The design of sampling transects for characterizing water quality in estuaries
A.D. Jassby, B.E. Cole, J. E. Cloern
1997, Estuarine, Coastal and Shelf Science (45) 285-302
The high spatial variability of estuaries poses a challenge for characterizing estuarine water quality. This problem was examined by conducting monthly high-resolution transects for several water quality variables (chlorophyll a, suspended particulate matter and salinity) in San Francisco Bay (California, U.S.A.). Using these data,...
Risk of nitrate in groundwaters of the United States - A national perspective
B. T. Nolan, B. C. Ruddy, K.J. Hitt, D.R. Helsel
1997, Environmental Science & Technology (31) 2229-2236
Nitrate contamination of groundwater occurs in predictable patterns, based on findings of the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Program. The NAWQA Program was begun in 1991 to describe the quality of the Nation's water resources, using nationally consistent methods. Variables affecting nitrate concentration in groundwater were...
Debris-flow hazard map units from gridded probabilities
Russell H. Campbell, Richard L. Bernknopf
1997, Conference Paper, International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment, Proceedings
The common statistical practice of dividing a range of probabilities into equal probability intervals may not result in useful landslide-hazard map units for areas populated by equal-area cells, each of which has a unique probability. Most hazard map areas contain very large numbers of cells having low probability of failure,...
Scale and modeling issues in water resources planning
H.F. Lins, D.M. Wolock, G.J. McCabe
1997, Climatic Change (37) 63-88
Resource planners and managers interested in utilizing climate model output as part of their operational activities immediately confront the dilemma of scale discordance. Their functional responsibilities cover relatively small geographical areas and necessarily require data of relatively high spatial resolution. Climate models cover a large geographical, i.e. global, domain and...
A unique Middle Ordovician K-bentonite bed succession at Röstånga, S. Sweden
Stig M. Bergstrom, Warren D. Huff, Dennis R. Kolata, Deborah A. Yost, Charles P. Hart
1997, GFF (119) 231-244
An approximately 8.5 m thick sequence of upper Viruan (upper Middle Ordovician) shales, mudstones, and limestones in an outcrop at Kyrkbäcken near Röstånga in W‐central Skåne contains 19 K‐bentonite beds, several of which are as much as 40–67 cm thick. Thirteen of these beds are in the upper part of...
Recognition of maximum flooding events in mixed siliciclastic-carbonate systems: Key to global chronostratigraphic correlation
E. A. Mancini, B.H. Tew
1997, Geology (25) 351-354
The maximum flooding event within a depositional sequence is an important datum for correlation because it represents a virtually synchronous horizon. This event is typically recognized by a distinctive physical surface and/or a significant change in microfossil assemblages (relative fossil abundance peaks) in...
Measuring flood discharge in unstable stream channels using ground-penetrating radar
K.R. Spicer, J. E. Costa, G. Placzek
1997, Geology (25) 423-426
Field experiments were conducted to test the ability of ground-penetrating radar (GPR) to measure stream-channel cross sections at high flows without the necessity of placing instruments in the water. Experiments were conducted at four U.S. Geological Survey gaging stations in southwest Washington State....
A new method for automated dynamic calibration of tipping-bucket rain gauges
M.D. Humphrey, J.D. Istok, J.Y. Lee, J.A. Hevesi, A. L. Flint
1997, Journal of Atmospheric and Oceanic Technology (14) 1513-1519
Existing methods for dynamic calibration of tipping-bucket rain gauges (TBRs) can be time consuming and labor intensive. A new automated dynamic calibration system has been developed to calibrate TBRs with minimal effort. The system consists of a programmable pump, datalogger, digital balance, and computer. Calibration is performed in two steps:...
Spatial and temporal variability in nutrient concentrations in surface waters of the Chattahoochee River basin near Atlanta, Georgia, USA
N.E. Peters, G. R. Buell, E. A. Frick
1997, IAHS-AISH Publication (243) 153-165
Nutrient concentrations from the early 1970s through 1995 were evaluated at several sites along the Chattahoochee River and its tributaries near Atlanta, to determine general patterns and processes controlling nutrient concentrations in the river. A spatial analysis was conducted on data collected in 1994 and 1995 from an intensive nutrient...
