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USGS2026

Guide and data requirements for submission of mineral deposit mineral chemistry data in the Critical Minerals in Ores - Mineral Chemistry (CMiO-MIN) database

The Critical Minerals in Ores - Mineral Chemistry (CMiO-MIN) database (Hawkins et al., 2026) is designed to capture ore and ore-related mineral compositional data from critical mineral-bearing deposits across the globe. Samples included within this database must be well-characterised and come from localities that have been sufficiently studied to have a reasonable constraint on their deposit type and environment of formation. As such, only samples analysed by modern geochemical methods, and with certain minimum metadata attribution, can be accepted. Data that is submitted to the CMiO-MIN database will also be published via the Geoscience Australia Portal (portal.ga.gov.au) and Critical Minerals Mapping Initiative Portal (www.criticalminerals.org). The CMiO-MIN database is a companion database for the Critical Minerals in Ores (CMiO) database (Champion et al., 2021) that was first published in 2021. This guide draws heavily from the submission guide for CMiO (Case et al., 2024) to ensure similar processes for each database. For more information about the CMiO database please refer Champion et al. (2021) and Case et al. (2024; 2025).

Report↗

USGS2022

Environmental DNA methods for ecological monitoring and biodiversity assessment in estuaries

Environmental DNA (eDNA) detection methods can complement traditional biomonitoring to yield new ecological insights in aquatic systems. However, the conceptual and methodological frameworks for aquatic eDNA detection and interpretation were developed primarily in freshwater environments and have not been well established for estuaries and marine environments that are by nature dynamic, turbid, and hydrologically complex. Environmental context and species life history are critical for successful application of eDNA methods, and the challenges associated with eDNA detection in estuaries were the subject of a symposium held at the University of California Davis on January 29, 2020 ( https://marinescience.ucdavis.edu/engagement/past-events/edna ). Here, we elaborate upon topics addressed in the symposium to evaluate eDNA methods in the context of monitoring and biodiversity studies in estuaries. We first provide a concise overview of eDNA science and methods, and then examine the San Francisco Estuary (SFE) as a case study to illustrate how eDNA detection can complement traditional monitoring programs and provide regional guidance on future potential eDNA applications. Additionally, we offer recommendations for enhancing communication between eDNA scientists and natural resource managers, which is essential for integrating eDNA methods into existing monitoring programs. Our intent is to create a resource that is accessible to those outside the field of eDNA, especially managers, without oversimplifying the challenges or advantages of these methods.

Estuaries and Coasts↗

USGS2008

Biomedical and veterinary science can increase our understanding of coral disease

A balanced approach to coral disease investigation is critical for understanding the global decline of corals. Such an approach should involve the proper use of biomedical concepts, tools, and terminology to address confusion and promote clarity in the coral disease literature. Investigating disease in corals should follow a logical series of steps including identification of disease, systematic morphologic descriptions of lesions at the gross and cellular levels, measurement of health indices, and experiments to understand disease pathogenesis and the complex interactions between host, pathogen, and the environment. This model for disease investigation is widely accepted in the medical, veterinary and invertebrate pathology disciplines. We present standard biomedical rationale behind the detection, description, and naming of diseases and offer examples of the application of Koch's postulates to elucidate the etiology of some infectious diseases. Basic epidemiologic concepts are introduced to help investigators think systematically about the cause(s) of complex diseases. A major goal of disease investigation in corals and other organisms is to gather data that will enable the establishment of standardized case definitions to distinguish among diseases. Concepts and facts amassed from empirical studies over the centuries by medical and veterinary pathologists have standardized disease investigation and are invaluable to coral researchers because of the robust comparisons they enable; examples of these are given throughout this paper. Arguments over whether coral diseases are caused by primary versus opportunistic pathogens reflect the lack of data available to prove or refute such hypotheses and emphasize the need for coral disease investigations that focus on: characterizing the normal microbiota and physiology of the healthy host; defining ecological interactions within the microbial community associated with the host; and investigating host immunity, host-agent interactions, pathology, pathogenesis, and factors that promote the pathogenicity of the causative agent(s) of disease.

