Published literature about six Pacific Northwest stream systems was contrasted
to provide a regional perspective on channel response to disturbance. This
investigation was prompted by a combination of recent environmental legislation,
mounting social pressures to plan projects at a drainage basin scale, and the difficulty
in defining and predicting the...
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,...
Bar-pool morphology in rivers can provide vital habitat to aquatic species, notably salmonids, which require gravel riffles to bury eggs and pools for hydraulic and cold-water refuge. In some cases, the erosion and subsequent deposition of coarse sediment downstream of a dam removal can modify habitat by inundating bar-pool structure,...
Debris flows, which occur in mountain settings worldwide, have been particularly damaging in the glaciated basins flanking the stratovolcanoes in the Cascade Range of the northwestern United States. This thesis contains two manuscripts that respectively investigate the (1) initiation processes of debris flows in these glaciated catchments, and (2) debris...
Management of small dams may have profound implications for the health and integrity of small rivers and freshwater diversity. Global indicators suggest future growth in the small hydropower sector, particularly in developing countries. As a renewable energy source, it is often presumed that small hydropower entails fewer and less severe...
The composition and distribution of fish assemblages was examined in a
floodplain lake system in the Amazon basin. Quantitative samples were
collected during the 1992-1993 flooding season at Marchantaria Island, Solimoes
River. A total of 25,819 specimens representing 8 orders, 30 families, 101
genera and 139 species of fish were...
The nature of upper plate deformation along the Cascadia subduction zone (CSZ) is poorly understood. Systematic covariation among topographic relief, geodetically determined uplift rates, decadal to millennial erosion rates, and the frequency of episodic tremor and slip (ETS) along the Cascadia forearc suggest a genetic association between forearc topography and...
This study examined channel structure and position and riparian
vegetation and land use on the upper 70 km of the McKenzie River, Oregon in
the 1940s, compared the 1940s conditions to present conditions, and explored
the processes driving change in this system and the implications for aquatic
habitat. The hydrologic...
Excavations at the Cooper’s Ferry site (10IH73) revealed a long record of repeated human occupation extending from the late Pleistocene into the early Holocene (~16,000-10,000 cal BP) and have yielded unique insights into the Western Stemmed Tradition (WST), which includes. Several studies have focused on WST pit features encountered at...
Surface water and groundwater are intimately connected by a two-way flux between the stream and the underlying aquifers; a complicated yet crucial relationship to represent in models. However, the National Water Model currently only considers a one-way flux, where groundwater can enter a stream but cannot return to the aquifer....