Skip to Main Content
Skip Nav Destination

Issues

This review attempts to summarize the current literature on adsorption-desorption reaction mechanisms, models for adsorption-desorption reactions at the molecular scale, empirical representations of adsorption-desorption equilibria, and field-scale applications of subsurface reactive transport modeling with adsorption-desorption equilibria.

Vadose Zone Journal August 01, 2007, Vol.6, 407-435. doi:https://doi.org/10.2136/vzj2006.0085

We present a general model for describing the movement of water in soils with variable pore-surface properties. It applies for wettable, subcritically water repellent, and hydrophobic soils. A microscopic water-content and time-dependent contact angle is coupled with the macroscopic water retention function. Few additional parameters are needed.

Vadose Zone Journal August 01, 2007, Vol.6, 436-445. doi:https://doi.org/10.2136/vzj2006.0060

We test a general model for describing water in texturally heterogeneous soils exhibiting various degrees of water repellency by simulating a drying-rewetting cycle in soils. For the hydrophobic soils we predict distribution, fingering and redistribution zones. With rewetting the fingers slowly widen and dissipate.

Vadose Zone Journal August 01, 2007, Vol.6, 446-457. doi:https://doi.org/10.2136/vzj2006.0061

An experiment focusing on water movement into discrete flow channels was conducted. A steady or quasi-periodic “leaking” of water occurred, contrary to capillary break theory. This work demonstrates that surprising and complex behavior can occur in relatively simple and well-characterized systems with scales on the order of several meters.

Vadose Zone Journal August 01, 2007, Vol.6, 458-470. doi:https://doi.org/10.2136/vzj2006.0125

A methodology to dynamically measure nonaqueous-phase liquid (NAPL) migration in space and time using a multiple-energy x-ray attenuation technique is presented. Flow and entrapment of NAPL in a saturated layered formation were studied, and methods of characterizing entrapment architecture were tested. The saturation history dependence of entrapment was also demonstrated.

Vadose Zone Journal August 01, 2007, Vol.6, 471-482. doi:https://doi.org/10.2136/vzj2006.0171

Spatially correlated random permeability fields were carefully built in a saturated 2D sand tank creating systems of complex but well-known heterogeneity. Non-aqueous phase liquid migration and entrapment at capillary barriers and by snap-off processes were studied taking precise measurements of fluid saturations in space and time using an x-ray-attenuation technique.

Vadose Zone Journal August 01, 2007, Vol.6, 483-495. doi:https://doi.org/10.2136/vzj2006.0172

Depth profiles of chlorofluorocarbon concentrations in soil gas at nine sites of irrigated cropland and rangeland in the High Plains were used to calibrate a gas-phase diffusive transport model. Vadose-zone measurements of nitrous oxide, a significant greenhouse gas, were used with the calibrated model to estimate its flux to the atmosphere from the various sites.

Vadose Zone Journal August 01, 2007, Vol.6, 496-510. doi:https://doi.org/10.2136/vzj2006.0164

We examined the seasonal dynamics of moisture in a Vertisol using the electrical-resistivity geophysical method. Results show that there are three soil moisture regimes and that seasonal hydrodynamics of the soil are influenced by microrelief variability and cracks. Implications of the results to agricultural management and soil taxonomy are discussed.

Vadose Zone Journal August 01, 2007, Vol.6, 511-523. doi:https://doi.org/10.2136/vzj2007.0005
Vadose Zone Journal August 01, 2007, Vol.6, 524-526. doi:https://doi.org/10.2136/vzj2007.0036
Vadose Zone Journal August 01, 2007, Vol.6, 527-528. doi:https://doi.org/10.2136/vzj2007.0042L

The guest editors introduce the special section Groundwater Resources Assessment under the Pressures of Humanity and Climate Change (GRAPHIC) derived from the conference by the same name that was held in Kyoto, Japan in 2006. Sponsored by UNESCO's International Hydrological Program, GRAPHIC is a collaborative effort and umbrella for international research and education. The conference was hosted by the Research Institute for Humanity and Nature, Japan.

Vadose Zone Journal August 01, 2007, Vol.6, 531-532. doi:https://doi.org/10.2136/vzj2007.0098

Spectral analysis of hydrologic time series and reconstruction of frequency components reveal that unsaturated water and chemical fluxes, including recharge, respond to interannual to multidecadal climate cycles, particularly the Pacific Decadal Oscillation. Using this conceptualization, a method is presented to estimate climate-varying recharge.

Vadose Zone Journal August 01, 2007, Vol.6, 533-547. doi:https://doi.org/10.2136/vzj2006.0087

Effects of rainfall patterns on nitrate leaching in homogeneous and heterogeneous porous media were investigated. Nitrate leaches only under extreme rainfall in both media, whereas considerable degradation and large spreading are observed only in heterogeneous porous media. The increase of nitrate leaching by potential climate change is suggested.