Journal of Experimental Marine Biology and Ecology↗

USGS2011

Silver nanoparticles: Behaviour and effects in the aquatic environment

This review summarises and evaluates the present knowledge on the behaviour, the biological effects and the routes of uptake of silver nanoparticles (Ag NPs) to organisms, with considerations on the nanoparticle physicochemistry in the ecotoxicity testing systems used. Different types of Ag NP syntheses, characterisation techniques and predicted current and future concentrations in the environment are also outlined. Rapid progress in this area has been made over the last few years, but there is still a critical lack of understanding of the need for characterisation and synthesis in environmental and ecotoxicological studies. Concentration and form of nanomaterials in the environment are difficult to quantify and methodological progress is needed, although sophisticated exposure models show that predicted environmental concentrations (PECs) for Ag NPs in different environmental compartments are at the range of ng L − 1 to mg kg − 1 . The ecotoxicological literature shows that concentrations of Ag NPs below the current and future PECs, as low as just a few ng L − 1 , can affect prokaryotes, invertebrates and fish indicating a significant potential, though poorly characterised, risk to the environment. Mechanisms of toxicity are still poorly understood although it seems clear that in some cases nanoscale specific properties may cause biouptake and toxicity over and above that caused by the dissolved Ag ion. This review concludes with a set of recommendations for the advancement of understanding of the role of nanoscale silver in environmental and ecotoxicological research.

Environment International↗

USGS1975

Land subsidence caused by dissolution of salt near four oil and gas wells in central Kansas

Collapse of the overlying strata into voids caused by dissolution of salt is the apparent cause of progressive land subsidence at the sites of several oil wells that were drilled through the salt beds of the Wellington Formation in Kansas. The purpose of this investigation was to determine if data from four sites, shown in figure 1, substantiate the hypothesis that corroded, broken, or improperly sealed casing permitted relatively fresh water from the shallow aquifers to circulate within the salt zone and that the resulting brine solution leaked downward into permeable zones that would accept the fluid under hydrostatic pressure. Strata similar to those penetrated by wells at the four sites (shown in tables 1 and 2) underlie much of central Kansas. Many thousands of oil and gas wells have been drilled through the salt beds, but land subsidence has been reported at few of the sites. Reported sites are near highways, and two well-documented instances of subsidence involve the stability of highway right-of-way. Because many wells have been drilled in remote areas, similar occurrences may remain unreported. The scope of this investigation is limited to the compilation, analysis and interpretation of the available data from four sites shown in figure 1, and the mention of a fifth site. The photograph (fig. 2) shows a deteriorated casing pulled from a well located between Sites 3 and 4 in western Rice County. The casing consists of inner and outer pipes with the annular space between filled with cement. The almost complete failure of the outer pipe is evident. The casing is believed to be from the well in the concrete pit that is in the lower right of the photograph. The pond in the background is a sink that has developed near the well; detailed historical data, however, were unavailable for further study of this site. The investigation was requested by the Energy Research and Develop-ment Administration (formerly U.S. Atomic Energy Commission) as part of a study of bedded salt in Kansas as a repository for radioactive wastes. Data for the report were collected from the files of several Kansas State agencies; the Highway Commission, Department of Health and Environment, Geological Survey, and the Corporation Commission. The author particularly wishes to thank V. A. Burgat and W. K. Taylor of the Highway Commission; B. F. Latta, D. L. Butcher, and M. W. Glotzback of the Department of Health and Environment; and F. W. Wilson of the Geological Survey for information based on personal observations and for resolving apparent contradictions in the available data. The geologic formations that underlie the four sites selected for this study are described in table 1 and information about the oil and gas wells at the sites is given in table 2.

Kansas↗

USGS2014

Openness to the unexpected: Our Pathways to Careers in a Federal Research Laboratory.

