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Results for “Nature Water”

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At least 1,459 records · Page 81Linked to original sources

USGS1997

A physically-based method for predicting peak discharge of floods caused by failure of natural and constructed earthen dams

We analyse a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V.D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether < ??? 1 or < ??? 1. Theoretical predictions agree well with data from dam failures for which k could be reasonably estimated. The analysis provides a rapid and in many cases graphical way to estimate plausible values of Qp at the breach.We analyze a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V/D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether ?????1 or ?????1. Theoretical predictions agree well with data from dam failures for which k could be reasonably estimated. The analysis provides a rapid and in many cases graphical way to estimate plausible values of Qp at the breach.

Destructive water: water-caused natural disasters,↗

USGS2001

Relation of shallow water quality in the Central Oklahoma Aquifer to geology, soils, and land use

The purpose of this report is to identify, describe, and explain relations between natural and land-use factors and ground-water quality in the Central Oklahoma aquifer NAWQA study unit. Natural factors compared to water quality included the geologic unit in which the sampled wells were completed and the properties of soils in the areas surrounding the wells. Land-use factors included types of land use and population densities surrounding sampled wells. Ground-water quality was characterized by concentrations of inorganic constituents, and by frequencies of detection of volatile organic compounds and pesticides. Water-quality data were from samples collected from wells 91 meters (300 feet) or less in depth as part of Permian and Quaternary geologic unit survey networks and from an urban survey network. Concentrations of many inorganic constituents were significantly related to geology. In addition, concentrations of many inorganic constituents were greater in water from wells from the Oklahoma City urban sampling network than in water from wells from low-density survey networks designed to evaluate ambient water quality in the Central Oklahoma aquifer study unit. However, sampling bias may have been induced by differences in hydrogeologic factors between sampling networks, limiting the ability to determine land-use effects on concentrations of inorganic constituents. Frequencies of detection of pesticide and volatile organic compounds (VOC's) in ground-water samples were related to land use and population density, with these compounds being more frequently detected in densely-populated areas. Geology and soil properties were not significantly correlated to pesticide or VOC occurrence in ground water. Lesser frequencies of detection of pesticides in water from wells in rural areas may be due to low to moderate use of those compounds on agricultural lands in the study unit, with livestock production being the primary agricultural activity. There are many possible sources of pesticides and VOC's in the urban areas of Central Oklahoma. Because only existing water-supply wells were sampled, it is not clear from the data collected whether pesticides and VOC's: (1) occur in low concentrations throughout upper portions of the aquifer in urban areas, or (2) are present in ground water only in the immediate vicinity of the wells due to back-flow of those chemicals into the wells or to inflow around cement seals and through gravel packs surrounding well casings of surface runoff containing those compounds.

Oklahoma↗

USGS1984

Wave-formed structures and paleoenvironmental reconstruction

Wave-formed sedimentary structures can be powerful interpretive tools because they reflect not only the velocity and direction of the oscillatory currents, but also the length of the horizontal component of orbital motion and the presence of velocity asymmetry within the flow. Several of these aspects can be related through standard wave theories to combinations of wave dimensions and water depth that have definable natural limits. For a particular grain size, threshold of particle movement and that of conversion from a rippled to flat bed indicate flow-velocity limits. The ratio of ripple spacing to grain size provides an estimate of the length of the near-bottom orbital motion. The degree of velocity asymmetry is related to the asymmetry of the bedforms, though it presently cannot be estimated with confidence. A plot of water depth versus wave height (h-H diagram) provides a convenient approach for showing the combination of wave parameters and water depths capable of generating any particular structure in sand of a given grain size. Natural limits on wave height and inferences or assumptions regarding either water depth or wave period based on geologic evidence allow refinement of the paleoenvironmental reconstruction. The assumptions and the degree of approximation involved in the different techniques impose significant constraints. Inferences based on wave-formed structures are most reliable when they are drawn in the context of other evidence such as the association of sedimentary features or progradational sequences.

