Grazing trails formed by soldier fly larvae (Diptera: Stratiomyidae) and their paleoenvironmental and paleoecological implications for the fossil record
M. Gabriela Mángano, Luis A. Buatois, Guillermo L. Claps
1996, Ichnos: An International Journal for Plant and Animal Traces (4) 163-167
Recent trails formed by soldier fly larvae (Díptera: Stratiomyidae) were examined in a shallow pond in the floodplain of a braided river in Jujuy Province, northwestern Argentina. Collected specimens were identified as Stratiomys convexa van der Wulp. Simple, irregularly meandering trails were produced across the surface of a muddy‐silty substrate. Since soldier...
A precise vertical network: Establishing new orthometric heights with static surveys in Florida tidal marshes
E. A. Raabe, R. P. Stumpf, N.J. Marth, R.L. Shrestha
1996, Surveying and Land Information Systems (56) 200-211
Elevation differences on the order of 10 cm within Florida's marsh system influence major variations in tidal flooding and in the associated plant communities. This low elevation gradient combined with sea level fluctuation of 5-to-10 cm over decadel and longer periods can generate significant alteration and erosion of marsh habitats...
Riparian vegetation and fluvial geomorphic processes
C.R. Hupp, W. R. Osterkamp
1996, Geomorphology (14) 277-295
Riparian vegetation and fluvial-geomorphic processes and landforms are intimately connected parts of the bottomland landscape. Relations among vegetation, processes, and landforms are described here for representative streams of four areas of the United States: high-gradient streams of the humid east, coastal-plain streams. Great Plains streams, and stream channels of the...
Sand deposition in the Colorado River in the Grand Canyon from flooding of the Little Colorado River
S.M. Wiele, J.B. Graf, J.D. Smith
1996, Water Resources Research (32) 3579-3596
Methods for computing the volume of sand deposited in the Colorado River in Grand Canyon National Park by floods in major tributaries and for determining redistribution of that sand by main-channel flows are required for successful management of sand-dependent riparian resources. We have derived flow, sediment transport, and bed evolution...
Properties and variability of soil and trench fill at an arid waste-burial site
Brian J. Andraski
1996, Soil Science Society of America Journal (60) 54-66
Arid sites commonly are assumed to be ideal for long-term isolation of wastes. Information on properties and variability of desert soils is limited, however, and little is known about how the natural site environment is altered by installation of a waste facility. During fall construction of two test trenches next...
Open-ocean boundary conditions from interior data: Local and remote forcing of Massachusetts Bay
P.S. Bogden, P. Malanotte-Rizzoli, R. Signell
1996, Journal of Geophysical Research C: Oceans (101) 6487-6500
Massachusetts and Cape Cod Bays form a semienclosed coastal basin that opens onto the much larger Gulf of Maine. Subtidal circulation in the bay is driven by local winds and remotely driven flows from the gulf. The local-wind forced flow is estimated with a regional shallow water model driven by...
Benthic foraminiferal response to the emergence of the Isthmus of Panama and coincident paleoceanographic changes
K. McDougall
1996, Marine Micropaleontology (28) 133-169
Late Cenozoic benthic foraminiferal faunas from the Caribbean Deep Sea Drilling Project (DSDP) Site 502 (3052 m) and East Pacific DSDP Site 503 (3572 m) were analyzed to interpret bottom-water masses and paleoceanographic changes occurring as the Isthmus of Panama emerged. Major changes during the past 7 Myr occur at...
Pumping strategies for management of a shallow water table: The value of the simulation-optimization approach
P. M. Barlow, B.J. Wagner, K. Belitz
1996, Ground Water (34) 305-317
The simulation-optimization approach is used to identify ground-water pumping strategies for control of the shallow water table in the western San Joaquin Valley, California, where shallow ground water threatens continued agricultural productivity. The approach combines the use of ground-water flow simulation with optimization techniques to build on and refine pumping...
