The dominant controls on flow generation in steep, forested hillslopes are poorly understood. This dissertation examined the dominant flow processes operating at the hillslope scale, using a combined macroscale measurement and model development and analysis framework. Irrigation experiments at two steep forested hillslopes were conducted to isolate individual hillslope flow...
Stream discharge is a key water balance component and important factor in global change evaluations. Nevertheless, the mechanisms for streamflow generation are poorly understood. Near- stream surface saturation during precipitation events is one of the most iconic, visible indicators of rapid runoff production in upland humid catchments around the world....
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Jeffrey J. McDonnell
Stream discharge is a key water balance component and important factor in
Bedrock groundwater dynamics in headwater catchments are poorly understood and
poorly characterized. Direct hydrometric measurements have been limited due to the
logistical challenges associated with drilling through hard rock in steep, remote and
often roadless terrain. Here we develop and use an inexpensive, portable bedrock
drilling system to explore bedrock...
The physical controls of snowmelt in the Pacific Northwest (PNW) are poorly
understood. While there have been numerous field and modeling investigations at the
plot and watershed scale, few studies have identified how the snow energy balance
(EB) components vary in importance both spatially and temporally. The identification
of how...
This dissertation integrates a process-based hydrological investigation with an
ongoing paired-catchment study to better understand how forest harvest impacts
catchment function at multiple scales. We do this by addressing fundamental questions
related to the stocks, flows and transit times of water. Isotope tracers are used within a
top-down catchment intercomparison...
Understanding how the interactions and feedbacks between plant function, climate, and soils ultimately affects the terrestrial water balance and subsurface flow processes is major challenge in scientific hydrology. This dissertation summarizes the findings of a manipulative climate warming experiment, an observational field study that utilized stable-isotope tracers, and associated modeling...
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Luke A. Pangle, Author
ACKNOWLEDGEMENTS
I thank my advisor, JeffMcDonnell, for
The specific objectives of this dissertation are to determine subsurface flow
behaviors across different antecedent wetness conditions from a top-down perspective
and to mechanistically assess the hydrological controls on DOC and N transport at the
hillslope and catchment scale. The study area is a small catchment where hillslopes
issue directly...
This dissertation re-examines the now standard perceptual model of hillslope
hydrological response to rainfall, which includes the growth of a saturated wedge at the soil-bedrock interface or impeding layer. It also challenges the notion of bedrock impermeability and the assumption that the pattern of subsurface stormflow is determined by the...
Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death in the United States. Patients with cirrhosis are more likely to develop HCC. More than 80% of HCC patients are found have preexisting cirrhosis. The prevalence of cirrhosis increased from 0.26% to 0.3.% between 1999 to 2010 and...