In an effort to restore summer flows in the Walla Walla River to provide passage
and habitat for ESA (endangered species act) listed bull and steelhead trout irrigation
districts left 13 cubic-feet-per-second (c.f.s) (0.37 m ³/s) in the main channel during
irrigation season (May-November) for the first time in over...
The myxozoan parasite, Ceratomyxa shasta, is the most significant pathogen of juvenile Chinook salmon (Oncorhynchus tshawytscha) in the Klamath River, CA, USA. This parasite requires two hosts - a freshwater polychaete (Manayunkia speciosa) and a salmonid - to complete its life cycle. The complex life cycle and large geographic area...
This study was initiated to characterize the distribution of Fe-Mn nodules and to elucidate trends of Fe, Mn, and P relative to the intensity of the annual cycles of reduction and oxidation. Nodules were enriched in Fe, Mn, and P relative to the soil matrix making them an integral part...
Elk River is a sixth order stream, draining a 200 square
kilometer basin in the Klainath Mountain province of
southwestern Oregon. Timber harvesting began in the basin
during the 1950's, with peak removal of wood occurring in the
mid to late 1960's. This activity lead to an increase in the...
This study investigates riparian cover change between 1939 and 1996 utilizing aerial
photography, bank conditions and stream gauge data. Three sites under 1.0 km2, along a 10-
km reach north of Harrisburg, Oregon, were evaluated. The cover classification scheme
included 18 classes composed of 3 canopy densities and 8 structural...
The hazards associated with tsunamis are well known and have been studied for decades. The majority of research is, however, focused on open coastlines which bear the brunt of a tsunamis force. Other regions that can be strongly impacted by a tsunami are large estuaries. Here, the tsunami encounters a...
The Columbia River Estuary was sampled during high (May-June), intermediate (July), and low (September-October) river flow seasons to further define the role of the ETM with respect to its effect on primary biomass and production, and to discover how this effect changes in space and time.
Strong ETMs were determined...
The Tualatin River Basin is located in the Washington County, Oregon. The river was detected having high chlorophyll a concentration and low dissolved oxygen concentration during summer time, which violated DEQ water quality standards. A mathematical model (HSPF) was used to simulate physical, chemical and biological processes in the basin...
The mouth of the Columbia River (MCR) has a longstanding reputation of hazardous navigational conditions. This reputation has been developing since the first ship, the Columbia, traversed through the inlet in 1792. The hazardous conditions are related to the large waves and strong tidal currents that are common in the...
Pacific Coast estuaries provide important rearing habitats leading to improved growth and survival for juvenile chinook salmon. However, research has suggested that juvenile salmon have little use for estuarine habitats in the Columbia River. To further understand salmonid recovery needs in estuaries, I compared historical and contemporary life history patterns...