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At least 1,765 records · Page 98Linked to original sources
USGS2016

Wetting and drying of soil in response to precipitation: Data analysis, modeling, and forecasting

This paper investigates methods to analyze and forecast soil moisture time series. We extend an existing Antecedent Water Index (AWI) model, which expresses soil moisture as a function of time and rainfall. Unfortunately, the existing AWI model does not forecast effectively for time periods beyond a few hours. To overcome this limitation, we develop a novel AWI-based model. Our model accumulates rainfall over a time interval and can fit a diverse range of wetting and drying curves. In addition, parameters in our model reflect hydrologic redistribution processes of gravity and suction.We validate our models using experimental soil moisture and rainfall time series data collected from steep gradient post-wildfire sites in Southern California, where rapid landscape change was observed in response to small to moderate rain storms. We found that our novel model fits the data for three distinct soil textures, occurring at different depths below the ground surface (5, 15, and 30 cm). Our model also successfully forecasts soil moisture trends, such as drying and wetting rate.

Conference Paper↗
USGS2009

Adaptive management of watersheds and related resources

The concept of learning about natural resources through the practice of management has been around for several decades and by now is associated with the term adaptive management. The objectives of this paper are to offer a framework for adaptive management that includes an operational definition, a description of conditions in which it can be usefully applied, and a systematic approach to its application. Adaptive decisionmaking is described as iterative, learning-based management in two phases, each with its own mechanisms for feedback and adaptation. The linkages between traditional experimental science and adaptive management are discussed.

Conference Paper↗
USGS2010

A practitioner's tool for assessing glide crack activity

Glide cracks can result in full-depth glide avalanche release. Avalanches from glide cracks are notoriously difficult to forecast, but are a reoccurring problem in a number of different avalanche forecasting programs across a range of snow climates. Despite this, there is no consensus for how to best manage, mitigate, or even observe glide cracks and the potential resultant avalanche activity. It is thought that an increase in the rate of snow gliding occurs prior to full-depth avalanche activity, so frequent measuring of glide crack movement provides an index of instability. Therefore, a comprehensive avalanche program with glide crack avalanche activity, should at the least, undertake some form of direct monitoring of glide crack movement. In this paper we present a simple, cheap and repeatable method to track glide crack activity using a series of stakes, reflectors and a laser rangefinder (LaserTech TruPulse360B) linked to a GPS (Trimble Geo XH). We tested the methodology in April 2010, on a glide crack above the Going to the Sun Road in Glacier National Park, Montana, USA. This study suggests a new method to better track the development and movement of glide cracks. It is hoped that by introducing a workable method to easily record glide crack movement, avalanche forecasters will improve their understanding of when, or if, avalanche activity will ensue. Our initial results suggest that these new observations, when combined with local micrometeorological data will result in improved process understanding and forecasting of these phenomena.

Conference Paper↗
USGS1963

Quantitation of microorganic compounds in waters of the Great Lakes by adsorption on activated carbon

Microorganic compounds in waters of Lakes Michigan and Huron have been sampled by adsorption on activated carbon in filters installed aboard the M/V Cisco and at the Hammond Bay Laboratory of the U.S. Bureau of Commercial Fisheries. The organic compounds were eluted from the carbon according to techniques developed at the U.S. Public Health Service. On the assumption that chloroform eluates represent less polar compounds from industrial sources and alcohol eluates the more polar varieties of natural origin, plots of chloroform eluates against alcohol eluates appear to be useful in judging water qualities. Based upon these criteria, the data in this paper indicate that both the waters of northern Lake Michigan and of Lake Huron, in the vicinity of Hammond Bay, Michigan, are relatively free from pollution. The limnetic waters of Lake Michigan showed a particularly high ratio of alcohol to chloroform eluates. Data for monthly samples indicated that this ratio fluctuated seasonally. The periodicity of the fluctuations was similar to those of lake levels and water temperatures.

