The role of water exchange between a stream channel and its hyporheic zone in nitrogen cycling at the terrestrial-aquatic interface
F.J. Triska, J.H. Duff, R.J. Avanzino
1993, Hydrobiologia (251) 167-184
The subsurface riparian zone was examined as an ecotone with two interfaces. Inland is a terrestrial boundary, where transport of water and dissolved solutes is toward the channel and controlled by watershed hydrology. Streamside is an aquatic boundary, where exchange of surface water and dissolved solutes is bi-directional and flux...
Application of mixed-mode, solid-phase extraction in environmental and clinical chemistry. Combining hydrogen-bonding, cation-exchange and Van der Waals interactions
M. S. Mills, E.M. Thurman, M.J. Pedersen
1993, Journal of Chromatography A (629) 11-21
Silica- and styrene-divinylbenzene-based mixed-mode resins that contain C8, C18 and sulphonated cation-exchange groups were compared for their efficiency in isolation of neutral triazine compounds from water and of the basic drug, benzoylecgonine, from urine. The triazine compounds were isolated by a combination of Van der Waals and hydrogen-bonding interactions, and...
Effect of treated-sewage contamination upon bacterial energy charge, adenine nucleotides, and DNA content in a sandy aquifer on Cape Cod
David W. Metge, Myron H. Brooks, Richard L. Smith, Ronald W. Harvey
1993, Applied and Environmental Microbiology (59) 2304-2310
Changes in adenylate energy charge (ECA) and in total adenine nucleotides (AT) and DNA content (both normalized to the abundance of free-living, groundwater bacteria) in response to carbon loading were determined for a laboratory-grown culture and for a contaminated aquifer. The latter study involved a 3-km-long transect through a contaminant...
Heat flow from four new research drill holes in the Western Cascades, Oregon, U.S.A.
S. E. Ingebritsen, M. A. Scholl, D. R. Sherrod
1993, Geothermics (22) 151-163
Conceptual models of the thermal structure of the Oregon Cascade Range propose either (1) a narrow zone of magmatic heat sources, flanked by shallow heat-flow anomalies caused by lateral ground-water flow; or (2) a wide zone of magmatic heat sources, with localized, generally negligible ground-water effects. The proposed narrow heat...
Summary of revised potentiometric-surface map for Yucca Mountain and vicinity, Nevada
E. M. Ervin, R. R. Luckey, D.J. Burkhardt
1993, Conference Paper, High Level Radioactive Waste Management
The revised map for the potentiometric surface of the uppermost saturated zone in Tertiary volcanic rocks at Yucca Mountain, Nevada, is based mainly on 1988 water levels. Refinement of the water-level corrections has increased understanding of the area immediately east-southeast and hydrologically downgradient of Yucca Mountain. This small-gradient area is...
Variations in aqueous sulfate concentrations at Panola Mountain, Georgia
J. B. Shanley, N.E. Peters
1993, Journal of Hydrology (146) 361-382
Aqueous sulfate concentrations were measured in incident precipitation, canopy throughfall, stemflow, soil water, groundwater, and streamwater at three locations in a 41 ha forested watershed at Panola Mountain State Park in the Georgia Piedmont. To evaluate the variations in sulfate concentrations,...
Seismic reflection profiling: essential geophysical data for Yucca mountain, Nevada
W.C. Hunter, R.W. Spengler, T.M. Brocher
1993, Conference Paper, High Level Radioactive Waste Management
Yucca Mountain, Nevada, consists of a thick sequence of ashflow tuffs and lavas fractured into intact blocks with east-dipping strata, marginal broken zones characterized by dense faulting and brecciation, and intervening down-to-the-west fault zones with locally atypical west-dipping strata. Uncertainty in the structural setting of Yucca Mountain has resulted in...
Effects of small-scale vertical variations in well-screen inflow rates and concentrations of organic compounds on the collection of representative ground-water-quality samples
Jacob Gibs, G. Allan Brown, Kenneth S. Turner, Cecilia L. MacLeod, James Jelinski, Susan A. Koehnlein
1993, Ground Water (31) 201-208
Because a water sample collected from a well is an integration of water from different depths along the well screen, measured concentrations can be biased if analyte concentrations are not uniform along the length of the well screen. The resulting concentration in the sample, therefore, is a function of variations...
