Denitrification in nitrate-contaminated groundwater: Occurrence in steep vertical geochemical gradients
R. L. Smith, B.L. Howes, J.H. Duff
1991, Geochimica et Cosmochimica Acta (55) 1815-1825
A relatively narrow vertical zone (5–6 m thick) of NO3− containing groundwater was identified using multilevel sampling devices in a sand and gravel aquifer on Cape Cod, MA, USA. The aquifer has been chronically contaminated by surface disposal of treated sewage 0.3 km upgradient...
Selectivity and effectiveness of extractants used to release metals associated with organic matter
C. S.E. Papp, L.H. Filipek, K. S. Smith
1991, Applied Geochemistry (6) 349-353
Partial extraction procedures can be used to release metals associated with organic matter in natural materials. Reagents commonly employed for this purpose include hydrogen peroxide, Na hypochlorite and Na pyrophosphate. This study tested the selectivity of these reagents by comparing the amount...
Applications of hydrologic information automatically extracted from digital elevation models
Susan K. Jenson
1991, Hydrological Processes (5) 31-44
Digital elevation models (DEMs) can be used to derive a wealth of information about the morphology of a land surface. Traditional raster analysis methods can be used to derive slope, aspect, and shaded relief information; recently-developed computer programs can be used to delineate depressions, overland flow paths, and watershed boundaries....
Brine evolution and mineral deposition in hydrologically open evaporite basins
W. E. Sanford, W.W. Wood
1991, American Journal of Science (291) 687-710
A lumped-parameter, solute mass-balance model is developed to define the role of water outflow from a well-mixed basin. A mass-balance model is analyzed with a geochemical model designed for waters with high ionic strengths. Two typical waters, seawater and a Na-HCO3 ground water, are analyzed to illustrate the control that...
Volcanic ash dispersed in the Wyodak-Anderson coal bed, Powder River Basin, Wyoming
Don M. Triplehorn, R.W. Stanton, Leslie F. Ruppert, Sharon S. Crowley
1991, Organic Geochemistry (17) 567-575
Minerals derived from air-fall volcanic ash were found in two zones in the upper Paleocene Wyodak-Anderson coal bed of the Fort Union Formation in the Powder River Basin of Wyoming, and are the first reported evidence of such volcanic material in this thick (> 20 m) coal bed. The volcanic...
An intercomparison of hydrological network-design technologies
M. E. Moss, Gary D. Tasker
1991, Hydrological Sciences Journal (36) 209-221
Two network-design technologies are compared by random sub-sampling of actual streamflow data. The technologies, Network Analysis for Regional Information (NARI) and Network Analysis Using Generalized Least Squares (NAUGLS), have a common objective, viz. to maximize regional information within a limited budget and time horizon. The data used for intercomparison are...
Data standardization. The key to effective management
C. Russell Wagner
1991, Conference Paper, ASTM Special Technical Publication
Effective management of the nation's water resources is dependent upon accurate and consistent hydrologic information. Before the emergence of environmental concerns in the 1960's, most hydrologic information was collected by the U.S. Geological Survey and other Federal agencies that used fairly consistent methods and equipment. In the past quarter century,...
Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 1. Sulfate from confining beds as an oxidant in microbial CO2 production
F. H. Chapelle, P.B. McMahon
1991, Journal of Hydrology (127) 85-108
A primary source of dissolved inorganic carbon (DIC) in the Black Creek aquifer of South Carolina is carbon dioxide produced by microbially mediated oxidation of sedimentary organic matter. Groundwater chemistry data indicate, however, that the available mass of inorganic electron acceptors (oxygen, Fe(III),...
MBSSAS: A code for the computation of margules parameters and equilibrium relations in binary solid-solution aqueous-solution systems
P. D. Glynn
1991, Computers & Geosciences (17) 907-966
The computer code MBSSAS uses two-parameter Margules-type excess-free-energy of mixing equations to calculate thermodynamic equilibrium, pure-phase saturation, and stoichiometric saturation states in binary solid-solution aqueous-solution (SSAS) systems. Lippmann phase diagrams, Roozeboom diagrams, and distribution-coefficient diagrams can be constructed from the output data files,...
Drought description
N.C. Matalas
1991, Stochastic Hydrology and Hydraulics (5) 255-260
What constitutes a comprehensive description of drought, a description forming a basis for answering why a drought occurred is outlined. The description entails two aspects that are "naturally" coupled, named physical and economic, and treats the set of hydrologic measures of droughts in terms of their multivariate distribution, rather than...
Visible and near-infrared (0.4-2.5 μm) reflectance spectra of playa evaporite minerals
James K. Crowley
1991, Journal of Geophysical Research (96) 16231-16240
Visible and near-infrared (VNIR; 0.4–2.4 μm) reflectance spectra were recorded for 35 saline minerals that represent the wide range of mineral and brine chemical compositions found in playa evaporite settings. The spectra show that many of the saline minerals exhibit diagnostic near-infrared absorption bands, chiefly attributable to vibrations of hydrogen-bonded...
Pumping tests in non-uniform aquifers - The linear strip case
J.J. Butler Jr., W.Z. Liu
1991, Journal of Hydrology (128) 69-99
Many pumping tests are performed in geologic settings that can be conceptualized as a linear infinite strip of one material embedded in a matrix of differing flow properties. A semi-analytical solution is presented to aid the analysis of drawdown data obtained from pumping tests performed in settings that can be...
In situ bacterial selenate reduction in the agricultural drainage systems of western Nevada
R.S. Oremland, N.A. Steinberg, T. S. Presser, L.G. Miller
1991, Applied and Environmental Microbiology (57) 615-617
Dissimilatory in situ selenate reduction to elemental selenium in sediments from irrigated agricultural drainage regions of western Nevada was measured at ambient Se oxyanion concentrations. Selenate reduction was rapid, with turnover rate constants ranging from 0.04 to 1.8 h-1 at total Se concentrations in pore water of 13 to 455...
