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At least 829 records · Page 46Linked to original sources

Using borehole geophysics and cross-borehole flow testing to define hydraulic connections between fracture zones in bedrock aquifers

Nearly a decade of intensive geophysical logging at fractured rock hydrology research sites indicates that geophysical logs can be used to identify and characterize fractures intersecting boreholes. However, borehole-to-borehole flow tests indicate that only a few of the apparently open fractures found to intersect boreholes conduct flow under test conditions. This paper presents a systematic approach to fracture characterization designed to define the distribution of fractures along boreholes, relate the measured fracture distribution to structure and lithology of the rock mass, and define the nature of fracture flow paths across borehole arrays. Conventional electrical resistivity, gamma, and caliper logs are used to define lithology and large-scale structure. Borehole wall image logs obtained with the borehole televiewer are used to give the depth, orientation, and relative size of fractures in situ. High-resolution flowmeter measurements are used to identify fractures conducting flow in the rock mass adjacent to the boreholes. Changes in the flow field over time are used to characterize the hydraulic properties of fracture intersections between boreholes. Application of this approach to an array of 13 boreholes at the Mirror Lake, New Hamsphire site demonstrates that the transient flow analysis can be used to distinguish between fractures communicating with each other between observation boreholes, and those that are hydraulically isolated from each other in the surrounding rock mass. The Mirror Lake results also demonstrate that the method is sensitive to the effects of boreholes on the hydraulic properties of the fractured-rock aquifer. Experiments conducted before and after the drilling of additional boreholes in the array and before and after installation of packers in existing boreholes demonstrate that the presence of new boreholes or the inflation of packers in existing boreholes has a large effect on the measured hydraulic properties of the rock mass surrounding the borehole array.

Journal of Applied Geophysics↗

Predicting coastal impacts by wave farms: A comparison of wave-averaged and wave-resolving models

Wave energy converters (WECs) will have to be arranged into arrays of many devices to extract commercially viable amounts of energy. To understand the potential coastal impacts of WEC arrays, most research to date has relied on wave-averaged models given their computational efficiency. However, it is unknown how accurate wave-averaged model predictions are given a lack of validation data and their inherent simplifications of various hydrodynamic processes (e.g., diffraction). This paper compares the predictions of coastal wave farm impacts from a coupled wave-averaged and flow model (Delft3D-SNL-SWAN), to a wave-resolving wave-flow model (SWASH) that intrinsically accounts for more of the relevant physics. Model predictions were compared using an idealized coastal bathymetry over a range of wave conditions and wave farm geometries. Both models predicted the largest impacts (changes to the nearshore hydrodynamics) for large and dense wave farms located close to the shore (1 km) and the smallest impacts for the small and widely spaced farm at a greater offshore distance (3 km). However, the wave-resolving model generally predicted somewhat larger impacts (i.e., changes to the nearshore wave heights, mean velocities and mean water levels). We also found that coupling the wave-averaged model to a flow model resulted in more realistic downstream predictions than the stand-alone wave-averaged model.

Renewable Energy↗

Manipulating wild and tamed phytobiomes: Challenges and opportunities

This white paper presents a series of perspectives on current and future phytobiome management, discussed at the Wild and Tamed Phytobiomes Symposium in University Park, PA, USA, in June 2018. To enhance plant productivity and health, and to translate lab- and greenhouse-based phytobiome research to field applications, the academic community and end-users need to address a variety of scientific, practical, and social challenges. Prior discussion of phytobiomes has focused heavily on plant-associated bacterial and fungal assemblages, but the phytobiomes concept covers all factors that influence plant function. Here we discuss various management considerations, including abiotic conditions (e.g. soil, nutrient applications), microorganisms (e.g. bacterial and fungal assemblages, bacterial and fungal inoculants, viruses), macroorganisms (e.g. arthropods, plant genetics), and societal factors (e.g. communication approaches, technology diffusion). An important near-term goal for this field should be to estimate the potential relative contribution of different components of the phytobiome to plant health, as well as the potential and risk of modifying each in the near-future.

