Increasing background salinity in watersheds has largely been attributed to road salt retention groundwaters due their long residence times. However, laboratory studies demonstrate that soils temporarily store salts, either porewater or adsorbed onto particles. Field of are nevertheless rare, and mechanisms transport across multiple hydrological reservoirs (e.g., from soil groundwater) unknown....

242 A dispersion are considered to be the dominant mechanisms of solute transport in the vadose zone, i.e., the variably saturated layer of soils and sediments between the soil surface and groundwater table (Jury and Flühler, 1992). Advection is associated with the average water fl ux or velocity, whereas hydrodynamic dispersion is modeled using an analog of Fick’s law corresponding to the Brow...

Modelling solute transport in an unsaturated zone (vadose) depends very much on the simulation of soil moisture and moisture fluxes, which are strongly influenced by precipitation, evapotranspiration, surface runoff and land-surface properties. To provide good approximations of soil moisture and moisture fluxes, a model capable of simulating land-surface processes is required. In this study, a ...

Steady, Darcian, 1-D, 1-phase evaporation through a vertically inhomogeneous soil from a horizontal water table is simulated as an optimal control problem, i.e. the hydraulic properties of the porous medium (relative permeability of moisture and capillary water retention curve) are considered as control functions. The Richards nonlinear ordinary differential equation is integrated twice as a bo...