A comparison of winter mercury accumulation at forested and no-canopy sites measured with different snow sampling techniques
S.J. Nelson, K.B. Johnson, K.C. Weathers, C.S. Loftin, I.J. Fernandez, J. S. Kahl, D. P. Krabbenhoft
2008, Applied Geochemistry (23) 384-398
Atmospheric mercury (Hg) is delivered to ecosystems via rain, snow, cloud/fog, and dry deposition. The importance of snow, especially snow that has passed through the forest canopy (throughfall), in delivering Hg to terrestrial ecosystems has received little attention in the literature. The snowpack...
A fully distributed implementation of mean annual streamflow regional regression equations
K.L. Verdin, B. Worstell
2008, Journal of the American Water Resources Association (44) 1537-1547
Estimates of mean annual streamflow are needed for a variety of hydrologic assessments. Away from gage locations, regional regression equations that are a function of upstream area, precipitation, and temperature are commonly used. Geographic information systems technology has facilitated their use for projects, but traditional approaches using the polygon overlay...
Evapotranspiration rates and crop coefficients for a restored marsh in the Sacramento-San Joaquin Delta, California, USA
Judith Z. Drexler, Frank E. Anderson, Richard L. Snyder
2008, Hydrological Processes (22) 725-735
The surface renewal method was used to estimate evapotranspiration (ET) for a restored marsh on Twitchell Island in the Sacramento–San Joaquin Delta, California, USA. ET estimates for the marsh, together with reference ET measurements from a nearby climate station, were used to determine crop coefficients over a 3‐year period during...
Hydrochemical characterization of groundwater in the Akyem area, Ghana
B. Banoeng-Yakubo, S.M. Yidana, Y. Anku, T. Akabzaa, D. Asiedu
2008, Journal of Environmental Hydrology (16) 1-12
The Akyem area is a small farming community located in southeastern Ghana. Groundwater samples from wells in the area were analyzed for concentrations of the major ions, silica, electrical conductivity and pH. The objective was to determine the main controls on the hydrochemistry of ground-water. Mass balance modeling was used...
Mass balance and isotope effects during nitrogen transport through septic tank systems with packed-bed (sand) filters
S.R. Hinkle, J.K. Böhlke, L.H. Fisher
2008, Science of the Total Environment (407) 324-332
Septic tank systems are an important source of NO3− to many aquifers, yet characterization of N mass balance and isotope systematics following septic tank effluent discharge into unsaturated sediments has received limited attention. In this study, samples of septic tank effluent before and after transport through single-pass packed-bed filters...
Dry down impacts on apple snail (Pomacea paludosa) demography: Implications for wetland water management
P.C. Darby, R.E. Bennetts, H.F. Percival
2008, Wetlands (28) 204-214
Florida apple snails (Pomacea paludosa Say) are prey for several wetland-dependent predators, most notably for the endangered Florida snail kite (Rostrhamus sociabilis Vieillot). Management concerns for kites have been raised regarding the impacts of wetland dry downs on snails, but little data exists to validate these concerns. We simulated drying...
Occurrence and turnover of nitric oxide in a nitrogen-impacted sand and gravel aquifer
R. L. Smith, T. Yoshinari
2008, Environmental Science & Technology (42) 8245-8251
Little is known about nitric oxide (NO) production or consumption in the subsurface, an environment which may be conducive to NO accumulation. A study conducted in a nitrogen-contaminated aquifer on Cape Cod, Massachusetts assessed the occurrence and turnover of NO within a contaminant plume in which nitrification...
The effects of land use on fluvial sediment chemistry for the conterminous U.S. - Results from the first cycle of the NAWQA Program: Trace and major elements, phosphorus, carbon, and sulfur
A. J. Horowitz, V. C. Stephens
2008, Science of the Total Environment (400) 290-314
In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S....
Detection and attribution of temperature changes in the mountainous Western United States
Celine Bonfils, B.D. Santer, D.W. Pierce, H.G. Hidalgo, G. Bala, T. Das, T.P. Barnett, D.R. Cayan, C. Doutriaux, A.W. Wood, A. Mirin, T. Nozawa
2008, Journal of Climate (21) 6404-6424
Large changes in the hydrology of the western United States have been observed since the mid-twentieth century. These include a reduction in the amount of precipitation arriving as snow, a decline in snowpack at low and midelevations, and a shift toward earlier arrival of both snowmelt and the centroid (center...
