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At least 919 records · Page 51Linked to original sources
USGS2010

Organic petrology of subbituminous carbonaceous shale samples from Chalāw, Kabul Province, Afghanistan: Considerations for paleoenvironment and energy resource potential

Neogene (?) subbituminous carbonaceous shale deposits from Chalāw, Afghanistan, were investigated through organic petrology techniques and standard coal analyses to determine paleoenvironment and potential for resource utilization. The Chalāw deposit, approximately 30 km southeast of Kabul, currently is exploited for brick making and domestic heating and cooking. Three multiple-bench channel samples of the mined bed at Chalāw were collected and evaluated. The presence of significant huminite (ranging from 0.2 to 59.0 vol.%, mineral-inclusive basis) is suggestive of a terrestrial lignin-rich precursor plant material. Measured reflectance values of 0.38–0.55% indicate subbituminous rank. This rank suggests burial depths of approximately 1500 m and maximum temperatures of approximately 50 °C. Structured liptinite macerals generally are absent except for some fluorescing morphologies interpreted to be poorly-preserved root cork suberinite. Sponge spicule bioliths including gemmoscleres and megascleres are common. These petrographic observations, in addition to high mineral matter content (33 to > 95 vol.%), medium to high sulfur content (2.1–11.5 wt.%, dry basis; db), and the presence of common gastropod? shell fragments and an aragonite-needle chalk bed are consistent with, but not directly indicative of, a marginal marine or estuarine mangrove depositional environment. However, additional data are necessary to confirm this hypothesis and deposition in a freshwater environment cannot be ruled out at this time. Commercial-scale development and utilization of the Chalāw deposit as a thermal fuel resource may be possible using a fluidized bed combustion system which could accept the low-quality mine product currently produced. Samples examined herein contain high-ash yield (45–90 wt.%, db), high total moisture content (17–39 wt.%), low calorific value (980–6860 Btu/lb, m,mmf), and have poor agglomerating properties (FSI = 0), consistent with fuels utilized in fluidized bed combustors. However, delineation of the extent of the deposit through field investigation will be necessary to make a quantified resource estimate for mine planning.

Kabul Province↗
USGS2013

Coal resources, reserves and peak coal production in the United States

In spite of its large endowment of coal resources, recent studies have indicated that United States coal production is destined to reach a maximum and begin an irreversible decline sometime during the middle of the current century. However, studies and assessments illustrating coal reserve data essential for making accurate forecasts of United States coal production have not been compiled on a national basis. As a result, there is a great deal of uncertainty in the accuracy of the production forecasts. A very large percentage of the coal mined in the United States comes from a few large-scale mines (mega-mines) in the Powder River Basin of Wyoming and Montana. Reported reserves at these mines do not account for future potential reserves or for future development of technology that may make coal classified currently as resources into reserves in the future. In order to maintain United States coal production at or near current levels for an extended period of time, existing mines will eventually have to increase their recoverable reserves and/or new large-scale mines will have to be opened elsewhere. Accordingly, in order to facilitate energy planning for the United States, this paper suggests that probabilistic assessments of the remaining coal reserves in the country would improve long range forecasts of coal production. As it is in United States coal assessment projects currently being conducted, a major priority of probabilistic assessments would be to identify the numbers and sizes of remaining large blocks of coal capable of supporting large-scale mining operations for extended periods of time and to conduct economic evaluations of those resources.

International Journal of Coal Geology↗
USGS2024

Multi-criteria decision approach for climate adaptation of cultural resources along the Atlantic coast of the southeastern United States: Application of AHP method

