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At least 505 records · Page 28Linked to original sources
USGS2008

Distribution of geogenic arsenic in hydrologic systems: Controls and challenges

The presence of elevated concentration of arsenic (As) in natural hydrologic systems is regarded as the most formidable environmental crisis in the contemporary world. With its substantial presence in the drinking water of more than thirty countries worldwide, and with an affected population of more than 100 million, it has been termed as the largest mass poisoning in human history. In this special issue, we have tried to provide the most recent research advances on controls and challenges of this severe groundwater contaminant. The articles in this issue, originally presented in the 2006 Geological Society of America Annual Meeting, address the distribution of As in various geologic and geographic settings, the controls of redox and other geochemical parameters on its spatial and temporal variability, the influence of sedimentology and stratigraphy on its occurrence, and mechanisms controlling its mobility. The knowledge available from these studies should provide a roadmap for future research in arsenic contamination hydrology.

Journal of Contaminant Hydrology↗
USGS2019

Incorporating uncertainty and risk into decision making to reduce nitrogen inputs to impaired waters

This article aims to understand decision making under uncertainty and risk, with a case study on Cape Cod, Massachusetts. Decision makers need to consider imperfect information on the cost and effectiveness of advanced nitrogen-removing on-site wastewater treatment systems as options to mitigate water quality degradation. Research included modeling nitrogen load reduction to impaired coastal waters from seven treatment system technologies and eliciting expert knowledge on their costs. Predictions of nitrogen load removal and cost for each technology incorporated variation in effectiveness and uncertainty in household water use, costs, and expert confidence in costs. The predictions were evaluated using the Pareto efficiency concept to reveal tradeoffs between cost and effectiveness. The stochastic dominance index was used to identify preferred technologies for risk-averse decision making, assuming no further learning is possible. Lastly, the predictions were combined into a cost-effectiveness metric to estimate the expected payoff of implementing the best treatment system in the face of uncertainty and the expected payoff of learning which treatment systems are most cost-effective over time. The expected value of perfect information was calculated as the difference between the expected payoffs. Three technologies revealed Pareto efficient tradeoffs between cost and effectiveness, whereas one technology was the preferred risk-averse option in the absence of future learning. There was a high expected value of perfect information, which could motivate adaptive management on Cape Cod. This research demonstrated decision analysis methods to guide future research and decision making toward meeting water quality objectives and reducing uncertainty.

Massachusetts↗
USGS2022

Data synthesis for environmental management: A case study of Chesapeake Bay

Synthesizing large, complex data sets to inform resource managers towards effective environmental stewardship is a universal challenge. In Chesapeake Bay, a well-studied and intensively monitored estuary in North America, the challenge of synthesizing data on water quality and land use as factors related to a key habitat, submerged aquatic vegetation, was tackled by a team of scientists and resource managers operating at multiple levels of governance (state, federal). The synthesis effort took place over a two-year period (2016–2018), and the results were communicated widely to a) scientists via peer review publications and conference presentations; b) resource managers via web materials and workshop presentations; and c) the public through newspaper articles, radio interviews, and podcasts. The synthesis effort was initiated by resource managers at the United States Environmental Protection Agencys’ Chesapeake Bay Program and 16 scientist participants were recruited from a diversity of organizations. Multiple short, immersive workshops were conducted regularly to conceptualize the problem, followed by data analysis and interpretation that supported the preparation of the synthetic products that were communicated widely. Reflections on the process indicate that there are a variety of structural and functional requirements, as well as enabling conditions, that need to be considered to achieve successful outcomes from synthesis efforts.

