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At least 1,297 records · Page 72Linked to original sources
USGS1990

Ground-water control of evaporite deposition

Topographically closed basins may be hydrologically open as a result of seepage losses to underlying or surrounding ground-water systems. In such cases, these losses can have a substantial control over the suite and the thicknesses of evaporite minerals formed in the basin. The ratio of ground-water outflow to inflow (flux ratio) in hydrologically open basins is as important in determining the mineralogy and thicknesses of evaporite deposits as the solute composition of the inflow water. Attainment of steady state flux ratios permits large thicknesses of two or three minerals to form rather than thin veneers of many minerals. The presence or absence of glauberite, mirabilite, halite, bloedite, polyhalite, and hexahydrite, caused by subtle changes in the ground-water seepage is illustrated using an example from the Southern High Plains of Texas and New Mexico. However, the model is general and is applicable with any solute composition including that of seawater and the use of surface rather than ground water. An analytical, lumped parameter, solute mass balance model is developed to define the concept of a ground-water flux ratio as it applies to topographically closed basins in which evaporation exceeds precipitation. Diffusion, advection, and density-driven flow are proposed as mechanisms by which solutes can escape to the ground water from these closed basins. The geochemical reaction computer program PHRQPITZ is used to document the effects of various flux ratios on the mineralogy and thickness of deposits. Solute analyses used in conjunction with the model can be used to screen prospective basins as well as to provide insights for exploratory drilling program.

Texas, New Mexico↗
USGS1999

Spatial Data Transfer Standard (SDTS)

The American National Standards Institute?s (ANSI) Spatial Data Transfer Standard (SDTS) is a mechanism for archiving and transferring of spatial data (including metadata) between dissimilar computer systems. The SDTS specifies exchange constructs, such as format, structure, and content, for spatially referenced vector and raster (including gridded) data. The SDTS includes a flexible conceptual model, specifications for a quality report, transfer module specifications, data dictionary specifications, and definitions of spatial features and attributes.

Fact Sheet↗
USGS2014

Earthquake mechanism and seafloor deformation for tsunami generation

Tsunamis are generated in the ocean by rapidly displacing the entire water column over a significant area. The potential energy resulting from this disturbance is balanced with the kinetic energy of the waves during propagation. Only a handful of submarine geologic phenomena can generate tsunamis: large-magnitude earthquakes, large landslides, and volcanic processes. Asteroid and subaerial landslide impacts can generate tsunami waves from above the water. Earthquakes are by far the most common generator of tsunamis. Generally, earthquakes greater than magnitude (M) 6.5–7 can generate tsunamis if they occur beneath an ocean and if they result in predominantly vertical displacement. One of the greatest uncertainties in both deterministic and probabilistic hazard assessments of tsunamis is computing seafloor deformation for earthquakes of a given magnitude.

Book chapter↗
USGS2008

Bathymetric Survey and Storage Capacity of Upper Lake Mary near Flagstaff, Arizona

Upper Lake Mary is a preferred drinking-water source for the City of Flagstaff, Arizona. Therefore, storage capacity and sedimentation issues in Upper Lake Mary are of interest to the City. The U.S. Geological Survey, in cooperation with the City of Flagstaff, collected bathymetric and land-survey data in Upper Lake Mary during late August through October 2006. Water-depth data were collected using a single-beam, high-definition fathometer. Position data were collected using real-time differential global position system receivers. Data were processed using commercial software and imported into geographic information system software to produce contour maps of lakebed elevations and for the computation of area and storage-capacity information. At full pool (spillway elevation of 6,828.5 feet above mean sea level), Upper Lake Mary has a storage capacity of 16,300 acre-feet, a surface area of 939 acres, a mean depth of 17.4 feet, and a depth near the dam of 39 feet. It is 5.6 miles long and varies in width from 308 feet near the central, narrow portion of the lake to 2,630 feet in the upper portion. Comparisons between this survey and a previous survey conducted in the 1950s indicate no apparent decrease in reservoir area or storage capacity between the two surveys.

