variables as input (e.g., Rawls and Brakensiek, 1985; Ahuja et al., 1989; Vereecken et al., 1989; Schaap et In many vadose zone hydrological studies, it is imperative that the al., 1998). Far fewer alternatives exist for unsaturated soil’s unsaturated hydraulic conductivity is known. Frequently, the Mualem–van Genuchten model (MVG) is used for this purpose behydraulic conductivity. Although som...

At the regional scale, vadose-zone processes are recognized for controlling both short-term dynamics in watershed hydrology and long-term water balances of hydrologic basins. In this paper we explore the various conceptual and mathematical models that have been proposed or could be considered to represent water fluxes in the vadose zone at the catchment, watershed or regional scale. Such models...

Surface-applied chemicals move through the unsaturated zone with complex flow and transport processes due to soil heterogeneity and reach the saturated zone, resulting in groundwater contamination. Such complex processes need to be studied by advanced measurement and modeling techniques to protect soil and water resources from contamination. In this study, the interactive effects of factors lik...

DURING the last few decades hydrologists have made significant progress toward applying physically based simulation models for the analysis and understanding of field-scale flow and transport phenomena in the vadose zone. This progress has been enabled in part by the development of advanced parameter estimation and uncertainty assessment methods such as statistically based pedotransfer function...

abstract microbial contaminants transport to groundwater is a serious environmental problem that can result in large outbreaks of waterborne diseases. some of bacteria can travel from vadose zone and cause contamination of groundwater resources. thus, an accurate prediction of transport and fate of pathogenic microorganisms in unsaturated soil is needed to protect groundwater resources. the mai...

The nuclear weapons testing programme of the USA has released radionuclides to the subsurface at the Nevada Test Site. One of these tests has been used to study the hydrological transport of radionuclides for over 25 years in groundwater and the deep unsaturated zone. Ten years after the weapon's test, a 16 year groundwater pumping experiment was initiated to study the mobility of radionuclides...