Modifications of the Kozeny-Carman approach (Ks=AΦB) for the determination of saturated hydraulic conductivity Ks using the van Genuchten model parameters and the effective porosity Φe are presented in this study. Two models {a two-parametric Ks(a, Φe) and a three-parametric Ks(a, Si, Φe)} were developed for Ks determination. In the two-parametric model the power constant was replaced by the f factor (f=aΦe). The factor f includes the parameter a of the van Genuchten model, in order to describe its effect on the part of the pore size distribution which participates in the effective porosity Φe. The three-parametric model was improved by inclusion of the water retention curve slope Si at the inflection point. The models were calibrated and validated using two published data sets which cover the 12 USDA soil texture classes. The proposed models were also compared with other published models of Ks, which are based on the van Genuchten parameters and the Kozeny-Carman approach. The results indicated an adequate predictive accuracy of the models through a calibration and validation procedure using data sets from different sources and better performance compared to other models, setting a new approach for the indirect determination of Ks using only data from the water retention curve.
NEW EQUATIONS FOR THE DETERMINATION OF SOIL SATURATED HYDRAULIC CONDUCTIVITY USING THE VAN GENUCHTEN MODEL PARAMETERS AND EFFECTIVE POROSITY
ASCHONITIS, Vasileios;
2013
Abstract
Modifications of the Kozeny-Carman approach (Ks=AΦB) for the determination of saturated hydraulic conductivity Ks using the van Genuchten model parameters and the effective porosity Φe are presented in this study. Two models {a two-parametric Ks(a, Φe) and a three-parametric Ks(a, Si, Φe)} were developed for Ks determination. In the two-parametric model the power constant was replaced by the f factor (f=aΦe). The factor f includes the parameter a of the van Genuchten model, in order to describe its effect on the part of the pore size distribution which participates in the effective porosity Φe. The three-parametric model was improved by inclusion of the water retention curve slope Si at the inflection point. The models were calibrated and validated using two published data sets which cover the 12 USDA soil texture classes. The proposed models were also compared with other published models of Ks, which are based on the van Genuchten parameters and the Kozeny-Carman approach. The results indicated an adequate predictive accuracy of the models through a calibration and validation procedure using data sets from different sources and better performance compared to other models, setting a new approach for the indirect determination of Ks using only data from the water retention curve.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
