Social and Behavioral Sciences Commons^™

Warmer Conditions Favor Conifer Tree Establishment At The Muddy River Lahar In Mt. St. Helens, Washington, Ignacio D. Falcon-Dvorsky

Dissertations and Theses

Climate variability impacts on Pacific Northwest forests are of great concern, especially on evergreen coniferous ecosystems which dominate a large portion of the landscape. Understanding the effect of climate variability and its potential impacts on forest regeneration is crucial, as this is a foundational process with long-lasting consequences on structure and composition of future ecosystems. The objective of this study was to uncover the possible influences of natural climate variability on conifer tree establishments on the Muddy Rivers Lahar following the 1980 eruption of Mount St. Helens, WA. We hypothesized that tree establishment increased gradually over time, tree establishments was …

Glacial Meltwater Modeling To Simulate Lake Water Budget (1996-2013) In Taylor Valley, Antarctica, Julian Michael Cross

Dissertations and Theses

The McMurdo Dry Valleys (MDV), the largest ice-free region (4,500 km²) in Antarctica, are a polar desert with an average annual temperature of -18ºC. In Taylor Valley, one of the MDV, closed-basin, perennially ice-covered lakes occupy the valley floor. Their water balance is controlled by inflow from glacial meltwater runoff and loss due to sublimation, making them sensitive indicators of climate. In this study, a physically-based model of glacier meltwater and lake ice sublimation is adapted to explain modern (1996 to 2013) lake-level variations. Meltwater model results were improved by the inclusion of MODIS remotely-sensed albedo measurements (E …

A 30-Year Climatology Of Meteorological Conditions Associated With Lightning Days In The Western United States, Dmitri Alexander Kalashnikov

Dissertations and Theses

A 30-year climatology of lightning and associated synoptic meteorological patterns are characterized across the Western United States (WUS), utilizing a comprehensive composite analysis. Results generally show a preferred synoptic meteorological setup with positive 500-hPa geopotential height anomalies to the northeast of the location experiencing a lightning day, and negative sea level pressure anomalies co-located and to the northwest. Variation in preferred anomaly patterns across the western US reflects the divide between those areas affected by the North American monsoon system and areas outside the monsoonal core. Locations in the western Great Basin and northern Rocky Mountains, which are outside the …

Politics In The San Clemente Dam Removal, Aylan Matthew Lee

Dissertations and Theses

This study examines the role of politics in the removal of the 106-foot tall San Clemente Dam. The removal project and negotiations provide a case study of the contemporary phenomenon of dam removal. My analysis joins a growing body of social science literature on the social, political, and human dimensions of removal. The San Clemente Dam, which impounded the Carmel River near Monterey, California, was removed in 2015, the largest such project completed in California. Drawing on political ecology and science and technology studies, and using a mixed qualitative approach, I assess both the role of politics in shaping the …

Forest Structure, Composition, And Regeneration After High-Severity And Rapidly Repeated Wildfires In The Central Cascade Range, Sebastian Upton Busby

Dissertations and Theses

Within mid-to-high elevation conifer forests in the Cascade Range, wildfire extent, severity, and frequency are expected to rise due to increasingly drier forest fuels under climate change. Considering dominant species composition, existing forests may be poorly adapted to absorb stress and recover following altered wildfire patterns. We tested the hypothesis that increased fire activity may disrupt the recovery of upper-montane and subalpine forest types by quantifying post-fire forest structure and conifer regeneration after spatially large, severe, and rapidly repeated wildfires in the Central Cascade Range. A stratified random sampling design was used to select field plots (n=122) and drivers of …

Hydrologic Trends And Spatial Relationships Of Stream Temperature And Discharge In Urbanizing Watersheds In The Portland Metropolitan Area Of The Pacific Northwest, Emma Lee Brenneman

Dissertations and Theses

This study explores various relationships of streamflow and stream temperature over the Portland Metropolitan area in two urbanizing watersheds. Four stream temperature and discharge metrics were derived from USGS stream gauges in the Tualatin River and Johnson Creek watersheds and were analyzed for monotonic trends. Additionally, this study explored the sensitivity of stream temperature to air temperature and streamflow to assess where locations throughout the watershed may be more sensitive to these changes. Relationships among stream temperature, air temperature, and streamflow were assessed using linear and nonlinear bivariate regression for yearly values and summer months. Additionally, this study seeks to …