Phytobiomes Journal↗

Synthesis of current knowledge on post-fire seeding for soil stabilization and invasive species control

The General Accounting Office has identified a need for better information on the effectiveness of post-fire emergency stabilization and rehabilitation methods used by the U.S. Forest Service and Department of Interior (DOI) agencies. Since reviews were published on treatment effectiveness in the early 2000s, treatment choices have changed and increased monitoring has been done. Greater use of native species has added substantially to burned area emergency response (BAER) treatment costs, for example, but quantitative data on this treatment were scarce in earlier reviews. We synthesized current information on the effectiveness of post-fire seeding for both soil stabilization and for prevention of the spread of invasive species in rangelands. We reviewed published literature (peer-reviewed and “gray”) and agency monitoring reports, as well as compiled and analyzed quantitative data in agency files. Products of this review include a web-accessible database of monitoring reports and published information, a scientific journal paper summarizing findings of scientific studies, an annotated bibliography of peer-reviewed papers, a summary report published as a General Technical Report that will be available online (in progress), and presentations to scientific meetings and BAER/ESR team training sessions and workshops. By combining results from studies done by Forest Service and DOI agency personnel with research studies published since the initial reviews, we presented a comprehensive synthesis of seeding effectiveness knowledge that complements the review of other hillslope treatments published by other researchers. This information will help federal land managers make more cost-effective decisions on post-fire stabilization and rehabilitation treatments.

Report↗

Ages of rocks in southwestern Washington and northwestern Oregon as indicated by paleontological and isotopic dates

This report presents a compilation of 1,019 paleontologic dates and 301 isotopic dates of rocks in southwestern Washington and northwestern Oregon. The study area extends from Portland, Oregon (latitude 45°30' N.) to Bellevue, Washington (latitude 47°35' N.) and from the east flank of the Cascade Range (longitude 121°20' W.) to the coastline (longitude approximately 124°00' W.). The data are presented in two tables and come from previous summaries of isotopic ages, open-file reports, published papers and maps, and theses. Parke D. Snavely, Jr. of the U.S. Geological Survey and Weldon W. Rau of the Washington Division of Geology and Earth Resources (WDGER) generously allowed us access to files and records of more than 40 years of micropaleontological research in western Washington and Oregon. We also present unpublished data from our research since 1971 in northwestern Oregon. This compilation was undertaken for the southwestern Washington and northwestern Oregon project of the U.S. Geological Survey Evolution of Sedimentary Basins Program.

Oregon, Washington↗

The current status of amphibian and reptile ecotoxicological research

The extent of research conducted on the effects of contaminants on reptiles and amphibians has been scant compared to that of other vertebrate classes including fishes, birds and mammals. In a review of literature from 1972 until 1998 we found that only about 2.7% of the papers published on ecotoxicology in vertebrates concerned amphibians and 1.4% for reptiles. Most studies on amphibian ecotoxicology were on metals, pesticides, and acid deposition. For reptiles the greatest frequency of papers included metals, organochlorines, and others. In proportion to the taxonomic importance, far more papers were written on turtles than on other reptile orders. Most of the papers dealt with residues and very few dealt with effects of contaminant exposure.

Book chapter↗

Degree of reduction of sediments in the East Texas basin as an index of source beds

The research project on source beds, sponsored jointly by the U. S. Geological Survey and the American Petroleum Institute, for the past 18 months has undertaken a study of the degree of reduction as an index of source beds. As indicated in a previous paper on this same subject presented before the Institute at the Los Angeles meeting, this index has to be tested in several petroliferous provinces before its value can be definitely ascertained. Thus far it has been found to prevail in two petroliferous regions, viz., the Rocky Mountains and the Mid Continent; as sediments regarded as source beds in these areas have been observed commonly to have a relatively high degree of reduction. In this paper this relationship is extended to the East Texas basin, as most of the sediments associated with oil zones there in general have been found to have a comparatively high degree of reduction. The relationship, as in other areas, however, has not been observed to hold invariably. Each succeeding area in which the relationship is found to prevail strengthens the probability that it is real and not anomalous. If it is found to hold in the three remaining petroliferous provinces that are now being studied, viz., California, Gulf Coast, and Appalachian, the probability will be strong that it is a true relationship, with the result that it can be recommended to geologists for consideration in prospecting for oil.

Conference Paper↗

Geological Survey research 1980

A summary of recent significant scientific and economic results accompanied by a list of geologic, hydrologic, and cartographic investigations in progress.

Professional Paper↗

The superior analyses of igneous rocks from Roth's Tabellen, 1869 to 1884, arranged according to the quantitative system of classification

In Professional Paper No. 14 there were collected the chemical analyses of igneous rocks published from 1884 to 1900, inclusive, arranged according to the quantitative system of classification recently proposed by Cross, Iddings, Pirsson, and Washington. In order to supplement this work it has appeared advisable to select the more reliable and complete of the earlier analyses collected by Justus Roth and arrange them also in the same manner for publication. Petrographers would thus have available for use according to the new system almost the entire body of chemical work of real value on igneous rocks, the exceptions being a few analyses published prior to 1900 which may have been overlooked by both Roth and myself. The two collections would form a foundation as broad as possible for future research and discussion. I must express my sense of obligation to the United States Geological Survey for publishing the present collection of analyses, and my thanks to my colleagues in the new system of classification for their friendly advice and assistance.

