Motivated by mitigating flash flood-related damages, this study conducts a comprehensive exploration of hillslope hydrological processes, which includes data collection and experimental measurement, analysis of the rainfall-runoff features and modeling hydrological processes. To study the temporal and spatial variation of TF (throughfall), rainfall data recorded at eight rain gauges near and under a 6-m-tall multiple-layer deciduous tree (Macaranga tanarius) are analyzed. This study reveals that the leaf convergence and divergence can significantly influence TF temporal and spatial variations. For some rain gauges, the TF values can be larger than the GR (gross rainfall) for 30% of total rainfall events. Using three classical baseflow separation methods (namely, the straight line method, inflection point method and one parameter filter method), this study computes the direct runoff volumes for 24 storms. Their runoff coefficients (which are the ratios of direct runoff volumes to the total rainfall volumes) are obtained. The analysis indicates that direct runoffs can contribute about 82% of flood peak discharges, but the average runoff coefficients are less than 4%. To make use of the observed hydrological data, a numerical model, TOPMODEL, is used to simulate the hydrological processes. Further, to determine the model parameters, several field surveys have been conducted to collect land cover, soil properties, and hydraulic features of the catchment. Model parameters for the catchment are calibrated using a global optimization method, namely the SCE-UA (shuffled complex evolution-The University of Arizona), and Nash-Sutcliffe efficiency (E) as the objective function. To enhance TOPMODEL, this study confirms that the interflow process is important in improving runoff simulation. / published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

The present study examines the cycling of elements in the biosphere. The first chapter proposes a theoretical framework for this cycling based on both metal/ligand theory and mass balance studies. Empirical modelling serves as an alternative and complement to mass balance studies in predicting the export of elements from watersheds. Watershed output (export per unit area per unit of time) is predicted using atmospheric deposition rates, an element bonding strength index, the watershed area and a forest classification (deciduous vs coniferous). Finally the last chapter examines, in a speculative fashion, the partitioning of elements between the atmosphere and hydrosphere as a function of element behaviour and discusses the ecological consequences of human activity on this partitioning.

No description available.

No description available.

The main focus of the present study is to identify and integrate the factors affecting the degree of irregularity of five continental divide traces, as expressed by their fractal characteristics measured by the divider method. The factors studied are climate, relief and tectonic environment. The second objective of this study is to determine the relationship between uplift rates and divide trace fractal dimension. Analysis of the results suggests that the degree of irregularity of continental divide traces at fine scale (approximately 10-70 km of resolution) is strongly affected by both climate and tectonics. It is found that control of the factors is generally weaker at coarse scale (above approximately 70 km of resolution). Generic relief should be ranked below both climate and tectonic environment as a factor affecting the complexity of continental divide traces. In terms of the second objective, the fractal dimension at fine scales follows a weakly inverse relationship with uplift. At coarse scale, there is stronger inverse relationship between uplift rate and fractal dimension. / Introduction -- Methodology -- Geomorphic environment -- Evaluation of results -- Significance of control factors -- Conclusion. / Department of Geological Sciences

Previous works have applied the Divider Method to the shapes of drainage divides as measured from maps. This study focuses on the shapes of several drainage divides measured in the field at very fine scale. These divides, chosen for their sharp crests, include portions of the Continental Divide in Colorado and badlands-type divides in Arizona, Wyoming, South Dakota, and Texas. The badlands type divides were delineated using a laser theodolite to collect data at decimeter point spacing, and the Continental Divide segments were delineated using pace and bearing at a constant point spacing of 30 meters. A GIS was used to store and visualize the divide data, and an automated divider analysis was performed for each of the 16 drainage divides.The Richardson plots produced for each of the drainage divide datasets were visually inspected for portions of linearity. Fractal dimensions (D) were calculated using linear regression techniques for each of the linear segments identified in the Richardson plots. Six of the plots exhibited two distinct segments of linearity, nine plots exhibited one segment, and one plot exhibited no segments of linearity. Residual analyses of the trend lines show that about half of the Richardson plot segments used to calculate D exhibit slight curvature. While these segments are not strictly linear, linear models and associated D values may still serve well as approximations to describe degree of divide wandering.Most (20 out of 21) of the dimensions derived from the Richardson plots for the drainage divides fall within the range from 1.01-1.07. The D values calculated for the Continental Divide range from 1.02-1.07. The dimensions calculated for the badlandtype divides were distributed evenly across the range of 1.01-1.06, with a single exceptional D value at 1.12. Only four of the divide D values fall within a range of 1.06–1.12, the range for D established for drainage divides in published map-based studies, despite the apparent dominance of erosion processes on the measured divides. / Department of Geology

Thesis (M.S. - Renewable Natural Resources)--University of Arizona. / Includes bibliographical references.

Thesis (M.S. - Watershed Management)--University of Arizona. / Includes bibliographical references.

Thesis (M.S. - Renewable Natural Resources)--University of Arizona, 1989. / Includes bibliographical references (leaves 139-142).

Thesis (M.S. - Renewable Natural Resources)--University of Arizona, 1989. / Includes bibliographical references (leaves 139-142).