The effects of wind forcing on coastal ocean circulation are studied using a
numerical modeling approach. The first region of interest is on the North Carolina
shelf, where the Coastal Ocean Processes (CoOP) Inner Shelf Study (ISS) took place
during August - November 1994. ISS observations are used to initialize,...
By implementing a series of mass-conserving nested high-resolution models down to approximately 1 km resolution that have realistic bathymetry, coastline, wind forcing and river run-off, the winter 1996-1997 shelf flow near Cape Mendocino, California, is simulated and compared with available observations from the Strata Formation on Margins (STRATAFORM) marine geology...
The mesoscale circulation in the Gulf of California is investigated using a numerical model (Princeton Ocean Model). Forced by satellite-derived winds, the circulation in the gulf shows a complex pattern dominated in the southern gulf by multiple eddies. Near the coast and in most of the north gulf, the circulation...
The response on the continental shelf of a baroclinic ocean to
driving by an alongshore coastal wind stress and by barotropic and
baroclinic wind forced interior motions is studied as a function of
latitude. The relative excitation of continental shelf waves and
internal Kelvin waves is studied.
The response of...
Swash zone processes are of significant importance to foreshore morphologic change. This thesis addresses the importance of the uprush and backwash fluid motions and flow duration effects to the resulting sediment transport. The analysis relates the field observations to well known sediment transport formulations as well as investigates the importance...
Diking and channelizing in the Toppenish Creek basin, associated with irrigated agricultural development, has altered its natural ecosystem function and hydraulic processes. We seek to answer two research questions: if surface waters are diverted for aquifer recharge in the winter, will this water be available for ecosystem function in the...
Sand dams – low-head dams built in ephemeral streambeds that store water within saturated sediments – are a proven means to increase water supplies for rural communities in arid and semiarid regions. Water percolates into the reservoir-impounded sediments during wet season rains and can subsequently be extracted during the dry...
Survival of ecological systems pivot on critical moments. In the arid John Day Basin of Eastern Oregon, extensive restoration of the stream and floodplain focused on supporting salmon has been ongoing for the past 20 years, but recurring short periods of extreme temperature increase and low flows result in mortality...
Finding trees and crops that are resistant to pathogens is key in preparing for current and future disease threats. In this dissertation, we analyzed the potential of using hyperspectral imaging (HSI) to find infection while identifying issues and strategies addressing differences over time, in spatial resolution, the application of machine...
In the face of climate change droughts are predicted to become more persistent, further intensifying the need for accurately predicting the timing and magnitude of summer streamflow in rivers. In order to determine the sensitivity of a watershed to drought, there is a need to describe what these drought conditions...
Urban development causes changes in the hydrology, increasing stormwater runoff volumes, which often leads to flooding and ecosystem degradation. This is a common phenomenon in most urban Africa, due to lack of stormwater drainage infrastructures. Green Infrastructure (GI) has been shown to be an effective approach to lessen the effects...
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....
As the number of weather stations declines globally, ensuring that meteorological monitoring networks efficiently and effectively monitor weather variables becomes increasingly important. Multi-variable weather sensors are becoming more widely available and make monitoring weather phenomena more economical. However, when seeking an optimal spatial distribution of these stations, choosing an objective...
The Middle Fork John Day Basin in Northeastern Oregon is prime habitat for spring Chinook salmon and Steelhead trout. In 2008, a major tributary supporting rearing habitat, Big Boulder Creek, was restored to its historic mid-valley channel along a 1 km stretch of stream 800 m upstream of the mouth....
Surface water and groundwater interactions are a key component in the functioning of stream ecosystems. Exchange of water between the stream and the hyporheic zone creates habitat for aquatic organisms and serves as a control for stream biogeochemical, thermal, and flow processes. This study takes a multi-method field-based approach to...
Rainfall scarcity and variability present serious challenges to water security for many rural communities throughout the world's drylands. Sand dams--weirs built across ephemeral or seasonal rivers--provide an appropriate water harvesting and storage option for many regions. The structures quickly fill with sediment during rainy season flow events and store water...
Linkages between land use and its influence on the atmosphere have been a long-standing research area. For example, what is the impact of irrigated agriculture on downwind rainfall? Global-scale models show that moisture recycling is an important source of water for inland regions around the world, but they do not...
In microwave network analysis, proper matching of the measurement system is necessary to prevent measurement errors and provide a
proper terminating impedance for the device-under-test. To obtain
this matching, a buffer amplifier is often used in the first stage of
the network analyzer.
This study describes the design and analysis...
The effectiveness of tangential flow filtration (TFF) for
recovery of infectious hematopoietic necrosis virus (IHNV) and
infectious pancreatic necrosis virus (IPNV) from large volumes of
water was evaluated. In laboratory studies, virus recovery from
IHNV-seeded water following concentration by TFF was approximately
13%. However, addition of 0.1 and 1% FBS...
