

@mastersthesis {6196,
	title = {Solute transport in an unsaturated field soil: {Describing} heterogeneous flow fields using spatial distributions of hydraulic properties},
	year = {1998},
	note = {C663997},
	school = {Eidgenoessische Technische Hochschule Zuerich (Switzerland)},
	type = {phdDr.{Sc}.{Nat}.},
	address = {Ann Arbor},
	abstract = {Distributions of (dye) tracers are generally used to interpret the water flow and mixing regime in soils. Heterogeneities in observed flow patterns are mainly caused by the spatial variability in texture and structure, and is therefore expressed in the hydraulic properties. The objective of this study is to improve our understanding of the factors affecting the flow regimes in the vadose zone by measuring and by numerically generating the heterogeneity in unsaturated soils using the spatial distributions of hydraulic properties. A constant irrigation experiment was conducted in a field soil (Typic Eutrochrept) to obtain a validation data set for the simulation models. The dye tracer Brilliant Blue (C.I. 42090) was applied as a continuous line source using two irrigation rates. A qualitative comparison between the dye patterns observed for both rates showed a more pronounced lateral dye spreading and lower penetration depth under the regime of the high irrigation rate. Layer boundaries seem to provoke the lateral spreading. In total 154 undisturbed small soil cores were collected from this field site for measuring the hydraulic properties in the laboratory. A scaling concept for similar media was used to characterize the spatial variability of the water retention curves and hydraulic conductivity functions using the laboratory measurements. Numerical simulations of water flow and solute transport in two-dimensional, heterogeneous media were performed based on information obtained from the field and laboratory experiments. The spatial pattern of the water fluxes were similar in relative terms for both irrigation rates. The change in mixing regime as observed in the field could also not be reproduced by the simulations. Subtle differences in saturation degrees causing capital modifications in the flow field may depend on even minor local heterogeneities then those which have been experimentally accessible in this study.},
	keywords = {0285:Agronomy, 0388:Hydrology, 0481:Soil sciences, 0768:Environmental science, Agronomy, Biological sciences, Earth sciences, Environmental science, Health and environmental sciences, Hydrology, Irrigation, mixing regime, Soil sciences, unsaturated soils},
	url = {http://search.proquest.com/docview/304471354?accountid=14270},
	author = {Kasteel, Romualdus Theodorus Antonius}
}
