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At least 271 records · Page 15Linked to original sources

USGS2018

Downstream fish passage guide walls: A hydraulic scale model analysis

Partial-depth guide walls are used to improve passage efficiency and reduce the delay of out-migrating anadromous fish species by guiding fish to a bypass route (i.e. weir, pipe, sluice gate) that circumvents the turbine intakes, where survival is usually lower. Evaluation and monitoring studies, however, indicate a high propensity for some fish to pass underneath, rather than along, the guide walls, compromising their effectiveness. In the present study we evaluated a range of guide wall structures to identify where/if the flow field shifts from sweeping (i.e. flow direction primarily along the wall and towards the bypass) to downward-dominant. Many migratory fish species, particularly juveniles, are known to drift with the flow and/or exhibit rheotactic behaviour during their migration. When these behaviours are present, fish follow the path of the flow field. Hence, maintaining a strong sweeping velocity in relation to the downward velocity along a guide wall is essential to successful fish guidance. Nine experiments were conducted to measure the three-dimensional velocity components upstream of a scale model guide wall set at a wide range of depths and angles to flow. Results demonstrated how each guide wall configuration affected the three-dimensional velocity components, and hence the downward and sweeping velocity, along the full length of the guide wall. In general, the velocities produced in the scale model were sweeping dominant near the water surface and either downward dominant or close to the transitional depth near the bottom of the guide wall. The primary exception to this shift from sweeping do downward flow was for the minimum guide wall angle tested in this study (15°). At 15° the flow pattern was fully sweeping dominant for every cross-section, indicating that a guide wall with a relatively small angle may be more likely to produce conditions favorable to efficient guidance. A critical next step is to evaluate the behaviour of migratory fish as they approach and swim along a guide wall in a controlled laboratory environment.

Ecological Engineering↗

USGS1976

Field trip to Nevada test site

Two road logs guide the reader through the geologic scene from Las Vegas to Mercury and from Mercury through eight stops on the Nevada Test Site. Maps and cross sections depict the geology and hydrology of the area. Included among the tables is one showing the stratigraphic units in the southwestern Nevada volcanic field and another that lists the geologic maps covering the Nevada Test Site and vicinity. The relation of the geologic environment to nuclear-explosion effects is alluded to in brief discussions of collapse, surface subsidence, and cratering resulting from underground nuclear explosions.

Open-File Report↗

USGS2010

Teachers guide to geologic trails in Delaware Water Gap National Recreation Area, Pennsylvania–New Jersey

T he Delaware Water Gap National Recreation Area (DEWA) contains a rich geologic and cultural history within its 68,714 acre boundary. Following the border between New Jersey and Pennsylvania, the Delaware River has cut a magnificent gorge through Kittatinny Mountain, the Delaware Water Gap, to which all other gaps in the Appalachian Mountains have been compared. Proximity to many institutions of learning in this densely populated area of the northeastern United States (Fig. 1 ) makes DEWA an ideal locality to study the geology of this part of the Appalachian Mountains. This one-day field trip comprises an overview discussion of structure, stratigraphy, geomorphology, and glacial geology within the gap. It will be highlighted by hiking a choice of several trails with geologic guides, ranging from gentle to difficult. It is hoped that the “professional” discussions at the stops, loaded with typical geologic jargon, can be translated into simple language that can be understood and assimilated by earth science students along the trails. This trip is mainly targeted for earth science educators and for Pennsylvania geologists needing to meet state-mandated education requirements for licensing professional geologists. The National Park Service, the U.S. Geological Survey, the New Jersey Geological Survey, and local schoolteachers had prepared “The Many Faces of Delaware Water Gap: A Curriculum Guide for Grades 3–6” ( Ferrence et al., 2003 ). Copies of this guide will be given to trip participants and can be downloaded from the GSA Data Repository 1 . The trip will also be useful for instruction at the graduate level. Much of the information presented in this guidebook is modified from Epstein (2006) .

