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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 1,279 records · Page 71Linked to original sources
USGS1987

The use of surface geophysical techniques to detect fractures in bedrock; an annotated bibliography

This annotated bibliography compiles references about the theory and application of surface geophysical techniques to locate fractures or fracture zones within bedrock units. Forty-three publications are referenced, including journal articles, theses, conference proceedings, abstracts, translations, and reports prepared by private contractors and U.S. Government agencies. Thirty-one of the publications are annotated. The remainder are untranslated foreign language articles, which are listed only as bibliographic references. Most annotations summarize the location, geologic setting, surface geophysical technique used, and results of a study. A few highly relevant theoretical studies are annotated also. Publications that discuss only the use of borehole geophysical techniques to locate fractures are excluded from this bibliography. Also excluded are highly theoretical works that may have little or no known practical application.

Circular↗
USGS2015

Literature review of the potential effects of hydrogen peroxide on nitrogen oxidation efficiency of the biofilters of recirculating aquaculture systems (RAS) for freshwater finfish

A comprehensive literature review was done for the effects of hydrogen peroxide (HP) on biofilter function in recirculating aquaculture systems (RAS) using these databases: ISI/Web of Knowledge, Scopus, and Pubmed. Inclusion and exclusion criteria were developed as the literature review was conducted. The initial search produced 5,748 potential citations. Once the literature search was complete, these 5,748 titles were screened for applicable papers using the inclusion and exclusion criteria. If the title contained any of the inclusion terms, it was retained. Titles of the remaining papers were then screened for exclusion terms. If the title contained one or more of the exclusion terms, it was eliminated from further consideration. This refined search produced 1,405 papers. After the initial screening, the remaining 1,405 papers underwent a second screening. Titles and abstracts (when available) were again read to verify that the topic of the paper was related to RAS. During the second screening, a second person verified that the papers proposed for elimination were not related to RAS. A combined reference list of the 512 remaining papers was created and submitted to the U.S. Geological Survey (USGS) Upper Midwest Environmental Sciences Center (UMESC) librarian in order to obtain the actual papers; electronic copies of those citations were obtained and reviewed. The UMESC librarian also received weekly updates from Scopus (a bibliographic database containing abstracts and citations for academic journal articles) using the search terms. Any resulting papers from those updates were screened using the inclusion criteria and relevant papers were requested. From those, 86 were cited in the literature review. An additional 11 papers from other search methods (e.g., mining references lists) also were obtained.

Open-File Report↗
USGS2006

A rainfall loading response recorded at 300 meters depth: Implications for geological weighing lysimeters

Static pore water pressures in confined aquifers vary in response to ground surface loading changes, including precipitation and evaporation. Under certain hydrogeological conditions such aquifers can function as giant natural weighing lysimeters, referenced here as 'geological weighing lysimeters'. The extent of the land area 'weighed' increases with aquifer depth and it is of interest to establish at what depth it is still possible to monitor surface water budgets. An 86 mm rainfall event produced a clear loading signal in a well in western Kansas at 300 m depth. The loading effect is quantitatively consistent with elastic deformation induced by the rainfall mass and suggests that geological weighing lysimeters could operate at considerably greater depths, thereby monitoring water budgets over a significant land area. ?? 2005 Elsevier Ltd All rights reserved.

Journal of Hydrology↗
USGS2011

A regional modeling framework of phosphorus sources and transport in streams of the southeastern United States

We applied the SPARROW model to estimate phosphorus transport from catchments to stream reaches and subsequent delivery to major receiving water bodies in the Southeastern United States (U.S.). We show that six source variables and five land-to-water transport variables are significant ( p < 0.05) in explaining 67% of the variability in long-term log-transformed mean annual phosphorus yields. Three land-to-water variables are a subset of landscape characteristics that have been used as transport factors in phosphorus indices developed by state agencies and are identified through experimental research as influencing land-to-water phosphorus transport at field and plot scales. Two land-to-water variables – soil organic matter and soil pH – are associated with phosphorus sorption, a significant finding given that most state-developed phosphorus indices do not explicitly contain variables for sorption processes. Our findings for Southeastern U.S. streams emphasize the importance of accounting for phosphorus present in the soil profile to predict attainable instream water quality. Regional estimates of phosphorus associated with soil-parent rock were highly significant in explaining instream phosphorus yield variability. Model predictions associate 31% of phosphorus delivered to receiving water bodies to geology and the highest total phosphorus yields in the Southeast were catchments with already high background levels that have been impacted by human activity.

