PubAg

Main content area

You searched for: Journal Vadose zone journal Remove constraint Journal: Vadose zone journal Publication Year 2007 Remove constraint Publication Year: 2007 Source 2007 v.6 no.3 Remove constraint Source: 2007 v.6 no.3
Start Over

Search

22  Search Results

« Previous | 1 - 20 of 22 |
Number of results to display per page

Search Results

1. Adsorption-Desorption Processes in Subsurface Reactive Transport Modeling

Author:
Goldberg, S.; Criscenti, L.J.; Turner, D.R.; Davis, J.A.; Cantrell, K.J.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 407
ISSN:
1539-1663
Subject:
soil pollution; vadose zone; aquifers; groundwater contamination; pollutants; adsorption; desorption; metal ions; radionuclides; geochemistry; mathematical models; chemical reactions; soil water movement; groundwater flow; saturated flow; unsaturated flow
Abstract:
... Adsorption-desorption reactions are important processes that affect the transport of contaminants in the environment. Various empirical approaches, such as the distribution coefficient and Freundlich and Langmuir isotherm equations, have been used to represent adsorption. The empirical approaches are not capable of accounting for the effects of variable chemical conditions, such as pH, on adsorpti ...
Handle:
10113/11109
DOI:
10.2136/vzj2006.0085

2. A Review of Multidimensional, Multifluid, Intermediate-Scale Experiments: Flow Behavior, Saturation Imaging, and Tracer Detection and Quantification

Author:
Oostrom, M.; Dane, J. H.; Wietsma, T. W.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 610-637
ISSN:
1539-1663
Subject:
groundwater contamination; groundwater flow; infiltration (hydrology); solutes; porous media; analytical methods; dense nonaqueous phase liquids; saturated flow
Abstract:
... A review is presented of original multidimensional, intermediate-scale experiments involving nonaqueous phase liquid (NAPL) flow behavior, imaging, and detection and quantification with solute tracers. In a companion paper (Oostrom et al., 2006a), experiments related to aqueous dissolution and enhanced remediation were discussed. The experiments investigating flow behavior include infiltration and ...
DOI:
10.2136/vzj2006.0178

3. Climate Variability Controls on Unsaturated Water and Chemical Movement, High Plains Aquifer, USA

Author:
Gurdak, Jason J.; Hanson, Randall T.; McMahon, Peter B.; Bruce, Breton W.; McCray, John E.; Thyne, Geoffrey D.; Reedy, Robert C.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 533-547
ISSN:
1539-1663
Subject:
temporal variation; El Nino; evapotranspiration; vadose zone; chlorides; leaching; infiltration (hydrology); nitrate nitrogen; climatic factors; nitrates; water table; High Plains (United States)
Abstract:
... Responses in the vadose zone and groundwater to interannual, interdecadal, and multidecadal climate variability have important implications for groundwater resource sustainability, yet they are poorly documented and not well understood in most aquifers of the USA. This investigation systematically examines the role of interannual to multidecadal climate variability on groundwater levels, deep infi ...
DOI:
10.2136/vzj2006.0087

4. Climatic and Human Influences on Groundwater in Low Atolls

Author:
White, Ian; Falkland, Tony; Metutera, Taboia; Metai, Eita; Overmars, Marc; Perez, Pascal; Dray, Anne
Source:
Vadose zone journal 2007 v.6 no.3 pp. 581-590
ISSN:
1539-1663
Subject:
islands; groundwater; water table; rain; El Nino; drought; wells; infiltration (hydrology); water quality; aquifers; freshwater; saturated hydraulic conductivity; groundwater contamination; Escherichia coli; atolls; Kiribati
Abstract:
... Population centers in low, small islands have water supply problems that are among the most critical in the world. Limited land areas and extremely large soil hydraulic conductivities severely reduce surface runoff and surface storage, so that thin lenses of fresh groundwater floating over seawater comprise the major source of fresh water for people in many atolls. Atoll groundwater is extremely v ...
DOI:
10.2136/vzj2006.0092