Prioritizing climate adaptation actions is often made difficult by stakeholders and decision-makers having multiple objectives, some of which may be competing. Transparent, transferable, and objective methods are needed to assess and weight different objectives for complex decisions with multiple interests. In this study, the Analytic Hierarchy Process (AHP) was used to examine priorities in managing cultural resources in the face of climate change at Cape Lookout National Seashore on the Atlantic coast of the southeastern United States. In this process, we conducted facilitated discussion sessions with the selected stakeholder representatives to elicit a comprehensive list of management objectives. Objectives were then merged into three categories: 1) Maximize retention of historic character and condition (HCC); 2) Foster heritage awareness (HA); and 3) Maximize financial benefits (FB). We facilitated two AHP exercise sessions, both individually and in groups, to seek consensus on the relative importance of the objectives. The AHP process created a space for stakeholders (government agencies and local citizens) to consider and present arguments that we used to contextualize their trade-offs between the objectives. The stakeholders' top priority was to maximize the HCC. This objective was prioritized more than HA and FB in the individual trade-off choices, while HA was given nearly equal priority to FB. The consensus priority vectors of two management objectives (HCC and HA) differ significantly from FB, but the difference between HCC and HA is slight and not statistically different. FB and HA had larger changes in consensus priority vectors among the three objectives relative to individual priority vectors. For HCC, the difference between individual and consensus priority vectors was the smallest and nearly equal. Moreover, very high levels of consistency were found in consensus priority trade-off discussions and AHP application. Our research highlights the advantage of using a two-step AHP process in climate adaptation planning of vulnerable resources to enhance robustness in decision making. Coupling this approach with future efforts to develop management priorities would help estimate indices to determine the order in which adaptation treatments are applied to vulnerable cultural resources.

Climate Risk Management↗
USGS2007

Conditions for coexistence of freshwater mussel species via partitioning of fish host resources

Riverine freshwater mussel species can be found in highly diverse communities where many similar species coexist. Mussel species potentially compete for food and space as adults, and for fish host resources during the larval (glochidial) stage. Resource partitioning at the larval stage may promote coexistence. A model of resource utilization was developed for two mussel species and analyzed to determine conditions for coexistence. Mussel species were predicted to coexist when they differed in terms of their success in contacting different fish host species; very similar strategies offered limited possibilities for coexistence. Differences in the mussel species' maximum infestation loads on the fish hosts that coincided with differences in their fish host contact success promoted coexistence. Mussel species with a given set of trade-offs in fish host use were predicted to coexist only for a subset of relative fish host abundances, so a shift in relative fish host abundances could result in the loss of a mussel species. An understanding of the conditions for freshwater mussel species coexistence can help explain high mussel diversity in rivers and guide ongoing conservation activities. ?? 2006 Elsevier B.V. All rights reserved.

Ecological Modelling↗
USGS2011

A comparison of effects from prescribed fires and wildfires managed for resource objectives in Sequoia and Kings Canyon National Parks

Current goals for prescription burning are focused on measures of fuel consumption and changes in forest density. These benchmarks, however, do not address the extent to which prescription burning meets perceived ecosystem needs of heterogeneity in burning, both for overstory trees and understory herbs and shrubs. There are still questions about how closely prescribed fires mimic these patterns compared to natural wildfires. This study compared burn patterns of prescribed fires and managed unplanned wildfires to understand how the differing burning regimes affect ecosystem properties. Measures of forest structure and fire severity were sampled in three recent prescribed fires and three wildfires managed for resource objectives in Sequoia and Kings Canyon National Parks. Fine scale patterns of fire severity and heterogeneity were compared between fire types using ground-based measures of fire effects on fuels and overstory and understory vegetation. Prescribed fires and wildfires managed for resource objectives displayed similar patterns of overstory and understory fire severity, heterogeneity, and seedling and sapling survival. Variation among plots within the same fire was always greater than between fire types. Prescribed fires can provide burned landscapes that approximate natural fires in many ways. It is recognized that constraints placed on when wildfires managed for resource objectives are allowed to burn freely may bias the range of conditions that might have been experienced under more natural conditions. Therefore they may not exactly mimic natural wildfires. Overall, the similarity in fire effects that we observed between prescribed fires and managed wildfires indicate that despite the restrictions that are often placed on prescribed fires, they appear to be creating post-fire conditions that approximate natural fires when assessed on a fine spatial scale.

California↗
USGS2022

Role of landscape features in resource selection by female Greater Prairie-chickens within a constrained environment