Journal of the American Water Resources Associatio↗
USGS2001

Report list Arizona's oil, gas potential

This article is a summary of Arizona geological survey circular 29, which addresses the petroleum geology of Arizona, USA. Eight areas have been identified with fair to excellent oil and gas potential, and some Tertiary basins have evidence of source or reservoir rocks. The following are considered here: production history, lands status and services, regulation and permitting, petroleum geology, hydrocarbon indications, and areas with hydrocarbon potential and their petroleum geology and characteristics. The full report contains detailed figures of each of these basin areas, a descriptive tabulation of seeps and petroliferous rocks and extensive references.

Arizona↗
USGS2021

Genetics as a tool for conservation and management of West Indian manatee populations in Brazil

A study conducted by the National Center for Research and Conservation of Aquatic Mammals (CMA), United States Geological Survey Wetland and Aquatic Research Center, and partner researchers found that the marine Antillean manatee ( Trichechus manatus manatus ) has low genetic diversity in regions where there are territorial interfaces with the Amazonian manatee ( Trichechus inunguis ). The study was published as an article in the journal, Frontiers in Marine Science.

Sirenews↗
USGS2023

Evaluating brook trout egg and alevin survival at different temperatures in simulated karst environments with marl sedimentation

Brook trout ( Salvelinus fontinalis ) have been extirpated from many karst-geology streams in West Virginia; however, the causes are not fully understood. Specifically, the impact of calcareous precipitate (marl), which is common in hard-water environments, has not been evaluated as an im- pediment to juvenile survival. Accordingly, two lab-based studies were conducted to determine if brook trout egg and alevin survival is inhibited by marl. In the first study, three aeration treatments were applied to water from a limestone spring source (13–14 C; ~300 mg L–1 hardness), resulting in different pH levels and an increasing degree of marl precipitate. Treatments included raw/untreated (RU; no marl), once-aerated (OA; limited marl), and continuously aerated (CA; significant marl) water. Brook trout eggs obtained from a local hatchery were fertilized and stocked among gravel-filled trays receiving each water type. Mortality occurred faster in CA water where marl coated egg surfaces, but cumulative survival was negligible for all water types. After 53 days, no surviving alevins remained in RU or CA, and 1% survival was observed in OA water. However, extra eggs maintained in a marl-producing system at 8 C without gravel demonstrated >50% survival. A second study was carried out to investigate this discrepancy. Survival was evaluated at three temperatures with and without gravel while producing a thin coating of marl. Increased prevalence of alevin deformities and significantly lower survival were observed at 13.7 C versus 8.1 and 11.2 C, but gravel inclusion did not affect these variables. Potentially harmful effects of marl were observed; however, juvenile brook trout survival was higher during Study 2. This research suggests that brook trout reintroduction efforts in karst-geology streams should be focused on microhabitats with limited marl production and adequate water temperatures for juvenile survival.

Journal of the Southeastern Association of Fish an↗
USGS2023

Utilizing anthropogenic compounds and geochemical tracers to identify preferential structurally controlled groundwater pathways influencing springs in Grand Canyon National Park, Arizona, USA

Study region: This study focuses on the Colorado River watershed in the area along the South Rim of the Grand Canyon. Study focus: This study utilizes anthropogenic chemical tracers to investigate the fate of treated wastewater effluent discharged within Grand Canyon National Park. Anthropogenic chemical tracers were used to discern preferential structurally controlled pathways in a complex regional network of faults and fractures in which some are conduits and others barriers to flow. New hydrological insights for the region : Previous investigations on water resources of Grand Canyon have suggested two different discharge locations (Garden Springs versus Monument Spring) for the treated wastewater discharged on the South Rim of Grand Canyon yet the presence of wastewater at the springs remained unstudied for decades. The treated wastewater from Grand Canyon Village is released into Bright Angel Wash that flows along the surface expression of the Bright Angel Fault and past the inferred intersection with the perpendicular Monument Fault. Multiple anthropogenic compounds (pharmaceuticals, per- and polyfluoroalkyl substances (PFAS), and elevated nitrate) were found in Bright Angel Wash and Monument Spring. Stable isotopic measurements at Monument Spring show depletion over time also suggesting contribution from a depleted stable isotopic source found in the treated wastewater. The anthropogenic tracers utilized in this study provide good insight to which geologic structures are conduits versus barriers to flow and can be useful in other fracture flow and karst settings.

