells in areas where data are sparse, and increasing the number of wells in areas with elevated groundwater nitrate concentrations. Including the analysis of arsenic in samples from the active groundwater monitoring well network will provide more detail on the temporal and spatial variability of arsenic concentrations. A visualization tool for the Carson River Basin was developed to provide access to discrete and near real-time hydrologic and water-quality data. The Carson River Basin Hydro Mapper (CBH; U.S. Geological Survey, 2023b) shows active and historical discrete water levels measured by the USGS and the State of Nevada Division of Water Resources, discrete groundwater nitrate and arsenic concentration data collected by the USGS, near real-time streamflow, and surface water levels for select waterbodies. The hydrologic data in the CBH provides resource managers, the public, and the scientific community with an easily accessible tool to present and communicate the most up-to-date information available about local and basin-wide water resources.

Nevada↗
USGS2005

Public access management as an adaptive wildlife management tool

Wildlife populations across the United States are benefiting from improved wildlife management techniques. However, these benefits also create new challenges including overpopulation, disease, increased winter kill, and forage degradation. These issues have become the challenges for natural resource managers and landowners. Specifically, elk (Cervus elaphus) populations in the Gunnison River Valley of Colorado are growing and causing increased resource damage on public and private lands. On public lands elk threaten sage grouse habitat and compete with domestic livestock for available forage; on private lands they diminish available livestock forage. Management of elk and elk habitat in this area is a shared responsibility of the NPS (Black Canyon of the Gunnison National Park and Curecanti National Recreation Area), BLM (Uncompahgre Field Office), USFS (Gunnison National Forest), and the CDOW (Colorado Division of Wildlife). All of these agencies participate in this research and adaptive management project. One key issue in the Black Mesa &ndash; Black Canyon area is the interaction between motorized vehicles and. The working hypothesis for this study is that early season elk movement onto private lands and the National Park is precipitated by increased use of Off Highway Vehicles (OHV&rsquo;s). Data on intensity of motorized use is extremely limited. In this study, we monitor intensity of motorized vehicle and trail use on elk movements and habitat usage and analyze interactions. If management agencies decide to alter accessibility, we will monitor wildlife responses to changes in the human-use regime. This provides a unique opportunity for adaptive management experimentation based on coordinated research and monitoring. The products from this project will provide natural resource managers across the nation with tools and information to better meet these resource challenges.

Open-File Report↗
USGS1984

Refuge management analyses: research needs for Muscatatuck National Wildlife Refuge

Muscatatuck National Wildlife Refuge, located in southeastern Indiana, was established by the Migratory Bird Conservation Commission in 1966. Land use planning for the Refuge formally began in 1971, and development of facilities designed in that planning effort is now nearing completion. As these facilities become operational, Refuge personnel will be manipulating water (both spatially and temporally) and other habitat components to achieve the joint Refuge goals of natural resource conservation and public use. This situation offers a unique opportunity to institute research and management studies designed to evaluate and enhance the effectiveness of the management regime in providing for the needs of migratory waterfowl and other wildlife resources.

Indiana↗
USGS1971

Classification of public lands valuable for geothermal steam and associated geothermal resources

The Organic Act of 1879 (43 U.S.C. 31) that established the U.S. Geological Survey provided, among other things, for the classification of the public lands and for the examination of the geological structure, mineral sources, and products of the national domain. In order to provide uniform executive action in classifying public lands, standards for determining which lands are valuable for mineral resources, for example, leasable mineral lands, or for other products are prepared by the U.S. Geological Survey. This report presents the classification standards for determining which Federal lands are classifiable as geothermal steam and associated geothermal resources lands under the Geothermal Steam Act of 1970 (84 Star. 1566). The concept of a geothermal resources province is established for classification of lands for the purpose of retention in Federal ownership of rights to geothermal resources upon disposal of Federal lands. A geothermal resources province is defined as an area in which higher than normal temperatures are likely to occur with depth and in which there is a reasonable possibility of finding reservoir rocks that will yield steam or heated fluids to wells. The determination of a 'known geothermal resources area' is made after careful evaluation of the available geologic, geochemical, and geophysical data and any evidence derived from nearby discoveries, competitive interests, and other indicia. The initial classification required by the Geothermal Steam Act of 1970 is presented.

