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Concept and Application of Generalized Preferential Flow Model (GPFM)  

Kim, Young-Jin (Department of Civil and Environmental Engineering, Seoul National University)
Steenhuis, Tammo (Department of Bio. & Environmental Engineering, Cornell University)
Nam, Kyoung-Phile (Department of Civil and Environmental Engineering, Seoul National University)
Publication Information
Journal of Soil and Groundwater Environment / v.12, no.5, 2007 , pp. 33-36 More about this Journal
Abstract
In recent years the convective-dispersive equation has been often discredited in predicting subsurface solute transport under field conditions due to presence of preferential flow paths. Kim et al. (2005) proposed a simple equation that can predict the breakthrough of solutes without excessive data requirements. In their Generalized Preferential Flow Model (GPFM), the soil is conceptually divided in a saturated "distribution layer" near the surface and a "conveyance zone" with preferential flow paths below. In this study, we test the model with previously published data, and compare it with a classical convective-dispersive model (CDM). With three parameters required-apparent water content of the distribution zone, and solute velocity and dispersion in the conveyance zone-GPFM was able to describe the breakthrough of solutes both through silty and sandy loam soils. Although both GPFM and CDM fitted the data well in visual, variables for GPFM were more realistic. The most sensitive parameter was the apparent water content, indicating that it is the determining factor to apply GPFM to various soil types, while Kim et al. (2005) reported that changing the velocity of GPFM reproduced solute transport when same soils were used. Overall, it seems that the GPFM has a great potential to predict solute leaching under field conditions with a wide range of generality.
Keywords
Unsaturated zone; Preferential flow; Solute transport; Convective-dispersive model;
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