Open-File Report↗
USGS2016

Bathymetric survey and estimation of storage capacity of lower Sixmile Creek reservoir, Ithaca, New York

During 2015, the U.S. Geological Survey, in cooperation with the City of Ithaca, New York, and the New York State Department of State, conducted a bathymetric survey of the lower Sixmile Creek reservoir in Tompkins County, New York. A former water-supply reservoir for the City of Ithaca, the reservoir is no longer a functional component of Ithaca’s water-supply system, having been replaced by a larger reservoir less than a mile upstream in 1911. Excessive sedimentation has substantially reduced the reservoir’s water-storage capacity and made the discharge gate at the base of the 30-foot dam, which creates the reservoir, inoperable. U.S. Geological Survey personnel collected bathymetric data by using an acoustic Doppler current profiler. Across more than half of the approximately 14-acre reservoir, depths were manually measured because of interference from aquatic vegetation with the acoustic Doppler current profiler. City of Ithaca personnel created a bottom-elevation surface from these depth data. A second surface was created from depths that were manually measured by City of Ithaca personnel during 1938. Surface areas and storage capacities were computed at 1-foot increments of elevation for both bathymetric surveys. The results indicate that the current storage capacity of the reservoir at its normal water-surface elevation is about 84 acre-feet and that sediment accumulated between 1938 and 2015 has decreased the reservoir’s capacity by about 68 acre-feet. This sediment load is attributed to annual inputs from the watershed above the reservoir, as well as from an episodic landslide that filled a large part of the reservoir along its northern edge in 1949.

New York↗
USGS2006

Synthesis of monthly and annual streamflow records (water years 1950-2003) for Big Sandy, Clear, Peoples, and Beaver Creeks in the Milk River basin, Montana

To address concerns expressed by the State of Montana about the apportionment of water in the St. Mary and Milk River basins between Canada and the United States, the International Joint Commission requested information from the United States government about water that originates in the United States but does not cross the border into Canada. In response to this request, the U.S. Geological Survey synthesized monthly and annual streamflow records for Big Sandy, Clear, Peoples, and Beaver Creeks, all of which are in the Milk River basin in Montana, for water years 1950-2003. This report presents the synthesized values of monthly and annual streamflow for Big Sandy, Clear, Peoples, and Beaver Creeks in Montana. Synthesized values were derived from recorded and estimated streamflows. Statistics, including long-term medians and averages and flows for various exceedance probabilities, were computed from the synthesized data. Beaver Creek had the largest median annual discharge (19,490 acre-feet), and Clear Creek had the smallest median annual discharge (6,680 acre-feet). Big Sandy Creek, the stream with the largest drainage area, had the second smallest median annual discharge (9,640 acre-feet), whereas Peoples Creek, the stream with the second smallest drainage area, had the second largest median annual discharge (11,700 acre-feet). The combined median annual discharge for the four streams was 45,400 acre-feet. The largest combined median monthly discharge for the four creeks was 6,930 acre-feet in March, and the smallest combined median monthly discharge was 48 acre-feet in January. The combined median monthly values were substantially smaller than the average monthly values. Overall, synthesized flow records for the four creeks are considered to be reasonable given the prevailing climatic conditions in the region during the 1950-2003 base period. Individual estimates of monthly streamflow may have large errors, however. Linear regression was used to relate logarithms of combined annual streamflow to water years 1950-2003. The results of the regression analysis indicated a significant downward trend (regression line slope was -0.00977) for combined annual streamflow. A regression analysis using data from 1956-2003 indicated a slight, but not significant, downward trend for combined annual streamflow.

Scientific Investigations Report↗
USGS2011

Flash floods of August 10, 2009, in the Villages of Gowanda and Silver Creek, New York