Circular↗
USGS2011

The development of an EDSS: Lessons learned and implications for DSS research

The Solar and Wind Energy Resource Assessment (SWERA) project is focused on providing renewable energy (RE) planning resources to the public. Examples include wind, solar, and hydro assessments. SWERA DSS consists of three major components. First, SWERA 'Product Archive' provides for a discovery DSS upon which users can find and access renewable energy data and supporting models. Second, the 'Renewable Resource EXplorer' (RREX) component serves as a web-based, GIS analysis tool for viewing RE resource data available through the SWERA Product Archive. Third, the SWERA web service provides computational access to the data available in the SWERA spatial database through a location based query, and is also utilized in the RREX component. We provide a discussion of various design decisions used in the construction of this EDSS, followed by project experiences and implications for EDSS and broader DSS research.

Conference Paper↗
USGS2022

Status and understanding of groundwater quality in the Sacramento Metropolitan Domestic-Supply Aquifer study unit, 2017—California GAMA Priority Basin Project

Groundwater quality in the Sacramento Metropolitan Domestic-Supply Aquifer study unit (SacMetro-DSA) was studied from August to November 2017 as part of the second phase of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is in parts of Amador, Placer, Sacramento, and Sutter Counties, and the extent of the study unit was defined by the location of three California Department of Water Resources groundwater subbasins: the North American, the South American, and the Cosumnes. The SacMetro-DSA focused on groundwater resources used for domestic drinking-water supply, which generally correspond to shallower parts of aquifer systems than those of groundwater resources used for public drinking water supply in the same area. The assessments characterized the quality of untreated groundwater, not the quality of drinking water. This study included two components: (1) a status assessment, which characterized the status of the quality of the groundwater resources used for domestic supply and (2) an understanding assessment, which evaluated the natural and human factors potentially affecting water quality in those resources. The first component of this study—the status assessment—was based on water-quality data collected from 49 sites sampled by the U.S. Geological Survey for the GAMA Priority Basin Project in 2017. The samples were analyzed for volatile organic compounds, pesticides, and naturally present inorganic constituents, such as major ions and trace elements. To provide context, concentrations of constituents measured in groundwater were compared to U.S. Environmental Protection Agency and California State Water Resources Control Board Division of Drinking Water regulatory and non-regulatory benchmarks for drinking-water quality. The status assessment used a grid-based method to estimate the proportion of the groundwater resources that had concentrations of water-quality constituents approaching or above benchmark concentrations. This method provides statistically unbiased results at the study-area scale and permits comparisons to other GAMA Priority Basin Project study areas. The second component of this study—the understanding assessment—identified the natural and human factors that potentially affect groundwater quality by evaluating land-use characteristics, groundwater age, and geochemical and hydrologic conditions of the domestic-supply aquifer and related these data to constituents identified in the status assessment for further evaluation. In the SacMetro-DSA study unit, arsenic was the only inorganic constituent detected above health-based benchmarks and was detected in 10 percent of the domestic-supply aquifer system. Inorganic constituents were detected above the non-health-based California State Water Resources Control Board—Division of Drinking Water secondary maximum contaminant levels (SMCL-CA) in 16 percent of the system. The inorganic constituents detected above the SMCL-CA were chloride, iron, manganese, and total dissolved solids (TDS). Organic constituents (volatile organic compounds and pesticides) with health-based benchmarks were not detected above health-based benchmarks; however, chloroform was detected at concentrations higher than 10 percent of the health-based benchmark (80 micrograms per liter) in 2 percent of the domestic-supply aquifer system. Of the 310 organic constituents analyzed, 16 constituents were detected; however, only bentazon and chloroform had detection frequencies greater than 10 percent. Inorganic constituents with health-based benchmarks that were evaluated in the understanding assessment included arsenic and hexavalent chromium. Arsenic and hexavalent chromium are natural constituents of aquifer sediments in the study unit and did not appear to be influenced by anthropogenic processes; rather, the presence of arsenic and hexavalent chromium appeared to be related to geochemical conditions controlled by oxidation–reduction reactions in the aquifer system. Naturally occurring inorganic constituents with SMCL-CAs evaluated in the understanding assessment were the trace elements iron and manganese, the major ion chloride, and TDS. Like arsenic and hexavalent chromium, the presence of iron and manganese was most strongly related to geochemical conditions in the aquifer system, specifically reducing conditions, which were most common near the western edge of the study unit close to the Sacramento River. Concentrations of chloride and TDS are indicators of salinity and were correlated with variables related to well location and included redox, agricultural land use, and elevation. Chloride and TDS were positively correlated to reducing conditions, and agricultural land use was negatively correlated to elevation and well depth. Observed correlations among variables were likely driven by the characteristics of the western part of the study unit, such as its higher proportion of agricultural land use and its relatively low elevation. A large portion of the western edge of the study unit is located in the center of the Sacramento Valley, defined by the location of the Sacramento River. The special-interest constituent perchlorate, also included in the understanding assessment, has natural and anthropogenic sources. Perchlorate was detected frequently and at moderate relative concentrations. In some areas of the study unit, concentrations of perchlorate were higher than what might be expected in nature; therefore, anthropogenic introduction of perchlorate or anthropogenically induced migration of native perchlorate could be occurring.