Marine Geology↗

USGS2004

Impacts of water development on aquatic macroinvertebrates, amphibians, and plants in wetlands of a semi-arid landscape

We compared the macroinvertebrate and amphibian communities of 12 excavated and 12 natural wetlands in western North Dakota, USA, to assess the effects of artificially lengthened hydroperiods on the biotic communities of wetlands in this semi-arid region. Excavated wetlands were much deeper and captured greater volumes of water than natural wetlands. Most excavated wetlands maintained water throughout the study period (May to October 1999), whereas most of the natural wetlands were dry by June. Excavated wetlands were largely unvegetated or contained submergent and deep-marsh plant species. The natural wetlands had two well-defined vegetative zones populated by plant species typical of wet meadows and shallow marshes. Excavated wetlands had a richer aquatic macroinvertebrate community that included several predatory taxa not found in natural wetlands. Taxa adapted to the short hydroperiods of seasonal wetlands were largely absent from excavated wetlands. The amphibian community of natural and excavated wetlands included the boreal chorus frog ( Pseudacris maculata ), northern leopard frog ( Rana pipiens ), plains spadefoot ( Scaphiopus bombifrons ), Woodhouse's toad ( Bufo woodhousii woodhousii ), and tiger salamander ( Ambystoma tigrinum ). The plains spadefoot occurred only in natural wetlands while tiger salamanders occurred in all 12 excavated wetlands and only one natural wetland. Boreal chorus frogs and northern leopard frogs were present in both wetland types; however, they successfully reproduced only in wetlands lacking tiger salamanders. Artificially extending the hydroperiod of wetlands by excavation has greatly influenced the composition of native biotic communities adapted to the naturally short hydroperiods of wetlands in this semi-arid region. The compositional change of the biotic communities can be related to hydrological changes and biotic interactions, especially predation related to excavation.

Aquatic Ecosystem Health & Management↗

USGS2024

Greenness and actual evapotranspiration in the unrestored riparian corridor of the Colorado River Delta in response to in-channel water deliveries in 2021 and 2022

Natural resource managers may utilize remotely sensed data to monitor vegetation within their decision-making frameworks for improving habitats. Under binational agreements between the United States and Mexico, seven reaches were targeted for riparian habitat enhancement. Monitoring was carried out using Landsat 8 16-day intervals of the two-band enhanced vegetation index 2 (EVI2) for greenness and actual evapotranspiration (ETa). In-channel water was delivered in 2021 and 2022 at four places in Reach 4. Three reaches (Reaches 4, 5 and 7) showed no discernable difference in EVI2 from reaches that did not receive in-channel water (Reaches 1, 2, 3 and 6). EVI2 in 2021 was higher than 2020 in all reaches except Reach 3, and EVI2 in 2022 was lower than 2021 in all reaches except Reach 7. ET(EVI2) was higher in 2020 than in 2021 and 2022 in all seven reaches; it was highest in Reach 4 (containing restoration sites) in all years. Excluding restoration sites, compared with 2020, unrestored reaches showed that EVI2 minimally increased in 2021 and 2022, while ET(EVI2) minimally decreased despite added water in 2021–2022. Difference maps comparing 2020 (no-flow year) to 2021 and 2022 (in-channel flows) reveal areas in Reaches 5 and 7 where the in-channel flows increased greenness and ET(EVI2).

Colorado River and Delta↗

USGS2015

Monitoring, field experiments, and geochemical modeling of Fe(II) oxidation kinetics in a stream dominated by net-alkaline coal-mine drainage, Pennsylvania, USA

Watershed-scale monitoring, field aeration experiments, and geochemical equilibrium and kinetic modeling were conducted to evaluate interdependent changes in pH, dissolved CO 2 , O 2 , and Fe(II) concentrations that typically take place downstream of net-alkaline, circumneutral coal-mine drainage (CMD) outfalls and during aerobic treatment of such CMD. The kinetic modeling approach, using PHREEQC, accurately simulates observed variations in pH, Fe(II) oxidation, alkalinity consumption, and associated dissolved gas concentrations during transport downstream of the CMD outfalls (natural attenuation) and during 6-h batch aeration tests on the CMD using bubble diffusers (enhanced attenuation). The batch aeration experiments demonstrated that aeration promoted CO 2 outgassing, thereby increasing pH and the rate of Fe(II) oxidation. The rate of Fe(II) oxidation was accurately estimated by the abiotic homogeneous oxidation rate law −d[Fe(II)]/d t = k 1 ·[O 2 ]·[H + ] − 2 ·[Fe(II)] that indicates an increase in pH by 1 unit at pH 5–8 and at constant dissolved O 2 (DO) concentration results in a 100-fold increase in the rate of Fe(II) oxidation. Adjusting for sample temperature, a narrow range of values for the apparent homogeneous Fe(II) oxidation rate constant ( k 1 ′) of 0.5–1.7 times the reference value of k 1 = 3 × 10 −12 mol/L/min (for pH 5–8 and 20 °C), reported by Stumm and Morgan (1996), was indicated by the calibrated models for the 5-km stream reach below the CMD outfalls and the aerated CMD. The rates of CO 2 outgassing and O 2 ingassing in the model were estimated with first-order asymptotic functions, whereby the driving force is the gradient of the dissolved gas concentration relative to equilibrium with the ambient atmosphere. Although the progressive increase in DO concentration to saturation could be accurately modeled as a kinetic function for the conditions evaluated, the simulation of DO as an instantaneous equilibrium process did not affect the model results for Fe(II) or pH. In contrast, the model results for pH and Fe(II) were sensitive to the CO 2 mass transfer rate constant ( k L , CO2 a). The value of k L , CO2 a estimated for the stream (0.010 min −1 ) was within the range for the batch aeration experiments (0–0.033 min −1 ). These results indicate that the abiotic homogeneous Fe(II) oxidation rate law, with adjustments for variations in temperature and CO 2 outgassing rate, may be applied to predict changes in aqueous iron and pH for net-alkaline, ferruginous waters within a stream (natural conditions) or a CMD treatment system (engineered conditions).

