The nonlinear solvers in numerical solution of water flow in variably saturated soils are prone to convergence difficulties. Many aspects can give rise to such difficulties, like very dry initial conditions, a steep pressure gradient and great variation of hydraulic conductivity occur across the wetting front during the infiltration of water.  So, the averaging method applied to compute hydraul...

Unsaturated hydraulic conductivity (K) is a measurement of soil water-retaining ability in unsaturated soil. The properties are necessary to predict the movement water current study aims create an alternative experimental device estimate theKusing moisturesensors. set up was designed and fabricated order measure volumetric content using GS3 (Campbell) sensors at different heights. data obtained...

abstract to estimate spatial variability of soil hydraulic functions, scaling methods were developed and have been widely used. among these functions, physically based methods have been found more desirable because of possibility of estimating soil hydraulic functions from soil physical properties. in this paper, a new and physically based method has been described for scaling soil hydraulic co...

[1] The simulation of conservative solute transport in a heterogeneous unsaturated soil depends on the description of spatial variability of soil hydraulic and chemical properties. The data from the Las Cruces Trench Site were used to explore the impact of alternative ways of describing the variability of hydraulic properties. Three different approaches were considered: Miller and Miller scalin...

Aquifer drainage was numerically simulated by a coupled, unsaturated-saturated flow equation. The effect of the vadose zone on aquifer parameter predictions of classical hydraulic theory was investigated. Saturated-zone hydraulic theory was shown to be fairly robust in estimating the saturated hydraulic conductivity but less so in estimating drainable porosity, mainly because of the much tighte...

Closed-form expressions of the hydraulic conductivity function for linearly superposed subretention (multimodal) functions were derived arbitrary sets Brooks and Corey (BC), van Genuchten (VG), Kosugi (KO) water retention models. The generalized Mualem model was evaluated using mathematical approach Priesack Durner. Three types modification to multimodel also proposed. Firstly, equations can be...

It is well known that there is a spectrum of pores in a soil profile. The conventional use of a single lumped value of soil hydraulic conductivity to describe a spectrum of hydraulically active pores may have unintentionally impeded the development of field-scale chemical transport theoryand perhaps indirectly hindered the development ofmanagement protocols for chemical application andwaste dis...