California↗
USGS2014

Platinum-group elements in southern Africa: mineral inventory and an assessment of undiscovered mineral resources

The platinum-group elements, platinum, palladium, rhodium, ruthenium, iridium, and osmium, possess unique physical and chemical characteristics that make them indispensable to modern technology and industry. However, mineral deposits that are the main sources of these elements occur only in three countries in the world, raising concerns about potential disruption in mineral supply. Using information in the public domain, mineral resource and reserve information has been compiled for mafic and ultramafic rocks in South Africa and Zimbabwe that host most of the world&rsquo;s platinum-group element resources. As of 2012, exploration and mining companies have delineated more than 20 billion metric tons of mineralized rock containing 42,000 metric tons of platinum, 29,000 metric tons of palladium, and 5,200 metric tons of rhodium, primarily in mafic and ultramafic intrusions of the Bushveld Complex and the Great Dyke, in southern Africa. Additional mineralized rock is likely to occur in extensions to the well-explored and characterized volumes of mineralized rock. Underexplored extensions of stratabound platinum-group element (PGE) deposits in the Bushveld Complex in South Africa may contain 65,000 metric tons of platinum, palladium, and rhodium to a depth of 3 km. Rocks enriched in PGE, which occur near the contact of the Bushveld Complex with older Transvaal Supergroup sedimentary rocks, may contain 1,100 metric tons of platinum and 1,370 metric tons of palladium (mean estimate to a depth of 1 km). A stratabound platinum-group element deposit in the Great Dyke in Zimbabwe may contain 6,900 metric tons of undiscovered platinum, palladium, and rhodium. By comparison, the global net demand for PGE in 2012 was approximately 460 metric tons. Since the 1920s, mining has recovered 7,200 and 107 metric tons of platinum-group elements from the Bushveld Complex and the Great Dyke, respectively. The large layered intrusions in southern Africa&mdash;the Bushveld Complex and the Great Dyke&mdash;are now and will continue to be a major source of the world&rsquo;s supply of PGE. Mining will not deplete the identified mineral resources and reserves or potential undiscovered mineral resources for many decades; however, in the near-term, PGE supply could be affected by social, environmental, political, and economic factors.

