Hydrodynamic characterization using the disc infiltrometer of Loukkos soils (Morocco)

Soil hydraulic properties are necessary to study the transfer of water and solute through the vadose zone,but often cannot be measured because of practical and material constraints. the focus of this work is the hydrodynamic characterization in-situ of the loukkos basin soils,located in the north of morocco,by analyzing the soil water retention and hydraulic conductivity functions of unsaturated soils. the study of hydric transfer requires,in the first place,knowing the hydrodynamic parameters (θr,θs,α,n,ks) of the unsaturated zone and to establish characteristic curves k (h) and θ (h) reflecting the evolution of the hydraulic conductivity (k) and water retention (θ) versus pressure (h). as a first step,we have used tension disc infiltrometer associated with a transient axisymmetric infiltration method of haverkamp et al. (1994) to determine the hydraulic conductivity. this procedure reduces the time of the measurements,thus allowing to characterize a large area and to make several measurements. the measurements of infiltration were carried out,during in the dry season the month july 2013,on two sites rmel and m'risa in the area of loukkos,whose soils have different textures respectively: sand and clay-loam. in a second step,we used the cumulative infiltration i (t) measured,associated with a levenberg marquardt algorithm to estimate the hydrodynamic parameters (θr,θs,α,n,ks). experimental and simulation results of this study indicated that the tension infiltrometer is suitable for the hydrodynamic characterization of the soils loukkos basin. the value of r2 > 0.8 and rmse=0.043 are highest.