Conference Paper↗
USGS1989

Management of fish populations in large rivers: a review of tools and approaches

In common with most branches of science, the management of riverine fish populations is characterised by reductionist and isolationist philosophies. Traditional fish management focuses on stocking and controls on fishing. This paper presents a consensus of scientists involved in the LARS workshop on the management of fish populations in large rivers. A move towards a more holistic philosophy is advocated, with fish management forming an integral part of sustainable river development. Based upon a questionnaire survey of LARS members, with wide-ranging expertise and experience from all parts of the world, lists of management tools currently in use are presented. Four categories of tools are described: flow, water-quality, habitat, and biological. The potential applications of tools for fish management in large rivers is discussed and research needs are identified. The lack of scientific evaluations of the different tools remains the major constraint to their wider application.

Conference Paper↗
USGS1999

Comparative ecology of exotic invaders and ecologically equivalent species of hydrobionths in the Great Lakes of the world: Results of Russia-USA cooperation

This paper presents brief fragments of the results of joint Russia-US research conducted through the cooperative project entitled, 'Comparative ecology of exotic invaders and ecologically equivalent species of hydrobionths in the Great Lakes of the world: Lake Baikal and the Laurentian Great Lakes.' The project was executed under the Agreement on Scientific Cooperation between the Institute of General and Experimental Biology (formerly Buryat Institute of Biology) of the Siberian Branch of the Russian Academy of Sciences and the Great Lakes Science Center of the U.S. Geological Survey.

Conference Paper↗
USGS2016

Enriching the national map database for multi-scale use: Introducing the visibilityfilter attribution

The US Geological Survey’s (USGS) National Geospatial Technical Operations Center is prototyping and evaluating the ability to filter data through a range of scales using 1:24,000-scale The National Map (TNM) datasets as the source. A “VisibilityFilter” attribute is under evaluation that can be added to all TNM vector data themes and will permit filtering of data to eight target scales between 1:24,000 and 1:5,000,000, thus defining each feature’s smallest applicable scale-of-use. For a prototype implementation, map specifications for 1:100,000- and 1:250,000-scale USGS Topographic Map Series are being utilized to define feature content appropriate at fixed mapping scales to guide generalization decisions that are documented in a ScaleMaster diagram. This paper defines the VisibilityFilter attribute, the generalization decisions made for each TNM data theme, and how these decisions are embedded into the data to support efficient data filtering.

Conference Paper↗
USGS1999

The spring runoff pulse from the Sierra Nevada

Just about every year there is one major first pulse of snowmelt runoff (streamflow) that marks the transition from winter to spring in high elevation, snowmelt driven watersheds in the western United States. As a index, we have used the record of relatively pristine streamflow at the Merced River, Happy Isles in Yosemite National Park to identify this transition for each year beginning in 1916. Two factors are prominent in determining the timing of the spring runnoff pulse: (1) it is delayed with greater seasonal accumulation of snow pack in the Yosemite region, and (2) the runoff pulse is triggered by a regional weather fluctuation that establishes a warm high pressure ridge over the California region during the spring (mid-March to Mid-May) period. Thus, the pulse involves both seasonal climate variability vis a vis the character of winter/spring water delivery to the western mountains and synoptic conditions associated with abrupt spring warming. Inspection of an extensive array of stream gage records over the western states finds that a simultaneous pulse occurs over a broad collection of high-elevation streams in the region. In this paper, we explore the predictability of the onset of these spring regional warmings, which often are marked by development of high pressure ridge over much of the western United States

Conference Paper↗
USGS2015

Representativeness of soil samples collected to assess mining-related contamination of flood plains in southeast Kansas

