Dispersion parameters for undisturbed partially saturated soil

A dual‐domain mass transfer approach for modeling solute transport in heterogeneous aquifers: Application to the Macrodispersion Experiment (MADE) site

“…As such, models based on the Fickian advection-dispersion approach, while useful for approximating solute transport in relatively homogeneous aquifers with randomly occurring macroscopic heterogeneities, have severe limitations when applied to highly heterogeneous aquifers with potentials for preferential pathways. Uncertainty due to the assumption of Fickian macrodispersive mixing embedded in the classical advectiondispersion equation tends to increase as the plume scale decreases or as the scale of velocity field correlations increases [Beven et al, 1993;Carrera, 1993;Fitts, 1996]. The hydraulic conductivity interpolation algorithm of ordinary kriging generates a unique hydraulic conductivity field, preserves local accuracy near data points but smoothens data in areas of sparse sampling, and provides no measure of uncertainty.…”

Numerical Evaluation of Nitrate Distributions in the Onion Root Zone under Conventional Furrow Fertigation

“…Molecular diffusion was neglected because it was considered negligible relative to hydrodynamic dispersion. The longitudinal dispersivity was considered equal to one-tenth of the profile depth (i.e., 11 cm) and the transverse dispersivity equal to onetenth of the longitudinal dispersivity (i.e., 1.1 cm) (Beven et al 1993;Cote et al 2003;Hanson et al 2006). Because of the lack of experimental data, the parameters μ a and μ n were also taken from the literature.…”

The effect of different fertigation strategies and furrow surface treatments on plant water and nitrogen use

“…Schematic showing a half-furrow and the implementation of a special boundary condition accounting for variable water depth in the furrow (Q p is the irrigation water supply rate, c p is the solute concentration in the incoming irrigation water, Q in is the water infiltration rate from the furrow into the soil profile across the furrow walls, c is the solute concentration in the furrow water and in the infiltration water, S is the volume of water in the half-furrow, h w is the water level in the furrow, α is the angle defining the slope of the ridge side, a is the half-width of the bottom of the furrow, b is the half-width of the water surface, and P and E are precipitation and evaporation fluxes, respectively) 1 3 transverse dispersivities were set at 10 and 1 cm that is at one-tenth and one-hundreds of the depth of the soil profile (Beven et al 1993), respectively. Note that no reactions are considered in (4) so it can only be used to describe the transport of nonreactive solutes such as chloride and nitrate.…”