Water conservation and water quality are rapidly increasing in importance in all areas of the world. The ability to accurately measure soil water content and salinity, over a wide variety of conditions, is key to meeting this need. A set of forward prediction models and waveform interpretation algorithms to extract...
Erythrocytic inclusion body syndrome (EIBS), a viral disease
of salmon, was investigated. Reliable artificial infections were
established in coho salmon (Oncorhynchus kisutch) via
intraperitoneal injection of homogenized kidney, spleen, and blood
from naturally infected animals. By examining the exposed fish
periodically for viral inclusion bodies and hematocrits, the disease
progression...
The development of an effective infectious
hematopoietic necrosis virus (IHNV) vaccine depends on a
better understanding of the antigenic structure and
variation among isolates. Three objectives to elucidate
this were: (1) to generate a panel of antigenic
derivatives of the IHNV glycoprotein by monoclonal
antibody-mediated selection of neutralization-resistant
variant viruses,...
Vertisols and other vertic-intergrade soils are found all over the globe, including many agricultural and urban areas. These soils are characterized by their cyclical shrinking and swelling behaviors, where bulk density and porosity distribution both vary as functions of time and/or soil moisture. In turn, alterations in physical soil parameters...
Soil solution samplers have certain inadequacies that limit their range of
possible applications. Passive Capillary Samplers (PCAPS), which apply suction to the
soil pore-water via a fiber glass wick, have shown promising results in preliminary
experiments in regard to collection efficiency of water and of bromide tracers. The
objectives of...
Land application of industrial wastewater with high levels of nitrogen requires
adequate management practices to prevent groundwater pollution by nitrates. In this study
a predictive computerized model was developed for nitrate leachate concentrations
resulting from land application of wastewater onto crop systems including poplars. The
study included a literature review,...
Erythrocytic inclusion body syndrome (EIBS) was artificially
established in selected stocks of juvenile fall and spring chinook
salmon (Oncorhynchus tshawytscha), chum salmon (0. keta), coho
salmon (0. kisutch), Atlantic salmon (Salmo salar), and rainbow
trout (0. mykiss). Adult spring chinook salmon were also
artificially infected with the EIBS virus. Adult...
Detection and treatment of bacterial kidney disease (BKD)
was investigated. Experiments were conducted to evaluate the
quantitative, fluorescent antibody technique (QFAT) that is used
to detect, identify, and quantify both typical and 'bar form'
Renibacterium salmoninarum cells. Smears of kidney tissue from
naturally and artificially infected salmonids, both with and...
Groundwater contamination on irrigated land is of concern in this nation
and around the world. In order to reduce the potential of groundwater
contamination by agricultural practices such as irrigation, fertilizer and pesticide
application, vadose-zone monitoring and sampling are needed. The main
objective of this study was to evaluate impacts...
Assessment of the environmental impacts of an agricultural production system
requires information on both soil water quality and solute flux. Passive Capillary Samplers
(PCAPS), which sample water from the vadose zone using fiber glass wicks, have shown
potential to provide both flux and solute concentration in unsaturated zone sampling but...
The agricultural production of peppermint has been shown to contribute significant quantities of nitrate-nitrogen to groundwater recharge. In an effort to provide new tools for increasing nitrogen efficiency within peppermint production, three research questions were proposed: i) How should plant tissue samples be collected to achieve the greatest precision when...
The contamination of ground water resources represents a serious
problem and a prominent threat to the health of our society. This study
focuses on the leaching of inorganic anions as a function of agricultural
practices under natural field conditions. In order to enhance the
understanding of such leaching processes, this...
The study of the subsurface flow and distribution of water is critical to the evaluation of the unsaturated zone for a potential geologic high-level radioactive waste repository. This site is located at Yucca Mountain, Nevada in the northern Mojave Desert. and was chosen on the basis of its low precipitation,...
Infiltration of highly concentrated solutions into unsaturated sand is suspected to be affected by the liquid-gas interfacial tension between the resident water and that of the infiltrating solution. The wetting of non-porous solid surfaces by liquids is commonly quantified by contact angle measurements. However, it is well known that wettability...
An experimental and numerical modeling investigation was conducted to study interactions between microbial dynamics and transport processes in variably saturated porous media. These interactions are important in a variety of applied problems such as water and wastewater treatment, bioremediation, and oil-field recovery operations. These processes and interactions also have great...
Non-dilute salt strength solutions occur in many near surface geologic environments. In order to better understand the occurrence and movement of the water and salt, mathematical models for this non-ideal fluid need to be developed. Initial boundary value problems may then be solved to predict behavior for comparison with observations....
Water temperature in rivers and streams is an important factor for aquatic ecosystem health. Measurement of stream temperature has traditionally been accomplished by point temperature measurements, continuous point temperature loggers, and more recently, airborne remote sensing techniques such as Forward-Looking Infrared Radar (FLIR) or Thermal Infrared Radiometry. While each of...