GSLIB-style programs for discriminant analysis and regionalized classification
Geoffrey C. Bohling
1997, Computers & Geosciences (23) 739-761
Discriminant analysis is a statistical technique used to predict the group membership of a set of multivariate observations, each of which is assumed to arise from one of a set of distinct classes or groups. Each group is characterized by a certain distribution in multivariate space, and group allocations are...
The roles of time and displacement in velocity-dependent volumetric strain of fault zones
N.M. Beeler, T.E. Tullis
1997, Journal of Geophysical Research B: Solid Earth (102) 22595-22609
The relationship between measured friction μA and volumetric strain during frictional sliding was determined using a rate and state variable dependent friction constitutive equation, a common work balance relating friction and volume change, and two types of experimental faults: initially bare surfaces of Westerly granite and rock surfaces separated by...
Permo-Carboniferous sedimentary basins related to the distribution of planetary cryptoblemes
J. F. Windolph Jr.
1997, Prace - Panstwowego Instytutu Geologicznego (157) 87-89
Massive/high velocity solar, galactic, and cosmic debris impacting the Earths surface may account for the enormous energy required for the formation of Permo-Carboniferous sedimentary basins and related mountain building orogenies. Analysis of satellite immagry, sea floor sonar, geophysical data, and geotectonic fabrics show a strong correlation throughout geologic time between...
The forms of trace metals in an Illinois basin coal by x-ray absorption fine structure spectroscopy
I.-M. Chou, J.A. Bruinius, J.M. Lytle, R.R. Ruch, Frank E. Huggins, G.P. Huffman, K.K. Ho
1997, ACS Division of Fuel Chemistry, Preprints (42) 1113-1116
Utilities burning Illinois coals currently do not consider trace elements in their flue gas emissions. After the US EPA completes an investigation on trace elements, however, this may change and flue gas emission standards may be established. The mode of occurrence of a trace element may determine its cleanability and...
Land cover mapping, fire regeneration, and scaling studies in the Canadian boreal forest with 1 km AVHRR and Landsat TM data
L. T. Steyaert, F.G. Hall, Thomas R. Loveland
1997, Journal of Geophysical Research D: Atmospheres (102) 29581-29598
A multitemporal 1 km advanced very high resolution radiometer (AVHRR) land cover analysis approach was used as the basis for regional land cover mapping, fire disturbance-regeneration, and multiresolution land cover scaling studies in the boreal forest ecosystem of central Canada. The land cover classification was developed by using regional field...
Field-scale tests for determining mixing patterns associated with coarse-bubble air diffuser configurations, Egan Quarry, Illinois
Nancy J. Hornewer, G.P. Johnson, Dale M. Robertson, Miki Hondzo
1997, Conference Paper, Proceedings, Congress of the International Association of Hydraulic Research, IAHR
The U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers, Chicago District did field-scale tests in August-September 1996 to determine mixing patterns associated with different configurations of coarse-bubble air diffusers. The tests were done in an approximately 13-meter deep quarry near Chicago, Ill. Three-dimensional velocity, water-temperature, dissolved...
Analysis of environmental data with censored observations
S. Liu, J.-C. Lu, D.W. Kolpin, W.Q. Meeker
1997, Environmental Science & Technology (31) 3358-3362
The potential threats to humans and to terrestrial and aquatic ecosystems from environmental contamination could depend on the sum of the concentrations of different chemicals. However, direct summation of environmental data is not generally feasible because it is common for some chemical concentrations to be recorded as being below the...
Ophiolitic basement to the Great Valley forearc basin, California, from seismic and gravity data: Implications for crustal growth at the North American continental margin
N. J. Godfrey, B. C. Beaudoin, S.L. Klemperer, A. Levander, J. Luetgert, A. Meltzer, Walter D. Mooney, A. Trehu
1997, Geological Society of America Bulletin (109) 1536-1562
The nature of the Great Valley basement, whether oceanic or continental, has long been a source of controversy. A velocity model (derived from a 200-km-long east-west reflection-refraction profile collected south of the Mendocino triple junction, northern California, in 1993), further constrained by density and magnetic models, reveals an ophiolite underlying...