Many fisheries professionals may not be in the job they originally envisioned for themselves when they began their undergraduate studies. Rather, their current positions could be the result of unexpected, opportunistic, or perhaps even “lucky” open doors that led them down an unexpected path. In many cases, a mentor helped facilitate the unforeseen trajectory. We offer three unique stories about joining a federal fisheries research laboratory, from the perspective of a scientist, a joint manager-scientist, and a manager. We also use our various experiences to form recommendations that should help the next generation of fisheries professionals succeed in any stop along their journey, including being open to opportunities, setting high expectations, and finding a strong and supportive team environment to work in.

Book chapter↗

USGS2016

Methane emissions from oceans, coasts, and freshwater habitats: New perspectives and feedbacks on climate

Methane is a powerful greenhouse gas, and atmospheric concentrations have risen 2.5 times since the beginning of the Industrial age. While much of this increase is attributed to anthropogenic sources, natural sources, which contribute between 35% and 50% of global methane emissions, are thought to have a role in the atmospheric methane increase, in part due to human influences. Methane emissions from many natural sources are sensitive to climate, and positive feedbacks from climate change and cultural eutrophication may promote increased emissions to the atmosphere. These natural sources include aquatic environments such as wetlands, freshwater lakes, streams and rivers, and estuarine, coastal, and marine systems. Furthermore, there are significant marine sediment stores of methane in the form of clathrates that are vulnerable to mobilization and release to the atmosphere from climate feedbacks, and subsurface thermogenic gas which in exceptional cases may be released following accidents and disasters (North Sea blowout and Deepwater Horizon Spill respectively). Understanding of natural sources, key processes, and controls on emission is continually evolving as new measurement and modeling capabilities develop, and different sources and processes are revealed. This special issue of Limnology and Oceanography gathers together diverse studies on methane production, consumption, and emissions from freshwater, estuarine, and marine systems, and provides a broad view of the current science on methane dynamics of aquatic ecosystems. Here, we provide a general overview of aquatic methane sources, their contribution to the global methane budget, and key uncertainties. We then briefly summarize the contributions to and highlights of this special issue.

Limnology and Oceanography↗

USGS2020

Mapping perceived social values to support a respondent-defined restoration economy: Case study in southeastern Arizona, USA

Investment in conservation and ecological restoration depends on various socioeconomic factors and the social license for these activities. Our study demonstrates a method for targeting management of ecosystem services based on social values, identified by respondents through a collection of social survey data. We applied the Social Values for Ecosystem Services (SolVES) geographic information systems (GIS)-based tool in the Sonoita Creek watershed, Arizona, to map social values across the watershed. The survey focused on how respondents engage with the landscape, including through their ranking of 12 social values (eg, recreational, economic, or aesthetic value) and their placement of points on a map to identify their associations with the landscape. Additional information was elicited regarding how respondents engaged with water and various land uses, as well as their familiarity with restoration terminology. Results show how respondents perceive benefits from the natural environment. Specifically, maps of social values on the landscape show high social value along streamlines. Life-sustaining services, biological diversity, and aesthetics were the respondents’ highest rated social values. Land surrounding National Forest and private lands had lower values than conservation-based and state-owned areas, which we associate with landscape features. Results can inform watershed management by allowing managers to consider social values when prioritizing restoration or conservation investments.

Arizona↗

USGS2021

On the human appropriation of wetland primary production

Humans are changing the Earth's surface at an accelerating pace, with significant consequences for ecosystems and their biodiversity. Landscape transformation has far-reaching implications including reduced net primary production (NPP) available to support ecosystems, reduced energy supplies to consumers, and disruption of ecosystem services such as carbon storage. Anthropogenic activities have reduced global NPP available to terrestrial ecosystems by nearly 25%, but the loss of NPP from wetland ecosystems is unknown. We used a simple approach to estimate aquatic NPP from measured habitat areas and habitat-specific areal productivity in the largest wetland complex on the USA west coast, comparing historical and modern landscapes and a scenario of wetland restoration. Results show that a 77% loss of wetland habitats (primarily marshes) has reduced ecosystem NPP by 94%, C (energy) flow to herbivores by 89%, and detritus production by 94%. Our results also show that attainment of habitat restoration goals could recover 12% of lost NPP and measurably increase carbon flow to consumers, including at-risk species and their food resources. This case study illustrates how a simple approach for quantifying the loss of NPP from measured habitat losses can guide wetland conservation plans by establishing historical baselines, projecting functional outcomes of different restoration scenarios, and establishing performance metrics to gauge success.