Chesapeake Bay↗
USGS2014

An ecological basis for future fish habitat restoration efforts in the Huron-Erie Corridor

This perspective describes the major natural and anthropogenic forces driving change in the abundance and quality of fish habitats in the Huron-Erie Corridor (HEC), the Great Lakes connecting channel comprised of the St. Clair River, the Lake St. Clair, and the Detroit River. Channels connecting the Laurentian Great Lakes discharge large volumes of water equal to or greater than most other large rivers in the world that is of consistent high quality and volume, all year. Owing to creation of the St. Lawrence Seaway through the Great Lakes, the connecting channels have been modified by dredging over 200 km of deep-draft shipping lanes with a maintained depth of no less than 8.2 m. Combined with modification of their shorelines for housing and industries, use of the connecting channels for discharges of industrial and municipal wastes and shipping has resulted in numerous beneficial use impairments, such as restrictions on fish and wildlife consumption, degradation of fish and wildlife populations, and losses of fish and wildlife habitat. Various options for remediation of native fish populations and their habitats in the Great Lakes connecting channels, including construction of spawning habitat for threatened and high-value food fishes, such as lake sturgeon (Acipenser fulvescens), walleye (Sander vitreus), and lake whitefish (Coregonus clupeaformis), have been implemented successfully in two of the channels, and form the basis for further recommended research described in this article.

Huron-Erie corridor↗
USGS2016

An overview of current applications, challenges, and future trends in distributed process-based models in hydrology

Process-based hydrological models have a long history dating back to the 1960s. Criticized by some as over-parameterized, overly complex, and difficult to use, a more nuanced view is that these tools are necessary in many situations and, in a certain class of problems, they are the most appropriate type of hydrological model. This is especially the case in situations where knowledge of flow paths or distributed state variables and/or preservation of physical constraints is important. Examples of this include: spatiotemporal variability of soil moisture, groundwater flow and runoff generation, sediment and contaminant transport, or when feedbacks among various Earth’s system processes or understanding the impacts of climate non-stationarity are of primary concern. These are situations where process-based models excel and other models are unverifiable. This article presents this pragmatic view in the context of existing literature to justify the approach where applicable and necessary. We review how improvements in data availability, computational resources and algorithms have made detailed hydrological simulations a reality. Avenues for the future of process-based hydrological models are presented suggesting their use as virtual laboratories, for design purposes, and with a powerful treatment of uncertainty.

Journal of Hydrology↗
USGS2018

Managing the water-energy-food nexus: Opportunities in Central Asia

This article examines impacts of infrastructure development and climate variability on economic outcomes for the Amu Darya Basin in Central Asia. It aims to identify the most economically productive mix of expanded reservoir storage for economic benefit sharing to occur, in which economic welfare of all riparians is improved. Policies examined include four combinations of storage infrastructure for each of two climate futures. An empirical optimization model is developed and applied to identify opportunities for improving the welfare of Tajikistan, Uzbekistan, Afghanistan, and Turkmenistan. The analysis 1) characterizes politically constrained and economically optimized water-use patterns for these combinations of expanded reservoir storage capacity, 2) describes Pareto-Improving packages of expanded storage capacity that could raise economic welfare for all four riparians, and accounts for impacts for each of two climate scenarios. Results indicate that a combination of targeted water storage infrastructure and efficient water allocation could produce outcomes for which the discounted net present value of benefits are favorable for each riparian. Results identify a framework to provide economic motivation for all riparians to cooperate through development of water storage infrastructure. Our findings illustrate the principle that development of water infrastructure can expand the negotiation space by which all communities can gain economic benefits in the face of limited water supply. Still, despite our optimistic findings, patient and deliberate negotiation will be required to transform potential improvements into actual gains.

Journal of Hydrology↗
USGS2023

Integrating urban water fluxes and moving beyond impervious surface cover: A review

Though urban areas represent a small fraction of global land cover, they have an outsized impact on hydrological processes. Within these areas, the pathways that water follows are fundamentally transformed by the disturbance of soils, land cover, vegetation, topography, and built infrastructure. While progress has been made across many cities to quantify interactions between hydrological processes and the urban environment, many fundamental questions remain unanswered. In this article, we review the state of urban hydrologic science, with an eye towards identifying gaps in our understanding of how water flows through built landscapes. Our review focuses on key topics within urban hydrology related to water quantity, including runoff and streamflow generation, soils and soil water, groundwater, vegetation, and climate. We also describe some of the challenges and opportunities within the field of urban hydrology that we envision will drive future work and collaboration.