Pennsylvania↗

USGS1976

Reassessment of mercury in surface water in the Adirondack region, New York

A study in 1970 established a natural background concentration of mercury in surface water in the Adirondack region of New York. In 1974, new methods of sample preservation and analysis were used in determining concentrations of mercury of samples of water from the same surface-water sites sampled in 1970-71. Concentrations of mercury for all sites in the 1974 study were virtually the same as those obtained in 1970-71, less than 0.5 microgram per litre, which is the detection limit of the methods.

New York↗

USGS2013

Analyzing the water budget and hydrological characteristics and responses to land use in a monsoonal climate river basin in South China

Hydrological models have been increasingly used by hydrologists and water resource managers to understand natural processes and human activities that affect watersheds. In this study, we use the physically based model, Soil and Water Assessment Tool (SWAT), to investigate the hydrological processes in the East River Basin in South China, a coastal area dominated by monsoonal climate. The SWAT model was calibrated using 8-year (1973–1980) record of the daily streamflow at the basin outlet (Boluo station), and then validated using data collected during the subsequent 8 years (1981–1988). Statistical evaluation shows that SWAT can consistently simulate the streamflow of the East River with monthly Nash–Sutcliffe efficiencies of 0.93 for calibration and 0.90 for validation at the Boluo station. We analyzed the model simulations with calibrated parameters, presented the spatiotemporal distribution of the key hydrological components, and quantified their responses to different land uses. Watershed managers can use the results of this study to understand hydrological features and evaluate water resources of the East River in terms of sustainable development and effective management.

Environmental Management↗

USGS2007

Klamath Basin: A watershed approach to support habitat restoration, species recovery, and water resource planning

Water allocation among human and natural resource uses in the American West is challenging. Western rivers have been largely managed for hydropower, irrigation, drinking water, and navigation. Today land and water use practices have gained importance, particularly as aging dams are faced with re-licensing requirements and provisions of the Endangered Species and Clean Water Acts. Rising demand for scarce water heightens the need for scientific research to predict consequences of management actions on habitats, human resource use, and fish and wildlife. Climate change, introduction of invasive species, or restoration of fish passage can have large, landscape-scaled consequences - research must expand to encompass the appropriate scale and by applying multiple scientific disciplines to complex ecosystem challenges improve the adaptive management framework for decision-making.

Oregon; California↗

USGS1995

Evaluating barnyard Best Management Practices in Wisconsin using upstream-downstream monitoring

The Nonpoint Source Water Pollution Abatement Program was created in 1978 by the Wisconsin Legislature. The goal of the program is to improve and protect the water quality of lakes, streams, wetlands, and ground water within selected priority watersheds by controlling sources of nonpoint pollution. For each selected watershed, the Wisconsin Department of Natural Resources drafts a management plan that guides the implementation of pollution-control strategies known as Best Management Practices (BMP's). This plan summarizes resource and land-use inventories, describes the results of pollution-source modeling, and suggests pollution reduction goals. The U.S. Geological Survey, through a cooperative effort with the Wisconsin Department of Natural Resources, is monitoring water-quality improvements that result from the implementation of BMP's. The data collected are then compared to the watershed plans to assess progress and determine whether goals are being realized. This fact sheet describes the data-collection efforts, preliminary results, and planned data-analysis techniques of monitoring projects for pre-BMP conditions at two barnyards, one each on Otter Creek and Halfway Prairie Creek.

