Field investigation into unsaturated flow and transport in a fault: Model analyses
H.-H. Liu, R. Salve, J.-S. Wang, G.S. Bodvarsson, D. Hudson
2004, Journal of Contaminant Hydrology (74) 39-59
Results of a fault test performed in the unsaturated zone of Yucca Mountain, Nevada, were analyzed using a three-dimensional numerical model. The fault was explicitly represented as a discrete feature and the surrounding rock was treated as a dual-continuum (fracture-matrix) system. Model calibration against seepage and water-travel-velocity data suggests that...
Using fish communities to assess streams in Romania: Initial development of an index of biotic integrity
P. L. Angermeier, G. Davideanu
2004, Hydrobiologia (511) 65-78
Multimetric biotic indices increasingly are used to complement physicochemical data in assessments of stream quality. We initiated development of multimetric indices, based on fish communities, to assess biotic integrity of streams in two physiographic regions of central Romania. Unlike previous efforts to develop such indices for European streams, our metrics...
Airflows and turbulent flux measurements in mountainous terrain: Part 2: Mesoscale effects
A.A. Turnipseed, D.E. Anderson, S. Burns, P.D. Blanken, Russell K. Monson
2004, Agricultural and Forest Meteorology (125) 187-205
The location of the Niwot Ridge Ameriflux site within the rocky mountains subjects it to airflows which are common in mountainous terrain. In this study, we examine the effects of some of these mesoscale features on local turbulent flux measurements; most notably, the formation of valley/mountain flows and mountain lee-side...
Comparison of in situ uranium KD values with a laboratory determined surface complexation model
G.P. Curtis, P. Fox, M. Kohler, J.A. Davis
2004, Applied Geochemistry (19) 1643-1653
Reactive solute transport simulations in groundwater require a large number of parameters to describe hydrologic and chemical reaction processes. Appropriate methods for determining chemical reaction parameters required for reactive solute transport simulations are still under investigation. This work compares U(VI) distribution coefficients (i.e. KD values) measured under field conditions with...
Use of qualitative and quantitative information in neural networks for assessing agricultural chemical contamination of domestic wells
A. Mishra, C. Ray, D.W. Kolpin
2004, Journal of Hydrologic Engineering (9) 502-511
A neural network analysis of agrichemical occurrence in groundwater was conducted using data from a pilot study of 192 small-diameter drilled and driven wells and 115 dug and bored wells in Illinois, a regional reconnaissance network of 303 wells across 12 Midwestern states, and a study of 687 domestic wells...
Effects of nutrient enrichment on the decomposition of wood and associated microbial activity in streams
V. Gulis, A.D. Rosemond, K. Suberkropp, H.S. Weyers, J.P. Benstead
2004, Freshwater Biology (49) 1437-1447
1. We determined the effects of nutrient enrichment on wood decomposition rates and microbial activity during a 3-year study in two headwater streams at Coweeta Hydrologic Laboratory, NC, U.S.A. After a 1-year pretreatment period, one of the streams was continuously enriched with inorganic nutrients (nitrogen and phosphorus) for 2 years...
Estimation of hydraulic conductivity in an alluvial system using temperatures
G.W. Su, James Jasperse, D. Seymour, J. Constantz
2004, Ground Water (42) 890-901
Well water temperatures are often collected simultaneously with water levels; however, temperature data are generally considered only as a water quality parameter and are not utilized as an environmental tracer. In this paper, water levels and seasonal temperatures are used to estimate hydraulic conductivities in a stream-aquifer system. To demonstrate...
Stable metal isotopes reveal copper accumulation and loss dynamics in the freshwater bivalve Corbucula
M.-N. Croteau, S. N. Luoma, B.R. Topping, C.B. Lopez
2004, Environmental Science & Technology (38) 5002-5009
Characterization of uptake and loss dynamics is critical to understanding risks associated with contaminant exposure in aquatic animals. Dynamics are especially important in addressing questions such as why coexisting species in nature accumulate different levels of a contaminant. Here we manipulated copper (Cu) stable isotopic ratios (as...