Arizona↗
USGS2018

Using mercury injection pressure analyses to estimate sealing capacity of the Tuscaloosa marine shale in Mississippi, USA: Implications for carbon dioxide sequestration

This work used mercury injection capillary pressure (MICP) analyses of the Tuscaloosa Group in Mississippi, including the Tuscaloosa marine shale (TMS), to assess their efficacy and sealing capacity for geologic carbon dioxide (CO 2 ) sequestration. Tuscaloosa Group porosity and permeability from MICP were evaluated to calculate CO 2 column height retention. TMS and Lower Tuscaloosa shale samples have, respectively, Swanson permeability values less than 0.003 md and 0.00245 md; porosity from 3.86% to 9.86% and 1.34% to 7.96%; median pore throat sizes from 0.00342 to 0.0111 μm and 0.00311 to 0.017 μm; and pore radii from 0.0130 to 0.152 μm and 0.0132 to 0.149 μm. Mercury entry pressures for the TMS and Lower Tuscaloosa range from 4.9 to 57.1 MPa and 5.0 to 56.3 MPa, respectively. Calculated CO 2 column heights that the TMS sample set can retain in the reservoir range from 23 to 255 m when the TMS is near 100% water saturation. Potential top seal leakage is more likely to be influenced by the numerous well penetrations through the confining system of the TMS rather than capillary failure. Results of this study demonstrate desirable sealing capacity of the TMS for geologic CO 2 sequestration in reservoir sandstones of the Lower Tuscaloosa and could provide an analogue to other potential CO 2 sequestration top seals.

Louisiana, Mississippi↗
USGS2022

Review of past gas Production attempts from subsurface gas hydrate deposits and necessity of long-term production testing

This paper summarizes the conditions, applied techniques, results, and lessons of major field gas production attempts from gas hydrates in the past and the necessity of longer term production testing with the scale of years to fulfill the gap between the currently available information and the knowledge required for commercial development. The temporal and spatial scales of field production test projects employing depressurization have expanded since 2002. The results from the projects have proved the applicability of these techniques in both onshore and offshore conditions. However, many technical and reservoir condition-related issues have emerged in gas production, and the gap between current status and industrial requirements is still large. Sand control, artificial lift, and related flow assurance issues are common technical issues that impact onshore and offshore production testing operations. Different reservoir responses were observed well by well, and discrepancy between model predictions and actual field measurements were seen, although reasonable matches were made for short-term behaviors. Those observations suggest that temporal change of the wellbore and near-wellbore conditions and reservoir heterogeneity that cannot be fully modeled have caused complex short-term responses to the depressurization operations. To ensure the long-term operational stability and reliability of the prediction technologies for production behaviors that are essential for commercialization of gas hydrate resources, gas hydrate production testing with comparable duration with commercial operations are necessary. Due to the locality of geological conditions in gas hydrate reservoirs, numerous gas production tests will be required to understand the factors controlling gas production.

Journal of Energy and Fuels↗
USGS2012

Evidence for a shallow pluton beneath the Goat Rocks Wilderness, Washington, from gravity and magnetic data

A gravity and aeromagnetic study was conducted in and adjacent to the Goat Rocks Wilderness area, Washington. This work was done in conjunction with geologic and geochemical studies which were critically important to our interpretation. The Bouguer gravity anomaly map displays a large central positive gravity anomaly and three superimposed smaller positive anomalies. The main anomaly, about 26 by 11 km with an amplitude of about 16 mGal seems to delineate a dense large pluton or sheeted dike complex intruding less dense, older volcanic and sedimentary rocks lying directly below the volcano. The pluton or sheeted dike complex may have fed the Goat Rocks volcano throughout its 1–2 m.y. history. Three small feeders, mapped on the surface as andesite intrusions, may be the cause of three smaller gravity anomalies superimposed on the main anomaly. The magnetic anomaly maps also exhibit a large central anomaly whose source is the Goat Rocks pluton. The magnetic data suggest that the three shallow intrusive cupolas have undergone a significant amount of hydrothermal alteration. In addition, to some extent the magnetic data reflect the terrain of the area. Topographic highs produce magnetic highs, and topographic lows produce magnetic lows. The deviations from this pattern delineate subsurface geology. Magnetic lows may be of particular interest in locating zones of mineralization where magnetic minerals have been altered and have become significantly less magnetic.