California↗

USGS2006

Apparent Consumption vs. Total Consumption--A Lead-Acid Battery Case Study

Introduction: This report compares estimates of U.S. apparent consumption of lead with estimates of total U.S. consumption of this mineral commodity from a materials flow perspective. The difference, attributed to the amount of lead contained in imported and exported products, was found to be significant for this sector. The study also assesses the effects of including mineral commodities incorporated in manufactured products on the interpretation of observed trends in minerals consumption and trade. Materials flow is a systems approach to understanding what happens to the materials we use from the time a material is extracted, through its processing and manufacturing, to its ultimate disposition. The U.S. Geological Survey (USGS) provides accurate and detailed mineral production and mineral commodity consumption statistics that are essential for government, nongovernment organizations, and the public to gain a better understanding of how and where materials are used and their effect on the environment and society. Published statistics on mineral apparent consumption are limited to estimates of consumption of raw material forms (ore, concentrate, and [or] refined metal). For this study, apparent consumption is defined as mine production + secondary refined production + imports (concentrates and refined metal) ? exports (concentrates and refined metal) + adjustments for government and industry stock changes. These estimates do not account for the amount of mineral commodities contained in manufactured products that are imported to the United States, nor do they deduct the amount of these mineral commodities contained in manufactured products that are exported from the United States. When imports or exports of manufactured products contribute significantly to the total use of a particular raw material, an estimate of consumption that does not consider the incorporated forms of these mineral commodities within imported or exported manufactured products can be either under- or overreported (depending on the net trade flow). Factors that influence consumption and trade patterns include variations in industry structure, labor or financial markets, legislation, and technology. As U.S. trade patterns of manufactured products change, omitting mineral commodities incorporated into these goods as part of U.S. mineral commodity consumption estimates may affect the interpretation of observed trends in minerals consumption and trade. Although it may be desirable to include minerals contained in manufactured products as part of consumption estimates, collection and estimation of these data are sometimes difficult. Consumption and trade data for every traded product may not be readily available. Compiling comprehensive consumption statistics for mineral commodities, which have many end uses, each including multiple products, may be time consuming. For these reasons, studies of all mineral commodities are not feasible. Mineral commodity selection for this study is based on data accessibility considerations and the relative importance of lead contained in imported and exported products when considered part of total U.S. lead consumption. Lead was selected for this initial evaluation of total mineral consumption because of the need to understand the consumption pattern of this potentially toxic metal and its compounds, the relative simplicity of this sector?s end-use structure, and the availability of trade data. This study draws upon the findings of an earlier lead consumption study (Biviano and others, 1999) conducted by the USGS for the period 1984 to 1993, but uses a different study methodology for an industry whose structure has changed from that considered in the earlier study. Figure 1 shows the quantity of material contributing to U.S. total consumption of lead metal from domestic and foreign industrial sectors in 2004, based upon trade data reported by the USGS and the U.S. International Trade Commission (USITC). For