Late during the night of August 9, 2009, two storm systems intersected over western New York and produced torrential rain that caused severe flash flooding during the early morning hours of August 10 in parts of Cattaraugus, Chautauqua, and Erie Counties. Nearly 6 inches of rain fell in 1.5 hours as recorded by a National Weather Service weather observer in Perrysburg, which lies between Gowanda and Silver Creek-the communities that suffered the most damage. This storm intensity had an annual exceedance probability of less than 0.2 percent (recurrence interval greater than 500 years). Although flooding along Cattaraugus Creek occurred elsewhere, Cattaraugus Creek was responsible for very little flooding in Gowanda. Rather the small tributaries, Thatcher Brook and Grannis Brook, caused the flooding in Gowanda, as did Silver Creek and Walnut Creek in the Village of Silver Creek. Damages from the flooding were widespread. Numerous road culverts were washed out, and more than one-quarter of the roads in Cattaraugus County were damaged. Many people were evacuated or rescued in Gowanda and Silver Creek, and two deaths occurred during the flood in Gowanda. The water supplies of both communities were compromised by damages to village reservoirs and water-transmission infrastructures. Water and mud damage to residential and commercial properties was extensive. The tri-county area was declared a Federal disaster area and more than $45 million in Federal disaster assistance was distributed to more than 1,500 individuals and an estimated 1,100 public projects. The combined total estimate of damages from the flash floods was greater than $90 million. Over 240 high-water marks were surveyed by the U.S. Geological Survey; a subset of these marks was used to create flood-water-surface profiles for four streams and to delineate the areal extent of flooding in Gowanda and Silver Creek. Flood elevations exceeded previously defined 0.2-percent annual exceedance probability (500-year recurrence interval) elevations by 2 to 4 feet in Gowanda and as much as 6 to 8 feet in Silver Creek. Most of the high-water marks were used in indirect hydraulic computations to estimate peak flows for four streams. The peak flows in Grannis Brook and Thatcher Brook were computed, using the slope-area method, to be 1,400 and 7,600 cubic feet per second, respectively, and peak flow in Silver Creek was computed, using the width-contraction method, to be 19,500 cubic feet per second. The annual exceedance probabilities for flows in these and other basins with small drainage areas that fell almost entirely within the area of heaviest precipitation were less than 0.2 percent (or recurrence intervals greater than 500 years). The peak flow in Cattaraugus Creek at Gowanda was computed, using the slope-area method, to be 33,200 cubic feet per second with an annual exceedance probability of 2.2 percent (recurrence interval of 45 years).

Scientific Investigations Report↗
USGS1994

An interactive code (NETPATH) for modeling NET geochemical reactions along a flow PATH, version 2.0

NETPATH is an interactive Fortran 77 computer program used to interpret net geochemical mass-balance reactions between an initial and final water along a hydrologic flow path. Alternatively, NETPATH computes the mixing proportions of two to five initial waters and net geochemical reactions that can account for the observed composition of a final water. The program utilizes previously defined chemical and isotopic data for waters from a hydrochemical system. For a set of mineral and (or) gas phases hypothesized to be the reactive phases in the system, NETPATH calculates the mass transfers in every possible combination of the selected phases that accounts for the observed changes in the selected chemical and (or) isotopic compositions observed along the flow path. The calculations are of use in interpreting geochemical reactions, mixing proportions, evaporation and (or) dilution of waters, and mineral mass transfer in the chemical and isotopic evolution of natural and environmental waters. Rayleigh distillation calculations are applied to each mass-balance model that satisfies the constraints to predict carbon, sulfur, nitrogen, and strontium isotopic compositions at the end point, including radiocarbon dating. DB is an interactive Fortran 77 computer program used to enter analytical data into NETPATH, and calculate the distribution of species in aqueous solution. This report describes the types of problems that can be solved, the methods used to solve problems, and the features available in the program to facilitate these solutions. Examples are presented to demonstrate most of the applications and features of NETPATH. The codes DB and NETPATH can be executed in the UNIX or DOS1 environment. This report replaces U.S. Geological Survey Water-Resources Investigations Report 91-4078, by Plummer and others, which described the original release of NETPATH, version 1.0 (dated December, 1991), and documents revisions and enhancements that are included in version 2.0. 1 The use of trade, brand or product names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey.