Dynamics Of Wet-Season Turbidity In Relations To Precipitation, Discharge, And Land Cover In Three Urbanizing Watersheds, Oregon, Junjie Chen

Dissertations and Theses

Frequent intense precipitation events can mobilize and carry sediment and pollutants into rivers, degrading water quality. However, how seasonal rainfall and land cover affect the complex relationship between discharge and turbidity in urban watersheds is still under investigation. Using hourly discharge, rainfall, and turbidity data collected from six stations in three adjacent watersheds between 2008 and 2017, we examined the temporal variability of the discharge-turbidity relationship along an urban-rural gradient. We quantified hysteresis between normalized discharge and turbidity by a Hysteresis Index (HI) and classified hysteresis loops during 377 storm events in early, mid, and late wet season. Hysteresis loop …

Tree Canopy Cover And Potential In Portland, Or: A Spatial Analysis Of The Urban Forest And Capacity For Growth, Jeff Ramsey

Dissertations and Theses

Urban forests have positive impacts on human and ecosystem health, reduce stress on aging stormwater infrastructure, increase property values, and reduce energy consumption. The scale of these benefits ranges from the hyper-local to the global. While the benefits of urban forests can extend well beyond the boundaries of cities, they often do not reach all residents of the city equally. Urban forest policies do not adequately address environmental equity or employ planting strategies with knowledge of the social and political factors that determine the spatial variations of tree canopy extent in cities. Chapter I analyzes the determinants of current canopy …

Lidar Predictive Modeling Of Kalapuya Mound Sites In The Calapooia Watershed, Oregon, Tia Rachelle Cody

Dissertations and Theses

Archaeologists grapple with the problematic nature of archaeological discovery. Certain types of sites are difficult to see even in the best environmental conditions (e.g., low-density lithic scatters) and performing traditional archaeological survey is challenging in some environments, such as the dense temperate rain forests of the Pacific Northwest. Archaeologists need another method of survey to assess large areas and overcome environmental and archaeological barriers to site discovery in regions like the Pacific Northwest. LiDAR (light detection and ranging) technology, a method for digitally clearing away swaths of vegetation and surveying the landscape, is one possible solution to some of these …

Stratospheric Polar Vortex Variability In The Northern Hemisphere: The Effects Of Climate Change On Polar Vortex Trends And Future Projections, John Earl Rogers

Dissertations and Theses

Regions that have experienced recent successive cold winters such as the Northeast of North America and Siberia have endured critical social and economic impacts from anomalous low temperatures in recent years, despite warming global temperatures. It is well known that the Tropospheric Polar Vortex (TPV), or jet stream, is a primary influence on many mid-latitude winter weather patterns. However, the strong circumpolar westerlies that maximize at around 60° latitude just above the tropopause, known as the Stratospheric Polar Vortex (SPV), can affect tropospheric circulation and thus winter weather in the Northern Hemisphere. Strong upward propagating waves can affect the geographic …

Evaluating The Impact And Distribution Of Stormwater Green Infrastructure On Watershed Outflow, Benjamin Fahy

Dissertations and Theses

Green Stormwater Infrastructure (GSI) has become a popular method for flood mitigation as it can prevent runoff from entering streams during heavy precipitation. In this study, a recently developed neighborhood in Gresham, Oregon hosts a comparison of various GSI projects on runoff dynamics. The study site includes dispersed GSI (rain gardens, retention chambers, green streets) and centralized GSI (bioswales, detention ponds, detention pipes). For the 2017-2018 water year, hourly rainfall and observed discharge data is used to calibrate the EPA's Stormwater Management Model to simulate rainfall-runoff dynamics, achieving a Nash-Sutcliffe efficiency of 0.75 and Probability Bias statistic of 3.3%. A …

Lone Wolves And Copycats: Assessing Policy And Infrastructure For Flood Hazard And Floodplain Management, Samantha L. Hamlin