Greater Prairie-chickens ( Tympanuchus cupido ) historically occupied 20 states within the contiguous United States; however, due to habitat degradation and loss, they are currently found in 11 states, only four of which have a stable population. Kansas supports a relatively large abundance of Greater Prairie-chickens, where the Flint Hills ecoregion historically supported the largest population density of all ecoregions. In the past decade, the Flint Hills population has declined by 75 % to an estimated 8,334 individuals in 2021 from 34,180 individuals in 2015 due to landscape changes and intensification of grassland management practices. The Fort Riley Military Reservation in the northwest portion of the Flint Hills ecoregion is one of a few areas within the ecoregion that does not implement grazing or vast annual burning. The Greater Prairie-chicken population within Fort Riley has remained relatively stable over the past 25 years despite being constrained by surrounding landscape features and development. We analyzed multiple scales of resource selection by 46 female Greater Prairie-chickens during March-April 2019–2021 on Fort Riley to investigate why this population is doing relatively well compared to populations in surrounding areas. We tested landscape feature, vegetation, and burn mosaic variables to evaluate which variables had the greatest influence on resource selection. Landscape features had the greatest influence on resource selection. Females avoided trees within Fort Riley for both breeding season use and nest-site selection at a greater margin than any other study in Kansas. Additionally, fourth-order selection was not evident within this study system, contrary to studies within surrounding areas. Our findings join a growing body of literature that suggests containment of woody encroachment as a high priority for managers to maintain or expand prairie grouse habitat in many different environments. This containment is especially critical on Fort Riley because of its constrained environment, and further woody encroachment could lead to loss of habitat that is inescapable by the Greater Prairie-chicken population on Fort Riley. Spatially-explicit evaluations of habitat availability are increasingly important as more areas within the Greater Prairie-chicken range become constrained by urbanization, agricultural expansion, and intensive management practices.

Kansas↗
USGS2015

Coupling geophysical investigation with hydrothermal modeling to constrain the enthalpy classification of a potential geothermal resource.

An appreciable challenge in volcanology and geothermal resource development is to understand the relationships between volcanic systems and low-enthalpy geothermal resources. The enthalpy of an undeveloped geothermal resource in the Karckar region of Armenia is investigated by coupling geophysical and hydrothermal modeling. The results of 3-dimensional inversion of gravity data provide key inputs into a hydrothermal circulation model of the system and associated hot springs, which is used to evaluate possible geothermal system configurations. Hydraulic and thermal properties are specified using maximum a priori estimates. Limited constraints provided by temperature data collected from an existing down-gradient borehole indicate that the geothermal system can most likely be classified as low-enthalpy and liquid dominated. We find the heat source for the system is likely cooling quartz monzonite intrusions in the shallow subsurface and that meteoric recharge in the pull-apart basin circulates to depth, rises along basin-bounding faults and discharges at the hot springs. While other combinations of subsurface properties and geothermal system configurations may fit the temperature distribution equally well, we demonstrate that the low-enthalpy system is reasonably explained based largely on interpretation of surface geophysical data and relatively simple models.

Karckar Region↗
USGS2022

Defining oyster resource zones across coastal Louisiana for restoration and aquaculture

Eastern oysters ( Crassostrea virginica ) are a critical ecological and commercial resource in the northern Gulf of Mexico facing changing environmental conditions from river management and climate change. In Louisiana, USA, development of restored reefs, and off-bottom aquaculture would benefit from the identification of locations supportive of sustainable oyster populations ( i.e., metapopulations) and high consistent production. This study defines four oyster resource zones across coastal Louisiana based on environmental conditions known to affect oyster survival, growth, and reproduction. Daily data from 2015 to 2019 were interpolated to generate salinity and temperature profiles across Louisiana's estuaries, which were then used to classify zones based on monthly and annual salinity mean and variance. Zones were classified as supportive of (1) broodstock sanctuary reefs (i.e., support reproductive populations), (2) productive reefs during dry (salty) years, (3) productive reefs during wet (fresh) years, and (4) off-bottom aquaculture development. Of the 38,000 km 2 investigated, over 11,000 km 2 of potential oyster zone area was identified across the Louisiana coast. The Broodstock Sanctuary Zone was the smallest (∼540 km 2 ), as salinity variance limited this zone in many areas, as it is driven largely by riverine inputs across many estuaries. Located up-estuary (Dry Restoration Zone) and down-estuary (Wet Restoration Zone) of the Broodstock Sanctuary Zone, Dry and Wet Restoration Zone areas covered ∼2400 km 2 and ∼3900 km 2 , respectively. Mapped reefs in Louisiana currently exist largely within the Dry Restoration zones, suggesting a potential strategy to focus reef development in Wet Restoration zones to ensure reef network sustainability through years with high precipitation and river inflow. The off-bottom Aquaculture Zone was the largest (∼6400 km 2 ) zone identified, with much of this area located more down-estuary and off-shore. Accounting for variable water quality conditions enables the development of a network of reefs resilient to environmental variability, and more stable areas for consistent off-bottom aquaculture production. Spatial planning and identification of oyster resource zones reduces focus on individual reef success and supports management of oyster metapopulation outcomes, while identifying zones supportive of off-bottom aquaculture.