Professional Paper↗

Summary of the Second International Planetary Dunes Workshop: Planetary Analogs - Integrating Models, Remote Sensing, and Field Data, Alamosa, Colorado, USA, May 18-21, 2010

The Second International Planetary Dunes Workshop took place in Alamosa, Colorado, USA from May 18-21, 2010. The workshop brought together researchers from diverse backgrounds to foster discussion and collaboration regarding terrestrial and extra-terrestrial dunes and dune systems. Two and a half days were spent on five oral sessions and one poster session, a full-day field trip to Great Sand Dunes National Park, with a great deal of time purposefully left open for discussion. On the last day of the workshop, participants assembled a list of thirteen priorities for future research on planetary dune systems. ?? 2010.

Conference Paper↗

Paleoflood investigations for Cherry Creek Basin, Eastern Colorado

In 1950 when Cherry Creek dam, which is located in Denver. Colorado, was completed, the design flood was 5,126 m 3 /s. Two recent probable maximum flood (PMF) estimates for the dam range from 14,840 to 18,750 m 3 /s demonstrate the uncertainty in estimating extreme flooding in eastern Colorado. PMF difference is due in part to a lack of extreme rainfall and flood data in eastern Colorado. A paleoflood study was conducted to assist dam-safety officials in assessing the risk of large floods in Cherry Creek basin. An envelope curve encompassing maximum contemporary floods (19 sites) and paleofloods (99 sites) was developed for Cherry Creek basin streams; paleoflood data reflect maximum flooding during the last few hundred to many thousands of years. Maximum paleofloods in Cherry Creek range from about 1,050 m 3 /s near Franktown (in about 5,000 to at least 10,000 years), about 2,100 m 3 /s near Melvin (in about 1,500 to 5,000 years), and about 2,270 m 3 /s at Cherry Creek Reservoir (also in about 1,500 to 5,000 years). Flood-frequency relations for Cherry Creek, which incorporate paleoflood data, indicate the 10,000-year flood (10 -4 annual exceedence probability) ranges from about 1,200 m 3 /s (near Franktown) to about 2,200 m 3 /s (near Melvin). PMF estimates are about six to eight times larger than paleofloods in Cherry Creek basin. Additional research in flood hydrometeorology is needed to help dam safety officials evaluate potential safety problems related to large floods in Cherry Creek basin. Copyright ASCE 2004.

Conference Paper↗

Geothermal systems of the Great Basin and U.S. Geological Survey plans for a regional resource assessment

Based on current projections, the United States faces the need to increase its electrical power generating capacity by 40% (approximately 300,000 Megawatts-electrical or MWe) over the next 20 years (Energy Information Administration, EIA - Department of Energy). A critical question for the near future is the extent to which geothermal resources can contribute to this increasing demand for electricity. Geothermal energy constitutes one of the nation's largest sources of renewable and environmentally benign electrical power, yet the installed capacity of 2860 MWe falls far short of estimated geothermal resources. This is particularly true for the Great Basin region of the western United States, which has an installed capacity of about 500 MWe, much lower than the 7500 MWe resource estimated by the U.S. Geological Survey (USGS) in the late 1970s. The reasons for the limited development of geothermal power are varied, but political, economic and technological developments suggest the time is ripe for a new assessment effort. Technologies for power production from geothermal systems and scientific understanding of geothermal resource occurrence have improved dramatically in recent years. The primary challenges facing geothermal resource studies are (1) understanding the thermal, chemical and mechanical processes that lead to the colocation of high temperatures and high permeabilities necessary for the formation of geothermal systems and (2) developing improved techniques for locating, characterizing and exploiting these systems. Starting in the fall of 2002, the USGS will begin work with institutions funded by the Department of Energy's (DOE) Geothermal Research Program to investigate the nature and extent of geothermal systems in the Great Basin and to produce an updated assessment of available geothermal resources.

Conference Paper↗

Estimating direct fatality impacts at wind farms: how far we’ve come, where we have yet to go

Measuring the potential impacts of wind farms on wildlife can be difficult and may require development of new statistical tools and models to accurately reflect the measurement process. This presentation reviews the recent history of approaches to estimating wildlife fatality under the unique conditions encountered at wind farms, their unifying themes and their potential shortcomings. Avenues of future research are suggested to continue to address the needs of resource managers and industry in understanding direct impacts of wind turbine-caused wildlife fatality.