Dissertations and Theses

To mitigate flood hazard, which affects millions of people every year, increasing numbers of communities are developing green infrastructure policies to not only mitigate the hazard, but to meet other community policy objectives, as green infrastructure is often cited for the multiple benefits it confers. To support the implementation of policies that help communities meet their policy objectives, however, it is imperative to understand how policy is innovated and adopted. To do so, I applied the internal determinants and regional diffusion models, what I refer to as the lone wolf and copycat models. In policy, a lone wolf innovates a …

Characterizing Temperature Variability States Across Southern South America And Associated Synoptic-Scale Meteorological Patterns, Judah Adam Detzer

Dissertations and Theses

The aim of this thesis is to understand spatiotemporal temperature variability in southern South America by identifying overarching temperature variability states and their associated synoptic-scale meteorological patterns. Further, the temporal frequency of occurrence of those temperature variability states is investigated as is the role of recurrent low-frequency modes of climate variability (El Niño Southern Oscillation and the Southern Annular Mode) on temperature variability. K-means cluster analysis is used to group all months during the period 1980-2015 into four primary categories for summer and winter separately. Monthly maps of temperature anomalies are provided as input to the k-means algorithm and the …

Assessing Ppgis Usability And Its Relationship To Spatial Data Production: A Case Study, Timothy Michael Hitchins

Dissertations and Theses

Modern Geoweb-enabled PPGIS methodologies incorporate interactive map applications as the main driver for public engagement and data collection. However, little research explores exactly how the public interact with these applications to produce spatial data, a fact that contributes to criticisms of final data quality. Usability evaluation offers a solution for developing better PPGIS data production systems by identifying problems in the application interface for which the public engage. Drawing on a case study example of a PPGIS application developed to collect socio-spatial data from members of a random public, this paper addresses usability in a three-stage approach. First, controlled experimentation …

Examining The Spatial Characteristics Of Pluvial Flooding Through Citizen Science In Portland, Oregon, Katelyn Rachel Michelson

Dissertations and Theses

Pluvial flooding is caused by rainfall events that overwhelm drainage systems and do not allow excess water to be absorbed by soils or water infrastructure. This type of flooding occurs frequently in urban systems and leads to public inconveniences and infrastructure deterioration, which could cost more than fluvial flooding over time. Increased rainfall intensity, which is projected to increase with climate change, could result in increased pluvial flooding. This study aims to examine the vulnerability of pluvial flooding in Portland, OR (2010-2017) by incorporating an interdisciplinary framework that examines the physical and socioeconomic vulnerability of flooding through citizen-reported flooding data. …

Assessing Spatiotemporal Stream Temperature Trends And Drivers Through Integrated Longitudinal Thermal Profiling And Stationary Data Logger Methodology On The Upper Chehalis River, Wa, Whitney Vonada

Dissertations and Theses

This study encompasses 25 kilometers of the Chehalis River in Washington, USA that currently has sections under a Total Maximum Daily Load (TMDL) plan for stream temperature impairments that exceed 18°C, a regulatory standard set at the time of the listing to protect salmonid spawning, rearing, and migration. Using information integrated from stationary data loggers (n=22) that collected stream temperature information from August 4-September 10, 2017, and longitudinal thermal profiling performed on July 29-30, August 4-5, and September 9-10, 2017, this study aimed to quantify the spatial distribution of stream temperature, evaluate relative consistencies of the riverine thermal regime over …

Glacier Inventories And Change In Glacier National Park, Melissa Carrie Brett

Dissertations and Theses

Glacier National Park, in northwestern Montana, is a unique and awe-inspiring national treasure that is often used by the media and public-at-large as a window into the effects of climate change. An updated inventory of glaciers and perennial snowfields (G&PS) in the Park, along with an assessment of their change over time, is essential to understanding the role that glaciers are playing in the environment of this Park. Nine inventories between 1966 and 2015 were compiled to assess area changes of G&PS. Over that 49-year period, total area changed by nearly -34 ± 11% between 1966 and 2015. Volume change, …

Making Software, Making Regions: Labor Market Dualization, Segmentation, And Feminization In Austin, Portland And Seattle, Dillon Mahmoudi

Dissertations and Theses

Through mixed-methods research, this dissertation details the regionally variegated and place-specific software production processes in three second-tier US software regions. I focus on the relationship between different industrial, firm, and worker production configurations and broad-based economic development, prosperity, and inequality. I develop four main empirical findings.

