SPATIAL VARIABILITY OF CONDUCTIVITY AS APPLIED TO DISTRIBUTED-PARAMETER INFILTRATION MODELS

Two infiltration models, called VVSIM (variable variance stochastic in filtration model) and EVVSIM (enhanced variable variance stochastic in filtration model), are developed in this study. A distributed paramete r infiltration model can estimate the amount of infiltration over a fi eld area by computing the infiltration over zones of the field area. H ydraulic conductivity is the most important parameter determining infi ltration in simulations by infiltration models. The performance of an infiltration model depends on how well the model accommodates the comp licated spatial distribution of hydraulic conductivity. The two propos ed models include the effects of spatial correlation of the conductivi ty distribution. Virtual conductivity fields are generated using the t urning bands method. Monte Carlo simulations show that the proposed mo dels give infiltration estimates more accurate than those obtained by the other models employed.