Surface chemistry of ferrihydrite: Part 1. EXAFS studies of the geometry of coprecipitated and adsorbed arsenate
G.A. Waychunas, B.A. Rea, C. C. Fuller, J.A. Davis
1993, Geochimica et Cosmochimica Acta (57) 2251-2269
EXAFS spectra were collected on both the As and Fe K-edges from samples of two-line ferrihydrite with adsorbed (ADS) and coprecipitated (CPT) arsenate prepared over a range of conditions and arsenate surface coverages. Spectra also were collected for arsenate adsorbed on the surfaces of three FeOOH crystalline polymorphs, α (goethite),...
Surface chemistry of ferrihydrite: Part 2. Kinetics of arsenate adsorption and coprecipitation
C. C. Fuller, J.A. Dadis, G.A. Waychunas
1993, Geochimica et Cosmochimica Acta (57) 2271-2282
The kinetics of As(V) adsorption by ferrihydrite was investigated in coprecipitation and postsynthesis adsorption experiments conducted in the pH range 7.5-9.0. In coprecipitation experiments, As(V) was present in solution during the hydrolysis and precipitation of iron. In adsorption experiments, a period of rapid (<5 min) As(V) uptake from solution was...
Tectonic characterization of a potential high-level nuclear waste repository at Yucca Mountain, Nevada
John W. Whitney, Dennis W. O’Leary
1993, Conference Paper, Dynamic Analysis and Design Considerations for High-Level Nuclear Waste Repositories
Tectonic characterization of a potential high-level nuclear waste repository at Yucca Mountain, Nevada, is needed to assess seismic and possible volcanic hazards that could affect the site during the preclosure (next 100 years) and the behavior of the hydrologic system during the postclosure (the following 10,000 years) periods. Tectonic characterization...
Selected precipitation characteristics in Antelope Valley, Mojave Desert, CA
James C. Blodgett, Iraj Nasseri
1993, Conference Paper, Proceedings of the Symposium on Engineering Hydrology
An urban hydrology study currently in progress in Antelope Valley, California, includes the collection and analyses of precipitation and runoff data. Storms in Antelope Valley are most prevalent during the months of December, January, February, and March, but major storms have occurred during all months of the year except April,...
Flood elevation limits in the rocky mountains
Robert D. Jarrett
1993, Conference Paper, Proceedings of the Symposium on Engineering Hydrology
An analysis of 77,987 station-years of streamflow-gaging station data from 3,748 stations in the Rocky Mountains indicates that there is a latitude-dependent elevation limit to substantial rainfall-produced flooding. The elevation limit ranges from about 1,650 m in Montana to about 2,350 m in New Mexico. Above this elevation limit, large...
Tidal, Residual, Intertidal Mudflat (TRIM) Model and its Applications to San Francisco Bay, California
R. T. Cheng, V. Casulli, J. W. Gartner
1993, Estuarine, Coastal and Shelf Science (36) 235-280
A numerical model using a semi-implicit finite-difference method for solving the two-dimensional shallow-water equations is presented. The gradient of the water surface elevation in the momentum equations and the velocity divergence in the continuity equation are finite-differenced implicitly, the remaining terms are finite-differenced explicitly. The convective terms are treated using...
Statistical evaluation of hydrologic conditions in the vicinity of abandoned underground coal mines around Cannelburg, Indiana
D. Harper, G.A. Olyphant
1993, Journal of Hydrology (146) 49-71
A statistical analysis of daily water-level changes in an abandoned coal mine indicates that precipitation affects the potentiometric level of the mine, independent of associated atmospheric pressure changes and changes in the water level of an overlying aquifer. The independent statistical...
Manganese minerals and associated fine particulates in the streambed of Pinal Creek, Arizona, U.S.A.: a mining-related acid drainage problem
Carol J. Lind, J.D. Hem
1993, Applied Geochemistry (8) 67-80
The Pinal creek drainage basin in Arizona is a good example of the principal non-coal source of mining-related acid drainage in the U.S.A., namely copper mining. Infiltration of drainage waters from mining and ore refining has created an acid groundwater plume that has reacted with calcite during passage through the...