Holocene paleoseismicity, temporal clustering, and probabilities of future large (M > 7) earthquakes on the Wasatch fault zone, Utah
J.P. McCalpin, S.P. Nishenko
1996, Journal of Geophysical Research B: Solid Earth (101) 6233-6253
The chronology of M > 7 paleoearthquakes on the central five segments of the Wasatch fault zone (WFZ) is one of the best dated in the world and contains 16 earthquakes in the past 5600 years with an average repeat time of 350 years. Repeat times for individual segments vary by a...
Death Valley regional groundwater flow model calibration using optimal parameter estimation methods and geoscientific information systems
F. A. D’Agnese, C.C. Faunt, M. C. Hill, A. K. Turner
1996, IAHS-AISH Publication (237) 41-52
A three-layer Death Valley regional groundwater flow model was constructed to evaluate potential regional groundwater flow paths in the vicinity of Yucca Mountain, Nevada. Geoscientific information systems were used to characterize the complex surface and subsurface hydrogeological conditions of the area, and this characterization was used to construct likely conceptual...
Calculated volatilization rates of fuel oxygenate compounds and other gasoline-related compounds from rivers and streams
J. F. Pankow, R. E. Rathbun, J.S. Zogorski
1996, Chemosphere (33) 921-937
Large amounts of the 'fuel-oxygenate' compound methyl-tert-butyl ether (MTBE) are currently being used in gasoline to reduce carbon monoxide and ozone in urban air and to boost fuel octane. Because MTBE can be transported to surface waters in various ways, established theory was used to calculate half-lives for MTBE volatilizing...
Using nonlinear forecasting to learn the magnitude and phasing of time-varying sediment suspension in the surf zone
B. E. Jaffe, D. M. Rubin
1996, Journal of Geophysical Research C: Oceans (101) 14283-14296
The time-dependent response of sediment suspension to flow velocity was explored by modeling field measurements collected in the surf zone during a large storm. Linear and nonlinear models were created and tested using flow velocity as input and suspended-sediment concentration as output. A sequence of past velocities (velocity history), as...
Use of 2D and 3D GIS in well selection and interpretation of nitrate data, central Nebraska, USA
Ingrid M. Verstraeten, V. L. McGuire, W.A. Battaglin
Kovar K.Nachtnebel H.P., editor(s)
1996, Application of geographic information systems in hydrology and water resources management. Proc. HydroGIS'96 conference, Vienna, 1996 585-591
Nonpoint-source contamination of the principal aquifers in an area of central Nebraska was evaluated utilizing aquifer condition, well depth, soil type, and physiographical and land use settings. A two-dimensional geographical information system linked with a three-dimensional geological visualization and analytical program was used in the random selection of acceptable wells...
Holocene slip rate of the Hayward fault at Union City, California
J. J. Lienkaemper, G. Borchardt
1996, Journal of Geophysical Research B: Solid Earth (101) 6099-6108
Measured offsets of well-dated alluvial fan deposits near the Masonic Home in Union City constrain Holocene slip rate of the Hayward fault between 7 and 9 mm/yr. Our best minimum geologic slip rate over the past 8.27 ± 0.08 kyr (i.e., 8270 years) is 8.0 ± 0.7 mm/yr. A steep...
Compensating for estimation smoothing in kriging
Ricardo A. Olea, Vera Pawlowsky
1996, Mathematical Geology (28) 407-417
Smoothing is a characteristic inherent to all minimum mean-square-error spatial estimators such as kriging. Cross-validation can be used to detect and model such smoothing. Inversion of the model produces a new estimator-compensated kriging. A numerical comparison based on an exhaustive permeability sampling of a 4-fr2 slab of Berea Sandstone shows...
Amphibian and reptile abundance in riparian and upslope areas of five forest types in western Oregon
D.M. Gomez, R.G. Anthony
1996, Northwest Science (70) 109-119
We compared species composition and relative abundance of herpetofauna between riparian and upslope habitats among 5 forest types (shrub, open sapling-pole, large sawtimber and old-growth conifer forests, and deciduous forests) in Western Oregon. Riparian- and upslope- associated species were identified based on capture frequencies from pitfall trapping. Species richness was similar among forest...