Southern Africa↗
USGS2022

Taking steps to address inequities in open-access publishing through an early career publication honor

Access to resources—whether human, financial, or social—is a key indicator of research output and, in turn, academic career progression. However, resources are not equally distributed among scientists and disparities often stem from external factors. This reality is particularly impactful for early career researchers (ECRs) who have limited control over the resources available to them to advance their careers. The resources needed to fund open-access (OA) publishing are a well-known source of academic inequity (Ross-Hellauer 2022 ). Despite this, wide support for OA publishing exists across the scientific community, largely because OA articles increase access to the scientific literature by removing costly paywalls (Piwowar et al. 2018 ). Benefits of OA publishing also exist for individual researchers; OA studies are read and cited more, so much so that an “open access citation advantage” has been described (McCabe and Snyder 2014 ). Depending on the methods and journals studied, this advantage ranges from an 8 to 40% increase in citation rate (Piwowar et al. 2018 ). The OA publishing model is set to expand further, with influential groups seeking to mandate OA publishing (e.g., Plan S; Else 2021 ) including recent guidance from the United States Office of Science and Technology Policy (The White House 2022 ). However, OA publishing remains expensive, often prohibitively so, and OA fees deter ECRs broadly (Sarabipour et al. 2019 ), and particularly those from the Global South (Kwon 2022 ; Santidrián Tomillo et al. 2022 ).

Limnology and Oceanography Letters↗
USGS2023

Toward a national eDNA strategy for the United States

Environmental DNA (eDNA) data make it possible to measure and monitor biodiversity at unprecedented resolution and scale. As use-cases multiply and scientific consensus grows regarding the value of eDNA analysis, public agencies have an opportunity to decide how and where eDNA data fit into their mandates. Within the United States, many federal and state agencies are individually using eDNA data in various applications and developing relevant scientific expertise. A national strategy for eDNA implementation would capitalize on recent scientific developments, providing a common set of next-generation tools for natural resource management and public health protection. Such a strategy would avoid patchwork and possibly inconsistent guidelines in different agencies, smoothing the way for efficient uptake of eDNA data in management. Because eDNA analysis is already in widespread use in both ocean and freshwater settings, we focus here on applications in these environments. However, we foresee the broad adoption of eDNA analysis to meet many resource management issues across the nation because the same tools have immediate terrestrial and aerial applications.

Environmental DNA↗
USGS2024

When do we need multiple infectious disease models? Agreement between projection rank and magnitude in a multi-model setting

Mathematical models are useful for public health planning and response to infectious disease threats. However, different models can provide differing results, which can hamper decision making if not synthesized appropriately. To address this challenge, multi-model hubs convene independent modeling groups to generate ensembles, known to provide more accurate predictions of future outcomes. Yet, these hubs are resource intensive, and how many models are sufficient in a hub is not known. Here, we compare the benefit of predictions from multiple models in different contexts: (1) decision settings that depend on predictions of quantitative outcomes (e.g., hospital capacity planning), where assessments of the benefits of multi-model ensembles have largely focused; and (2) decisions settings that require the ranking of alternative epidemic scenarios (e.g., comparing outcomes under multiple possible interventions and biological uncertainties). We develop a mathematical framework to mimic a multi-model prediction setting, and use this framework to quantify how frequently predictions from different models agree. We further explore multi-model agreement using real-world, empirical data from 14 rounds of U.S. COVID-19 Scenario Modeling Hub projections. Our results suggest that the value of multiple models could be different in different decision contexts, and if only a few models are available, focusing on the rank of alternative epidemic scenarios could be more robust than focusing on quantitative outcomes. Although additional exploration of the sufficient number of models for different contexts is still needed, our results indicate that it may be possible to identify decision contexts where it is robust to rely on fewer models, a finding that can inform the use of modeling resources during future public health crises.