Water-Resources Investigations Report↗
USGS2022

Absolute accuracy assessment of lidar point cloud using amorphous objects

The accuracy assessment of airborne lidar point cloud typically estimates vertical accuracy by computing RMSEz (root mean square error of the z coordinate) from ground check points (GCPs). Due to the low point density of the airborne lidar point cloud, there is often not enough accurate semantic context to find an accurate conjugate point. To advance the accuracy assessment in full three-dimensional (3D) context, geometric features, such as the three-plane intersection point or two-line intersection point, are often used. Although the point density is still low, geometric features are mathematically modeled from many points. Thus, geometric features provide a robust determination of the intersection point, and the point is considered as a GCP. When no regular built objects are available, we describe the process of utilizing features of irregular shape called amorphous natural objects, such as a tree or a rock. When scanned to a high-density point cloud, an amorphous natural object can be used as ground truth reference data to estimate 3D georeferencing errors of the airborne lidar point cloud. The algorithm to estimate 3D accuracy is the optimization that minimizes the sum of the distance between the airborne lidar points to the ground scanned data. The search volume partitioning was the most important procedure to improve the computational efficiency. We also performed an extensive study to address the external uncertainty associated with the amorphous object method. We describe an accuracy assessment using amorphous objects (108 trees) spread over the project area. The accuracy results for ∆ x , ∆ y , and ∆ z obtained using the amorphous object method were 3.1 cm, 3.6 cm, and 1.7 cm RMSE, along with a mean error of 0.1 cm, 0.1 cm, and 4.5 cm, respectively, satisfying the accuracy requirement of U.S. Geological Survey lidar base specification. This approach shows strong promise as an alternative to geometric feature methods when artificial targets are scarce. The relative convenience and advantages of using amorphous targets, along with its good performance shown here, make this amorphous object method a practical way to perform 3D accuracy assessment.

Remote Sensing↗
USGS2019

Isotopic ratios of Saturn's rings and satellites: Implications for the origin of water and Phoebe

Isotopic ratios have long been used to learn about physical processes acting over a wide range of geological environments, and in constraining the origin and/or evolution of planetary bodies. We report the spectroscopic detection of deuterium in Saturn's rings and satellites, and use these measurements to determine the (D/H) ratios in their near-surface regions. Saturn's moons, Phoebe and Iapetus, show a strong signature of CO2 and the 13C component of this molecule is detected and quantified. Large averages of spectra obtained by the Cassini Visual and Infrared Mapping Spectrometer, VIMS, were computed for the rings and icy satellites. The observed intensities of the infrared absorptions in H2O and CO2 and their isotopes were calibrated using laboratory data and radiative transfer models to derive the D/H and 13C/12C ratios. We find that the D/H in Saturn's rings and satellites is close to the Vienna Standard Mean Ocean Water (VSMOW) and bulk Earth (4% lower than VSMOW) value except for Phoebe, which is 8.3 times the VSMOW value. This is the highest value for any Solar-System surface yet measured, and suggests that Phoebe formed from material with a different D/H ratio than the other satellites in the Saturn system. Phoebe’s 13C/12C ratio is also unusual: 4.7 times greater than terrestrial, and greater than values measured for the interstellar medium and the galactic center. The high 13C abundance in the CO2 suggests that Phoebe was never warm enough for the large D/H ratio in its surface to have originated by evaporative fractionation of its waterice (e.g., from heating in the inner Solar System before its eventual capture by Saturn). We also report the detection of a probable O-D stretch absorption due to OD in minerals on Phoebe at 3.62 μm. This absorption is not detected on other Saturnian satellites. Stronger signatures of bound water absorptions are found in the dark material of Iapetus and we report a new detection of bound water at 1.9 μm. The position of this absorption matches that seen in spectra of hydrated iron oxides but does not match absorptions seen in spectra of tholins. Despite the strong bound water signature in the Iapetus dark material, no 3.62-μm OD absorption is seen in the spectra, further indicating the high deuterium level on Phoebe is unusual. As such, it is likely that Phoebe originated in a colder part of the outer Solar System, relative to the prevailing temperatures at Saturn’s distance from the Sun.

Icarus↗
USGS2005

An efficient algorithm for double-difference tomography and location in heterogeneous media, with an application to the Kilauea volcano

Improving our understanding of crustal processes requires a better knowledge of the geometry and the position of geological bodies. In this study we have designed a method based upon double-difference relocation and tomography to image, as accurately as possible, a heterogeneous medium containing seismogenic objects. Our approach consisted not only of incorporating double difference in tomography but also partly in revisiting tomographic schemes for choosing accurate and stable numerical strategies, adapted to the use of cross-spectral time delays. We used a finite difference solution to the eikonal equation for travel time computation and a Tarantola-Valette approach for both the classical and double-difference three-dimensional tomographic inversion to find accurate earthquake locations and seismic velocity estimates. We estimated efficiently the square root of the inverse model's covariance matrix in the case of a Gaussian correlation function. It allows the use of correlation length and a priori model variance criteria to determine the optimal solution. Double-difference relocation of similar earthquakes is performed in the optimal velocity model, making absolute and relative locations less biased by the velocity model. Double-difference tomography is achieved by using high-accuracy time delay measurements. These algorithms have been applied to earthquake data recorded in the vicinity of Kilauea and Mauna Loa volcanoes for imaging the volcanic structures. Stable and detailed velocity models are obtained: the regional tomography unambiguously highlights the structure of the island of Hawaii and the double-difference tomography shows a detailed image of the southern Kilauea caldera-upper east rift zone magmatic complex. Copyright 2005 by the American Geophysical Union.