First, I argue for a periodization of software production that tracks with changes in software laboring activity, software technologies, and wage-employment relationships. Through a GIS-based method, I use the IPUMS-USA to extensively measure the amount and type of software labor in industries across the US between 1970 and 2015. I map the uneven geography …

Detecting Change In Rainstorm Properties From 1977-2016 And Associated Future Flood Risks In Portland, Oregon, Alexis Kirsten Cooley

Dissertations and Theses

In response to increased greenhouse gases and global temperatures, changes to the hydrologic cycle are projected to occur and new precipitation characteristics are expected to emerge. The study of these characteristics is facilitated by common indices to measure precipitation and temperature developed by the Expert Team on Climate Change Detection and Indices (ETCCDI). These indices can be used to describe the likely consequences of climate change such as increased daily precipitation intensity (SDII) and heavier rainfall events (R95p). This study calculates a subset of these indices from observed and modelled precipitation data in Portland, Oregon. Five rainfall gages from a …

Gis Spatial Analysis Of Arctic Settlement Patterns: A Case Study In Northwest Alaska, Justin Andrew Junge

Dissertations and Theses

In northwest Alaska, archaeologists hypothesize that environmental variability was a major factor in both growing coastal population density, with large aggregated villages and large houses, between 1000 and 500 years ago (ya), and subsequent decreasing population density between 500 ya and the contact era. After 500 ya people are thought to have dispersed to smaller settlements with smaller house sizes in coastal areas, and perhaps, upriver. This settlement pattern was identified through research at four site locations over 30 years ago. The changing geographic distribution of sites, associated settlement size, and house size has not been examined in detail. A …

Analyzing Dam Feasibility In The Willamette River Watershed, Alexander Cameron Nagel

Dissertations and Theses

This study conducts a dam-scale cost versus benefit analysis in order to explore the feasibility of each the 13 U.S. Army Corps of Engineers (USACE) commissioned dams in Oregon’s Willamette River network. Constructed between 1941 and 1969, these structures function in collaboration to comprise the Willamette River Basin Reservoir System (WRBRS). The motivation for this project derives from a growing awareness of the biophysical impacts that dam structures can have on riparian habitats. This project compares each of the 13 dams being assessed, to prioritize their level of utility within the system. The study takes the metrics from the top …

Incorporating Place And Space: A Hierarchical Spatial Approach To Exploring Preventable Congestive Heart Failure Hospitalizations In New York City, Rachael Weiss Riley

Dissertations and Theses

Background: Faced with rising medical care costs, increasing prevalence, and widening health disparities, preventing congestive heart failure (CHF) hospitalizations is a central public health concern. Despite evidence of geographical clustering in preventable CHF admissions, there is a lack of research designed to examine spatial patterning of CHF and the local area neighborhood determinants that contribute to this variability. This study sought to assess and evaluate the importance of both space and place in analyzing preventable CHF hospitalizations and readmissions by applying appropriate statistical techniques, clarifying the assumption inherent in each method, and interpreting the findings within the context of existing …

Effects Of Spatially Distributed Stream Power On Check Dam Function In Small Upland Watersheds: A Case Study Of The Upper Laja Watershed, Guanajuato, Mexico, Zachary Andrew Herzfeld

Dissertations and Theses

Watershed restoration comes in a variety of forms depending on which set of problems are sought to be remedied. Severe soil erosion, in the form of gullying and/or headcutting, can be mitigated through constructing check dams in well-selected locations. This practice has been used throughout the upland subwatersheds within the Upper Laja River watershed in Guanajuato, México. The present study employed Wolman pebble counts to systematically assess the effectiveness of 21 check dams located near the city of San Miguel de Allende. Particle size distributions taken directly downstream and upstream of each check dam were differentiated, aggregated and compared--with the …

Out In "The Numbers": Youth And Gang Violence Initiatives And Uneven Development In Portland's Periphery, Dirk Kinsey

Dissertations and Theses

Incidence of youth and gang violence in the Portland, Oregon metro area has increased dramatically over the past five years. This violence has recently become more spatially diffuse, shifting outwards from gentrified, inner city neighborhoods, towards the city's periphery. These incidents exist within the context of a shifting regional political economy, characterized by a process of gentrification associated displacement and growing, and distinctly racialized and spatialized, inequalities. While gang researchers have long argued a corollary between the emergence of gangs and economically and culturally polarized urban landscapes, the ongoing suburbanization of poverty in American cities suggests a new landscape of …

