As mentioned by the United Nations Convention to Combat Desertification [UNCCD, 2009], deserts and drylands form 41.2% of the total earth’s land, where “due to drought and desertification each year 12 million hectares are lost”. Knowledge of porous medium hydraulic properties and the related fluxes are of significant industrial and engineering importance. The coupled water – vapor movement through porous medium is influenced by many internal [porous medium] and external [meteorological, driving forces…etc.] factors.
Soil – atmosphere interaction mainly infiltration and evaporation fluxes are of particular interest for many geotechnical and geo – environmental problems. a) The actual evaporation from porous medium involves mass and energy transport including phase change, vapor diffusion, and liquid flow, resulting in complex displacement patterns affecting drying rates. The actual evaporation rate stages and governing forces is not completely understood yet [mechanism, boundaries and limiting forces]. b) Proper determination of the hydraulic properties of a porous medium is a key element to understand fluids movement that is directly related to the boundary fluxes. Development of a novel direct concurrent measurement of the unsaturated hydraulic conductivity function and the SWCC of porous mediums is being carried out.