Using the method of homogenization, we present a systematic derivation of the macroscopic equations for air ̄ow and chemical vapor transport in an unsaturated zone with a periodic structure of heterogeneity. The e€ective speci®c discharge and hydrodynamic dispersion coecient are expressible in terms of some cell functions, whose analytical solutions are sought for the simple case of alternate s...

Modelling solute transport in an unsaturated zone (vadose) depends very much on the simulation of soil moisture and moisture fluxes, which are strongly influenced by precipitation, evapotranspiration, surface runoff and land-surface properties. To provide good approximations of soil moisture and moisture fluxes, a model capable of simulating land-surface processes is required. In this study, a ...

Numerous models have been developed for predicting major ion chemistry in the soil zone and in recharge to groundwater. Soils that contain CaCO, are prevalent in arid and semiarid regions, as well as in humid and temperate regions that have been glaciated or contain carbonate bedrock. Under these conditions, carbonate-solution reactions and ion exchange are the dominant chemical processes. In t...

Laboratory column experiments were conducted by employing various porous media to delineate the characteristics of gaseous ozone transport in the unsaturated zone under various conditions. Water content, soil organic matter (SOM), and metal oxides (MOs) were found to be the factors most influential in the fate and transport of gaseous ozone in unsaturated porous media. The migration velocity of...

[1] Stream aquifer hydrology and nitrate removal were studied, over a period of 2 years, in an unsaturated riparian zone, bounded by an intermittent Mediterranean stream, (Fuirosos, northeastern Spain). The riparian groundwater system is characterized by drastic hydrological changes and by mixing of stream water with hillslope groundwater. The hillslope groundwater flowed through a medium with ...

We extend our methodology for three-dimensional parameter structure and value estimation and apply it to a Vermont test site. Ground-penetrating radar (GPR) cross-well travel times are inverted for estimation of heterogeneous GPR soil velocities before and after a controlled release of salt water in the unsaturated zone. The method, which is based on an approximation of the extended Kalman filt...

The distribution and composition of endogenous lipids in articular cartilage and transport of exogenous fatty acids have been investigated on a microscopic scale in fresh bovine articular cartilage. To investigate the distribution and composition of the endogenous lipids, hyperspectral Raman maps were taken of chondrocytes and their surrounding matrix in both the deep and superficial zones. The...

When implementing remediation programs to mitigate diffuse-source contamination of aquifers, tools are required to anticipate if the measures are sufficient to meet groundwater quality objectives and, if so, in what time frame. Transfer function methods are an attractive approach, as they are easier to implement than numerical groundwater models. However, transfer function approaches as commonl...