Historical lead and zinc mining in the Tri-State Mining District (TSMD), located in parts of southeast Kansas, southwest Missouri, and northeast Oklahoma, has resulted in a substantial ongoing input of lead and zinc to the environment (Juracek, 2006; Juracek and Becker, 2009). In response to concern about the mining-related contamination, southeast Cherokee County, Kansas, was listed on the U.S. Environmental Protection Agency’s (USEPA) National Priority List as a Superfund hazardous waste site (fig. 1). To provide some of the information needed to support remediation efforts in the Cherokee County Superfund site, a study was begun in 2009 by the U.S. Geological Survey (USGS) that was requested and funded by USEPA. As part of the study, surficial-soil sampling was used to investigate the extent and magnitude of mining-related lead and zinc contamination in the flood plains of the Spring River and several tributaries within the Superfund site. In mining-affected areas, flood-plain soils had lead and zinc concentrations that far exceeded background levels as well as probable-effects guidelines for toxic aquatic biological effects (Juracek, 2013). Lead- and zinc-contaminated flood plains are a concern, in part, because they represent a long-term source of contamination to the fluvial environment. An important issue is the within-site representativeness of the surficial-soil samples collected. Specifically, the question is whether or not the samples collected provide an acceptable representation of the lead and zinc concentrations at each site for the purpose of characterizing and comparing sites. The distribution of mining-contaminated sediment on flood plains is determined by several factors including the size and density of the contaminated particles, flood-plain width and topography, flood characteristics (frequency, magnitude, duration), and fluvial geomorphic processes. To evaluate within-site representativeness, additional samples were simultaneously collected to assess within-site variability. In this paper, the specific objectives were to: Describe the collection and analysis of surficial-soil samples using a 5-point sampling technique; Describe the collection and analysis of additional surficial-soil samples to assess within-site variability; and Evaluate the within-site representativeness of the original 5-point samples for assessing mining-related contamination.

Conference Paper↗
USGS1997

Two-dimensional habitat modeling in the Yellowstone/Upper Missouri River system

This study is being conducted to provide the aquatic biology component of a decision support system being developed by the U.S. Bureau of Reclamation. In an attempt to capture the habitat needs of Great Plains fish communities we are looking beyond previous habitat modeling methods. Traditional habitat modeling approaches have relied on one-dimensional hydraulic models and lumped compositional habitat metrics to describe aquatic habitat. A broader range of habitat descriptors is available when both composition and configuration of habitats is considered. Habitat metrics that consider both composition and configuration can be adapted from terrestrial biology. These metrics are most conveniently accessed with spatially explicit descriptors of the physical variables driving habitat composition. Two-dimensional hydrodynamic models have advanced to the point that they may provide the spatially explicit description of physical parameters needed to address this problem. This paper reports progress to date on applying two-dimensional hydraulic and habitat models on the Yellowstone and Missouri Rivers and uses examples from the Yellowstone River to illustrate the configurational metrics as a new tool for assessing riverine habitats.

Conference Paper↗
USGS2014

Meteorological variables associated with deep slab avalanches on persistent weak layers

Deep slab avalanches are a particularly challenging avalanche forecasting problem. These avalanches are typically difficult to trigger, yet when they are triggered they tend to propagate far and result in large and destructive avalanches. For this work we define deep slab avalanches as those that fail on persistent weak layers deeper than 0.9m (3 feet), and that occur after February 1st. We utilized a 44-year record of avalanche control and meteorological data from Bridger Bowl Ski Area to test the usefulness of meteorological variables for predicting deep slab avalanches. As in previous studies, we used data from the days preceding deep slab cycles, but we also considered meteorological metrics over the early months of the season. We utilized classification trees for our analyses. Our results showed warmer temperatures in the prior twenty-four hours and more loading over the seven days before days with deep slab avalanches on persistent weak layers. In line with previous research, extended periods of above freezing temperatures led to days with deep wet slab avalanches on persistent weak layers. Seasons with either dry or wet avalanches on deep persistent weak layers typically had drier early months, and often had some significant snow depth prior to those dry months. This paper provides insights for ski patrollers, guides, and avalanche forecasters who struggle to forecast deep slab avalanches on persistent weak layers late in the season.

