Numerous studies have explored how alluvial channel size and morphology are adjusted to different sediment and flow conditions, yet we still know very little about how and to what degree the flow regime controls channel form and processes. We use the term ‘channel form’ to refer to the size and...
Wet meadow ecosystems are a useful natural laboratory in which to explore feedbacks between biogenic and geologic controls on valley bottom landforms. Characterized by flat valley floors flanked by higher-gradient hillslopes, these meadows are singular both in that they represent depositional features in what is primarily an erosional environment, and...
Dams and reservoirs are important components of water resource management systems, but their operational sensitivity to streamflow variability may make them vulnerable to climate change. Climate change is likely to affect the magnitude and timing of streamflow, motivating the assessment of potential impacts on dams and reservoirs. Here I examine...
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GordonE. Grant
Dams and reservoirs are important components of water resource management
Geomorphic change along the lower Clackamas River is occurring at
a millennial scale due to climate change; a decadal scale as a result River
Mill Dam operation; and at an annual scale since 1996 due to a meander
cutoff. Channel response to these three mechanisms is incision.
Holocene strath terraces,...
The relationship between carbon burial and sedimentation in reservoirs is unknown, exposing gaps in our fundamental understanding of the transport, processing, and deposition of sediment and organic matter in fluvial and lacustrine systems and contributing to uncertainty in our understanding of the net impact of dams to the global carbon...
Although there has been extensive research on the geomorphic and ecologic role of
large woody debris (LWD) in streams, the dynamics of LWD in streams are poorly
known due to various measurement difficulties during floods. In this thesis I present the
results of two flume experiments on the dynamics of...
Debris flow initiation is controlled by a complex interaction of geology, geomorphology, climate, and weather. In the Cascade Range of Pacific Northwest and mountainous areas globally, patterns of temperature and precipitation are being altered by climate change, which may in turn impact debris flow initiation. Temperature has increased and patterns...
Despite the importance of rain and snowmelt in causing peakflows in the Pacific
Northwest, the interactive effects of a snowpack and watershed physiography on
streamflow are largely undocumented. This study investigated the influence of soil and
snowpack moisture on peakflow hydrograph shape in three small (< 60 ha) control sub-watersheds...
A first-order approximation is made of the frequency and magnitude of bedload transport downstream of the Pelton-Round Butte Dam Complex, lower Deschutes River, Oregon with implications for salmonid spawning habitat. Field measurements of channel hydraulics, geometry, and particle size were combined with one-dimensional hydraulic and bedload transport models to determine...
Geomorphic response to watershed disturbances commonly results in
alterations of landforms. Subsequent geomorphic recovery is dependent on the ability
of flows to entrain, transport, and organize inorganic and organic material on hillslopes
and in channels. This research analyzed changes in sediment production, channel
structure, and channel organization following disturbances in...