Fate of acetone in an outdoor model stream with a nitrate supplement, southern Mississippi, U.S.A.
R. E. Rathbun, D. W. Stephens, D. Y. Tai
1991, Journal of Hydrology (123) 225-242
The fate of acetone in an outdoor model stream to which nitrate was added as a nutrient supplement was determined. The stream, in southern Mississippi, U.S.A. was 234 m long. Water was supplied to the stream by an artesian well at about 1.21 s−1, resulting in a mean water velocity...
Use of a single-bowl continuous-flow centrifuge for dewatering suspended sediments: effect on sediment physical and chemical characteristics
T.F. Rees, J.A. Leenheer, J. F. Ranville
1991, Hydrological Processes (5) 201-214
The use of a single-bowl continuous-flow centrifuge (CFC, Sharples-Pennwalt Model AS-12) for dewatering suspended sediment from large volumes of river water is evaluated. Sediment-recovery efficiency of 86-91 per cent is comparable to that of other types of CFC units. The recovery efficiency is limited by...
Some current themes in physical hydrology of the land-atmosphere interface
P. C. D. Milly
1991, Conference Paper, IAHS Publication (International Association of Hydrological Sciences)
Certain themes arise repeatedly in current literature dealing with the physical hydrology of the interface between the atmosphere and the continents. Papers contributed to the 1991 International Association of Hydrological Sciences Symposium on Hydrological Interactions between Atmosphere, Soil and Vegetation echo these themes, which are discussed in this paper. The...
Seismicity and shear strain in the southern Great Basin of Nevada and California
J. Gomberg
1991, Journal of Geophysical Research (96) 16383-16399
This study examines the relationship between the distribution of small earthquakes (ML≤4.3) and mechanisms of strain accumulation and relaxation in an area with long repeat times between large events, the Southern Great Basin Seismic Network (SGBSN) region. The Great Basin is a unique continental extensional...
Importance of geologic characterization of potential low-level radioactive waste disposal sites
C.P. Weibel, R. C. Berg
1991, Environmental Geology and Water Sciences (18) 209-214
Using the example of the Geff Alternative Site in Wayne County, Illinois, for the disposal of low-level radioactive waste, this paper demonstrates, from a policy and public opinion perspective, the importance of accurately determining site stratigraphy. Complete and accurate characterization of geologic materials and determination of site stratigraphy at potential...
An exact solution of solute transport by one-dimensional random velocity fields
V.D. Cvetkovic, G. Dagan, A.M. Shapiro
1991, Stochastic Hydrology and Hydraulics (5) 45-54
The problem of one-dimensional transport of passive solute by a random steady velocity field is investigated. This problem is representative of solute movement in porous media, for example, in vertical flow through a horizontally stratified formation of variable porosity with a constant flux at the soil surface. Relating moments of...
Evaluation of geographic information systems for three-dimensional ground-water modeling, Yucca Mountain, Nevada
A. Keith Turner, Elisabeth M. Ervin, Joe S. Downey
Anon, editor(s)
1991, Conference Paper, High Level Radioactive Waste Management
Fully three-dimensional representations of the geologic system at Yucca Mountain have been developed using a Geoscientific Information System, which is an expansion of a traditional Geographic Information Systems. These advanced, three dimensional, representations of Yucca Mountain are required to adequately evaluate the complex geologic and hydrologic conditions surrounding the site....
Large-scale distribution of metal contamination in the fine-grained sediments of the Clark Fork River, Montana, U.S.A.
E.V. Axtmann, S. N. Luoma
1991, Applied Geochemistry (6) 75-88
Historic discharges from the mining and smelting complex at the head-waters of the Clark Fork River have resulted in elevated Ag, Cd, Cu, Pb and Zn concentrations in the <60 μm fraction of both bed and flood-plain sediments of the river. Processes affecting the trends in longitudinal distributions of these...
Electron transport in the dissimilatory iron reducer, GS-15
Y.A. Gorby, Derek R. Lovley
1991, Applied and Environmental Microbiology (57) 867-870
Mechanisms for electron transport to Fe(III) were investigated in GS-15, a novel anaerobic microorganism which can obtain energy for growth hy coupling the complete oxidation of organic acids or aromatic compounds to the reduction of Fe(III) to Fe(II). The results indicate that Fe(III) reduction proceeds through a type b cytochrome...
Coprecipitation mechanisms and products in manganese oxidation in the presence of cadmium
J.D. Hem, Carol J. Lind
1991, Geochimica et Cosmochimica Acta (55) 2435-2451
Manganese oxidation products were precipitated in an aerated open-aqueous system where a continuous influx of mixed Mn2+ and Cd2+ solution was supplied and pH was maintained with an automated pH-stat adding dilute NaOH. X-ray diffraction and electron diffraction identified the solids produced as mixtures of Cd2Mn34+O8, Mn2+2Mn4+3O8, MnO2 (ramsdellite), and CdCO3. Mean oxidation...
The neutral oil in commercial linear alkylbenzenesulfonate and its effect on organic solute solubility in water
C. T. Chiou, D. E. Kile, D.W. Rutherford
1991, Environmental Science & Technology (25) 660-665
No abstract available....
Convergent radial dispersion: A note on evaluation of the Laplace transform solution
Allen F. Moench
1991, Water Resources Research (27) 3261-3264
A numerical inversion algorithm for Laplace transforms that is capable of handling rapid changes in the computed function is applied to the Laplace transform solution to the problem of convergent radial dispersion in a homogeneous aquifer. Prior attempts by the author to invert this solution were unsuccessful for highly advective...
