Consistency of patterns in concentration‐discharge plots
Jeffrey G. Chanat, Karen C. Rice, George M. Hornberger
2002, Water Resources Research (38) 22-1-22-10
Concentration‐discharge (c‐Q) plots have been used to infer how flow components such as event water, soil water, and groundwater mix to produce the observed episodic hydrochemical response of small catchments. Because c‐Q plots are based only on observed streamflow and solute concentration, their interpretation requires assumptions about...
Using groundwater temperature data to constrain parameter estimation in a groundwater flow model of a wetland system
Hector R. Bravo, Feng Jiang, Randall J. Hunt
2002, Water Resources Research (38) 28-1-28-14
Parameter estimation is a powerful way to calibrate models. While head data alone are often insufficient to estimate unique parameters due to model nonuniqueness, flow‐and‐heat‐transport modeling can constrain estimation and allow simultaneous estimation of boundary fluxes and hydraulic conductivity. In this work, synthetic and field models that did not converge...
Isotope variations in a Sierra Nevada snowpack and their relation to meltwater
P.V. Unnikrishna, Jeffery J. McDonnell, C. Kendall
2002, Journal of Hydrology (260) 38-57
Isotopic variations in melting snow are poorly understood. We made weekly measurements at the Central Sierra Snow Laboratory, California, of snow temperature, density, water equivalent and liquid water volume to examine how physical changes within the snowpackgovern meltwater δ18O. Snowpack samples were extracted at 0.1 m intervals from ground level to the top of...
Mercury deposition in snow near an industrial emission source in the western U.S. and comparison to ISC3 model predictions
M.L. Abbott, D. D. Susong, D. P. Krabbenhoft, A.S. Rood
2002, Water, Air, & Soil Pollution (139) 95-114
Mercury (total and methyl) was evaluated in snow samples collected near a major mercury emission source on the Idaho National Engineering and Environmental Laboratory (INEEL) insoutheastern Idaho and 160 km downwind in Teton Range in westernWyoming. The sampling was done to assess near-field (<12 km)deposition rates around the source,...
Quantifying flow-dependent changes in subyearling fall chinook salmon rearing habitat using two-dimensional spatially explicit modeling
K.F. Tiffan, R.D. Garland, D.W. Rondorf
2002, North American Journal of Fisheries Management (22) 713-726
We used an analysis based on a geographic information system (GIS) to determine the amount of rearing habitat and stranding area for subyearling fall chinook salmon Oncorhynchus tshawytscha in the Hanford Reach of the Columbia River at steady-state flows ranging from 1,416 to 11,328 m3/s. High-resolution river channel bathymetry was...
Gravitational failure of sea cliffs in weakly lithified sediment
M. A. Hampton
2002, Environmental & Engineering Geoscience (8) 175-191
Gravitational failure of sea cliffs eroded into weakly lithified sediment at several sites in California involves episodic stress-release fracturing and cantilevered block falls. The principal variables that influence the gravitational stability are tensional stresses generated during the release of horizontal confining stress and weakening of the sediment with increased saturation...
Simulations of seismic hazard for the Pacific Northwest of the United States from earthquakes associated with the Cascadia subduction zone
M.D. Petersen, C.H. Cramer, A.D. Frankel
2002, Pure and Applied Geophysics (159) 2147-2168
We investigate the impact of different rupture and attenuation models for the Cascadia subduction zone by simulating seismic hazard models for the Pacific Northwest of the U.S. at 2% probability of exceedance in 50 years. We calculate the sensitivity of hazard (probabilistic ground motions) to the source parameters and the...
A comparison of models for estimating the riverine export of nitrogen from large watersheds
R. B. Alexander, P.J. Johnes, E.W. Boyer, R. A. Smith
2002, Biogeochemistry (57-58) 295-339
We evaluated the accuracy of six watershed models of nitrogen export in streams (kg km2 yr-1) developed for use in large watersheds and representing various empirical and quasi-empirical approaches described in the literature. These models differ in their methods of calibration and have varying levels of spatial resolution and process...
Nitrogen retention in rivers: Model development and application to watersheds in the northeastern U.S.A.
S.P. Seitzinger, R.V. Styles, E.W. Boyer, R. B. Alexander, G. Billen, R. W. Howarth, B. Mayer, N. Van Breemen
2002, Conference Paper, Biogeochemistry
A regression model (RivR-N) was developed that predicts the proportion of N removed from streams and reservoirs as an inverse function of the water displacement time of the water body (ratio of water body depth to water time of travel). When applied to 16 drainage networks in the eastern U.S.,...