Vadose Zone Journal August 01, 2007, Vol.6, 548-553. doi:https://doi.org/10.2136/vzj2006.0095

Regional climate model data are used in an integrated hydrological model to study the effects of future climate change. The main focus of this study is groundwater recharge, although the changes in stream discharge are also presented. The results show a clear influence of the geology and climatology of the study areas on the simulated effects.

Vadose Zone Journal August 01, 2007, Vol.6, 554-571. doi:https://doi.org/10.2136/vzj2006.0093

Climate change will have an impact on potential evaporation through an increase in average temperature. The goals of this work were to examine the storage capacity of sand dams, process historical climate data and future climate change scenarios, and model both current water availability and future water availability under climate change.

Vadose Zone Journal August 01, 2007, Vol.6, 572-580. doi:https://doi.org/10.2136/vzj2006.0097

The quality and quantity of atoll groundwater are susceptible to ENSO events and human settlement. Infiltration galleries minimize salinisation and provide estimates of the hydraulic conductivity of unconsolidated coral sediments. Strategies for protecting groundwater and increasing resilience of island communities to climate change are discussed.

Vadose Zone Journal August 01, 2007, Vol.6, 581-590. doi:https://doi.org/10.2136/vzj2006.0092

Subsurface termperatures in Asian cities were analyzed to evaluate the effects of surface warming due to urbanization. The magnitude of surface warming and the depth apart from the the geothermal gradient show the magnitude of heat island and elapsed time from the start of surface warming.

Vadose Zone Journal August 01, 2007, Vol.6, 591-596. doi:https://doi.org/10.2136/vzj2006.0094

A new method for simulating double carbon dioxide climate change effects on dynamic equilibrium vegetation and soil-water regimes affecting groundwater recharge was demonstrated for two sites in Australia with Mediterranean and subtropical climates. Potential changes in recharge versus rainfall were highly nonlinear and varied with the soil and vegetation.

Vadose Zone Journal August 01, 2007, Vol.6, 597-609. doi:https://doi.org/10.2136/vzj2006.0099

A review is presented of flow cell experiments involving characterization of NAPL flow behavior using imaging and detection/quantification with tracers. The techniques used for NAPL saturation mapping include photon-attenuation and photographic methods. Recommendations for future research at this laboratory scale are provided.

Vadose Zone Journal August 01, 2007, Vol.6, 610-637. doi:https://doi.org/10.2136/vzj2006.0178

Does aggregation level matter when only considering soil moisture? Can we derive a meta-model to scale model performance or effective parameters? Are some model performance criteria more scale independent than others? These questions were addressed by applying the SWAP model to observations from a small catchment in the Netherlands.

Vadose Zone Journal August 01, 2007, Vol.6, 638-650. doi:https://doi.org/10.2136/vzj2006.0077

This paper describes an improved two-dimensional numerical analysis of preferential water and bromide movement toward tile drains in structured glacial till soil. Dual- as compared with single-permeability model results indicate the importance of soil surface boundary conditions and plot- and field-scale mixing in addition to local nonequilibrium effects.

Vadose Zone Journal August 01, 2007, Vol.6, 651-667. doi:https://doi.org/10.2136/vzj2007.0033

A parallel soil column model quantifying trace element transport at the field scale for situations where site data are scarce is described. In combination with a two-dimensional Monte Carlo approach, it allows to distinguish effects of (irreducible) variability and (reducible) uncertainty on predicted concentrations.

Vadose Zone Journal August 01, 2007, Vol.6, 668-678. doi:https://doi.org/10.2136/vzj2006.0148

We develop analytical expressions for the effective matrix diffusion coefficient for two simple fracture-matrix systems and demonstrate that heterogeneities in the rock matrix at different scales may contribute to the scale dependence of the effective matrix diffusion coefficient.

Vadose Zone Journal August 01, 2007, Vol.6, 679-683. doi:https://doi.org/10.2136/vzj2006.0140

ERRATUM

Vadose Zone Journal August 01, 2007, Vol.6, 529. doi:https://doi.org/10.2136/vzj2006.0138er

Book Reviews

Edited by Vera Pawlowsky-Glahn and Ricardo Olea. International Association for Mathematical Geology, Studies in Mathematical Geology No. 7. Oxford University Press, New York. 2004. Hardcover, 304 pp. ISBN 0-19-517166-7.

Vadose Zone Journal August 01, 2007, Vol.6, 684-685. doi:https://doi.org/10.2136/vzj2007.0063br
Close Modal

or Create an Account

Close Modal
Close Modal