Scientific Investigations Report↗

USGS1981

Organic geochemistry of the 9.6 km Bertha Rogers No. 1. well, Oklahoma

Organic geochemical analyses of fine-grained rocks from the 9.590 km Bertha Rogers No. 1 well have been carried out: total organic carbon, Soxhlet extraction and silica gel chromatography, C 15+ saturated and aromatic hydrocarbon gas chromatography and mass spectrometry, pyrolysis, kerogen analysis, X-ray diffraction and visual kerogen analysis. Rocks ranged in age from Permian to Ordovician; the well has an estimated bottom hole temperature of 225°C. Some data from this study are inconsistent with conventional theories concerning the generation and thermal destruction of hydrocarbons. For example, appreciable amounts of C 15+ gas-condensate-like hydrocarbons are present in very old rocks currently at temperatures where current theory predicts that only methane and graphite should remain. Also, substantial amounts of pyrolyzable C 15+ hydrocarbons remain on the kerogen in these deeply buried Paleozoic rocks. This suggests, at least in somes cases, that temperatures much higher than those predicted by current theory are required for generation and thermal destruction of hydrocarbons. The data from this well also suggest that original composition of organic matter and environment of deposition may have a much stronger influence on the organic geochemical characteristics of fine-grained sediments than has previously been ascribed to them. The results from this well, from other deep hot wells in which temperatures exceed 200°C, and from laboratory experiments, suggest that some of the basic concepts of the generation and maturation of petroleum hydrocarbons may be in error and perhaps should be reexamined.

Oklahoma↗

USGS2003

Assessing toxicant effects in a complex estuary--A case study of effects of silver on reproduction in the bivalve, Potamocurbula amurensis, in San Francisco Bay

Contaminant exposures in natural systems can be highly variable. This variability is superimposed upon cyclic variability in biological processes. Together, these factors can confound determination of contaminant effects. Long term, multidisciplined studies with high frequency sampling can be effective in overcoming such obstacles. While studying trace metal contamination in the tissues of the clam, Potamocorbula amurensis , in the northern reach of San Francisco Bay, an episode of high Ag concentrations was identified (maximum of 5.5 µg g −1 ) at two mid-estuary sites. High concentrations were not seen in clams up-estuary (maximum of 1.92 µg g −1 ) from these sites and were reduced down-estuary (maximum of 2.67 µg g −1 ). Silver is not common naturally in the environment, so its elevated presence is usually indicative of anthropogenic influences such as municipal and industrial discharge. Monthly sampling of reproductive status of clams characterized the reproductive cycle and differences in the patterns of reproductive activity that corresponded to changes in Ag tissue concentrations. The proportion of reproductive clams was less than 60% during periods when tissue concentrations were high (generally >2 µg g −1 ). When tissue concentrations of Ag decreased (≤1 µg g −1 ), the proportion of reproductive clams was 80 to 100%. A comparison between the annual proportion of reproductive clams and annual Ag tissue concentrations showed a significant negative correlation. No other measured environmental variables were correlated with reproductive impairment. The weight-of-evidence approach strongly supports a cause and effect relationship between Ag contamination and reduced reproductive activity in P. amurensis .

California↗

USGS2018

Wildlife habitat management on college and university campuses

With the increasing involvement of higher education institutions in sustainability movements, it remains unclear to what extent college and university campuses address wildlife habitat. Many campuses encompass significant areas of green space with potential to support diverse wildlife taxa. However, sustainability rating systems generally emphasize efforts like recycling and energy conservation over green landscaping and grounds maintenance. We sought to examine the types of wildlife habitat projects occurring at schools across the United States and whether or not factors like school type (public or private), size (number of students), urban vs. rural setting, and funding played roles in the implementation of such initiatives. Using case studies compiled by the National Wildlife Federation’s Campus Ecology program, we documented wildlife habitat-related projects at 60 campuses. Ten management actions derived from nationwide guidelines were used to describe the projects carried out by these institutions, and we recorded data about cost, funding, and outreach and education methods. We explored potential relationships among management actions and with school characteristics. We extracted themes in project types, along with challenges and responses to those challenges. Native plant species selection and sustainable lawn maintenance and landscaping were the most common management actions among the 60 campuses. According to the case studies we examined, we found that factors like school type, size, and location did not affect the engagement of a campus in wildlife habitat initiatives, nor did they influence the project expenditures or funding received by a campus. Our results suggest that many wildlife habitat initiatives are feasible for higher education institutions and may be successfully implemented at relatively low costs through simple, but deliberate management actions.