Relationship of gas hydrate concentration to porosity and reflection amplitude in a research well, Mackenzie Delta, Canada
Y.K. Jin, Myung W. Lee, T. S. Collett
2002, Marine and Petroleum Geology (19) 407-415
Well logs acquired at the Mallik 2L-38 gas hydrate research well. Mackenzie Delta, Canada, reveal a distinct trend showing that the resistivity of gas-hydrate-bearing sediments increases with increases in density porosities. This trend, opposite to the general trend of decrease in resistivity with porosity, implies that gas hydrates are more...
Key Largo Limestone revisited: Pleistocene shelf-edge facies, Florida Keys, USA
Multer H. Gray, E. Gischler, J. Lundberg, K. R. Simmons, E.A. Shinn
2002, Facies 229-272
New dates and analysis of 12 deep and 57 shallow cores allow a more detailed interpretation of the Pleistocene shelf edge of the Florida Platform as found in various facies of the Key Largo Limestone beneath the Florida Keys. In this study a three-phase evolution of the Quaternary units (Q1-Q5)...
Sea-cliff erosion as a function of beach changes and extreme wave runup during the 1997-1998 El Nino
A. H. Sallenger Jr., W. Krabill, J. Brock, R. Swift, S. Manizade, H. Stockdon
2002, Marine Geology (187) 279-297
Over time scales of hundreds to thousands of years, the net longshore sand transport direction along the central California coast has been driven to the south by North Pacific winter swell. In contrast, during the El Nin??o winter of 1997-1998, comparisons of before and after airborne lidar surveys showed sand...
High-resolution seismic velocities and shallow structure of the San Andreas fault zone at Middle Mountain, Parkfield, California
R. D. Catchings, M. J. Rymer, M. R. Goldman, J.A. Hole, R. Huggins, C. Lippus
2002, Bulletin of the Seismological Society of America (92) 2493-2503
A 5-km-long, high-resolution seismic imaging survey across the San Andreas fault (SAF) zone and the proposed San Andreas Fault Observatory at Depth (SAFOD) drill site near Parkfield, California, shows that velocities vary both laterally and vertically. Velocities range from <1.0 km/sec near the surface to as much as 4.8 km/sec...
Effects of nutrient enrichment on channel catfish growth and consumption in Mount Storm Lake, West Virginia
T.J. Blanc, F.J. Margraf
2002, Lakes and Reservoirs: Research and Management (7) 109-123
With the objective of augmenting fish production in Mount Storm Lake, Virginia Electric and Power Company initiated a programme of phosphorus addition to increase primary production, and ultimately, channel catfish (Ictaturus punctatus) growth in the 486 ha cooling reservoir. We simulated channel catfish growth dynamics using two bioenergetics modelling scenarios:...
Inter-annual, seasonal and spatial variability in nutrient limitation of phytoplankton production in a river impoundment
P.A. Bukaveckas, A.S. Crain
2002, Hydrobiologia (481) 19-31
We characterize seasonal and spatial patterns in phytoplankton abundance, production and nutrient limitation in a mesotrophic river impoundment located in the southeastern United States to assess variation arising from inter-annual differences in watershed inputs. Short-term (48 h) in situ nutrient addition experiments were conducted between May and October at three...
Instrumental intensity distribution for the Hector Mine, California, and the Chi-Chi, Taiwan, earthquakes: Comparison of two methods
V. Sokolov, D.J. Wald
2002, Bulletin of the Seismological Society of America (92) 2145-2162
We compare two methods of seismic-intensity estimation from ground-motion records for the two recent strong earthquakes: the 1999 (M 7.1) Hector Mine, California, and the 1999 (M 7.6) Chi-Chi, Taiwan. The first technique utilizes the peak ground acceleration (PGA) and velocity (PGV), and it is used for rapid generation of...
Aftershock triggering by complete Coulomb stress changes
Debi Kilb, J. Gomberg, P. Bodin
2002, Journal of Geophysical Research B: Solid Earth (107) ESE 2-1-ESE 2-14
We examine the correlation between seismicity rate change following the 1992, M7.3, Landers, California, earthquake and characteristics of the complete Coulomb failure stress (CFS) changes (ΔCFS(t)) that this earthquake generated. At close distances the time-varying “dynamic” portion of the stress change depends on how the rupture develops temporally and spatially and...