Sources of Water to Wells for Transient Cyclic Systems
T. E. Reilly, D.W. Pollock
1996, Groundwater (34) 979-988
Many state agencies are currently (1995) developing wellhead protection programs. The thrust of some of these programs is to protect water supplies by determining the areas contributing recharge to water-supply wells and by specifying regulations to minimize the opportunity for contamination of the recharge...
Stream-aquifer interaction model with diffusive wave routing
S.P. Perkins, Antonis D. Koussis
1996, Journal of Hydraulic Engineering (122) 210-218
A practical approach to modeling the hydraulic interaction of a stream and aquifer via streambed leakage is based on the established U.S. Geological Survey (USGS) model, MODFLOW. To represent flood-wave propagation and the associated bank storage, MODFLOW's STREAM module is replaced by the Muskingum-Cunge diffusive-wave-routing scheme. The diffusive wave model...
Using remote sensing and GIS techniques to estimate discharge and recharge fluxes for the Death Valley regional groundwater flow system, USA
F. A. D’Agnese, C.C. Faunt, A. K. Turner
Kovar K.Nachtnebel H.P., editor(s)
1996, Application of geographic information systems in hydrology and water resources management. Proc. HydroGIS'96 conference, Vienna, 1996 503-511
The recharge and discharge components of the Death Valley regional groundwater flow system were defined by techniques that integrated disparate data types to develop a spatially complex representation of near-surface hydrological processes. Image classification methods were applied to multispectral satellite data to produce a vegetation map. The vegetation map was...
Observations of sediment transport on the Amazon subaqueous delta
R.W. Sternberg, D.A. Cacchione, B. Paulson, G.C. Kineke, D.E. Drake
1996, Continental Shelf Research (16) 697-715
A 19-day time series of fluid, flow, and suspended-sediment characteristics in the benthic boundary layer is analyzed to identify major sedimentary processes active over the prodelta region of the Amazon subaqueous delta. Measurements were made by the benthic tripod GEOPROBE placed on the seabed in 65 m depth near...
Linear alkylbenzenes as tracers of sewage-sludge-derived inputs of organic matter, PCBs, and PAHs to sediments at the 106-mile deep water disposal site
E.M. Lamoureux, Bruce J. Brownawell, Michael H. Bothner
1996, Journal of Marine Environmental Engineering (2) 325-342
Linear alkylbenzenes (LABs) are sensitive source-specific tracers of sewage inputs to the marine environment. Because they are highly particle reactive and nonspecifically sorbed to organic matter, LABs are potential tracers of the transport of both sludge-derived organic matter and other low solubility hydrophobic contaminants (e.g., PCBs and PAHs); sediment trap...
Diver-operated manometer: A simple device for measuring hydraulic head in underwater wells
C. D. Reich
1996, Journal of Sedimentary Research (66) 1032-1036
No abstract available....
Herbicide metabolites in surface water and groundwater: Introduction and overview
E.M. Thurman, M. T. Meyer
1996, ACS Symposium Series (630)
Several future research topics for herbicide metabolites in surface and ground water are outlined in this chapter. They are herbicide usage, chemical analysis of metabolites, and fate and transport of metabolites in surface and ground water. These three ideas follow the themes in this book, which are the summary of...
Surveying woodland hawks with broadcasts of great horned owl vocalization
James A. Mosher, Mark R. Fuller
1996, Wildlife Society Bulletin (24) 531-536
Pre-recorded vocalizations of great horned owls (Bubo virginianus) broadcast into predominantly wooded habitat along roadside survey routes resulted in as many detections of resident red-shouldered hawks (Buteo lineatus) and Cooper's hawks (Accipiter cooperii) as broadcasts of each conspecific calls. Survey results for 3 species, expressed as average number of contacts/route,...
The effects of snowpack grain size on satellite passive microwave observations from the Upper Colorado River Basin
E.G. Josberger, P. Gloersen, A. Chang, A. Rango
1996, Journal of Geophysical Research C: Oceans (101) 6679-6688
Understanding the passive microwave emissions of a snowpack, as observed by satellite sensors, requires knowledge of the snowpack properties: water equivalent, grain size, density, and stratigraphy. For the snowpack in the Upper Colorado River Basin, measurements of snow depth and water equivalent are routinely available from the U.S. Department of...