Washington↗
USGS2014

The value of geophysical methods in ground‐water studies

Two meanings are unfortunately given to the term geophysics. In the broad sense, based on the etymology of the term, geophysics means the physics of the Earth. This is its significance in the names “Geophysical Laboratory of the Carnegie Institution of Washington,” “International Union of Geodesy and Geophysics,” and “American Geophysical Union.” In this sense the sciences of geology and hydrology are largely geophysics, although in part they are geochemistry or biology. Geologists and hydraulic engineers who are elected to membership in the American Geophysical Union are, however, often surprised to find that they are regarded as “geophysicists.” I hope that when the Union establisnes a journal, its name will include the expression “Earth physics” or “Physics of the Earth,” in order that there will be no misunderstanding as to its scope.

Eos, Transactions, American Geophysical Union↗
USGS2010

A unique approach to estimating lateral anisotropy in complex geohydrologic environments

Aquifers in fractured rock or karstic settings are likely to have anisotropic transmissivity distributions. Aquifer tests that are performed in these settings also are frequently affected by leakage from adjacent confining units. Finite-difference models such as MODFLOW are convenient tools for estimating the hydraulic characteristics of the stressed aquifer and adjacent confining units but are poor tools for the estimation of lateral anisotropy. This limitation of finite-difference methods can be overcome by application of the spin method, a technique whereby the positions of the observation wells are rotated about the production well to estimate anisotropy and orientation. Formal parameter estimation is necessary to analyze aquifer tests because of the number of parameters that are estimated. As a test, transmissivity, anisotropy, and orientation were successfully estimated for a simple hypothetical problem with known properties. The technique also was applied to estimate hydraulic properties of the Santee Limestone/Black Mingo (SL/BM) aquifer and a leaky confining unit beneath Charleston, South Carolina. A 9-day aquifer test with an average discharge of 6441/min was analyzed numerically. Drawdowns in the SL/BM aquifer and confining unit were simulated with a 12-layer MODFLOW model that was discretized into 81 rows of 81 columns. Simulated drawdowns at seven observation wells that ranged from 23 to 2700 m from the production well were matched to measured drawdowns. Transmissivity estimated along the minor axis ranged from 10 to 15 m 2 /day and along the major axis ranged from 80 to 10Om 2 /day. The major axis of transmissivity was oriented along compass heading 116° (degrees clockwise from north), which agrees with geologic interpretations. Vertical hydraulic conductivity and specific storage estimates for the overlying confining unit were 4 x 10 -5 m/day and 2 x 10 -4 1/m, respectively.

South Carolina↗
USGS2009

Web GIS in practice VII: stereoscopic 3-D solutions for online maps and virtual globes

Because our pupils are about 6.5 cm apart, each eye views a scene from a different angle and sends a unique image to the visual cortex, which then merges the images from both eyes into a single picture. The slight difference between the right and left images allows the brain to properly perceive the 'third dimension' or depth in a scene (stereopsis). However, when a person views a conventional 2-D (two-dimensional) image representation of a 3-D (three-dimensional) scene on a conventional computer screen, each eye receives essentially the same information. Depth in such cases can only be approximately inferred from visual clues in the image, such as perspective, as only one image is offered to both eyes. The goal of stereoscopic 3-D displays is to project a slightly different image into each eye to achieve a much truer and realistic perception of depth, of different scene planes, and of object relief. This paper presents a brief review of a number of stereoscopic 3-D hardware and software solutions for creating and displaying online maps and virtual globes (such as Google Earth) in "true 3D", with costs ranging from almost free to multi-thousand pounds sterling. A practical account is also given of the experience of the USGS BRD UMESC (United States Geological Survey's Biological Resources Division, Upper Midwest Environmental Sciences Center) in setting up a low-cost, full-colour stereoscopic 3-D system.

