Angebotene Masterarbeit

Water flow in hydrophilic sand with hydrophobic lenses: Field experiments and modeling.

Olga Fishkis

Betreuer: Olga Fishkis

Soil water repellency has been recognized to have a great influence on ecosystems by enhancing soil erosion, decreasing soil infiltration and water retention, and generating preferential water flow in soils. The latter is difficult to prove in a field soil, since other factors such as soil structure, hydraulic effects, or root distribution could contribute as well to the flow pattern generation. This master`s thesis aims at visualizing and modeling the water flow pattern in homogeneous hydrophilic sand with and without hydrophobic sand lenses under field conditions. The water flow paths will be determined by means of dye tracer experiment and by water content measurements as well. The degree of the sand repellency and its dynamic behavior will be assessed with the capillary rise and sessile drop methods. The water flow will be simulated by Richards equation using modified van Genuchten-Mualem model for hydraulic properties, to account for spatial and temporal changes in soil wettability. Working plan: • Laboratory measurement of the contact angle dynamic behavior for hydrophilic and hydrophobic sand • Running and evaluation of the dye tracer experiments on two field plots artificially constructed • Water flow modeling with Hydrus 2D/3D