Horseshoe crab (Limulus polyphemus) reproductive activity on Delaware Bay beaches: Interactions with beach characteristics
D. R. Smith, P.S. Pooler, R.E. Loveland, M.L. Botton, S.F. Michels, R.G. Weber, Daniel B. Carter
2002, Journal of Coastal Research (18) 730-740
We used results from a survey of horseshoe crab reproductive activity that was conducted in 1999 throughout Delaware Bay to examine the relationship between estimates of spawning females and egg deposition and analyze how that relationship varies with geography, time within a spawning season, beach morphology, and wave energy. We...
Michigan basin regional ground water flow discharge to three Great Lakes
J. R. Hoaglund III, G.C. Huffman, N.G. Grannemann
2002, Ground Water (40) 390-406
Ground water discharge to the Great Lakes around the Lower Peninsula of Michigan is primarily from recharge in riparian basins and proximal upland areas that are especially important to the northern half of the Lake Michigan shoreline. A steady-state finite-difference model was developed to simulate ground water flow in four...
Using simple environmental variables to estimate below-ground productivity in grasslands
R.A. Gill, R.H. Kelly, W.J. Parton, K.A. Day, R.B. Jackson, J.A. Morgan, J.M.O. Scurlock, L.L. Tieszen, J.V. Castle, D.S. Ojima, X.S. Zhang
2002, Global Ecology and Biogeography (11) 79-86
In many temperate and annual grasslands, above-ground net primary productivity (NPP) can be estimated by measuring peak above-ground biomass. Estimates of below-ground net primary productivity and, consequently, total net primary productivity, are more difficult. We addressed one of the three main objectives of the Global Primary Productivity Data Initiative for...
Sequence stratigraphic and sedimentologic significance of biogenic structures from a late Paleozoic marginal- to open-marine reservoir, Morrow Sandstone, subsurface of southwest Kansas, USA
L.A. Buatois, M.G. Mangano, A. Alissa, T.R. Carr
2002, Sedimentary Geology (152) 99-132
Integrated ichnologic, sedimentologic, and stratigraphic studies of cores and well logs from Lower Pennsylvanian oil and gas reservoirs (lower Morrow Sandstone, southwest Kansas) allow distinction between fluvio-estuarine and open marine deposits in the Gentzler and Arroyo fields. The fluvio-estuarine facies assemblage is composed of both interfluve and valley-fill deposits, encompassing...
Draped aeromagnetic survey in Transantarctic Mountains over the area of the Butcher Ridge igneous complex showing extent of underlying mafic intrusion
John C. Behrendt, D. Damaske, C. A. Finn, P. Kyle, T. J. Wilson
2002, Journal of Geophysical Research B: Solid Earth (107) EPM 3-1-EPM 3-10
A draped aeromagnetic survey over the area surrounding the Butcher Ridge igneous complex (BRIC), Transantarctic Mountains, was acquired in 1997–1998 as part of a larger Transantarctic Mountains Aerogeophysical Research Activity survey. The BRIC is a sill-like hypoabyssal intrusion ranging in composition from tholeiitic basalt to rhyolite. An 40Ar/39Ar age of 174...
Regional seismic wavefield computation on a 3-D heterogeneous Earth model by means of coupled traveling wave synthesis
F. F. Pollitz
2002, Pure and Applied Geophysics (159) 2085-2112
I present a new algorithm for calculating seismic wave propagation through a three-dimensional heterogeneous medium using the framework of mode coupling theory originally developed to perform very low frequency (f < ???0.01-0.05 Hz) seismic wavefield computation. It is a Greens function approach for multiple scattering within a defined volume and...
Seismic-reflection profiles of the central part of the Clarendon-Linden fault system of western New York in relation to regional seismicity
R.H. Fakundiny, P.W. Pomeroy
2002, Tectonophysics (353) 173-213
Geological and geophysical research in upstate New York, with few exceptions, has not definitively associated seismicity with specific Proterozoic basement or Paleozoic bedrock structures. The central part of the Clarendon-Linden fault system (CLFS) between Batavia and Dale, NY is one of those exceptions where seismicity has been studied and has...
Locally refined block-centred finite-difference groundwater models: Evaluation of parameter sensitivity and the consequences for inverse modelling
S. Mehl, M. C. Hill
2002, IAHS-AISH Publication 227-232
Models with local grid refinement, as often required in groundwater models, pose special problems for model calibration. This work investigates the calculation of sensitivities and the performance of regression methods using two existing and one new method of grid refinement. The existing local grid refinement methods considered are: (a) a...