Geochemistry, radiocarbon ages, and paleorecharge conditions along a transect in the central High Plains aquifer, southwestern Kansas, USA
P.B. McMahon, J.K. Böhlke, S. C. Christenson
2004, Applied Geochemistry (19) 1655-1686
Water samples from short-screen monitoring wells installed along a 90-km transect in southwestern Kansas were analyzed for major ions, trace elements, isotopes (H, B, C, N, O, S, Sr), and dissolved gases (He, Ne, N2, Ar, O2, CH4) to evaluate the geochemistry, radiocarbon ages, and paleorecharge conditions in the unconfined...
Identifying storm flow pathways in a rainforest catchment using hydrological and geochemical modelling
D.A. Kinner, R.F. Stallard
2004, Hydrological Processes (18) 2851-2875
The hydrological model TOPMODEL is used to assess the water balance and describe flow paths for the 9??73 ha Lutz Creek Catchment in Central Panama. Monte Carlo results are evaluated based on their fit to the observed hydrograph, catchment-averaged soil moisture and stream chemistry. TOPMODEL, with a direct-flow mechanism that...
Decomposition and organic matter quality in continental peatlands: The ghost of permafrost past
M.R. Turetsky
2004, Ecosystems (7) 740-750
Permafrost patterning in boreal peatlands contributes to landscape heterogeneity, as peat plateaus, palsas, and localized permafrost mounds are interspersed among unfrozen bogs and fens. The degradation of localized permafrost in peatlands alters local topography, hydrology, thermal regimes, and plant communities, and creates unique peatland features called "internal lawns." I used...
Persistence of pharmaceutical compounds and other organic wastewater contaminants in a conventional drinking-water-treatment plant
P. E. Stackelberg, E. T. Furlong, M. T. Meyer, S.D. Zaugg, A.K. Henderson, D.B. Reissman
2004, Science of the Total Environment (329) 99-113
In a study conducted by the US Geological Survey and the Centers for Disease Control and Prevention, 24 water samples were collected at selected locations within a drinking-water-treatment (DWT) facility and from the two streams that serve the facility to evaluate the potential for...
Flood hydrology for Dry Creek, Lake County, Northwestern Montana
C. Parrett, R.D. Jarrett
2004, Conference Paper, Joint Conference on Water Resource Engineering and Water Resources Planning and Management 2000: Building Partnerships
Dry Creek drains about 22.6 square kilometers of rugged mountainous terrain upstream from Tabor Dam in the Mission Range near St. Ignatius, Montana. Because of uncertainty about plausible peak discharges and concerns regarding the ability of the Tabor Dam spillway to safely convey these discharges, the flood hydrology for Dry...
The rotating movement of three immiscible fluids - A benchmark problem
M. Bakker, Essink G.H.P. Oude, C.D. Langevin
2004, Journal of Hydrology (287) 270-278
A benchmark problem involving the rotating movement of three immiscible fluids is proposed for verifying the density-dependent flow component of groundwater flow codes. The problem consists of a two-dimensional strip in the vertical plane filled with three fluids of different densities separated by interfaces. Initially, the interfaces between the fluids...
Acoustic and optical borehole-wall imaging for fractured-rock aquifer studies
J.H. Williams, C. D. Johnson
2004, Journal of Applied Geophysics (55) 151-159
Imaging with acoustic and optical televiewers results in continuous and oriented 360° views of the borehole wall from which the character, relation, and orientation of lithologic and structural planar features can be defined for studies of fractured-rock aquifers. Fractures are more clearly defined under a wider range of conditions...
Using an ecoregion framework to analyze land-cover and land-use dynamics.
Alisa L. Gallant, Thomas R. Loveland, Terry L. Sohl, D.E. Napton
2004, Environmental Management (34) S89-S110
The United States has a highly varied landscape because of wide-ranging differences in combinations of climatic, geologic, edaphic, hydrologic, vegetative, and human management (land use) factors. Land uses are dynamic, with the types and rates of change dependent on a host of variables, including land accessibility, economic considerations, and the...
Climate and hydrology of the last interglaciation (MIS 5) in Owens Basin, California: Isotopic and geochemical evidence from core OL-92
H.-C. Li, J. L. Bischoff, T.-L. Ku, Z.-Y. Zhu
2004, Quaternary Science Reviews (23) 49-63
??18O, ??13C, total organic carbon, total inorganic carbon, and acid-leachable Li, Mg and Sr concentrations on 443 samples from 32 to 83 m depth in Owens Lake core OL-92 were analyzed to study the climatic and hydrological conditions between 60 and 155 ka with a resolution of ???200 a. The...