New Jersey, Pennsylvania↗

USGS1999

Assessing environmental contaminant threats to lands and biota managed by the U.S. Fish and Wildlife Service

The Contaminant Assessment Process (CAP) is a standardized approach for documenting and assessing threats posed by environmental contaminants to lands and biota managed by the Department of the Interior (DOI). The Biomonitoring of Environmental Status and Trends (BEST) Program of the U.S. Geological Survey Biological Resources Division (USGS/BRD) developed the CAP cooperatively with the U.S. Fish and Wildlife Service's (FWS) Division of Environmental Contaminants (DEC). The CAP involves two parts, a retrospective analysis, and if needed, field-sampling. The retrospective analysis documents the ecological characteristics, management goals, areas potentially vulnerable to hazardous substance spills, and habitats of importance for the DOI land unit of interest. In addition, contaminant transport pathways and sources (point and nonpoint) are identified and potentially contaminated areas delineated. The second part of the CAP involves developing field-sampling plans to confirm the presence or effects of contaminants identified in the retrospective analysis. Field-sampling deemed necessary to confirm contaminant issues on national wildlife refuges identified through the retrospective analyses of CAP is handled as part of DECs on- and off-refuge investigation programs. By gathering and interpreting information, the CAP generates valuable insight regarding contaminant issues that may be affecting refuges. Findings from the CAP can help FWS stewards select options that reduce contaminant impacts on the habitats and species that they manage. Information synthesized through the CAP also contributes to the development of Comprehensive Conservation Plans mandated through the National Wildlife Refuge System Improvement Act of 1997. To insure that this information has the maximum benefit to the agency, DEC and the BEST Program jointly developed a data management system to support the CAP. This system facilitates information acquisition from remote sources and serves as a permanent data repository. Thus, the system documents CAP findings, enhances FWS's institutional memory, and supports informed management decisions. This document is a user's guide, intended for use by FWS field biologists responsible for applying the retrospective analysis portion of the CAP to FWS national wildlife refuge lands and provides instructions for entering information into the data management system. This is the third revision of the original document written in 1993 by scientists of the Idaho National Engineering and Environmental Laboratory.

Open-File Report↗

USGS2016

Aging and sexing guide to the forest birds of Hawai‘i Island

We banded birds in Hakalau Forest National Wildlife Refuge from 2012 to 2016, collecting photographs of birds and making detailed observations on coloration, morphology, and molting patterns. While we believe the criteria in this guide are applicable to forest birds across Hawai’i Island, as well as on other Hawaiian islands for ‘Apapane, ‘I‘iwi, and Hawai‘i ‘Amakihi, certain characteristics such as morphometrics may vary across populations, and users should verify the guide’s criteria with other available field data.

Technical Report↗

USGS1941

Geologic structure and occurrence of gas in part of southwestern New York. Part 2. Subsurface structure in part of southwestern New York and mode of occurrence of gas in the Medina group

Based on the records of several hundred deep wells, contour maps have been prepared showing the monoclinal structure of part of western New York, and isopach lines have been drawn showing the westward convergence of the rocks. The mode of occurrence of natural gas in the Medina group is briefly discussed. The location of the gas fields has not been determined by structural traps, but rather stratigraphy and lithology are the controlling factors in trapping the gas, which occurs in porous lenses and streaks of sandstone sealed within impermeable beds. This mode of occurrences of the Medina gas makes the search for new fields in western New York more hazardous than in most natural gas regions. As structure has not formed traps for the gas there is no surface guide to favorable sites for testing, and new fields are found by haphazard drilling. It would be helpful, however, when wells are sunk, to study the lithology of the gas-bearing zone by an examination of the drill cuttings and core samples of the sand and to have electrical logs made of the wells to obtain measurements of permeability and porosity. Such tests may indicate the direction of greatest porosity in which the sand is more likely to contain gas.

New York↗

USGS2016

Continuity of the West Napa–Franklin fault zone inferred from guided waves generated by earthquakes following the 24 August 2014 Mw 6.0 South Napa Earthquake

We measure peak ground velocities from fault‐zone guided waves (FZGWs), generated by on‐fault earthquakes associated with the 24 August 2014 M w 6.0 South Napa earthquake. The data were recorded on three arrays deployed across north and south of the 2014 surface rupture. The observed FZGWs indicate that the West Napa fault zone (WNFZ) and the Franklin fault (FF) are continuous in the subsurface for at least 75 km. Previously published potential‐field data indicate that the WNFZ extends northward to the Maacama fault (MF), and previous geologic mapping indicates that the FF extends southward to the Calaveras fault (CF); this suggests a total length of at least 110 km for the WNFZ–FF. Because the WNFZ–FF appears contiguous with the MF and CF, these faults apparently form a continuous Calaveras–Franklin–WNFZ–Maacama (CFWM) fault that is second only in length (∼300 km) to the San Andreas fault in the San Francisco Bay area. The long distances over which we observe FZGWs, coupled with their high amplitudes (2–10 times the S waves) suggest that strong shaking from large earthquakes on any part of the CFWM fault may cause far‐field amplified fault‐zone shaking. We interpret guided waves and seismicity cross sections to indicate multiple upper crustal splays of the WNFZ–FF, including a northward extension of the Southhampton fault, which may cause strong shaking in the Napa Valley and the Vallejo area. Based on travel times from each earthquake to each recording array, we estimate average P ‐, S ‐, and guided‐wave velocities within the WNFZ–FF (4.8–5.7, 2.2–3.2, and 1.1–2.8 km/s, respectively), with FZGW velocities ranging from 58% to 93% of the average S ‐wave velocities.

