Physical Sciences and Mathematics Commons^™

Student Sustainability Leadership Development At Portland State University: Developing Holistic Sustainability Leaders, Megan Suzanne Schneider

Dissertations and Theses

In order to address the myriad of social, economic, and environmental challenges the world is facing, we need to be able to engage in leadership that fosters collective action towards sustainable solutions. Higher education is an institution that can equip people with the abilities to engage in sustainability leadership. This master's thesis research explores how students develop sustainability leadership through their college experience. Nine students, who had been identified as sustainability leaders through their participation in the Student Sustainability Center (SSC), a co-curricular sustainability program at Portland State University, were selected to be part of this grounded theory research project. …

Flood Dynamics In The Portland Metropolitan Area, Past, Present, And Future, Lumas Terence Helaire

Dissertations and Theses

The Portland area has an extensive flood history since it was founded in 1845. In the late 19th century, the Portland area was prone to flooding from snowmelt freshets (3-6 months duration) and brief winter rain or rain-on-snow events. Since that time the magnitude of spring freshets has been curtailed by 45% due to climate change, flow diversions, and reservoir management. Along with changes in hydrology, the bathymetry of the Lower Columbia River has been altered by the dredging of the navigation channel, diking, and land reclamation. To understand how these changes in hydrology and bathymetry have affected tidal and …

Stormwater Treatment Effectiveness Of Established Bioretention Facilities In Portland, Oregon, Emma Rose Kohlsmith

Dissertations and Theses

Bioretention systems are commonly used to treat and detain stormwater runoff and help mitigate for many negative effects of urbanization. Despite the widespread use of bioretention systems, few field-based studies have assessed how these facilities affect water quality many years after installation. The goal of this project is to assess the pollution reduction effectiveness of lined bioretention facilities that have been in use and functioning for 4-8 years. To meet this objective, this project measured water quality characteristics of stormwater flowing into and out of seven facilities installed throughout Portland, Oregon during real storm events. Stormwater grab samples were taken …

The Invasion Ecology Of Ivy (Hedera Spp.) In Portland's Forest Park, Eric Paul Butler

Dissertations and Theses

Invasive ivy (Hedera spp.) has extensive impacts on Pacific Northwest urban forests, many of which are not yet fully understood. In this study of Forest Park, Portland, Oregon, I evaluated several environmental variables obtained or derived from monitoring datasets at three spatial scales to determine the following: how ivy is spatially distributed; what factors are most correlated with ivy abundance; and how ivy abundance influences shrub community composition. I found that ivy is significantly clustered at all scales with multiple apparent epicenters along the park's urban periphery. Using NMDS ordination, I determined that ivy is a significant factor in …

The Influence Of Neighborhood Landscape Characteristics On Native Bird Communities: Implications For Increasing Biodiversity In Our Yards, Michael E. Vermeulen

Dissertations and Theses

Avian communities, because of their potential high diversity, are ideal for studying the response to potential quantity of resources provided by local and regional habitat. Urban neighborhoods vary in types and magnitudes of anthropogenic stressors they experience, resulting in a continuum of anthropogenic disturbance, often referred to as a gradient of urbanization. The aim of this study was to investigate anthropogenic drivers of urban bird communities in three Portland, OR neighborhoods (Hillsdale, Lents, and Pearl). The three major questions of this study were: 1) What are the significant landscape traits that characterize the neighborhoods? 2) Is there evidence that the …

The Fate Of Atmospherically Deposited Mercury In Mountain Lake Food Webs, And Implications For Fisheries Management, Ariana Martos Chiapella

Dissertations and Theses

Mountain lakes are an iconic feature of the landscape in the Mountain West. They hold significant ecological and cultural value, and are important sentinels of environmental change. Despite their pristine image, these remote waterbodies are subjected to numerous anthropogenic stressors. Mountain lakes are naturally fishless systems, but historical fish stocking has led to major changes in mountain lake food web structure, including declines of resident amphibians, large-bodied zooplankton, and emergent insect populations. Atmospherically deposited contaminants, such as mercury, can accumulate in mountain lake food webs, leading to relatively high levels in the fish relative to the water. Managing for these …

Are We Providing Preferred Floral Resources For Bees In Our Neighborhoods? : Assessing The Relationship Between Small Scale Vegetation Metrics And Bee Presence In Se Portland, Hailey Wallace