Cities and the Environment↗

USGS2012

The role of efflorescent sulfate salts in Indiana’s mine water quality

Efflorescent sulfate salts (ESS), which form from evaporating acid mine drainage and occur in a wide variety of environments, can significantly alter water quality and are, therefore, important considerations for remediation strategies at coal refuse sites. Many ESS, including melanterite, rozenite, siderotil, copiapite, halotrichite, coquimbite, epsomite, potash alum, and gypsum, are known to occur in Indiana. Because they build up on the gob-pile surface during dry periods and release acidity and metals in storm flushes, it is essential to understand the mineralogical and geochemical parameters that control ESS formation and dissolution in mine settings. The Friar Tuck site, in southwestern Indiana, is an ideal location for demonstrating the role of ESS in the generation of acid mine drainage and is included as a case study in this report. Examination of two gob piles at the site (northwest and southeast), in the same setting but with different mineralogies and depositional and reclamation histories, provides a unique opportunity to consider the transferability of lessons learned about the ESS between different sites. Hydraulic and chemical data, including data on aqueous and solid states (coal refuse and ESS), were collected from streams (adjacent to the gob piles and further downstream), seeps, surface runoff, and saturated and unsaturated groundwater at the northwest and southeast gob piles during 1988–89 and 1990–92, respectively. Samples were analyzed in the field for bulk indicators and in a laboratory (Indiana Geological Survey, Geochemistry Section) for concentrations of major and trace elements. Values of pH and specific conductance at the southeast gob pile indicated a trend of declining water quality with duration of the dry season, followed by dilution and improved water quality during the wet season; similar observations were made at the northwest gob pile. Concentrations of key water-quality indicators for the northwest and southeast gob piles show that acidity and concentrations of sulfate and iron are notably lower in the surface runoff and groundwater in saturated and unsaturated refuse at the southeast gob pile compared to the northwest gob pile. The dissolution of ESS is likely the cause for the decrease in water quality at both gob piles, but it has a greater effect at the northwest gob pile. The results of this study indicate that some generalizations about the effect of ESS on water quality (for example, the conditions that favor the precipitation of specific ESS; the development of acidic, metal-rich drainage; and so on) can be transferred from one coal-waste site to another. However, the specific geochemistry of the gob pile, the age and history of refuse, the source rock, and the coal-processing and reclamation activities at the specific site will determine the extent to which the processes described in this and other papers can be applied to unstudied gob piles.

Indiana↗

USGS2004

Chloroform in the hydrologic system--sources, transport, fate, occurrence, and effects on human health and aquatic organisms

Chloroform is one of the volatile organic compounds (VOCs) detected most frequently in both ground and surface water. Because it is also one of the four trihalomethanes (THMs) produced in the highest concentrations during the chlorination of drinking water and wastewater, the frequent detection of this compound in ground and surface water of the United States is presumed to be caused primarily by the input of chlorinated water to the hydrologic system. Although anthropogenic sources of the compound are substantial, they are currently estimated to constitute only 10 percent of the total global input to the hydrologic system. Natural sources of the compound include volcanic gases, biomass burning, marine algae, and soil microorganisms. Under most conditions (except in the presence of unusually high bromide concentrations), chloroform is the THM produced in the highest concentrations during chlorination. Furthermore, in most cases where more than one THM is produced from chlorination, the relative concentrations among the different compounds usually decrease with increasing bromination (chloroform > dichlorobromomethane > chlorodibromomethane > bromoform). This phenomenon is presumed to be responsible for the common observation that when more than one THM is detected during investigations of the occurrence of these compounds in the hydrologic system, this same trend is typically observed among their relative concentrations or, for a uniform reporting limit, their relative frequencies of detection. This pattern could provide a valuable means for distinguishing between chlorinated water and other potential sources of chloroform in the environment. Chloroform has been widely detected in national, regional, and local studies of VOCs in ground, surface, source, and drinking waters. Total THM (TTHM) concentrations of the compound, however, were typically less than the Maximum Contaminant Level (MCL) of 80 ?g/L (micrograms per liter) established by the U.S. Environmental Protection Agency (USEPA) for TTHMs. In the studies that compared land-use settings, frequencies of detection of chloroform were higher beneath urban and residential areas than beneath agricultural or undeveloped areas. Because chloroform is a suspected human carcinogen, its presence in drinking water is a potential human health concern. Liver damage, however, is known to occur at chloroform exposures lower than those required to cause cancer, an observation that has been considered by the USEPA as the basis for setting a new, non-zero Maximum Contaminant Level Goal of 70 ?g/L for the compound. As part of its National Water-Quality Assessment Program, the U.S. Geological Survey has been assembling and analyzing data on the occurrence of VOCs (including chloroform) in ground and surface water on a national scale from studies conducted between 1991 and the present. This report presents a summary of current (2004) information on the uses, sources, formation, transport, fate, and occurrence of chloroform, as well as its effects on human health and aquatic organisms.