Geochemical investigation of weathering processes in a forested headwater catchment: Mass-balance weathering fluxes
B.F. Jones, J.S. Herman
2008, Conference Paper, Mineralogical Magazine
Geochemical research on natural weathering has often been directed towards explanations of the chemical composition of surface water and ground water resulting from subsurface water-rock interactions. These interactions are often defined as the incongruent dissolution of primary silicates, such as feldspar, producing secondary weathering products, such as clay minerals and...
In situ estimation of the effective chemical diffusion coefficient of a rock matrix in a fractured aquifer
R.A. Gebrekristos, A.M. Shapiro, B.H. Usher
2008, Hydrogeology Journal (16) 629-639
An in situ method of estimating the effective diffusion coefficient for a chemical constituent that diffuses into the primary porosity of a rock is developed by abruptly changing the concentration of the dissolved constituent in a borehole in contact with the rock matrix and monitoring the time-varying concentration. The...
Water-quality monitoring and process understanding in support of environmental policy and management
N.E. Peters
2008, Conference Paper, IAHS-AISH Publication
The quantity and quality of freshwater at any point on the landscape reflect the combined effects of many processes operating along hydrological pathways within a drainage basin/watershed/catchment. Primary drivers for the availability of water are landscape changes and patterns, and the processes affecting the timing, magnitude, and intensity of precipitation,...
Late Quaternary MIS 6-8 shoreline features of pluvial Owens Lake, Owens Valley, eastern California
A. S. Jayko, S.N. Bacon
2008, Conference Paper, Special Paper of the Geological Society of America
The chronologic history of pluvial Owens Lake along the eastern Sierra Nevada in Owens Valley, California, has previously been reported for the interval of time from ca. 25 calibrated ka to the present. However, the age, distribution, and paleoclimatic context of higher-elevation shoreline features have not been formally documented. We...
Multistage late Cenozoic evolution of the Amargosa River drainage, southwestern Nevada and eastern California Society of America. All rights reserved
C.M. Menges
2008, Conference Paper, Special Paper of the Geological Society of America
Stratigraphic and geomorphic analyses reveal that the regional drainage basin of the modern Amargosa River formed via multistage linkage of formerly isolated basins in a diachronous series of integration events between late Miocene and latest Pleistocene-Holocene time. The 275-km-long Amargosa River system drains generally southward across a large (15,540 km<sup>...
Estimating groundwater recharge in Hebei Plain, China under varying land use practices using tritium and bromide tracers
B. Wang, M. Jin, J. R. Nimmo, L. Yang, W. Wang
2008, Journal of Hydrology (356) 209-222
Tritium and bromide were used as applied tracers to determine groundwater recharge in Hebei Plain, North China, to evaluate the impacts of different soil types, land use, irrigation, and crop cultivation practice on recharge. Additional objectives were to evaluate temporal variability of recharge and the effect on results of the...
Effects of residence time on summer nitrate uptake in Mississippi River flow-regulated backwaters
W.F. James, W. B. Richardson, D.M. Soballe
2008, River Research and Applications (24) 1206-1217
Nitrate uptake may be improved in regulated floodplain rivers by increasing hydrological connectivity to backwaters. We examined summer nitrate uptake in a series of morphologically similar backwaters on the Upper Mississippi River receiving flow-regulated nitrate loads via gated culverts. Flows into individual backwaters were held constant over a summer period...
Multi-residue method for the analysis of 85 current-use and legacy pesticides in bed and suspended sediments
K.L. Smalling, K.M. Kuivila
2008, Journal of Chromatography A (1210) 8-18
A multi-residue method was developed for the simultaneous determination of 85 current-use and legacy organochlorine pesticides in a single sediment sample. After microwave-assisted extraction, clean-up of samples was optimized using gel permeation chromatography and either stacked carbon and alumina solid-phase extraction cartridges or a deactivated Florisil column. Analytes were determined...
