Effects of Initial Moisture and Surface Properties on Sorptivity of Coarse Soil and Sand

Graduation date: 2015Many different models and mechanisms of water imbibition into soil have been described in the literature. Theoretical equations based on those models exist to predict how water will flow in porous media. These models can be useful, but have their weaknesses. Research on imbibition and infiltration into soils has mostly focused on moist soils, as those are more likely to be found in agricultural situations. It was found here that there is a different pattern of sorptivity found at low initial moisture contents - instead of the sorptivity decreasing between a dry medium and one with initial moisture, it increased. This pattern had been seen before in water repellent soils, but was also seen here in soils that exhibited no water repellency. A conceptual model is proposed to describe how water is imbibed into a sandy medium, taking into account the medium's initial moisture content and the surface roughness of the particles. This study answers some questions relating to the relative contributions of capillary and surface flow to the redistribution of soil moisture, but other unexpected observations of sorptivity as a function of moisture content lead to more questions