5. Combined Effects of Rainfall Patterns and Porous Media Properties on Nitrate Leaching

Author:
Sugita, Fumi; Nakane, Kazuro
Source:
Vadose zone journal 2007 v.6 no.3 pp. 548-553
ISSN:
1539-1663
Subject:
macropores; groundwater contamination; macropore flow; chlorides; infiltration (hydrology); lysimeters; nitrate nitrogen; leaching; porous media; rain; rain intensity; topsoil; climate change; sand; rainfall simulation; nitrates
Abstract:
... Laboratory experiments were conducted to investigate the effects of water input properties on the movement of nitrate in three different porous media. A series of artificial rainfall amounts from 4.0 to 26 mm were applied every 24 h in 10 min durations over a weighing lysimeter packed with either fine sand, field soil over fine sand, or fine sand with artificial macropores. Movements of nitrate, c ...
DOI:
10.2136/vzj2006.0095

6. Combined Effects of Urbanization and Global Warming on Subsurface Temperature in Four Asian Cities

Author:
Taniguchi, Makoto; Uemura, Takeshi; Jago-on, Karen
Source:
Vadose zone journal 2007 v.6 no.3 pp. 591-596
ISSN:
1539-1663
Subject:
groundwater; water temperature; wells; aquifers; urban areas; urbanization; global warming; air temperature; Japan; South Korea; Thailand
Abstract:
... Subsurface temperature profiles measured in boreholes can be analyzed to infer depths of thermal disturbance and associated surface warming due to combined global warming and urbanization (heat island effects). Asian cities are extremely vulnerable because of rapid increases in population. Average subsurface temperature profiles in four Asian cities (Tokyo, Osaka, Seoul, and Bangkok) were compared ...
DOI:
10.2136/vzj2006.0094

7. Comment on "Root Water Extraction and Limiting Soil Hydraulic Conditions Estimated by Numerical Simulation"

Author:
Schroder, T.; Javaux, M.; Vanderborght, J.; Vereecken, H.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 524-526
ISSN:
1539-1663
Subject:
simulation models; soil water content; equations; transpiration; water uptake; roots; soil water movement
DOI:
10.2136/vzj2007.0036

8. Comparing Performance and Parameterization of a One-Dimensional Unsaturated Zone Model across Scales

Author:
Sheikh, Vahedberdi; van Loon, E. Emiel
Source:
Vadose zone journal 2007 v.6 no.3 pp. 638-650
ISSN:
1539-1663
Subject:
vadose zone; soil water content; soil water; mathematical models; agricultural watersheds; model validation; unsaturated conditions; hydrologic models; Netherlands
Abstract:
... The utility of an unsaturated zone soil moisture model is not only its ability to describe the soil moisture dynamics at a given point but also the possibility to generalize the results to larger areas. In this study we investigated the predictive performance of a one-dimensional unsaturated zone soil moisture model when applied at point, field, response unit, and catchment scales, using detailed ...
DOI:
10.2136/vzj2006.0077

9. Geoelectric Studies of Seasonal Wetting and Drying of a Texas Vertisol

Author:
Amidu, Sikiru A.; Dunbar, John A.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 511-523
ISSN:
1539-1663
Subject:
soil cracks; saturated conditions; Vertisols; soil micromorphology; evaporation; soil water; preferential flow; electrical resistance; Texas
Abstract:
... Vertisols are complex soils with high clay content (>30%), high shrink–swell potential, and microrelief features known as gilgai We applied field and laboratory electrical-resistivity measurements to characterize seasonal wetting and drying of a Texas Vertisol, and to quantify the effects of gilgai and cracks on seasonal hydrodynamics of the soil. Thirty-two multielectrode resistivity-profiling li ...
DOI:
10.2136/vzj2007.0005

10. Modeling Water Movement in Heterogeneous Water-Repellent Soil: 2. A Conceptual Numerical Simulation

Author:
Deurer, M.; Bachmann, J.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 446-457
ISSN:
1539-1663
Subject:
simulation models; contact angle; equations; water repellent soils; infiltration (hydrology); seasonal variation; wettability; hydrophobicity; forest soils; soil profiles; soil water retention; drainage; wetting front
Abstract:
... A new approach by Bachmann et al. describes the wetting behavior of soil with reduced wettability with a macroscopic dynamic contact angle concept. The contact angle (CA) is hysteretic and depends on both time and water content. A maximum CA is reached at the permanent wilting point and decreases during rewetting until achieving the minimum CA at a water content close to field capacity. To simulat ...
DOI:
10.2136/vzj2006.0061