Journal of Hydrology↗
USGS2019

A global synthesis of lava lake dynamics

Active lava lakes represent a variety of open-vent volcanism in which a sizeable body of lava accumulates at the top of the magma column, constrained by the vent and/or crater geometry. The longevity of lava lakes reflects a balancing of cooling and outgassing occurring at the surface by input of hot and gas-rich magma from below. Due to their longevity and relative accessibility, lava lakes provide a natural laboratory for studying fundamental volcanic processes such as degassing, convection and cooling. This article examines all seven lakes that existed at the time of writing, located in the Pacific, Antarctica, Africa, and South and Central America. They span all tectonic environments, and a range of magma compositions. We focus on analysis of the lake surface motion using image velocimetry, which reveals both similarities and contrasts in outgassing and lake dynamics when comparing the different lakes. We identify two categories of lake behavior: Organized (Erta ’Ale, Nyiragongo, K¯ılauea after 2011, and Erebus) and Chaotic (Villarrica,Masaya, Marum). This division does not map directly to lake size, viscosity, gas emission rate, or temperature. Instead, when examined together, we find that the lakes follow a linear relationship between average surface speed and the ratio of total gas flux to lake surface area. This relationship points to the importance of both flux and lake size in addition to the total volumetric outgassing rate, and suggests a shared deep mechanism controls the supply of heat and gas to all lakes. On the other hand, the differences between Chaotic and Organized lakes highlight the important role of the geometry of the conduit-lake transition, which superimposes a shallow signal on that of the deep circulation. The spatial patterns of surface motion we document suggest the release of gas bubbles at Chaotic lakes is more efficient (i.e., bubbles are less likely to be retained and recycled) compared with Organized lakes. In addition, the data presented here indicate that the solidified crust of Organized lakes plays a role in regulating convection and outgassing in lava lakes.

Journal of Volcanology and Geothermal Research↗
USGS2020

Assessment of leachable elements in volcanic ashfall: A review and evaluation of a standardized protocol for ash hazard characterization

Volcanic ash presents a widespread and common hazard during and after eruptions. Complex interactions between solid ash surfaces and volcanic gases lead to the formation of soluble salts that may be mobilized in aqueous environments. A variety of stakeholders may be concerned about the effects of ash on human and animal health, drinking water supplies, crops, soils and surface runoff. As part of the immediate emergency response, rapid dissemination of information regarding potentially hazardous concentrations of soluble species is critical. However, substantial variability in the methods used to characterize leachable elements makes it challenging to compare datasets and eruption impacts. To address these challenges, the International Volcanic Health Hazard Network ( www.ivhhn.org ) organized a two-day workshop to define appropriate methods for hazard assessment. The outcome of this workshop was a ‘consensus protocol’ for analysis of volcanic ash samples for rapid assessment of hazards from leachable elements, which was subsequently ratified by leading volcanological organizations. The purpose of this protocol is to recommend clear, standard and reliable methods applicable to a range of purposes during eruption response, such as assessing impacts on drinking-water supplies and ingestion hazards to livestock, and also applicable to research purposes. Where possible, it is intended that the methods make use of commonly available equipment and require little training. To evaluate method transferability, an interlaboratory comparison exercise was organized among six laboratories worldwide. Each laboratory received a split of pristine ash, and independently analyzed it according to the protocol for a wide range of elements. Collated results indicate good repeatability and reproducibility for most elements, thus indicating that the development of this protocol is a useful step towards providing standardized and reliable methods for ash hazard characterization. In this article, we review recent ash leachate studies, report the outcomes of the comparison exercise and present a revised and updated protocol based on the experiences and recommendations of the exercise participants. The adoption of standardized methods will improve and facilitate the comparability of results among studies and enable the ongoing development of a global database of leachate information relevant for informing volcanic health hazards assessment.

Journal of Volcanology and Geothermal Research↗
USGS2021

Culturally diverse expert teams have yet to bring comprehensive linguistic diversity to intergovernmental ecosystem assessments

Multicultural representation is a stated goal of many global scientific assessment processes. These processes aim to mobilize a broader, more diverse knowledge base and increase legitimacy and inclusiveness of these assessment processes. Often, enhancing cultural diversity is encouraged through involvement of diverse expert teams and sources of knowledge in different languages. In this article, we examine linguistic diversity, as one representation of cultural diversity, in the eight published assessments of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). Our results show that the IPBES assessment outputs are disproportionately filtered through English-language literature and authors from Anglophone countries. To incorporate more linguistic diversity into global ecosystem assessment processes, we present actionable steps for global science teams to recognize and incorporate non-English-language literature and contributions from non-Anglophones. Our findings highlight the need for broad-scale actions that enhance inclusivity in knowledge synthesis processes through balanced representation of different knowledge holders and sources.