California↗

USGS2025

A transdisciplinary approach to growing an applied science of cultural evolution for a sustainable future

Addressing sustainability challenges requires an integrative approach that bridges scientific research with practical application. The field of cultural evolution (CE) offers a perspective that may guide transitions and cultural transformations for a sustainable future. However, there have been few efforts to apply this field to sustainability challenges. This study explores how CE can inform sustainability practices through mechanisms of social learning, processes of cultural adaptation and conditions that promote cooperative governance. Through a two-phase research design—comprising online discussions with professionals from six domains, and an international workshop—we examined the perceived benefits, challenges and opportunities for applying CE in real-world contexts. Our findings indicate that professionals recognize CE’s potential to enhance knowledge dissemination, foster adaptation to social–ecological changes, improve governance structures and generate cooperation. However, barriers such as complex terminology, unfamiliarity with CE, the lack of clear, context-specific evidence of added value and competition with existing frameworks hinder its application. To overcome these challenges, we propose simplifying CE concepts, demonstrating its unique contributions, and continuing to foster co-production with practitioners to refine its applicability. This study is an initial step in building an applied science of CE that can support sustainability transformations across diverse domains.

Philosophical Transactions of the Royal Society B ↗

USGS2009

Emergent insect production in post-harvest flooded agricultural fields used by waterbirds

California’s Tulare Lake Basin (TLB) is one of the most important waterbird areas in North America even though most wetlands there have been converted to cropland. To guide management programs promoting waterbird beneficial agriculture, which includes flooding fields between growing periods, we measured emergence rates of insects, an important waterbird food, in three crop types (tomato, wheat, alfalfa) in the TLB relative to water depth and days flooded during August–October, 2003 and 2004. We used corrected Akaike’s Information Criterion values to compare a set of models that accounted for our repeated measured data. The best model included crop type and crop type interacting with days flooded and depth flooded. Emergence rates (mg m −2 day −1 ) were greater in tomato than wheat or alfalfa fields, increased with days flooded in alfalfa and tomato but not wheat fields, and increased with water depth in alfalfa and wheat but not tomato fields. To investigate the relationship between the range of diel water temperatures and insect emergence rates, we reared Chironomus dilutus larvae in environmental chambers under high (15–32°C) and low fluctuation (20–26°C) temperature regimes that were associated with shallow and deep (respectively) sampling sites in our fields. Larval survival (4×) and biomass (2×) were greater in the low thermal fluctuation treatment suggesting that deeply flooded areas would support greater insect production.

Wetlands↗

USGS1950

Reconnaissance of Lake Chackachamna, Alaska

The purpose of this brief investigation was to obtain general information on Lake Chackachamna and its water-power possibilities which would serve as a guide in planning and executing future studies. Field investigation consisted of a flight to the lake in a small float plane (see Plate I-B) by the writer on August 3, 1948, landing on the lake near the outlet, making a brief study of conditions there and taking a number of pictures of which several are included in this report with appropriate descriptions. The flight was made with Jack Carr of Anchorage from whom the plane was chartered. It was rather windy at time of landing on the lake and as the wind velocity was increasing Mr. Carr recommended that the stay there be made as short as possible and was consequently less than an hour.

Alaska↗

USGS2003

Using sensitivity analysis in model calibration efforts

In models of natural and engineered systems, sensitivity analysis can be used to assess relations among system state observations, model parameters, and model predictions. The model itself links these three entities, and model sensitivities can be used to quantify the links. Sensitivities are defined as the derivatives of simulated quantities (such as simulated equivalents of observations, or model predictions) with respect to model parameters. We present four measures calculated from model sensitivities that quantify the observation-parameter-prediction links and that are especially useful during the calibration and prediction phases of modeling. These four measures are composite scaled sensitivities (CSS), prediction scaled sensitivities (PSS), the value of improved information (VOII) statistic, and the observation prediction (OPR) statistic. These measures can be used to help guide initial calibration of models, collection of field data beneficial to model predictions, and recalibration of models updated with new field information. Once model sensitivities have been calculated, each of the four measures requires minimal computational effort. We apply the four measures to a three-layer MODFLOW-2000 (Harbaugh et al., 2000; Hill et al., 2000) model of the Death Valley regional ground-water flow system (DVRFS), located in southern Nevada and California. D’Agnese et al. (1997, 1999) developed and calibrated the model using nonlinear regression methods. Figure 1 shows some of the observations, parameters, and predictions for the DVRFS model. Observed quantities include hydraulic heads and spring flows. The 23 defined model parameters include hydraulic conductivities, vertical anisotropies, recharge rates, evapotranspiration rates, and pumpage. Predictions of interest for this regional-scale model are advective transport paths from potential contamination sites underlying the Nevada Test Site and Yucca Mountain.