Louisiana↗
USGS2015

Risk assessment of brine contamination to aquatic resources from energy development in glacial drift deposits: Williston Basin, USA

Contamination to aquatic resources from co-produced water (brine) associated with energy development has been documented in the northeastern portion of the Williston Basin; an area mantled by glacial drift. The presence and magnitude of brine contamination can be determined using the contamination index (CI) value from water samples. Recently, the U.S. Geological Survey published a section (~ 2.59 km 2 ) level risk assessment of brine contamination to aquatic resources for Sheridan County, Montana, using oilfield and hydrogeological parameters. Our goal was to improve the Sheridan County assessment (SCA) and evaluate the use of this new Williston Basin assessment (WBA) across 31 counties mantled by glacial drift in the Williston Basin. To determine if the WBA model improved the SCA model, results from both assessments were compared to CI values from 37 surface and groundwater samples collected to evaluate the SCA. The WBA (R 2 = 0.65) outperformed the SCA (R 2 = 0.52) indicating improved model performance. Applicability across the Williston Basin was evaluated by comparing WBA results to CI values from 123 surface water samples collected from 97 sections. Based on the WBA, the majority (83.5%) of sections lacked an oil well and had minimal risk. Sections with one or more oil wells comprised low (8.4%), moderate (6.5%), or high (1.7%) risk areas. The percentage of contaminated water samples, percentage of sections with at least one contaminated sample, and the average CI value of contaminated samples increased from low to high risk indicating applicability across the Williston Basin. Furthermore, the WBA performed better compared to only the contaminated samples (R 2 = 0.62) versus all samples (R 2 = 0.38). This demonstrates that the WBA was successful at identifying sections, but not individual aquatic resources, with an increased risk of contamination; therefore, WBA results can prioritize future sampling within areas of increased risk.

Montana, North Dakota↗
USGS2020

Climate change effects on biodiversity, ecosystems, ecosystem services, and natural resource management in the United States

Climate change is a pervasive and growing global threat to biodiversity and ecosystems. Here, we present the most up-to-date assessment of climate change impacts on biodiversity, ecosystems, and ecosystem services in the U.S. and implications for natural resource management. We draw from the 4th National Climate Assessment to summarize observed and projected changes to ecosystems and biodiversity, explore linkages to important ecosystem services, and discuss associated challenges and opportunities for natural resource management. We find that species are responding to climate change through changes in morphology and behavior, phenology, and geographic range shifts, and these changes are mediated by plastic and evolutionary responses. Responses by species and populations, combined with direct effects of climate change on ecosystems (including more extreme events), are resulting in widespread changes in productivity, species interactions, vulnerability to biological invasions, and other emergent properties. Collectively, these impacts alter the benefits and services that natural ecosystems can provide to society. Although not all impacts are negative, even positive changes can require costly societal adjustments. Natural resource managers need proactive, flexible adaptation strategies that consider historical and future outlooks to minimize costs over the long term. Many organizations are beginning to explore these approaches, but implementation is not yet prevalent or systematic across the nation.

Science of the Total Environment↗
USGS2013

Temporal variation and scale in movement-based resource selection functions

A common population characteristic of interest in animal ecology studies pertains to the selection of resources. That is, given the resources available to animals, what do they ultimately choose to use? A variety of statistical approaches have been employed to examine this question and each has advantages and disadvantages with respect to the form of available data and the properties of estimators given model assumptions. A wealth of high resolution telemetry data are now being collected to study animal population movement and space use and these data present both challenges and opportunities for statistical inference. We summarize traditional methods for resource selection and then describe several extensions to deal with measurement uncertainty and an explicit movement process that exists in studies involving high-resolution telemetry data. Our approach uses a correlated random walk movement model to obtain temporally varying use and availability distributions that are employed in a weighted distribution context to estimate selection coefficients. The temporally varying coefficients are then weighted by their contribution to selection and combined to provide inference at the population level. The result is an intuitive and accessible statistical procedure that uses readily available software and is computationally feasible for large datasets. These methods are demonstrated using data collected as part of a large-scale mountain lion monitoring study in Colorado, USA.