One Earth↗
USGS2016

Conserving the Greater Sage-grouse: A social-ecological systems case study from the California-Nevada region

The Endangered Species Act (ESA) continues to serve as one of the most powerful and contested federal legislative mandates for conservation. In the midst of heated debates, researchers, policy makers, and conservation practitioners champion the importance of cooperative conservation and social-ecological systems approaches, which forge partnerships at multiple levels and scales to address complex ecosystem challenges. However, few real-world examples exist to demonstrate how multifaceted collaborations among stakeholders who share a common goal of conserving at-risk species may be nested within a systems framework to achieve social and ecological goals. Here, we present a case study of Greater Sage-grouse (Centrocercus urophasianus) conservation efforts in the “Bi-State” region of California and Nevada, United States. Using key-informant interviews, we explored dimensions and drivers of this landscape-scale conservation effort. Three themes emerged from the interviews, including 1) ESA action was transformed into opportunity for system-wide conservation; 2) a diverse, locally based partnership anchored collaboration and engagement across multiple levels and scales; and 3) best-available science combined with local knowledge led to “certainty of effectiveness and implementation”—the criteria used by the US Fish and Wildlife Service to evaluate conservation efforts when making listing decisions. Ultimately, collaborative conservation through multistakeholder engagement at various levels and scales led to proactive planning and implementation of conservation measures and precluded the need for an ESA listing of the Bi-State population of Greater Sage-grouse. This article presents a potent example of how a systems approach integrating policy, management, and learning can be used to successfully overcome the conflict-laden and “wicked” challenges that surround at-risk species conservation.

California, Nevada↗
USGS2023

The EnMAP imaging spectroscopy mission towards operations

EnMAP (Environmental Mapping and Analysis Program) is a high-resolution imaging spectroscopy remote sensing mission that was successfully launched on April 1st, 2022. Equipped with a prism-based dual-spectrometer, EnMAP performs observations in the spectral range between 418.2 nm and 2445.5 nm with 224 bands and a high radiometric and spectral accuracy and stability. EnMAP products, with a ground instantaneous field-of-view of 30 m x 30 m at a swath width of 30 km, allow for the qualitative and quantitative analysis of surface variables from frequently and consistently acquired observations on a global scale. This article presents the EnMAP mission and details the activities and results of the Launch and Early Orbit and Commissioning Phases until November 1st, 2022. The mission capabilities and expected performances for the operational Routine Phase are provided for existing and future EnMAP users.

Remote Sensing of Environment↗
USGS2024

On-orbit calibration and performance of the EMIT imaging spectrometer

The Earth surface Mineral dust source InvesTigation (EMIT) is a remote visible to shortwave infrared (VSWIR) imaging spectrometer that has been operating onboard the International Space Station since July 2022. This article describes EMIT's on-orbit spectroradiometric calibration and validation. Accurate spectroscopy is vital to achieve consistent mapping results with orbital imaging spectrometers. EMIT takes a unique approach to this challenge, with just six optical elements, no shutter, and no onboard calibration systems. Its simple design focuses on uniformity and stability to enable vicarious spectroradiometric calibration. Our experiments demonstrate that this approach is successful, approaching the fidelity of manual field spectroscopy in some cases, and enabling new and more accurate products across diverse Earth science disciplines. EMIT achieves several notable firsts for an instrument of its class. It demonstrates successful on-orbit adjustments of Focal Plane Array (FPA) alignment with sub-micron precision. It offers spectral uniformity better than 98%. Optical artifacts in the measurement channels are at least three orders of magnitude below the primary solar-reflected surface signals. Its noise performance enables percent-level discrimination in the depths of mineral absorption features. In these aspects, EMIT satisfies the stringent performance needs for the next generation of VSWIR imaging spectrometers to observe the Earth's ecosystems, geology , and water resources.