Are big basins just the sum of small catchments?
J. Shaman, M. Stieglitz, D. Burns
2004, Hydrological Processes (18) 3195-3206
Many challenges remain in extending our understanding of how hydrologic processes within small catchments scale to larger river basins. In this study we examine how low-flow runoff varies as a function of basin scale at 11 catchments, many of which are nested, in the 176 km2 Neversink River watershed in...
Delineation and evaluation of hydrologic-landscape regions in the United States using geographic information system tools and multivariate statistical analyses.
David M. Wolock, Thomas C. Winter, Gerard McMahon
2004, Environmental Management (34) S71-S88
Hydrologic-landscape regions in the United States were delineated by using geographic information system (GIS) tools combined with principal components and cluster analyses. The GIS and statistical analyses were applied to land-surface form, geologic texture (permeability of the soil and bedrock), and climate variables that describe the physical and climatic setting...
Influence of management history and landscape variables on soil organic carbon and soil redistribution
E.R. Venteris, G.W. McCarty, J.C. Ritchie, T. Gish
2004, Soil Science (169) 787-795
Controlled studies to investigate the interaction between crop growth, soil properties, hydrology, and management practices are common in agronomy. These sites (much as with real world farmland) often have complex management histories and topographic variability that must be considered. In 1993 an interdisiplinary study was started for a 20-ha site...
Redox transformations of arsenic oxyanions in periphyton communities
T.R. Kulp, S.E. Hoeft, R.S. Oremland
2004, Applied and Environmental Microbiology (70) 6428-6434
Periphyton (Cladophora sp.) samples from a suburban stream lacking detectable dissolved As were able to reduce added As(V) to As(III) when incubated under anoxic conditions and, conversely, oxidized added As(III) to As(V) with aerobic incubation. Both types of activity were abolished in autoclaved controls, thereby demonstrating its...
Overland flow generation in two lithologically distinct rainforest catchments
S. Godsey, H. Elsenbeer, R. Stallard
2004, Journal of Hydrology (295) 276-290
Streams on uniformly rainforest-covered, but lithologically very diverse Barro Colorado Island in central Panama?? show remarkable differences in their runoff response to rainfall. This lithological diversity is reflected in equally diverse soilscapes, and our objective was to test the hypothesis that contrasting runoff responses derive from soilscape features that control...
Baseflow contribution to nitrate-nitrogen export from a large, agricultural watershed, USA
K. Schilling, Y.-K. Zhang
2004, Journal of Hydrology (295) 305-316
Nitrate-nitrogen export from the Raccoon River watershed in west-central Iowa is among the highest in the United State and contributes to impairment of downstream water quality. We examined a rare long-term record of streamflow and nitrate concentration data (1972-2000) to evaluate annual and seasonal patterns of nitrate losses in streamflow...
Interpretation of concentration‐discharge patterns in acid‐neutralizing capacity during storm flow in three small, forested catchments in Shenandoah National Park, Virginia
Karen C. Rice, Jeffrey G. Chanat, George M. Hornberger, James R. Webb
2004, Water Resources Research (40)
Episodic concentration‐discharge (c‐Q) plots are a popular tool for interpreting the hydrochemical response of small, forested catchments. Application of the method involves assuming an underlying conceptual model of runoff processes and comparing observed c‐Q looping patterns with those predicted by the model. We analyzed and interpreted c‐Q plots of acid‐neutralizing capacity (ANC) for 133...
Reach-scale isotope tracer experiment to quantify denitrification and related processes in a nitrate-rich stream, midcontinent United States
J.K. Böhlke, J. W. Harvey, M.A. Voytek
2004, Limnology and Oceanography (49) 821-838
We conducted an in-stream tracer experiment with Br and 15N-enriched NO3- to determine the rates of denitrification and related processes in a gaining NO3- -rich stream in an agricultural watershed in the upper Mississippi basin in September 2001. We determined reach-averaged rates of N fluxes and reactions from isotopic analyses...