Epidemics↗
USGS2010

Science in the Public Sphere: Greater Sage-grouse Conservation Planning from a Transdisciplinary Perspective

Integration of scientific data and adaptive management techniques is critical to the success of species conservation, however, there are uncertainties about effective methods of knowledge exchange between scientists and decisionmakers. The conservation planning and implementation process for Greater Sage-grouse (Centrocercus urophasianus; ) in the Mono Basin, Calif. region, was used as a case study to observe the exchange of scientific information among stakeholders with differing perspectives; resource manager, scientist, public official, rancher, and others. The collaborative development of a risk-simulation model was explored as a tool to transfer knowledge between stakeholders and inform conservation planning and management decisions. Observations compiled using a transdisciplinary approach were used to compare the exchange of information during the collaborative model development and more traditional interactions such as scientist-led presentations at stakeholder meetings. Lack of congruence around knowledge needs and prioritization led to insufficient commitment to completely implement the risk-simulation model. Ethnographic analysis of the case study suggests that further application of epistemic community theory, which posits a strong boundary condition on knowledge transfer, could help support application of risk simulation models in conservation-planning efforts within similarly complex social and bureaucratic landscapes.

Open-File Report↗
USGS1982

Progress report to the Arkansas State Highway and Transportation Department, year ending September 30, 1981

The objectives of the cooperative program with the Arkansas State Highway and Transportation Department are described. Accomplishments within the program are summarized and reports are listed. The accomplishments include operation of a crest-stage station network, modeling of rainfall-runoff station data, publication of drainage-area reports for all major river basins in Arkansas, floodflow-characteristics reports at proposed bridge sites, furnishing peak-flow and stage information at many sites, and furnishing technical advice and field training to Highway and Transportation Department personnel. Program plans for the 1982 fiscal year are listed and discussed. Other water-resources programs and publications that may be of interest are discussed and all available flood-prone-area maps for Arkansas are listed.

Open-File Report↗
USGS1983

Alternate data sources for soil surveys on rangeland

Soil information is an essential theme in a digital information base for land management and resource monitoring, but public land management agencies seldom have detailed soil maps available for all of the area under their administration. Most of these agencies conduct soil surveys on a scheduled basis, but escalating costs and declining budgets are reducing the number of surveys that can be scheduled. Digital elevation and satellite spectral data are available or are obtainable for all areas in the continental United States and may be used as an aid to produce soils data. A study was conducted in the Grass Creek Resource Area in north-central Wyoming to assess the utility of incorporating digital elevation and Landsat data into an information base for soil survey and to evaluate the usefulness of these data as an input to an order-three soil survey. Slope-interval maps were produced from digital elevation data and topographic maps of three 7.5-minute quadrangle areas. These slope-interval maps were then overlaid on orthophotoquadrangles and used to produce photo-interpreted physiographic maps. These physiographic maps were digitized into a data base and used with Landsat multispectral scanner data to produce tabular summaries that describe each map polygon in terms of physiographic unit, slope, aspect, elevation, area, and spectral values. A good relationship was found between the physiographic units and soil mapping units defined during a conventional soil survey, and between the Landsat spectral categories and existing vegetation communities. Field evaluations confirmed the feasibility of using this approach for producing physiographic maps as an aid for mapping soils and range sites. The project is a cooperative investigation of the Earth Resources Observation Systems Data Center of the U.S. Geological Survey, the Soil Conservation Service, and the Bureau of Land Management.

Open-File Report↗
USGS2023

Prioritizing science efforts to inform decision making on public lands

Public land management agencies in the US are committed to using science-informed decision making, but there has been little research on the types and topics of science that managers need most to inform their decisions. We used the National Environmental Policy Act to identify four types of science information needed for making decisions relevant to public lands: (1) data on resources of concern, (2) scientific studies relevant to potential effects of proposed actions, (3) methods for quantifying potential effects of proposed actions, and (4) effective mitigation measures. We then used this framework to analyze 70 Environmental Assessments completed by the Bureau of Land Management in Colorado. Commonly proposed actions were oil and gas development, livestock grazing, land transactions, and recreation. Commonly analyzed resources included terrestrial wildlife, protected birds, vegetation, and soils. Focusing research efforts on the intersection of these resources and actions, and on developing and evaluating the effectiveness of mitigation measures to protect these resources, could strengthen the science foundation for public lands decision making.

Frontiers in Ecology and the Environment↗