Remote Sensing of Environment↗
USGS2011

Arsenic in Chinese coals: Distribution, modes of occurrence, and environmental effects

Arsenic, one of the most hazardous elements occurring in coals, can be released to the environment during coal processing and combustion. Based on the available literature and published results obtained in our laboratory, the content, distribution and the modes of occurrence of As in Chinese coals, and its environmental and impacts are reviewed in this article. With the 4763 sets of data (from the literature) rearranged, the arithmetic mean As concentration of each province and weighted mean As concentration of the entire country (using the expected coal reserves as the weighting factor) were calculated. The weighted mean As concentration in Chinese coals is 3.18 mg/kg, with As concentration increasing from northern China to southern China. The As concentration in coal varies with coal-forming ages and coal ranks. Arsenic has several modes of occurrence in coals. According to results obtained by other studies and our own experiments, As is mainly associated with mineral matter (such as pyrite and other sulfide minerals) in coals, although a significant amount of arsenic is associated with organic matter. The accumulation of As in coal is controlled by many geological factors during coal-forming processes, including plant decomposition, sedimentary environments, and epigenetic hydrothermal activity. During the combustion of coal, As is released to the air, water, and soil, causing serious environmental pollution. More than 45% of the coal consumed in China is utilized by power plants, and it is estimated that nearly 522 tonnes, 21 tonnes and 252 tonnes of As are emitted into the atmosphere by industries, residential buildings and coal-fired power plants, respectively, every year.

Article↗
USGS2022

Natural infrastructure in dryland streams (NIDS) can establish regenerative wetland sinks that reverse desertification and strengthen climate resilience

In this article we describe the natural hydrogeomorphological and biogeochemical cycles of dryland fluvial ecosystems that make them unique, yet vulnerable to land use activities and climate change. We introduce Natural Infrastructure in Dryland Streams (NIDS), which are structures naturally or anthropogenically created from earth, wood, debris, or rock that can restore implicit function of these systems. This manuscript further discusses the capability of and functional similarities between beaver dams and anthropogenic NIDS, documented by decades of scientific study. In addition, we present the novel, evidence-based finding that NIDS can create wetlands in water-scarce riparian zones, with soil organic carbon stock as much as 200 to 1400 Mg C/ha in the top meter of soil. We identify the key restorative action of NIDS, which is to slow the drainage of water from the landscape such that more of it can infiltrate and be used to facilitate natural physical, chemical, and biological processes in fluvial environments. Specifically, we assert that the rapid drainage of water from such environments can be reversed through the restoration of natural infrastructure that once existed. We then explore how NIDS can be used to restore the natural biogeochemical feedback loops in these systems. We provide examples of how NIDS have been used to restore such feedback loops, the lessons learned from installation of NIDS in the dryland streams of the southwestern United States, how such efforts might be scaled up, and what the implications are for mitigating climate change effects. Our synthesis portrays how restoration using NIDS can support adaptation to and protection from climate-related disturbances and stressors such as drought, water shortages, flooding, heatwaves, dust storms, wildfire, biodiversity losses, and food insecurity.

Science of the Total Environment↗
USGS2023

Global review reveals how disparate study motivations, analytical designs, and focal ions limit understanding of salinization effects on freshwater animals