Wisconsin↗

USGS1976

Historical review of the international water-resources program of the U.S. Geological Survey, 1940-70

The review describes the history of the U.S. Geological Survey 's (USGS) activities in international water-resources investigations and institutional development as well as exchange in scientific and applied hydrology during 1940-70. The bulk of these activities has been carried out under the auspices of the U.S. Department of State, U.S. Agency for International Development and its predecessors, the United Nations and its specialized agencies, and the regional intergovernmental agencies. The central objectives of the USGS ' international water-resources activities have been to strengthen the administrative, staff, and operational functions of counterpart governmental hydrological and water-resources agencies; to improve the skills and capabilities of host-country scientific, engineering, and technical personnel; to exchange research specialists and publications in the sharing of advances in hydrological knowledge and methodology; and to participate in mutually beneficial international organizations, symposia, conferences, seminars, and special programs dedicated to various aspects of scientific and applied hydrology. Between 1940 and 1970, USGS hydrogeologists, water chemists, engineers, and hydrologists completed 340 short- and long-term project-oriented international assignments in some 80 host countries. During the same time more than 428 water scientists, engineers, and technicians from 60 countries have received academic and in-service training through USGS water-resources facilities in the United States. Also in this period some 336 reports of a technical and scientific nature have resulted from water-resources projects in the U.S bilateral program. (Woodard-USGS)

Professional Paper↗

USGS1988

Changes in the morphometry of Las Vegas Wash and the impact on water quality

Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mean. Over 80 percent of the normal discharge of approximately 3.4 m 3 /s (120 ft 3 /s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly reduced the wetland area within Las Vegas Wash. The reduction in wetland area shortened water travel time in the wash and affected water quality. The primary impacts on the water entering Lake Mead have been an increase in temperature, a decrease in dissolved oxygen concentration, and an increase in ammonia levels. Other physical-chemical parameters and changes in nutrient transformations are also discussed.

Nevada↗

USGS2018

Review and development of ASABE Engineering Practice 621: “Guidelines for calibrating, validating, and evaluating hydrologic and water quality models”

In 2010, the Natural Resources and Environmental Systems Hydrology Committee (NRES-21) of ASABE initiated a long-term process to develop guidelines to improve modeling practice through better understanding of the calibration, validation, and evaluation process across applications and more effective interpretation and communication of model performance. This effort generated a compilation of 23 articles with model-specific descriptions and guidance (2012), a position paper outlining guidance for evaluating, interpreting, and communicating performance of hydrologic and water quality models considering intended use (2014), and a compilation of ten articles addressing key topics related to model calibration and validation (2015). In 2016, the first draft of ASABE Engineering Practice 621 (EP621), â€œGuidelines for Calibrating, Validating, and Evaluating Hydrologic and Water Quality (H/WQ) Models,â€ was developed, subsequently revised, and ultimately approved by the ASABE Standards Committee in 2017. EP621 provides guidelines, not prescriptive requirements, and as such recommends â€œgoodâ€ modeling practices to enhance calibration, validation, evaluation, and communication of H/WQ models through establishment of consistent terminology; model selection; compilation and processing of input data and calibration, validation, and evaluation data; determination of model performance measures; model parameterization and calibration; re-examination of input and calibration data and/or consideration of model refinement; re-evaluation of model performance; and documentation of modeling process and results. EP621 can be obtained from the ASABE Technical Library at https://elibrary.asabe.org/abstract.asp?aid=47804. The objectives of this technical note are to review the process and rationale used to develop EP621 and to briefly summarize its major components.

Transactions of the ASABE↗

USGS1984

Present and proposed ground-water-level program in Maine

A statewide observation-well program was designed for Maine. Three networks were designed to provide reliable data to describe the effects of natural and manmade stress on water levels in the State. They are a climatic-effects network, a terrain-effects network, and a local-effects network. Review of the 32 observation wells in the current program showed that only 17 wells should be retained. Each of these wells was assigned to one of the three types of networks. Fourteen wells were deactivated because of reliability problems and one was deactivated because it provided redundant data. The installation of seven additional wells in climatic-effects network is the highest priority of the proposed program. The next priority is to install 22 additional wells in the terrain-effects network. Implementation of local-effects network sites will be responsive to increases in ground-water usage and the data needs of water-resources managers. (USGS)

Water-Resources Investigations Report↗

USGS2013

Preliminary groundwater flow model of the basin-fill aquifers in Detrital, Hualapai, and Sacramento Valleys, Mohave County, northwestern Arizona