Statistical Methodology↗
USGS2011

Volcanology curricula development aided by online educational resource

Volcanic activity is an excellent hook for engaging college and university students in geoscience classes. An increasing number of Internet-accessible real-time and near–real time volcano monitoring data are now available and constitute an important resource for geoscience education; however, relatively few data sets are comprehensive, and many lack background information to aid in interpretation. In response to the need for organized, accessible, and well-documented volcano education resources, the U.S. Geological Survey's Hawaiian Volcano Observatory (HVO), in collaboration with NASA and the University of Hawai`i at Manoa, established the Volcanoes Exploration Project: Pu`u `Ō`ō (VEPP). The VEPP Web site (http://vepp.wr.usgs.gov) is an educational resource that provides access, in near real time, to geodetic, seismic, and geologic data from the active Pu`u `Ō`ō eruptive vent on Kilauea volcano, Hawaii, along with background and context information. A strength of the VEPP site is the common theme of the Pu`u `Ō`ō eruption, which allows the site to be revisited multiple times to demonstrate different principles and integrate many aspects of volcanology.

Hawai'i↗
USGS2017

Cross-scale phenological data integration to benefit resource management and monitoring

Climate change is presenting new challenges for natural resource managers charged with maintaining sustainable ecosystems and landscapes. Phenology, a branch of science dealing with seasonal natural phenomena (bird migration or plant flowering in response to weather changes, for example), bridges the gap between the biosphere and the climate system. Phenological processes operate across scales that span orders of magnitude—from leaf to globe and from days to seasons—making phenology ideally suited to multiscale, multiplatform data integration and delivery of information at spatial and temporal scales suitable to inform resource management decisions. A workshop report: Workshop held June 2016 to investigate opportunities and challenges facing multi-scale, multi-platform integration of phenological data to support natural resource management decision-making.

Conference Paper↗
USGS2017

Potentially exploitable supercritical geothermal resources in the ductile crust

The hypothesis that the brittle–ductile transition (BDT) drastically reduces permeability implies that potentially exploitable geothermal resources (permeability >10 −16 m 2 ) consisting of supercritical water could occur only in rocks with unusually high transition temperatures such as basalt. However, tensile fracturing is possible even in ductile rocks, and some permeability–depth relations proposed for the continental crust show no drastic permeability reduction at the BDT. Here we present experimental results suggesting that the BDT is not the first-order control on rock permeability, and that potentially exploitable resources may occur in rocks with much lower BDT temperatures, such as the granitic rocks that comprise the bulk of the continental crust. We find that permeability behaviour for fractured granite samples at 350–500 °C under effective confining stress is characterized by a transition from a weakly stress-dependent and reversible behaviour to a strongly stress-dependent and irreversible behaviour at a specific, temperature-dependent effective confining stress level. This transition is induced by onset of plastic normal deformation of the fracture surface (elastic–plastic transition) and, importantly, causes no ‘jump’ in the permeability. Empirical equations for this permeability behaviour suggest that potentially exploitable resources exceeding 450 °C may form at depths of 2–6 km even in the nominally ductile crust.

Nature Geoscience↗
USGS2017

Influence of precipitation and crop germination on resource selection by mule deer (Odocoileus hemionus) in southwest Colorado

Mule deer ( Odocoileus hemionus ) populations in the western United States provide many benefits to local economies but can also cause considerable damage to agriculture, particularly damage to lucrative crops. Limited information exists to understand resource selection of mule deer in response to annual variation in crop rotation and climatic conditions. We tested the hypothesis that mule deer select certain crops, and in particular sunflower, based on annual climatic variability. Our objective was to use movements, estimates of home range, and resource selection analysis to identify resources selected by mule deer. We used annually-derived crop-specific datasets along with Global Positioning System collars to monitor 14 mule deer in an agricultural area near public lands in southwestern Colorado, USA. We estimated home ranges for two winter seasons that ranged between 7.68 and 9.88 km 2 , and for two summer seasons that ranged between 5.51 and 6.24 km 2 . Mule deer selected areas closer to forest and alfalfa for most periods during 2012, but selected areas closer to sunflower in a majority of periods during 2013. Considerable annual variation in climate patterns and precipitation levels appeared to influence selection by mule deer because of variability in crop rotation and success of germination of specific crops.