Wetlands as principal zones of methylmercury production in southern Louisiana and the Gulf of Mexico region
B.D. Hall, G. R. Aiken, D. P. Krabbenhoft, M. Marvin-DiPasquale, C.M. Swarzenski
2008, Environmental Pollution (154) 124-134
It is widely recognized that wetlands, especially those rich in organic matter and receiving appreciable atmospheric mercury (Hg) inputs, are important sites of methylmercury (MeHg) production. Extensive wetlands in the southeastern United States have many ecosystem attributes ideal for promoting high MeHg production rates; however, relatively few mercury cycling studies...
Reconstructing late Pliocene to middle Pleistocene Death Valley lakes and river systems as a test of pupfish (Cyprinodontidae) dispersal hypotheses
J.R. Knott, M. N. Machette, R.E. Klinger, A.M. Sarna-Wojcicki, J. C. Liddicoat, J. C. Tinsley III, B.T. David, V.M. Ebbs
2008, Conference Paper, Special Paper of the Geological Society of America
During glacial (pluvial) climatic periods, Death Valley is hypothesized to have episodically been the terminus for the Amargosa, Owens, and Mojave Rivers. Geological and biological studies have tended to support this hypothesis and a hydrological link that included the Colorado River, allowing dispersal of pupfish throughout southeastern California and western...
The persistence of lead from past gasoline emissions and mining drainage in a large riparian system: Evidence from lead isotopes in the Sacramento River, California
C.E. Dunlap, Charles N. Alpers, R. Bouse, Howard E. Taylor, D.M. Unruh, A.R. Flegal
2008, Geochimica et Cosmochimica Acta (72) 5935-5948
Lead concentrations and isotope ratios measured in river water colloids and streambed sediment samples along 426 km of the Sacramento River, California reveal that the influence of lead from the historical mining of massive sulfide deposits in the West Shasta Cu-mining district (at the...
Is there enough sand? Evaluating the fate of Grand Canyon sandbars
S.A. Wright, J. C. Schmidt, Theodore S. Melis, D.J. Topping, D. M. Rubin
2008, GSA Today (18) 4-10
Large dams have the potential to dramatically alter the flow regime, geomorphology, and aquatic ecosystem of downstream river reaches. Development of flow release regimes in order to meet multiple objectives is a challenge facing dam operators, resource managers, and scientists. Herein, we review previous work and present new analyses related...
A satellite snow depth multi-year average derived from SSM/I for the high latitude regions
S. Biancamaria, N. M. Mognard, A. Boone, M. Grippa, E.G. Josberger
2008, Remote Sensing of Environment (112) 2557-2568
The hydrological cycle for high latitude regions is inherently linked with the seasonal snowpack. Thus, accurately monitoring the snow depth and the associated aerial coverage are critical issues for monitoring the global climate system. Passive microwave satellite measurements provide an optimal means to monitor the snowpack over the arctic region....
Transport of elemental mercury in the unsaturated zone from a waste disposal site in an arid region
Michelle Ann Walvoord, Brian J. Andraski, D. P. Krabbenhoft, Robert G. Striegl
2008, Applied Geochemistry (23) 572-583
Mercury contained in buried landfill waste may be released via upward emission to the atmosphere or downward leaching to groundwater. Data from the US Geological Survey’s Amargosa Desert Research Site (ADRS) in arid southwestern Nevada reveal another potential pathway of Hg release: long-distance (102 m) lateral migration of elemental Hg (Hg0)...
Do beavers promote the invasion of non-native Tamarix in the Grand Canyon riparian zone
S.G. Mortenson, P.J. Weisberg, B.E. Ralston
2008, Wetlands (28) 666-675
Beavers (Castor canadensis Kuhl) can influence the competitive dynamics of plant species through selective foraging, collection of materials for dam creation, and alteration of hydrologic conditions. In the Grand Canyon National Park, the native Salix gooddingii C.R.Ball (Goodding's willow) and Salix exigua Nutt. (coyote willow) are a staple food of...
Developing conceptual hydrogeological model for Potsdam sandstones in southwestern Quebec, Canada
Miroslav Nastev, R. Morin, Rejean Godin, Alain Rouleau
2008, Hydrogeology Journal (16) 373-388
A hydrogeological study was conducted in Potsdam sandstones on the international border between Canada (Quebec) and the USA (New York). Two sandstone formations, arkose and conglomerate (base) and well-cemented quartz arenite (upper), underlie the study area and form the major regional aquifer unit. Glacial till, littoral sand and gravel, and...