California, Nevada↗

USGS2001

User's guide for polyethylene-based passive diffusion bag samplers to obtain volatile organic compound concentrations in wells. Part 2, Field tests

Diffusion samplers installed in observation wells were found to be capable of yielding representative water samples for chlorinated volatile organic compounds. The samplers consisted of polyethylene bags containing deionized water and relied on diffusion of chlorinated volatile organic compounds through the polyethylene membrane. The known ability of polyethylene to transmit other volatile compounds, such as benzene and toluene, indicates that the samplers can be used for a variety of volatile organic compounds. In wells at the study area, the volatile organic compound concentrations in water samples obtained using the samplers without prior purging were similar to concentrations in water samples obtained from the respective wells using traditional purging and sampling approaches. The low cost associated with this approach makes it a viable option for monitoring large observation-well networks for volatile organic compounds.

Water-Resources Investigations Report↗

USGS2018

Remote sensing analysis of vegetation at the San Carlos Apache Reservation, Arizona and surrounding area

Mapping of vegetation types is of great importance to the San Carlos Apache Tribe and their management of forestry and fire fuels. Various remote sensing techniques were applied to classify multitemporal Landsat 8 satellite data, vegetation index, and digital elevation model data. A multitiered unsupervised classification generated over 900 classes that were then recoded to one of the 16 generalized vegetation/land cover classes using the Southwest Regional Gap Analysis Project (SWReGAP) map as a guide. A supervised classification was also run using field data collected in the SWReGAP project and our field campaign. Field data were gathered and accuracy assessments were generated to compare outputs. Our hypothesis was that a resulting map would update and potentially improve upon the vegetation/land cover class distributions of the older SWReGAP map over the 24,000 km 2 study area. The estimated overall accuracies ranged between 43% and 75%, depending on which method and field dataset were used. The findings demonstrate the complexity of vegetation mapping, the importance of recent, high-quality-field data, and the potential for misleading results when insufficient field data are collected.

Arizona↗

USGS2017

Sensitivity of the downward to sweeping velocity ratio to the bypass flow percentage along a guide wall for downstream fish passage

Partial-depth impermeable guidance structures (or guide walls) are used as a method to assist in the downstream passage of fish at a hydroelectric facility. However, guide walls can result in a strong downward velocity causing the approaching fish to pass below the wall and into the direction of the turbine intakes. The objective of this study was to describe how the ratio of the vertical velocity to the sweeping velocity magnitude changes along the full length and depth of a guide wall under a wide range of bypass flow percentages within a power canal. This paper focused on two guide wall configurations, each set at an angle of 45 ° to the approaching flow field and at a depth of 10 and 20 ft (3.05 and 6.10 m). The hydraulic conditions upstream of each guide wall configuration were shown to be impacted by a change in the bypass flow percentage, not only near the bypass but also at upstream sections of the guide wall. Furthermore, the effect of changing the bypass flow percentage was similar for both guide wall depths. In both cases, the effect of increasing the bypass flow percentage was magnified closer to the bypass and deeper in the water column along the guide wall.

Ecological Engineering↗

USGS1949

Ground-water in the Austin area, Lander County, Nevada

The U.S. Geological Survey, in cooperation with the State Engineer of Nevada, made a preliminary survey of ground-water conditions in the Austin area, Nev., during the period July 25 to 28, 1949. The purpose was to evaluate ground-water conditions with special reference to the quantity of ground water that might be available in the area--an adequate water supply has been a constant problem throughout the history of the Austin area. The investigation was made by the writer under the supervision of Thomas W. Robinson, district engineer, Ground Water Branch, U.S. Geological Survey. Material assistance was given in the field by local residents. Frank Bertrand, water commissioner, Thomas Peacock, county assessor, and George McGinnis, county commissioner, guided the writer to springs new utilized by the town of Austin and rendered other valuable field assistance.