Colorado, Utah↗
USGS2019

Three-dimensional partitioning of resources by congeneric forest predators with recent sympatry

Coexistence of ecologically similar species can be maintained by partitioning along one or more niche axes. Three-dimensional structural complexity is central to facilitating resource partitioning between many forest species, but is underrepresented in field-based studies. We examined resource selection by sympatric northern spotted owls (Strix occidentalis caurina), a threatened species under the US Endangered Species Act, and nonnative barred owls (S. varia) in western Oregon, USA to explore the relative importance of canopy heterogeneity, vertical complexity of forest, and abiotic features to resource selection and identify potential differences that may facilitate long-term coexistence. We predicted that within home range selection of understory densities, measured with airborne lidar, would differ between species based on proportional differences in arboreal and terrestrial prey taken by each owl species. We used discrete choice models and telemetry data from 41 spotted owls and 38 barred owls monitored during 2007–2009 and 2012–2015. Our results suggested that while both species used tall canopy areas more often than low canopy areas, spotted owls were more commonly found in areas with lower tree cover, more developed understory, and steeper slopes. This is the first evidence of fine-scale partitioning based on structural forest properties by northern spotted owls and barred owls.

Oregon↗
USGS2012

The Modular Modeling System (MMS): A modeling framework for water- and environmental-resources management

The interdisciplinary nature and increasing complexity of water- and environmental-resource problems require the use of modeling approaches that can incorporate knowledge from a broad range of scientific disciplines. The large number of distributed hydrological and ecosystem models currently available are composed of a variety of different conceptualizations of the associated processes they simulate. Assessment of the capabilities of these distributed models requires evaluation of the conceptualizations of the individual processes, and the identification of which conceptualizations are most appropriate for various combinations of criteria, such as problem objectives, data constraints, and spatial and temporal scales of application. With this knowledge, "optimal" models for specific sets of criteria can be created and applied. The U.S. Geological Survey (USGS) Modular Modeling System (MMS) is an integrated system of computer software that has been developed to provide these model development and application capabilities. MMS supports the integration of models and tools at a variety of levels of modular design. These include individual process models, tightly coupled models, loosely coupled models, and fully-integrated decision support systems. A variety of visualization and statistical tools are also provided. MMS has been coupled with the Bureau of Reclamation (BOR) object-oriented reservoir and river-system modeling framework, RiverWare, under a joint USGS-BOR program called the Watershed and River System Management Program. MMS and RiverWare are linked using a shared relational database. The resulting database-centered decision support system provides tools for evaluating and applying optimal resource-allocation and management strategies to complex, operational decisions on multipurpose reservoir systems and watersheds. Management issues being addressed include efficiency of water-resources management, environmental concerns such as meeting flow needs for endangered species, and optimizing operations within the constraints of multiple objectives such as power generation, irrigation, and water conservation. This decision support system approach is being developed, tested, and implemented in the Gunni-son, Yakima, San Juan, Rio Grande, and Truckee River basins of the western United States. Copyright ASCE 2004.

Conference Paper↗
USGS2008

Evaluation of the sustainability of deep groundwater as an arsenic-safe resource in the Bengal Basin

Tens of millions of people in the Bengal Basin region of Bangladesh and India drink groundwater containing unsafe concentrations of arsenic. This high-arsenic groundwater is produced from shallow (<100 m) depths by domestic and irrigation wells in the Bengal Basin aquifer system. The government of Bangladesh has begun to install wells to depths of >150 m where groundwater arsenic concentrations are nearly uniformly low, and many more wells are needed, however, the sustainability of deep, arsenic-safe groundwater has not been previously assessed. Deeper pumping could induce downward migration of dissolved arsenic, permanently destroying the deep resource. Here, it is shown, through quantitative, large-scale hydrogeologic analysis and simulation of the entire basin, that the deeper part of the aquifer system may provide a sustainable source of arsenic-safe water if its utilization is limited to domestic supply. Simulations provide two explanations for this result: deep domestic pumping only slightly perturbs the deep groundwater flow system, and substantial shallow pumping for irrigation forms a hydraulic barrier that protects deeper resources from shallow arsenic sources. Additional analysis indicates that this simple management approach could provide arsenic-safe drinking water to >90% of the arsenic-impacted region over a 1,000-year timescale. This insight may assist water-resources managers in alleviating one of the world's largest groundwater contamination problems.

Proceedings of the National Academy of Sciences of↗