Conference Paper↗

Public lakes, private lakeshore: Modeling protection of native aquatic plants

Protection of native aquatic plants is an important proenvironmental behavior, because plant loss coupled with nutrient loading can produce changes in lake ecosystems. Removal of aquatic plants by lakeshore property owners is a diffuse behavior that may lead to cumulative impacts on lake ecosystems. This class of behavior is challenging to manage because collective impacts are not obvious to the actors. This paper distinguishes positive and negative beliefs about aquatic plants, in models derived from norm activation theory (Schwartz, Adv Exp Soc Psychol 10:221–279, 1977 ) and the theory of reasoned action (Fishbein and Ajzen, Belief, attitude, intention, and behavior: an introduction to theory and research, Addison-Wesley, Boston 1975 ), to examine protection of native aquatic plants by Minnesota lakeshore property owners. We clarify how positive and negative evaluations of native aquatic plants affect protection or removal of these plants. Results are based on a mail survey ( n = 3,115). Results suggest that positive evaluations of aquatic plants (i.e., as valuable to lake ecology) may not connect with the global attitudes and behavioral intentions that direct plant protection or removal. Lakeshore property owners’ behavior related to aquatic plants may be driven more by tangible personal benefits derived from accessible, carefully managed lakeshore than intentional action taken to sustain lake ecosystems. The limited connection of positive evaluations of aquatic plants to global attitudes and behavioral intentions may reflect either lack of knowledge of what actions are needed to protect lake health and/or unwillingness to lose perceived benefits derived from lakeshore property.

Minnesota↗

Foreword: Control and conservation of lampreys beyond 2020 - Proceedings from the 3rd Sea Lamprey International Symposium (SLIS III)

Introduction to the special issue on the 3rd Sea Lamprey International Symposium. The compiled papers in this special issue consist of a combination of syntheses requested in advance of the symposium and perspectives that emerged from the symposium break-out discussions. These written contributions address the symposium goals of updating our understanding of sea lamprey control and research on lampreys since SLIS II and of exploring new ideas and posing new methods for controlling sea lamprey in the Great Lakes and supporting conservation of lampreys in their native ranges.

Journal of Great Lakes Research↗

Habitat suitability criteria for assessment of instream flow needs of fish

In the western portion of the United States, competition for stream water gas often been fierce. Water resource management agencies in the southeastern United States, where water has been relatively abundant, are not being faced with similar competing demands for water, and with increasing pressures to develop and defend recommendations for protecting fish and invertebrates in streams. Streamflow depletion at any time can result in severe long-term effects on fish populations(Peters, 1982). The allocation of stream water to any numerous instream or offstream uses is tied to the issues of water quantity, quality, and timing, which center on two critical questions: (1)when and how much water of an acceptable quality should be left in a stream, and (2) what happens if flow regimes are changed? Answers to these questions will probably be complex, but reliable answers are needed to protect instream and offstream values. If instream flow interests expect to compete with offstream uses for limited water supplies, they must be able to determine reliable and defensible methods for determining instream flow needs and demonstrate the environmental consequences of altered flow regimes. My objectives in this paper are: (a) to present an overview of the need, development, and use of stream habitat suitability criteria, and the use of these criteria for the assessment of instream flow needs; (b) to give a status report on the plan of the National Ecology Research Center (NERC) for expansion of instream flow research in the Southeast; and (c) to discuss the relevancy of the research to river corridor management.

Book↗

An overview of methods for developing bioenergetic and life history models for rare and endangered species

Many fish species are at risk to some degree, and conservation efforts are planned or underway to preserve sensitive populations. For many imperiled species, models could serve as useful tools for researchers and managers as they seek to understand individual growth, quantify predator-prey dynamics, and identify critical sources of mortality. Development and application of models for rare species however, has been constrained by small population sizes, difficulty in obtaining sampling permits, limited opportunities for funding, and regulations on how endangered species can be used in laboratory studies. Bioenergetic and life history models should help with endangered species-recovery planning since these types of models have been used successfully in the last 25 years to address management problems for many commercially and recreationally important fish species. In this paper we discuss five approaches to developing models and parameters for rare species. Borrowing model functions and parameters from related species is simple, but uncorroborated results can be misleading. Directly estimating parameters with laboratory studies may be possible for rare species that have locally abundant populations. Monte Carlo filtering can be used to estimate several parameters by means of performing simple laboratory growth experiments to first determine test criteria. Pattern-oriented modeling (POM) is a new and developing field of research that uses field-observed patterns to build, test, and parameterize models. Models developed using the POM approach are closely linked to field data, produce testable hypotheses, and require a close working relationship between modelers and empiricists. Artificial evolution in individual-based models can be used to gain insight into adaptive behaviors for poorly understood species and thus can fill in knowledge gaps. ?? Copyright by the American Fisheries Society 2008.

Transactions of the American Fisheries Society↗