Seasonal relationships between planktonic microorganisms and dissolved organic material in an alpine stream
Diane M. McKnight, R. L. Smith, R.A. Harnish, C.L. Miller, K.E. Bencala
1993, Biogeochemistry (21) 39-59
The relationships between the abundance and activity of planktonic, heterotrophic microorganisms and the quantity and characteristics of dissolved organic carbon (DOC) in a Rocky Mountain stream were evaluated. Peak values of glucose uptake, 2.1 nmol L−1 hr−1, and glucose concentration, 333 nM, occurred during spring snowmelt when the water temperature...
Characterizing the hydrogeologic framework of the Death Valley region, Southern Nevada and California
Claudia Faunt, Frank D'Agnese, Joe S. Downey, A. Keith Turner
1993, Conference Paper, High Level Radioactive Waste Management
Three-dimensional (3-D) hydrogeologic modeling of the complex geology of the Death Valley region requires the application of a number of Geoscientific Information System (GSIS) techniques. This study, funded by United States Department of Energy as a part of the Yucca Mountain Project, focuses on an area of approximately 100,000 square...
Interactions between ground water and wetlands, southern shore of Lake Michigan, USA
Robert J. Shedlock, Douglas A. Wilcox, Todd A. Thompson, David A. Cohen
1993, Journal of Hydrology (141) 127-155
Wetlands between, and within, dune-beach complexes along the south shore of Lake Michigan are strongly affected by ground water. The hydrogeology of the glacial drift aquifer system in a 26 km2 area was investigated to determine the effects of ground water on the hydrology and hydrochemistry of Cowles Bog and its...
Aspects of numerical and representational methods related to the finite-difference simulation of advective and dispersive transport of freshwater in a thin brackish aquifer
M. L. Merritt
1993, Journal of Hydrology (148) 61-92
The simulation of the transport of injected freshwater in a thin brackish aquifer, overlain and underlain by confining layers containing more saline water, is shown to be influenced by the choice of the finite-difference approximation method, the algorithm for representing vertical advective and dispersive fluxes, and the values assigned to...
Distributions of pesticides and organic contaminants between water and suspended sediment, San Francisco Bay, California
Joseph L. Domagalski, K.M. Kuivila
1993, Estuaries (16) 416-426
Suspended-sediment and water samples were collected from San Francisco Bay in 1991 during low river discharge and after spring rains. All samples were analyzed for organophosphate, carbamate, and organochlorine pesticides; petroleum hydrocarbons; biomarkers; and polynuclear aromatic hydrocarbons. The objectives were to determine the concentrations of these contaminants in water and...
Computation of type curves for flow to partially penetrating wells in water-table aquifers
Allen F. Moench
1993, Ground Water (31) 966-971
Evaluation of Neuman's analytical solution for flow to a well in a homogeneous, anisotropic, water-table aquifer commonly requires large amounts of computation time and can produce inaccurate results for selected combinations of parameters. Large computation times occur because the integrand of a semi-infinite integral involves the summation of an infinite...
Trace metals (Cd, Cu, Ni, and Zn) and nutrients in coastal waters adjacent to San Francisco Bay, California
A. VanGeen, Samuel N. Luoma
1993, Estuaries (16) 559-566
Samples collected in December 1990 and July 1991 show that dissolved Cd, Cu, Ni, and Zn distributions in the Gulf of the Farallones are dominated by mixing of two end-members: (1) metal-enriched San Francisco Bay water and (2) offshore California Current water. The range of dissolved metal concentrations observed is...
Trace contaminants and nutrients in estuaries: The importance of process interdependence
J.S. Kuwabara, J.E. Baker
1993, Estuaries (16) 383-384
No abstract available....
Geologic and hydrologic hazards in glacierized basins in North America resulting from 19th and 20th century global warming
J. E. O’Connor, J. E. Costa
1993, Natural Hazards (8) 121-140
Alpine glacier retreat resulting from global warming since the close of the Little Ice Age in the 19th and 20th centuries has increased the risk and incidence of some geologic and hydrologic hazards in mountainous alpine regions of North America. Abundant loose debris in recently deglaciated areas at the toe...