Conference Paper↗
USGS2010

Flow resistance in open channels with fixed movable bed

In spite of an increasingly large body of research by many investigators, accurate quantitative prediction of open channel flow resistance remains a challenge. In general, the relations between the elements influencing resistance (turbulence, boundary roughness, and channel shape features, such as discrete obstacles, bars, channel curvature, recirculation areas, secondary circulation, etc.) and mean flow variables are complex and poorly understood. This has resulted in numerous approaches to compute friction using many and diverse variables and equally diverse prescriptions for their use. In this paper, a new resistance law for surface (grain) resistance, the resistance due to the flow viscous effects on the channel boundary roughness elements, is presented for the cases of flow in the transition (5 < Re* <70) and fully rough (Re* ≥ 70) turbulent flow regimes, where Re* is the Reynolds number based on shear velocity and sediment particle mean diameter. It is shown that the new law is sensitive to bed movement without requiring previous knowledge of sediment transport conditions. Comparisons between computation and measurements, as well as comparisons with other well-known existing roughness predictors, are presented to demonstrate its accuracy and range of application. It is shown that the method accurately predicts total friction losses in channels and natural rivers with plane beds, regardless of sediment transport conditions. This work is useful to hydraulic engineers involved with the derivation of depth-discharge relations in open channel flow and with the estimation of sediment transport rates for the case of bedload transport.

Conference Paper↗
USGS2016

Field scale test of multi-dimensional flow and morphodynamic simulations used for restoration design analysis

Two- and three-dimensional morphodynamic simulations are becoming common in studies of channel form and process. The performance of these simulations are often validated against measurements from laboratory studies. Collecting channel change information in natural settings for model validation is difficult because it can be expensive and under most channel forming flows the resulting channel change is generally small. Several channel restoration projects designed in part to armor large meanders with several large spurs constructed of wooden piles on the Kootenai River, ID, have resulted in rapid bed elevation change following construction. Monitoring of these restoration projects includes post- restoration (as-built) Digital Elevation Models (DEMs) as well as additional channel surveys following high channel forming flows post-construction. The resulting sequence of measured bathymetry provides excellent validation data for morphodynamic simulations at the reach scale of a real river. In this paper we test the performance a quasi-three-dimensional morphodynamic simulation against the measured elevation change. The resulting simulations predict the pattern of channel change reasonably well but many of the details such as the maximum scour are under predicted.

Conference Paper↗
USGS2016

Noncontact methods for measuring water-surface elevations and velocities in rivers: Implications for depth and discharge extraction

Recently developed optical and videographic methods for measuring water-surface properties in a noninvasive manner hold great promise for extracting river hydraulic and bathymetric information. This paper describes such a technique, concentrating on the method of infrared videog- raphy for measuring surface velocities and both acoustic (laboratory-based) and laser-scanning (field-based) techniques for measuring water-surface elevations. In ideal laboratory situations with simple flows, appropriate spatial and temporal averaging results in accurate water-surface elevations and water-surface velocities. In test cases, this accuracy is sufficient to allow direct inversion of the governing equations of motion to produce estimates of depth and discharge. Unlike other optical techniques for determining local depth that rely on transmissivity of the water column (bathymetric lidar, multi/hyperspectral correlation), this method uses only water-surface information, so even deep and/or turbid flows can be investigated. However, significant errors arise in areas of nonhydrostatic spatial accelerations, such as those associated with flow over bedforms or other relatively steep obstacles. Using laboratory measurements for test cases, the cause of these errors is examined and both a simple semi-empirical method and computational results are presented that can potentially reduce bathymetric inversion errors.

Conference Paper↗
USGS2009

Adaptive management of watersheds and related resources

The concept of learning about natural resources through the practice of management has been around for several decades and by now is associated with the term adaptive management. The objectives of this paper are to offer a framework for adaptive management that includes an operational definition, a description of conditions in which it can be usefully applied, and a systematic approach to its application. Adaptive decisionmaking is described as iterative, learning-based management in two phases, each with its own mechanisms for feedback and adaptation. The linkages between traditional experimental science and adaptive management are discussed.

Conference Paper↗
USGS2009

An ecosystem services framework for multidisciplinary research in the Colorado River headwaters

