Nutrient pollution may perhaps be one of the oldest water quality problems and has recently been considered as one of the greatest threats to estuarine and coastal waters. Excessive nutrient loads have had a vast array of impacts on estuarine and coastal ecosystems globally. Direct negative effects include: shading out...
Bioremediation in the vadose zone is unpredictable because of poor understanding of factors influencing microbial growth in this environment. A lab-scale experimental system was developed to examine, noninvasively, interactions between microbial growth, water flow, and solute transport in unsaturated porous media. Measurements of microbial colonization, and its impact on hydrology,...
This thesis presents an experimental study of radial porosity in a manually filled cylindrical container with glass spheres. The symmetric distribution of bead diameter allowed for normalization of container properties and porosity models. The aspect ratio of the container was approximately 3.9, with tube-to-particle-diameter ratio λ ≈ 24.6 and height-to-particle-diameter...
It is considered best practice when designing pedestrian access at intersections to provide two curb ramps at each street corner. In Oregon, there are many locations where long ramp runs cause curb ramps to be set back a significant distance from the apex of the intersection corner to meet this...
Atmospheric carbon reduction is arguably the most crucial facet among efforts to mitigate climate change. The Fifth International Panel of Climate Change report emphasizes a worldwide goal of maintaining global temperature elevation less than 1.5°C above pre-industrial temperatures. This report also acknowledges without the proper utilization of counteractive emission strategies...
The cometabolic ability of Burkholderia vietnamiensis G4 grown on aromatic substrates was first assessed by resting suspended cells, and subsequently for cells encapsulated with and without slow release compounds (SRCs). In Chapter 3, benzyl alcohol was assessed as a food-grade growth substrate for promoting cometabolism of trichloroethene (TCE), via the...
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....
The two primary considerations for highway work-zones are its effect on commuter mobility and worker safety which are often spoken of together. However, it must be noted that they often conflict with each other. For example, traffic control plans that reduce travel speed in work-zones improve both commuter and worker...
Multi-phase flow in porous media includes many instances of subsurface flow. Three-phase flow in particular is important in situations of enhanced oil recovery, CO2 sequestration, and groundwater remediation. Many studies have been performed on how two fluid phases (oil/water or air/water) behave in porous media, but very few studies exist...