Hawaii↗
USGS2011

Hawaii Volcano Observatory 75th anniversary

The 75th anniversary of the founding of the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO) was celebrated during January 1987. The festivities began on January 9 with the opening in Hilo of a major exhibit at the Wailoa Center on the current work of HVO, its history, and its special relationship to Hawaii Volcanoes National Park. In addition to spectacular photographs of volcanic activity and HVO field work, the exhibit featured continuous showings of underwater footage taken during the recent eruptive activity (December 1986) and a computer monitor that displayed the activity of HVO seismic net in real time. The exhibit, which was coordinated by HVO librarian/photo archivist Taeko Jane Takahashi and which featured the professional work of HVO photographer J . D. Griggs, was well received and will probably form the core of a future traveling exhibit.

Hawaii↗
USGS2016

User guide for MODPATH Version 7—A particle-tracking model for MODFLOW

MODPATH is a particle-tracking post-processing program designed to work with MODFLOW, the U.S. Geological Survey (USGS) finite-difference groundwater flow model. MODPATH version 7 is the fourth major release since its original publication. Previous versions were documented in USGS Open-File Reports 89–381 and 94–464 and in USGS Techniques and Methods 6–A41. MODPATH version 7 works with MODFLOW-2005 and MODFLOW–USG. Support for unstructured grids in MODFLOW–USG is limited to smoothed, rectangular-based quadtree and quadpatch grids. A software distribution package containing the computer program and supporting documentation, such as input instructions, output file descriptions, and example problems, is available from the USGS over the Internet ( http://water.usgs.gov/ogw/modpath/) .

Open-File Report↗
USGS1975

Abundances of uranium, thorium, and potassium for some Australian crystalline rocks

This report contains a tabulation of the basic radioelement and radiogenic heat data obtained during an Australian National University (ANU) - United States Geological Survey (USGS) heat-flow project, directed jointly by J. C. Jaeger (ANU) and J. H. Sass (USGS). Most samples were collected during the periods June through September, 1971 and 1972. The measurements were made subsequently by two of us (C. M. Bunker and C. A. Bush) using the gamma-ray spec trometric techniques described by Bunker and Bush (1966, 1967). Interpreting the spectra for quantitative analyses of the radioelements was accomplished with an iterative leastsquares computer program modified from one by Schonfeld (1966). Uranium content determined by gamma-ray spectrometry is based on a measurement of the daughter products of 226 Ra. Equilibrium in the uranium-decay series was assumed for these analyses . Throughout the report, when U content is stated, radium-equivalent uranium is implied. The coefficient of variation for the accuracy of the radioelement data, when compared to ana lyses by isotope dilution and flame photometry is about 3 percent for radium-equivalent uranium and thorium and about 1 percent for potassium. These percentages are in addition to minimum standard deviations of about 0.05 ppm for U and Th, and about 0.03 percent for K.

Open-File Report↗
USGS2005

Implementation and use of direct-flow connections in a coupled ground-water and surface-water model

The U.S. Geological Survey's MODFLOW finite-difference ground-water flow model has been coupled with three surface-water packages - the MODBRANCH, River, and Stream packages - to simulate surface water and its interaction with ground water. Prior to the development of the coupling packages, the only interaction between these modeling packages was that leakage values could be passed between MODFLOW and the three surface-water packages. To facilitate wider and more flexible uses of the models, a computer program was developed and added to MODFLOW to allow direct flows or stages to be passed between any of the packages and MODFLOW. The flows or stages calculated in one package can be set as boundary discharges or stages to be used in another package. Several modeling packages can be used in the same simulation depending upon the level of sophistication needed in the various reaches being modeled. This computer program is especially useful when any of the River, Stream, or MODBRANCH packages are used to model a river flowing directly into or out of wetlands in direct connection with the aquifer and represented in the model as an aquifer block. A field case study is shown to illustrate an application.