Dissertations and Theses

Bee pollinators can thrive in highly urbanized environments if their preferred floral resources and habitat types are available. Enhanced pollinator habitats are being created globally, with a large local effort in Portland, Oregon. This project determined if we were providing the most preferred floral resources at enhanced pollinator sites for bees, if floral resources were available throughout the season, and if differences in dietary preferences between native and honey bees would allow for the identification of "native bee floral resources" in South East Portland. Bee pollinators were monitored from June to August at three enhanced pollinator sites in South East …

Attitudes, Behavior, And Archetypes In The Clackamas River Basin: A Model Of Water Customer Analysis And Outreach For Watershed Protection And Conservation, Daniel Close Larson

Dissertations and Theses

Fresh water resources around the globe are under threat of diminishing supply and quality due to rapid population growth, climate change, drought, and waste. This dissertation aims to address the protection of fresh water at the source, the tap, and how water customer attitudes influence protection and conservation using a watershed-wide lens. Using the Clackamas River Watershed which resides within the Portland Metropolitan Area (PMA), I seek to investigate water customer attitudes towards a source water protection program and their willingness to pay to support such an endeavor, attitudes and behaviors that result in household water conservation, and an exploration …

Scenes From The Swale: Investigating Spatial And Temporal Dimensions Of Nitrogen Cycling In Urban Stormwater Bioretention Facilities, Erin Nicole Looper

Dissertations and Theses

Urban development is transforming landscapes at unprecedented rates. Human activities and landscape modifications associated with urbanization extensively increase hydrologic demands and modify natural hydrologic systems; consequently, population growth occurring in urban areas increases pressure on water resources. Urban aquatic ecosystems are vulnerable to impacts associated with increased connectivity with urban surfaces and hydrologic changes that initiate long-term changes in receiving waterbodies. Nitrogen (N) loading from urban and suburban catchments to receiving surface waters can lead to impairment of aquatic ecosystems and is a concern in many cities with water quality issues. To improve urban water quality, cities are increasingly adopting …

The Impact Of Infrastructure On Habitat Connectivity For Wildlife, Leslie Lynne Bliss-Ketchum

Dissertations and Theses

While roads can present weak to complete barriers to wildlife, depending on the animal and traffic volume, mitigations such as under-crossings and green bridges on highways at least partially increase the permeability of the landscape to some of these species. The few studies evaluating the effectiveness of these structures for at least three years typically focused on a single species. Here, we monitored the crossing structure under Boeckman Road, in Wilsonville Oregon, for wildlife activity across summer seasons for ten years, since construction of the road and subsequent opening to traffic. This long-term multi-species dataset, which includes monitoring when the …

Comparison Of Gold Extraction Yields By Cyanide Treatment Vs. Bioleaching Procedure, Yilman Steven Pineda

Dissertations and Theses

Samples from the tailings of the Picacho mine in California were leached using NaCN and native bacteria, Alcaligenes faecalis, in column experiments to compare the gold recovery yields in the effluents. Four columns were treated with a different liquid: water, bacteria, NaCN and a mixture of cyanide and bacteria. After they were leached the effluents were analyzed to determine gold yields. During experiment I the total Au recovered in the effluent in the column treated with bacteria was only 10.09% less than those treated with cyanide (C2) and 81.7% more than the control. In experiment II, Au values measured were …

Towards Improving Accuracy And Interpretability Of Deep Learning Based On Satellite Image Classification, Yamile Patino Vargas

Dissertations and Theses

ABSTRACT

The study of satellite images provides a way to monitor changes in the surface of the Earth and the atmosphere. Convolutional Neural Networks (CNN) have shown accurate results in solving practical problems in multiple fields. Some of the more recognized fields using CNNs are satellite imagery processing, medicine, communication, transportation, and computer vision. Despite the success of CNNs, there remains a need to explain the network predictions further and understand what the network is determining as valuable information.

There are several frameworks and methodologies developed to explain how CNNs predict outputs and what their internal representations are [1, 4, …

Hydroclimate Drivers And Atmospheric Dynamics Of Floods, Nasser Najibi

Dissertations and Theses

Our preliminary survey showed that most of the recent flood-related studies did not formally explain the physical mechanisms of long-duration and large-peak flood events that can evoke substantial damages to properties and infrastructure systems. These studies also fell short of fully assessing the interactions of coupled ocean-atmosphere and land dynamics which are capable of forcing substantial changes to the flood attributes by governing the exceeding surface flow regimes and moisture source-sink relationships at the spatiotemporal scales important for risk management. This dissertation advances the understanding of the variability in flood duration, peak, volume, and timing at the regional to the …