Unmanned Aerial Vehicle Based Structure From Motion Biomass Inventory Estimates, Emily Jane Bedell

Dissertations and Theses

Riparian vegetation restoration efforts demand cost effective, accurate, and replicable impact assessments. In this thesis a method is presented using an Unmanned Aerial Vehicle (UAV) equipped with a GoPro digital camera to collect photogrammetric data of a 2.02-acre riparian restoration. A three-dimensional point cloud was created from the photos using Structure from Motion (SfM) techniques. The point cloud was analyzed and compared to traditional, ground-based monitoring techniques. Ground truth data collected using the status-quo approach was collected on 6.3% of the study site and averaged across the entire site to report stem heights in stems/acre in three height classes, 0-3 …

Community Schools: A Public Health Opportunity, Catherine Diamond

Dissertations and Theses

Community schools link students, families, and communities to educate children and strengthen neighborhoods. They have become a popular model for education in many U.S. cities in part because they build on community assets and address multiple determinants of educational disadvantage. Since community schools seek to have an impact on populations, not just the students enrolled, they provide an opportunity to improve community health. It has been proposed that community schools influence the health and education of the area residents through three pathways: building trust, establishing norms, and linking people to networks and services. However, no research has been published exploring …

Use Of Water Indices Derived From Landsat Oli Imagery And Gis To Estimate The Hydrologic Connectivity Of Wetlands In The Tualatin River National Wildlife Refuge, Debra Sue Blackmore

Dissertations and Theses

This study compared two remote sensing water indices: the Normalized Difference Water Index (NDWI) and the Modified NDWI (MNDWI). Both indices were calculated using publically-available data from the Landsat 8 Operational Land Imager (OLI). The research goal was to determine whether the indices are effective in locating open water and measuring surface soil moisture. To demonstrate the application of water indices, analysis was conducted for freshwater wetlands in the Tualatin River Basin in northwestern Oregon to estimate hydrologic connectivity and hydrological permanence between these wetlands and nearby water bodies. Remote sensing techniques have been used to study wetlands in recent …

Use Of Distance Weighted Metrics To Investigate Landscape-Stream Temperature Relationships Across Different Temporal Scales, Eric Craig Watson

Dissertations and Theses

Stream ecosystems have experienced significant negative impacts from land use, resource exploitation, and urban development. Statistical models allow researchers to explore the relationships between these landscape variables and stream conditions. Weighting the relevant landscape variables based on hydrologically defined distances offers a potential method of increasing the predictive capacity of statistical models. Using observations from three grouped watersheds in the Portland Metro Area (n=66), I have explored the use of three different weighting schemes against the standard method of taking an areal average. These four different model groups were applied to four stream temperature metrics: mean seven-day moving average maximum …

Assessment Of A Mycorrhizal Fungi Application To Treat Stormwater In An Urban Bioswale, Alaina Diane Melville

Dissertations and Theses

This study assessed the effect of an application of mycorrhizal fungi to stormwater filter media on urban bioswale soil and stormwater in an infiltration-based bioswale aged 20 years with established vegetation. The study tested the use of commercially available general purpose biotic soil blend PermaMatrix^® BSP Foundation as a treatment to enhance Earthlite^™ stormwater filter media amelioration of zinc, copper, and phosphorus in an ecologically engineered structure designed to collect and infiltrate urban stormwater runoff before it entered the nearby Willamette River.

These results show that the application of PermaMatrix^® BSP Foundation biotic soil amendment to Earthlite …

Factors Driving The Concentration Of Ephemeral Flow, Gretchen Anne Guyer

Dissertations and Theses

In spite of decades of related research, stream channel initiation is still not well understood. Current theories of channel initiation are grounded in research conducted by Montgomery and Dietrich, largely in the transport limited, temperate, humid climate of the Pacific Northwest, USA. This field data driven work concluded that the drainage area required for channel initiation is directly correlated to the slope of the contributing area. However, there are a host of related variables that have yet to be examined in the field. This study revisits the slope-area relationship focusing on ephemeral overland flow in headwaters of both the Pacific …