Groundwater↗
USGS1979

Streamflow statistical summaries for Colorado streams through September 30, 1975; Volume 2: Colorado River basin above Gunnison River

This report contains statistical summaries of daily streamflow data as of September 30, 1975, for 189 stations west of the Continental Divide in Colorado for use by agencies and individuals engaged in water studies. To be included in this report, a station had to have a minimum of 3 complete water years (October 1 to September 30) of record and 3 complete climatic years (April 1 to March 31) of record having virtually constant effects of regulation and diversion, and to have had streamflow records previously reviewed and published by the U.S. Geological Survey. Duration tables show the distribution of daily discharges for each water year ending September 30. High-flow sequence tables show the highest mean discharge for 1, 3, 7, 15, 30, 60, 90, 120, and 183 consecutive days of each water year. Low-flow sequence tables show the lowest mean discharge for 1, 3, 7, 14, 30, 60, 90, 120, and 183 consecutive days of each climatic year. For monthly flows the following statistics have been computed for each station having 5 or more complete water years of record: (1) Mean, (2) variance, (3) standard deviation, (4) skewness, (5) coefficient of variation, and (6) percentage of average flow. The first five items were also computed for the water year annual flows along with the first order serial correlation coefficient. For stations which have had virtually instantaneous significant changes in the effects of regulation or diversion, a maximum of two sets of summaries are shown. Referenced reports describe procedures for processing and interpreting the streamflow statistics.

Colorado↗
USGS1982

Catalog of available clear mylar templates used to determine latitude and longitude of sample localities between the latitudes of 51 degrees 00' and 71 degrees 30' at the scale of 1:63,360 and between the latitude of 49 degrees 00'00" north or south at the scale of 1:250,000

The present use of electro-mechanical plotting of sample points can give rise to location errors, particularly when map scale changes are involved, unless careful control is maintained. The following catalog of computer-generated mylar templates, with plots of latitude and longitude (longitudes equidistant north to south), sufficient to cover the latitudes between 49?00'00'' and 71?30'00'' N. or S., will help facilitate the plotting of points when there is a map scale change for two different map scales (1:63,360 and 1:250,000). Using the template overlays (available as individual page numbers in Open-File Report 82-724--xerographic clear film overlays from U.S. Geological Survey Open-File Services Section, Branch of Distribution, USGS, Box 25425, Denver, Colorado 80225, telephone (303) 234-5888), the point plotted on a composite final copy may be checked against field maps and notes when only degrees latitude and longitude are given.

Open-File Report↗
USGS1979

Streamflow statistical summaries for Colorado streams through September 30, 1975; Volume 3, Colorado River basin from Gunnison River to San Juan River

This report contains statistical summaries of daily streamflow data as of September 30, 1975, for 234 stations west of the Continental Divide in Colorado and adjacent States for use by agencies and individuals engaged in water studies. To be included in this report, a station had to have a minimum of 3 complete water years (October 1 to September 30) of record and 3 complete climatic years (April I to March 31) of record having virtually constant effects of regulation and diversion, and to have had streamflow records previously reviewed and published by the U.S. Geological Survey. Duration tables show the distribution of daily discharges for each water year ending September 30. High-flow sequence tables show the highest mean discharge for 1, 3, 7, 15, 30, 60, 90, 120, and 183 consecutive days of each water year. Low-flow sequence tables show the lowest mean discharge for 1, 3, 7, 14, 30, 60, 90, 120, and 183 consecutive days of each climatic year. For monthly flows the following statistics have been computed for each station having 5 or more complete water years of record: (1) mean, (2) variance, (3) standard deviation, (4) skewness, (5) coefficient of variation, and (6) percentage of average flow. The first five items were also computed for the water year annual flows along with the first order serial correlation coefficient. For stations which have had virtually instantaneous significant changes in the effects of regulation and diversion, a maximum of two sets of summaries are shown. Referenced reports describe procedures for processing and interpreting the streamflow statistics.

Open-File Report↗