Application of Kozeny-Carman Equation to Estimate Saturated Hydraulic Conductivity of an Alfisol at Samaru and a Cambisol at Kadawa, Nigeria

Abstract

Kozeny-Carman equation was used to estimate field and laboratory determined saturated hydraulic conductivity (Ks) based on Pe values obtained from soils of two Northern Savanna ecological zones of Nigeria (Samaru and Kadawa). Total porosity was determined from measured dry bulk density (Db), particle density (Dp) and moisture content at –33kPa pressure potential. Effective porosity was calculated as the difference between total porosity and volumetric moisture at -33kpa. The Ks and Pe values were fitted into the Kozeny-Carman equation using the linear least square fitting. In Samaru, 91.7 and 61% variation of Ks were explained respectively from field (K_fs) and laboratory measurements (K_ls) while 61% variation of Ks was explained from the average values of laboratory measurement for Kadawa. The proportionality constant (β) varied widely between 7.1 × 10^-3 to 6918.30 while the fitting parameters (n) varied from values < 1 to 2.37. The Relative Effective Porosity (REP) was adapted to substitute Pe in the Kozeny-Carman equation. Only field measured data (r² = 0.881) and laboratory measured data (r² = 0.573) from Samaru fit into the model and the regression coefficients were not improved. The REP- Model did not perform well with the data presented in this study.