A rapidly spreading Mountain Pine Beetle epidemic is killing lodgepole pine forest in the Rocky Mountains, causing landscape change on a massive scale. Approximately 1.5 million acres of lodgepoledominated forest is already dead or dying in Colorado, the infestation is still spreading rapidly, and it is expected that in excess of 90 percent of all lodgepole forest will ultimately be killed. Drought conditions combined with dramatically reduced foliar moisture content due to stress or mortality from Mountain Pine Beetle have combined to elevate the probability of large fires throughout the Colorado River headwaters. Large numbers of homes in the wildland-urban interface, an extensive water supply infrastructure, and a local economy driven largely by recreational tourism make the potential costs associated with such a fire very large. Any assessment of fire risk for strategic planning of pre-fire management actions must consider these and a host of other important socioeconomic benefits derived from the Rocky Mountain Lodgepole Pine Forest ecosystem. This paper presents a plan to focus U.S. Geological Survey (USGS) multidisciplinary fire/beetle-related research in the Colorado River headwaters within a framework that integrates a wide variety of discipline-specific research to assess and value the full range of ecosystem services provided by the Rocky Mountain Lodgepole Pine Forest ecosystem. Baseline, unburned conditions will be compared with a hypothetical, fully burned scenario to (a) identify where services would be most severely impacted, and (b) quantify potential economic losses. Collaboration with the U.S. Forest Service will further yield a distributed model of fire probability that can be used in combination with the ecosystem service valuation to develop comprehensive, distributed maps of fire risk in the Upper Colorado River Basin. These maps will be intended for use by stakeholders as a strategic planning tool for pre-fire management activities and can be updated and improved adaptively on an annual basis as tree mortality, climatic conditions, and management actions unfold.

Conference Paper↗
USGS2006

Applications of geophysical methods to volcano monitoring

The array of geophysical technologies used in volcano hazards studies - some developed originally only for volcano monitoring - ranges from satellite remote sensing including InSAR to leveling and EDM surveys, campaign and telemetered GPS networks, electronic tiltmeters and strainmeters, airborne magnetic and electromagnetic surveys, short-period and broadband seismic monitoring, even microphones tuned for infrasound. They include virtually every method used in resource exploration except large-scale seismic reflection. By “geophysical ” we include both active and passive methods as well as geodetic technologies. Volcano monitoring incorporates telemetry to handle high-bandwith cameras and broadband seismometers. Critical geophysical targets include the flux of magma in shallow reservoir and lava-tube systems, changes in active hydrothermal systems, volcanic edifice stability, and lahars. Since the eruption of Mount St. Helens in Washington State in 1980, and the eruption at Pu’u O’o in Hawai’i beginning in 1983 and still continuing, dramatic advances have occurred in monitoring technology such as “crisis GIS” and lahar modeling, InSAR interferograms, as well as gas emission geochemistry sampling, and hazards mapping and eruption predictions. The on-going eruption of Mount St. Helens has led to new monitoring technologies, including advances in broadband Wi-Fi and satellite telemetry as well as new instrumentation. Assessment of the gap between adequate monitoring and threat at the 169 potentially dangerous Holocene volcanoes shows where populations are dangerously exposed to volcanic catastrophes in the United States and its territories . This paper focuses primarily on Hawai’ian volcanoes and the northern Pacific and Cascades volcanoes. The US Geological Survey, the US National Park System, and the University of Utah cooperate in a program to monitor the huge Yellowstone volcanic system, and a separate observatory monitors the restive Long Valley caldera in collaboration with the US Forest Service.

Conference Paper↗
USGS2016

Undergraduate research projects help promote diversity in the geosciences

A workforce that draws from all segments of society and mirrors the ethnic, racial, and gender diversity of the United States population is important. The geosciences (geology, hydrology, geospatial sciences, environmental sciences) continue to lag far behind other science, technology, engineering and mathematical (STEM) disciplines in recruiting and retaining minorities (Valsco and Valsco, 2010). A report published by the National Science Foundation in 2015, “Women, Minorities, and Persons with Disabilities in Science and Engineering” states that from 2002 to 2012, less than 2% of the geoscience degrees were awarded to African-American students. Data also show that as of 2012, approximately 30% of African-American Ph.D. graduates obtained a bachelor’s degree from a Historic Black College or University (HBCU), indicating that HBCUs are a great source of diverse students for the geosciences. This paper reviews how an informal partnership between Tennessee State University (a HBCU), the U.S. Geological Survey, and Mammoth Cave National Park engaged students in scientific research and increased the number of students pursuing employment or graduate degrees in the geosciences.

Conference Paper↗