Scientific Investigations Report↗

USGS2003

Heat as a tool for studying the movement of ground water near streams

Stream temperature has long been recognized as an important water quality parameter. Temperature plays a key role in the health of a stream’s aquatic life, both in the water column and in the benthic habitat of streambed sediments. Many fish are sensitive to temperature. For example, anadromous salmon require specific temperature ranges to successfully develop, migrate, and spawn [see Halupka and others, 2000]. Metabolic rates, oxygen requirements and availability, predation patterns, and susceptibility of organisms to contaminants are but a few of the many environmental responses regulated by temperature. Hydrologists traditionally treated streams and ground water as distinct, independent resources to be utilized and managed separately. With increasing demands on water supplies, however, hydrologists realized that streams and ground water are parts of a single, interconnected resource [see Winter and others, 1998]. Attempts to distinguish these resources for analytical or regulatory purposes are fraught with difficulty because each domain can supply (or drain) the other, with attendant possibilities for contamination exchange. Sustained depletion of one resource usually results in depletion of the other, propagating adverse effects within the watershed. An understanding of the interconnections between surface water and ground water is therefore essential. This understanding is still incomplete, but receiving growing attention from the research community. Exchanges between streams and shallow ground-water systems play a key role in controlling temperatures not only in streams, but also in their underlying sediments. As a result, analyses of subsurface temperature patterns provide information about surface-water/ground-water interactions. Chemical tracers are commonly used for tracing flow between streams and ground water. Introduction of chemical tracers in near-stream environments is, however, limited by real and perceived issues regarding introduced contamination and practical constraints. As an alternative, naturally occurring variations in temperature can be used to track (or trace) the heat carried by flowing water. The hydraulic transport of heat enables its use as a tracer. Differences between temperatures in the stream and surrounding sediments are now being analyzed to trace the movement of ground water to and from streams. As shown in the subsequent chapters of this circular, tracing the transport of heat leads to a better understanding of the magnitudes and mechanisms of stream/ground-water exchanges, and helps quantify the resulting effects on stream and streambed temperatures. Chapter 1 describes the general principals and procedures by which the natural transport of heat can be utilized to infer the movement of subsurface water near streams. This information sets the foundation for understanding the advanced applications in chapters 2 through 8. Each of these chapters provides a case study, using heat tracing as a tool, of interactions between surface water and ground water for a different location in the western United States. Technical details of the use of heat as an environmental tracer appear in appendices.