Global salinization of freshwaters is adversely affecting biotic communities and ecosystem processes. We reviewed six decades (1960–2020) of literature published on animal responses to increased salinities across different taxonomic and ecological contexts and identified knowledge gaps. From 585 journal articles, we characterized 5924 responses of mollusks, crustaceans, zooplankton, non-arthropod invertebrates (NAI), insects, fishes, and amphibians to salinization. Insects and fishes were the most studied taxa; Na + and Cl − were the most studied ions − . Collectively, concentrations of the ions examined typically spanned five orders of magnitude. Species' invasiveness was a key motivation for studying mollusks, crustaceans, and fishes; threats of urbanization and road salts were key motivations for studying NAI, zooplankton, and amphibians. Laboratory studies were more common than field studies for most taxa. Focal life stages in laboratory studies varied widely but juveniles and adults were represented similarly in field studies. Studies of mollusks, NAI, and crustacean focused on adults; studies of zooplankton, insects, fishes, and amphibians focused on juveniles. Organismal- and population-level responses measuring solute uptake, internal chemistry, body condition, or ion concentrations predominated laboratory studies; population- and assemblage-level responses measuring abundance, spatial distribution, or assemblage composition predominated field studies. Negative responses to salinization predominated but positive and unimodal responses were apparent across all taxa and organizational levels. Key topics for further research include a) salinity responses by more taxa, b) responses to especially toxic ions (i.e., potassium, bicarbonate, sulfate, magnesium), c) mechanisms causing positive and unimodal responses, d) traits underpinning responses, e) effects transcending organizational levels, f) ion-specific response thresholds, and g) interactions between salinity and other stressors. Our review suggests inter-taxa variation in sensitivity to salinization reflects occurrence of certain biological traits, including gill-breathing, semi-permeable skin, multiple life stages, and limited mobility. We propose a traits-based framework to predict salinization sensitivity from shared traits. This evolutionary approach could inform management aimed at preventing or reducing adverse impacts of freshwater salinization.

Science of the Total Environment↗
USGS2024

Geologic sources and well integrity impact methane emissions from orphaned and abandoned oil and gas wells

The 160-year history of oil and gas drilling in the United States has left a legacy of unplugged orphaned and abandoned wells, some of which are leaking methane and other hazardous chemicals into the environment. The locations of around 120,000 documented orphaned wells are currently known with the number of undocumented orphaned wells possibly ranging towards a million. The bulk of methane emissions originate from only 10 % of orphaned and abandoned wells, while the remaining wells have undetectable emissions. Understanding the sources of methane emissions from orphaned wells is key to estimating emission rates and prioritizing plugging. In this article, we identify key studies reporting methane emission measurements from orphaned and abandoned wells in the published literature and analyze previously published isotopic methane data to categorize the sources of methane emissions. Three primary geologic sources provide methane to a leaking well that can migrate from geologic formations into or along the wellbore to contaminate groundwater, the surface environment, and the atmosphere. These geologic sources of methane are petroleum (oil and gas) sourced reservoirs, coal seams, and methanogenesis occurring in and around the wellbore. Thermogenic petroleum gas reservoirs are associated with the highest emission rates measured to date. The next highest rates are from coalbed methane sources, while biogenic sources are the lowest based on the publicly available measured emissions data. Well conditions that could potentially enable methane transport include decay of the wellhead and surface infrastructure, wellbore deterioration from corrosive fluids in the subsurface, delamination of the casing and cement, damage from seismicity, and new fracture networks created by hydraulic fracturing of newly drilled neighboring wells. With an understanding of these geologic sources and well conditions, we can (1) better identify areas where high-emitting wells are likely to be present, (2) improve emission rate estimates from orphaned and abandoned wells, and (3) better prioritize wells for plugging.

Science of the Total Environment↗
USGS2021

A generic soil velocity model that accounts for near-surface conditions and deeper geologic structure

Near-surface soil conditions can significantly alter the amplitude and frequency content of incoming ground motions – often with profound consequences for the built environment – and are thus important inputs to any ground-motion prediction. Previous soil-velocity models (SVM) have predicted shear-wave velocity profiles based on the time-averaged shear-wave velocity in the upper 30 m ( V S30 ). This article presents a generic soil-velocity model that accounts both for near-surface conditions ( V S30 ) and deeper geologic structure, as represented to the depth at which the profile reaches a velocity of 1.0 km/s ( Z 1.0 ). To demonstrate the advantages of our new SVM, we apply it to the Cascadia Region of North America, where numerous geologic basins and glaciated landscapes give rise to a wide range of V S30 and Z 1.0 combinations. This soil velocity model yields good estimates of site response across all site conditions, and significantly improves upon a model calibrated using only V S30 data. In conjunction with existing models that describe the deep velocity structure of the region (e.g., (Stephenson et al., 2017) [27]; the proposed model is particularly suited for use in regional-scale predictions of site response, liquefaction, landslides, infrastructure damage, and loss. The proposed methodology is broadly applicable to the development of SVMs elsewhere, and with improved understanding of near-surface and deep velocity structures, can facilitate more accurate ground-motion predictions globally.

Washington↗