11. Modeling Water Movement in Heterogeneous Water-Repellent Soil: 1. Development of a Contact Angle–Dependent Water-Retention Model

Author:
Bachmann, J.; Deurer, M.; Arye, G.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 436-445
ISSN:
1539-1663
Subject:
water repellent soils; soil water movement; contact angle; soil water retention; mathematical models; equations; hydrophobicity; wettability
Abstract:
... In the past, hydrophobic soils have been associated mostly with preferential flow phenomena. It has become increasingly evident that besides the phenomena of extremely (hydrophobic) water-repellent soils, soils with reduced wettability are more the rule than the exception. Despite the extensive literature on the hydraulic behavior of water-repellent soil, a conceptual model flexible enough to desc ...
DOI:
10.2136/vzj2006.0060

12. Nitrous Oxide Fluxes from Cultivated Areas and Rangeland: U.S. High Plains

Author:
Weeks, Edwin P.; McMahon, Peter B.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 496-510
ISSN:
1539-1663
Subject:
land use change; grasslands; agricultural soils; rhizosphere; Zea mays; rangeland soils; corn; arable soils; biological activity in soil; gas emissions; denitrification; water table; vadose zone; nitrous oxide; High Plains (United States)
Abstract:
... Concentration profiles of N₂O, a greenhouse gas, and the conservative trace gases SF₆ and the chlorofluorocarbons CFC-11, CFC-12, CFC-113, and were measured periodically through thick vadose zones at nine sites in the U.S. High Plains. The CFC and SF₆ measurements were used to calibrate a one-dimensional gas diffusion model, using the parameter identification program UCODE. The calibrated model wa ...
DOI:
10.2136/vzj2006.0164

13. Nonaqueous-Phase Liquid Infiltration and Immobilization in Heterogeneous Media: 2. Application to Stochastically Heterogeneous Formations

Author:
Fagerlund, F.; Illangasekare, T.H.; Niemi, A.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 483-495
ISSN:
1539-1663
Subject:
mathematical models; saturated conditions; groundwater contamination; infiltration (hydrology); aquifers; porous media; sand; dense nonaqueous phase liquids; saturated flow
Abstract:
... We performed a series of well-controlled laboratory experiments investigating the infiltration and subsequent immobilization of nonaqueous-phase liquid (NAPL) in saturated heterogeneous media. A system of two distinct aquifer zones separated by a dipping interface was considered. Heterogeneity was represented by a spatially correlated random field with known geostatistical parameters in one zone i ...
DOI:
10.2136/vzj2006.0172

14. Nonaqueous-Phase Liquid Infiltration and Immobilization in Heterogeneous Media: 1. Experimental Methods and Two-Layered Reference Case

Author:
Fagerlund, F.; Illangasekare, T.H.; Niemi, A.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 471-482
ISSN:
1539-1663
Subject:
mathematical models; saturated conditions; groundwater contamination; infiltration (hydrology); porous media; sand; dense nonaqueous phase liquids; saturated flow
Abstract:
... Accurate data to understand the migration and entrapment of nonaqueous-phase liquids (NAPLs) in heterogeneous formations are presently lacking. A series of well-controlled laboratory experiments were conducted to investigate the infiltration and subsequent immobilization of dense NAPLs in saturated heterogeneous media. The focus of this first study was the development of a special experimental met ...
DOI:
10.2136/vzj2006.0171

15. Physically Based Simulation of Potential Effects of Carbon Dioxide-Altered Climates on Groundwater Recharge

Author:
Green, T.R.; Bates, B.C.; Charles, S.P.; Fleming, P.M.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 597
ISSN:
1539-1663
Subject:
elevated atmospheric gases; carbon dioxide; climate change; groundwater recharge; physical models; simulation models; General Circulation Models; aquifers; infiltration (hydrology); saturated flow; evapotranspiration; vegetation; plant growth; senescence; subtropics; Mediterranean climate; Western Australia; Queensland
Abstract:
... Increasing concentrations of atmospheric CO2 will alter regional rainfall and evapotranspiration regimes that drive groundwater recharge. Improved methods of simulation and analysis are needed for assessing the potential sensitivities of soil-water-vegetation systems to climate change. This study demonstrates methods for generating climates and simulating soil-water and vegetation dynamics in resp ...
Handle:
10113/11017
DOI:
10.2136/vzj2006.0099