Circular↗

USGS2000

Applications of imaging spectroscopy data: A case study at Summitville, Colorado

From 1985 through 1992, the Summitville open-pit mine produced gold from lowgrade ore using cyanide heap-leach techniques, a method to extract gold whereby the ore pile is sprayed with water containing cyanide, which dissolves the minute gold grains. Environmental problems due to mining activity at Summitville include significant increases in acidic and metal-rich drainage from the site, leakage of cyanide-bearing solutions from the heap-leach pad into an underdrain system, and several surface leaks of cyanide-bearing solutions into the Wightman Fork of the Alamosa River. In general, drainage from the Summitville mine moves downslope into the Wightman Fork, a small tributary of the Alamosa River, which in turn flows east into the Terrace Reservoir before entering the agricultural lands of the San Luis Valley. The increase in the trace-metal burden of the Alamosa River watershed due to the mining activities at Summitville is of concern to farmers and fisherman, as well as Federal and State of Colorado agencies having responsibility for land stewardship. The environment of the Summitville area is a result of 1) its geologic evolution, that culminated in the formation of precious-metal mineral deposits; and 2) previous metal mining activity. Mining accentuates, accelerates, and pertubates natural geochemical processes. The development of underground workings, open pits, mill tailings, and spoil heaps and the extractive processing of ore enhances the likelihood of releasing chemicals and elements to the surrounding areas and at increased rates relative to unmined areas. Both mined and unmined mineralized areas can produce acid drainage from the formation and movement of highly acidic water rich in heavy metals. This acidic water forms principally through the chemical reaction of oxygenated surface water and shallow subsurface water with rocks that contain sulfide minerals, producing sulphuric acid. Heavy metals can be leached by the acid solution that comes in contact with mineralized rocks, a process that may be enhanced by bacterial action. The resulting fluids may be highly toxic and, when mixed with groundwater, surface water, and soil, may have harmful effects on humans, animals, and plants. Thus, understanding the geologic and hydrologic history of this area is a critical piece of the environmental puzzle in the Summitville area. The Summitville mine operators had ceased active mining and begun environmental remediation, including treatment of the heap-leach pile and installation of a water-treatment facility, when it declared bankruptcy in December 1992 and abandoned the mine site. The U.S. Environmental Protection Agency (EPA) immediately took over the Summitville site under EPA Superfund Emergency Response authority. Summitville has focused public attention on the environmental effects of modern mineral-resource development. Soon after the mine was abandoned, Federal, State, and local agencies, along with Alamosa River water users and private companies, began extensive studies at the mine site and surrounding areas. These studies included analysis of water, soil, livestock and vegetation. The role of the U.S. Geological Survey (USGS) was to provide geologic, hydrologic and agricultural information about the mine and surrounding area and to describe and evaluate the environmental condition of the Summitville mine and the downstream effects of the mine on the San Luis Valley (King 1995).

Colorado↗

USGS2017

Camera system considerations for geomorphic applications of SfM photogrammetry

The availability of high-resolution, multi-temporal, remotely sensed topographic data is revolutionizing geomorphic analysis. Three-dimensional topographic point measurements acquired from structure-from-motion (SfM) photogrammetry have been shown to be highly accurate and cost-effective compared to laser-based alternatives in some environments. Use of consumer-grade digital cameras to generate terrain models and derivatives is becoming prevalent within the geomorphic community despite the details of these instruments being largely overlooked in current SfM literature. This article is protected by copyright. All rights reserved. A practical discussion of camera system selection, configuration, and image acquisition is presented. The hypothesis that optimizing source imagery can increase digital terrain model (DTM) accuracy is tested by evaluating accuracies of four SfM datasets conducted over multiple years of a gravel bed river floodplain using independent ground check points with the purpose of comparing morphological sediment budgets computed from SfM- and lidar-derived DTMs. Case study results are compared to existing SfM validation studies in an attempt to deconstruct the principle components of an SfM error budget. This article is protected by copyright. All rights reserved. Greater information capacity of source imagery was found to increase pixel matching quality, which produced 8 times greater point density and 6 times greater accuracy. When propagated through volumetric change analysis, individual DTM accuracy (6–37 cm) was sufficient to detect moderate geomorphic change (order 100,000 m 3 ) on an unvegetated fluvial surface; change detection determined from repeat lidar and SfM surveys differed by about 10%. Simple camera selection criteria increased accuracy by 64%; configuration settings or image post-processing techniques increased point density by 5–25% and decreased processing time by 10–30%. This article is protected by copyright. All rights reserved. Regression analysis of 67 reviewed datasets revealed that the best explanatory variable to predict accuracy of SfM data is photographic scale. Despite the prevalent use of object distance ratios to describe scale, nominal ground sample distance is shown to be a superior metric, explaining 68% of the variability in mean absolute vertical error.

Earth Surface Processes and Landforms↗