As ornamental container nurseries face diminishing water allocations, many are looking to automated irrigation solutions to increase their water application efficiency. This thesis presents the findings of a study conducted at a commercial container nursery to determine 1) whether a capacitance or load cell sensor was better suited for monitoring...
Tile drainage increases aeration in the root zone of poorly drained soils by
accelerating water movement from the subsurface. Water movement is the main agent
of chemical transport, either transporting soluble materials directly (e.g., nitrate) or by
transporting the soil particles that bind adsorptive compounds (e.g., pesticides). The
detection frequency...
The Willamette Valley of Oregon has high rates of winter precipitation that cause leaching losses of residual fertilizer nitrogen (N) as nitrate (NO₃). Cover crops may have potential to mitigate N loss. Shallow groundwater was sampled for 11 years from plots planted in summer vegetables with and without winter cover...
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...
Headwater streams are an integral part of the ecological health of the greater stream network as they provide valuable biological habitat, provide upwards to 95% of total in channel flow, while providing downstream reaches with important constituents such as sediment and woody debris. Small headwater streams are particularly susceptible to...
The Clean Water Act imposes Total Maximum Daily Load (TMDL) limits on pollutant concentrations within wastewater effluent; in Oregon, thermal discharge is one of the pollutants subject to regulation. The City of Woodburn, Oregon, funded a series of pilot scale studies to investigate the utility of natural systems to reduce...
The Middle Fork of the John Day River (MFJD) in Northeastern Oregon contains important spawning grounds for spring Chinook and summer steelhead of the Columbia River Basin. In the summer of 2008 phase one of a river restoration project was completed which included the addition of engineered log jams (ELJs)...
The City of Woodburn, Oregon's Wastewater Treatment Plant (WWTP) has been investigating several natural alternatives for improving effluent quality. Based on its current National Pollution Discharge Elimination System (NPDES) permit, the WWTP will require additional reduction of temperature and ammonia levels in the summer, especially in the critical month of...
Fine particles and colloids, attached to grain surfaces, are abundant in the earth's subsurface. Under certain conditions these particles can be released from the matrix and transported with the mobile phase. One of the mechanisms for sudden particle release is a decrease in groundwater salt concentration below the critical salt...
A relatively stable, persistent and historical problem with elevated NO₃⁻ concentrations in rural drinking wells in the southern Willamette Valley, Oregon is evident. What is the origin of NO₃⁻ in rural drinking water wells in this area? The answer to the question is not simple. Many non-point sources contribute to...
A novel technique was developed for studying gas phase flow in unsaturated porous media. Carbon dioxide was pumped through a back-lit chamber packed with translucent sand which was variably saturated with water containing the pH indicator dye methyl red. As the carbon dioxide dissolved in the pore water, lowering the...
Development of a suitable thin-film technology has stimulated research in, and production of, a.c. thin film electroluminescent (ACTFEL) devices. The aim of this thesis is to provide a better understanding of the physical processes associated with the device characteristics
of such ACTFEL devices. The unique phenomena exhibited by these devices...
The accumulation of fuels in fire prone landscapes, and changing climatic conditions, have resulted in increasingly volatile fire behaviors. As a result, social and operational risk, management expenditures, and budgetary requirements for responsible agencies are increasing. The United States Forest Service (USFS) manages 193 million acres across the United States...
Soil water content and water potential are two important parameters in
determining the status of water in the soil. Improvement in the ability to measure these
parameters by way of increased speed, accuracy, resolution, imaging volume, ease of
automation, as well as reduced calibration requirements and reduced soil disturbance
would...
Contamination of ground water by non-aqueous phase liquids (NAPLs) has
received increasing attention. The most common approach to numerical modeling of
NAPL movement through the unsaturated zone is the use of the finite difference or finite
element methods to solve a set of partial differential equations derived from Darcy's law...
Time-domain models were developed to predict the response of a tethered buoy
subject to hydrodynamic loadings. A coupled analysis of the interaction of a buoy and
its mooring is included and three-dimensional response is assumed. External loadings
include hydrodynamic forces, tethers tensions, wind loadings and the weight of both
cable...
Efficient use of water in agricultural production involves accurate assessment
and control of the quantity and spatial uniformity of excess percolation. Passive
Capillary Samplers (PCAPS), which sample water from the vadose zone have shown
potential to provide superior estimates of soil water flux compared to alternative
methods. In a four-year...
Salicylate-induced, lux gene dependent bioluminescence was measured using a cooled charge-coupled device (CCD) camera to evaluate its potential as a quantitative measurement of cell density of Pseudomonas fluorescens HK44 in porous media. The CCD camera was able to detect bioluminescence from cell densities between 1x10⁶ and 1x10⁸ cells/ml in both...
Achieving and maintaining sustainability in irrigated agriculture production in the era of rapidly increasing stress on our natural resources require, among other essential actions, optimum control and management of the applied water. Thus, a significant upgrade of the currently available soil water monitoring technologies is needed. The primary goal of...