16. Potential Impacts of Climate Change and Human Activity on Subsurface Water Resources

Author:
Green, Timothy R.; Taniguchi, Makoto; Kooi, Henk
Source:
Vadose zone journal 2007 v.6 no.3 pp. 531-532
ISSN:
1539-1663
Subject:
aquifers; climate change; anthropogenic activities; groundwater
DOI:
10.2136/vzj2007.0098

17. Quantifying the Influence of Uncertainty and Variability on Groundwater Risk Assessment for Trace Elements

Author:
Altfelder, Sven; Duijnisveld, Wilhelmus H. M.; Streck, Thilo; Meyenburg, Gunnar; Utermann, Jens
Source:
Vadose zone journal 2007 v.6 no.3 pp. 668-678
ISSN:
1539-1663
Subject:
trace elements; heavy metals; leaching; cadmium; equations; simulation models; Monte Carlo method; risk assessment; groundwater contamination; soil pH; soil organic carbon; clay fraction; spatial variation; sorption; Germany
Abstract:
... The application of leaching models to predict field-scale heavy metal transport has been successful at several sites. Past studies involved site-specific sorption experiments to quantify the leaching process and to investigate its spatial variability. Uncertainty due to lack of knowledge was frequently ignored. Here we present a leaching model that is based on an extended Freundlich equation to de ...
DOI:
10.2136/vzj2006.0148

18. Regional Differences in Climate Change Impacts on Groundwater and Stream Discharge in Denmark

Author:
van Roosmalen, Lieke; Christensen, Britt S. B.; Sonnenborg, Torben O.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 554-571
ISSN:
1539-1663
Subject:
overland flow; stream flow; climate models; winter; geographical variation; streams; climate change; aquifers; watershed hydrology; summer; groundwater; hydrologic models; Denmark
Abstract:
... Regional impact studies of the effects of future climate change are necessary because projected changes in meteorological variables vary regionally, and different hydrological systems can react in various ways to the same changes. In this study the effects of climate change on groundwater recharge, storage, and discharge to streams are compared in two geologically and climatologically different re ...
DOI:
10.2136/vzj2006.0093

19. Robustness of Sand Storage Dams under Climate Change

Author:
Aerts, Jeroen; Lasage, Ralph; Beets, Wisse; de Moel, Hans; Mutiso, Gideon; Mutiso, Sam; de Vries, Arjen
Source:
Vadose zone journal 2007 v.6 no.3 pp. 572-580
ISSN:
1539-1663
Subject:
water harvesting; climate change; aquifers; dams (hydrology); rain; runoff; Kenya
Abstract:
... This study shows the robustness of subsurface storage using sand dams under long-term climate change for the Kitui District in Kenya. Climate change is predicted to enhance potential evaporation through an increase in average temperature of about 3°C. Even though average precipitation will also increase, approximately 13%, the net water availability is projected to decrease in the future, about 1 ...
DOI:
10.2136/vzj2006.0097

20. Scale Dependence of the Effective Matrix Diffusion Coefficient: Some Analytical Results

Author:
Liu, H. H.; Zhang, Y. Q.; Molz, F. J.
Source:
Vadose zone journal 2007 v.6 no.3 pp. 679-683
ISSN:
1539-1663
Subject:
rocks; equations; groundwater flow; solutes; aquifers; diffusion
Abstract:
... Matrix diffusion is an important process affecting solute transport in fractured rock, and the matrix diffusion coefficient is a key parameter for describing this process. Previous studies have indicated that effective matrix diffusion coefficient values obtained from a number of field tracer tests are enhanced in comparison with local values and may increase with test scale. In this communication ...
DOI:
10.2136/vzj2006.0140