Correlated errors in geodetic time series: Implications for time-dependent deformation
J. Langbein, H. Johnson
1997, Journal of Geophysical Research B: Solid Earth (102) 591-603
Analysis of frequent trilateration observations from the two-color electronic distance measuring networks in California demonstrate that the noise power spectra are dominated by white noise at higher frequencies and power law behavior at lower frequencies. In contrast, Earth scientists typically have assumed that only white noise is present in a...
Moss and soil contributions to the annual net carbon flux of a maturing boreal forest
J.W. Harden, K. P. O’Neill, S.E. Trumbore, H. Veldhuis, B.J. Stocks
1997, Journal of Geophysical Research D: Atmospheres (102) 28805-28816
We used input and decomposition data from 14C studies of soils to determine rates of vertical accumulation of moss combined with carbon storage inventories on a sequence of burns to model how carbon accumulates in soils and moss after a stand-killing fire. We used soil drainage—moss associations and soil drainage maps...
Recovery strategies for the California clapper rail (Rallus longirostris obsoletus) in the heavily-urbanized San Francisco estuarine ecosystem
Theodore C. Foin, E. Jacqueline Garcia, Robert E. Gill Jr., Steven D. Culberson, Joshua N. Collins
1997, Landscape and Urban Planning (38) 229-243
The California clapper rail (Rallus longirostris obsoletus), a Federal- and State-listed endangered marsh bird, has a geographic range restricted to one of the most heavily-urbanized estuaries in the world. The rail population has long been in a state of decline, although the exact contribution of each of the many contributing...
Use of inexpensive pressure transducers for measuring water levels in wells
B. D. Keeland, J.F. Dowd, W.S. Hardegree
1997, Wetlands Ecology and Management (5) 121-129
Frequent measurement of below ground water levels at multiple locations is an important component of many wetland ecosystem studies. These measurements, however, are usually time consuming, labor intensive, and expensive. This paper describes a water-level sensor that is inexpensive and easy to construct. The sensor is placed below the expected...
Permeability and porosity of the Illinois UPH 3 drillhole granite and a comparison with other deep drillhole rocks
C.A. Morrow, D.A. Lockner
1997, Journal of Geophysical Research B: Solid Earth (102) 3067-3075
Permeability, porosity, and volumetric strain measurements were conducted on granite cores obtained at depths of 0.7 to 1.6 km from the Illinois UPH 3 drillhole at effective confining pressures from 5 to 100 MPa. Initial permeabilities were in the range of 10-17 to 10-19 m2 and dropped rapidly with applied...
Long-term growth trends of baldcypress (Taxodium distichum (L.) rich.) at Caddo Lake, Texas
B. D. Keeland, P.J. Young
1997, Wetlands (17) 559-566
Caddo Lake, situated on the border of northeast Texas and northwest Louisiana, USA is a medium-sized lake dominated by stands of baldcypress (Taxodiwn distichum). A study of tree growth was initiated at Caddo Lake to address concerns about the health of the baldcypress ecosystem. The lake has been subjected to...
Kinetics of the coesite to quartz transformation
J.L. Mosenfelder, S.R. Bohlen
1997, Earth and Planetary Science Letters (153) 133-147
The survival of coesite in ultrahigh-pressure (UHP) rocks has important implications for the exhumation of subducted crustal rocks. We have conducted experiments to study the mechanism and rate of the coesite→quartz transformation using polycrystalline coesite aggregates, fabricated by devitrifying silica glass cylinders...
Vertebrate herbivory in managed coastal wetlands: A manipulative experiment
L.A. Johnson, A.L. Foote
1997, Aquatic Botany (59) 17-32
Structural marsh management and nutria herbivory are both believed to strongly influence plant production in the brackish, deltaic marshes of coastal Louisiana, USA. Previous studies have tested the effects of structural management on aboveground biomass after implementing management, but very few studies have collected data before and after management. Thus,...