International Journal of Health Geographics↗
USGS2014

Nitrate fate and transport through current and former depressional wetlands in an agricultural landscape, Choptank Watershed, Maryland, United States

Understanding local groundwater hydrology and geochemistry is critical for evaluating the effectiveness of wetlands at mitigating agricultural impacts on surface waters. The effectiveness of depressional wetlands at mitigating nitrate (NO 3 ) transport from fertilized row crops, through groundwater, to local streams was examined in the watershed of the upper Choptank River, a tributary of Chesapeake Bay on the Atlantic Coastal Plain. Hydrologic, geochemical, and water quality data were collected from January of 2008 through December of 2009 from surface waters and networks of piezometers installed in and around current or former depressional wetlands of three major types along a gradient of anthropogenic alteration: (1) natural wetlands with native vegetation (i.e., forested); (2) prior-converted croplands, which are former wetlands located in cultivated fields; and (3) hydrologically restored wetlands, including one wetland restoration and one shallow water management area. These data were collected to estimate the orientation of groundwater flow paths and likely interactions of groundwater containing NO 3 from agricultural sources with reducing conditions associated with wetlands of different types. Natural wetlands were found to have longer periods of soil saturation and reducing conditions conducive to denitrification compared to the other wetland types studied. Because natural wetlands are typically located in groundwater recharge areas along watershed divides, nitrogen (N) from nearby agriculture was not intercepted. However, these wetlands likely improve water quality in adjacent streams via dilution. Soil and geochemical conditions conducive to denitrification were also present in restored wetlands and prior-converted croplands, and substantial losses of agricultural NO 3 were observed in groundwater flowing through these wetland sediments. However, delivery of NO 3 from agricultural areas through groundwater to these wetlands resulting in opportunities for denitrification were limited, particularly where reducing conditions did not extend throughout the entire thickness of the surficial aquifer allowing NO 3 to pass conservatively beneath a wetland along deeper groundwater flow paths. The complexity of N fate and transport associated with depressional wetlands complicates the understanding of their importance to water quality in adjacent streams. Although depressional wetlands often contribute low NO 3 water to local streams, their effectiveness as landscape sinks, for N from adjacent agriculture varies with natural conditions, such as the thickness of the aquifer and the extent of reducing conditions. Measurement of such natural geologic, hydrologic, and geochemical conditions are therefore fundamental to understanding N mitigation in individual wetlands.

Maryl↗
USGS2009

Littoral transport rates in the Santa Barbara Littoral Cell: a process-based model analysis

Identification of the sediment transport patterns and pathways is essential for sustainable coastal zone management of the heavily modified coastline of Santa Barbara and Ventura County (California, USA). A process-based model application, based on Delft3D Online Morphology, is used to investigate the littoral transport potential along the Santa Barbara Littoral Cell (between Point Conception and Mugu Canyon). An advanced optimalization procedure is applied to enable annual sediment transport computations by reducing the ocean wave climate in 10 wave height - direction classes. Modeled littoral transport rates compare well with observed dredging volumes, and erosion or sedimentation hotspots coincide with the modeled divergence and convergence of the transport gradients. Sediment transport rates are strongly dependent on the alongshore variation in wave height due to wave sheltering, diffraction and focusing by the Northern Channel Islands, and the local orientation of the geologically-controlled coastline. Local transport gradients exceed the net eastward littoral transport, and are considered a primary driver for hot-spot erosion.

California↗
USGS1999

Publications of the Western Geologic Mapping Team 1997-1998

The Western Geologic Mapping Team (WGMT) of the U.S. Geological Survey, Geologic Division (USGS, GD), conducts geologic mapping and related topical earth-science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, potential geologic hazards, and land-use decisions. Areas of primary emphasis currently include southern California, the San Francisco Bay region, the Pacific Northwest, the Las Vegas urban corridor, and selected National Park lands. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. The results of research conducted by the WGMT are released to the public as a variety of databases, maps, text reports, and abstracts, both through the internal publication system of the USGS and in diverse external publications such as scientific journals and books. This report lists publications of the WGMT released in calendar years 1997 and 1998. Most of the publications listed were authored or coauthored by WGMT staff. However, the list also includes some publications authored by formal non-USGS cooperators with the WGMT, as well as some authored by USGS staff outside the WGMT in cooperation with WGMT projects. Several of the publications listed are available on the World Wide Web; for these, URL addresses are provided. Most of these Web publications are USGS open-file reports that contain large digital databases of geologic map and related information. For these, the bibliographic citation refers specifically to an explanatory pamphlet containing information about the content and accessibility of the database, not to the actual map or related information comprising the database itself.

Open-File Report↗