Evaporation synergy is a phenomenon that occurs between different classes of soil and allows for a greater amount/quantity of soil water evaporation. 20 of the 66 soil texture class combinations have been shown to exhibit evaporation synergy (Fisher, 2012), however the impact of column width on the functionality of this...
Many 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...
Aquifer recharge is generally driven by fluids that move from the Earth’s surface to groundwater through the unsaturated zone, also known as the vadose zone. When the vadose zone is fractured, fluids, which may include contaminants, can move through the fracture network as well as the porous matrix. Such a...
Evaporation from bare soil was investigated using a numeric model In one set of simulations, texture and evaporative demand were analyzed as they impacted short and long term evaporation. The effect of these factors on water redistribution was also analyzed. A second set of simulations was run to determine the...
Water availability is a critical limiting element in semi-arid ecosystem productivity and presents particular challenges in Sahelian countries such as Senegal. The landscapes are characterized by the presence of two common semi-arid shrubs (Piliostigma reticulatum and Guiera senegalensis), both of which may be important hydraulic regulators in these water-limited ecosystems....
Evaporation synergy is the phenomenon in which two porous medium textures that share a common vertical boundary experience a higher cumulative evaporation than either homogeneous texture can produce. Studies that have been conducted to date address this phenomenon in relatively fine and coarse sands but not in finer textured soils...
Irrigated agricultural production in sandy soils presents several unique challenges to growers, including naturally high permeability, low native water retention, as well as high rates of water drainage losses and leaching of chemicals to the shallow aquifers. This study is an initial investigation into water motion in the sandy agricultural...
Soil solarization trials were conducted during the growing seasons of 2016-2018 with the purpose of determining if solarization was an effective pre-planting soil disinfestation technique for tree nurseries in the Pacific Northwest. A large data set was collected on soil properties and biological indicators from 5 interdisciplinary experiments. This thesis...
The kinetics of physical and chemical processes controlling the precipitation of iron oxide minerals in unsaturated media were investigated in this study. The characteristic morphology, mineralogy, and chemistry of iron oxides were also explored. Laboratory column experiments using fine and coarse grades of silica sand were conducted to compare the...