Nevada↗

USGS2022

Remote sensing and mapping Miocene paleovalleys of the Marble, Bristol, and Old Dad Mountains in the Trilobite and Bristol Mountain Wildernesses, California

Wilderness areas in the Mojave Desert, California, are remote and rugged terrain, but they contain important geology for understanding faults of the eastern California shear zone (ECSZ), and remote sensing offers techniques that can optimize mapping. The Bristol–Granite Mountain fault zone (BGMFZ) is the easternmost fault of the ECSZ with the Marble, Bristol, and Old Dad mountains on either side of the fault, as are the Trilobite and Bristol Mountain Wildernesses. In the northern Marble Mountains, a west-trending Miocene paleovalley has been proposed to have a correlative in the Old Dad Mountains and provides a constraint for right-lateral separation across the BGMFZ; however, this correlation is based on the premise that there was a unique paleovalley with a well defined geometry. In the northern Marble Mountains, a paleovalley was mapped by the distribution of (1) thickness and facies within the Lost Marble gravel (LMg) and 18.8 Ma Peach Spring Tuff (PST), and (2) adjacent highlands where the PST was deposited on basalt and dacite lava flows. Whether this paleovalley is unique, or there are other paleovalleys farther south in the Marble Mountains, requires mapping of the entire 5 by 28 km area of Miocene volcanic rocks. In the south Bristol and Old Dad mountains, there is a similar 12 by 22 km area of Miocene basalt and dacite with deposits of PST and local sedimentary rocks, including the proposed offset Lost Marble paleovalley, but the entire range needs to be mapped to establish a unique correlate. The mountains are in the Mojave Trails National Monument, and the Trilobite and Bristol Mountains wilderness areas, so access is limited. Remote sensing data, including aerial photography and hyperspectral images, are important for identification and characterization of rocks. Airborne hyperspectral Mako data can distinguish the distinctive spectral characteristics of the PST as well as several more map units identified by detailed field mapping in the Bristol Mountains. Reconnaissance maps derived from high spatial resolution Mako data can guide the detailed mapping needed to identify paleovalley or paleohighland deposits and can be used to optimize field time.

California↗

USGS1986

Paleodrainages of the Eastern Sahara-The radar rivers revisited (SIR-A/B Implications for a Mid-Tertiary Trans-Afnrcan Drainage System)

A complex history of Cenozoic fluvial activity in the presently hyperarid Eastern Sahara is inferred from SIR data and postflight field investigations in southwest Egypt and northwest Sudan. SIR images were coregistered with Landsat and existing maps as a guide to exploration of the buried paleodrainages (radar rivers) first discovered by SIR-A. Field observations explain the radar responses of three types of radar rivers, RR-1, RR-2, and RR-3. RR-1 (broad, aggraded valleys or basins filled with alluvium) generally give a dark response relative to the surrounding radar-bright tone of the wind-roughened, discontinuously sand-covered bedrock of the remnant interfluves. The alluvial fill in some of the RR-1 valleys gives a locally intermediate to bright response where cemented by diagenetic CaCO3 (caliche). The RR-2 type (braided channels inset in the RR-1 valleys) are filled with noncalichified, loose sediment, and are visible on SIR because of the "caliche effect"-the dark response of unconsolidated alluvium in the inset channels contrasts with the brighter response of calichified alluvium in the broad valleys. The third type, RR-3 (narrow, long, bedrock-incised channels), which are partly visible on the ground and on Landsat in areas where the sand sheet is patchy, are conspicuous on SIR because the dark response of their unconsolidated channel fill contrasts with the brighter response of the surrounding bedrock. Disconformably overlying and concealing the RR-1 valleys, the RR- 2 channels, and parts of the RR-3 channels are eolian sand-sheetsheet de- deposits, which in turn are locally overridden by trains of barchan dunes.

IEEE Transactions on Geoscience and Remote Sensing↗

USGS2003

Use of input uncertainty and model sensitivity to guide site exploration

Three Quantitatively Directed Exploration (QDE) methods to identify optimum field sampling locations based on model input covariance and model sensitivity are presented. The first method bases site exploration only on the spatial variation in the uncertainty of input properties. The second method uses only the spatial variation in model sensitivities. The third method uses a first-order second-moment (FOSM) method to estimate the spatial variation in the output covariance. The FOSM method estimates output uncertainty using the product of the input covariance and model sensitivity. The three methods are illustrated by means of a synthetic groundwater site simulated with MODFLOW-2000. The groundwater-flow model computes piezometric head and the sensitivity of head to changes in input values. The QDE methods are evaluated by comparing model results to the "true" head. For the synthetic site used in this study, the most effective QDE method was the FOSM method.

Conference Paper↗