Preliminary numerical models were developed to simulate groundwater flow in the basin-fill alluvium in Detrital, Hualapai, and Sacramento Valleys in northwestern Arizona. The purpose of this exercise was to gather and evaluate available information and data, to test natural‑recharge concepts, and to indicate directions for improving future regional groundwater models of the study area. Both steady-state and transient models were developed with a single layer incorporating vertically averaged hydraulic properties over the model layer. Boundary conditions for the models were constant-head cells along the northern and western edges of the study area, corresponding to the location of the Colorado River, and no-flow boundaries along the bedrock ridges that bound the rest of the study area, except for specified flow where Truxton Wash enters the southern end of Hualapai Valley. Steady-state conditions were simulated for the pre-1935 period, before the construction of Hoover Dam in the northwestern part of the model area. Two recharge scenarios were investigated using the steady-state model—one in which natural aquifer recharge occurs directly in places where water is available from precipitation, and another in which natural aquifer recharge from precipitation occurs in the basin-fill alluvium that drains areas of available water. A transient model with 31 stress periods was constructed to simulate groundwater flow for the period 1935–2010. The transient model incorporates changing Colorado River, Lake Mead, and Lake Mohave water levels and includes time-varying groundwater withdrawals and aquifer recharge. Both the steady-state and transient models were calibrated to available water-level observations in basin-f ill alluvium, and simulations approximate observed water-level trends throughout most of the study area.

Arizona↗

USGS1999

Ground-water, large-lake interactions in Saginaw Bay, Lake Huron: A geochemical and isotopic approach

Delineating the nature and extent of ground-water inputs is necessary to understand the hydrochemistry of large lakes. Characterizing the interaction between ground water and large lakes (e.g., the Great Lakes) is facilitated by the use of geochemical and isotopic data. In this study, pore waters were extracted from sediment cores collected from Saginaw Bay and the surrounding Saginaw lowland area; the geochemistry and stable isotope signature of these pore waters were used to identify sources for the water and solutes. Cores from Saginaw Bay and the Saginaw lowland area yielded strong vertical gradients in chloride concentrations, suggesting that a high-chloride source is present at depth. The spatial distribution of cores with elevated chloride concentrations corresponds to the regional distribution of chloride in ground water. Most of the Saginaw lowland area cores contain water with significantly lower δ 18 O values than modern meteoric water, suggesting that the water had been recharged during a much cooler climate. The δ 18 O values measured in pore waters (from Saginaw Bay cores) containing high chloride concentrations are similar to modern meteoric water; however, values lighter than modern meteoric water are encountered at depth. Chloride:bromide ratios, used to distinguish between different chloride sources, identify formation brine as the likely source for chloride. Transport models indicate that a combination of advection and diffusion is responsible for the observed Saginaw lowland area pore-water profiles. Pore-water profiles in Saginaw Bay sediments are produced primarily by diffusion and require significantly less time to evolve. An upward flux of solutes derived from formation brine could occur elsewhere within the Great Lakes region and significantly affect the geochemical cycling of chloride and other contaminants (e.g., trace metals).

Michigan↗

USGS2017

A framework for modeling connections between hydraulics, water surface roughness, and surface reflectance in open channel flows

This paper introduces a framework for examining connections between the flow field, the texture of the air-water interface, and the reflectance of the water surface and thus evaluating the potential to infer hydraulic information from remotely sensed observations of surface reflectance. We used a spatial correlation model describing water surface topography to illustrate the application of our framework. Nondimensional relations between model parameters and flow intensity were established based on a prior flume study. Expressing the model in the spatial frequency domain allowed us to use an efficient Fourier transform-based algorithm for simulating water surfaces. Realizations for both flume and field settings had water surface slope distributions positively correlated with velocity and water surface roughness. However, most surface facets were gently sloped and thus unlikely to yield strong specular reflections; the model exaggerated the extent of water surface features, leading to underestimation of facet slopes. A ray tracing algorithm indicated that reflectance was greatest when solar and view zenith angles were equal and the sensor scanned toward the Sun to capture specular reflections of the solar beam. Reflected energy was concentrated in a small portion of the sky, but rougher water surfaces reflected rays into a broader range of directions. Our framework facilitates flight planning to avoid surface-reflected radiance while mapping other river attributes, or to maximize this component to exploit relationships between hydraulics and surface reflectance. This initial analysis also highlighted the need for improved models of water surface topography in natural rivers.

Journal of Geophysical Research F: Earth Surface↗

USGS2015

Aerobic biodegradation potential of endocrine disrupting chemicals in surface-water sediment at Rocky Mountains National Park, USA

Endocrine disrupting chemicals (EDC) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDC, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountains National Park (ROMO). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 14 C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. ROMO bed sediment microbial communities also effectively degraded the xenoestrogens, bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The current results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged.

Rocky Mountain National Park↗