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Development of a Geomorphic Model to Predict Erosion of Pre-Dam Colorado River Terraces Containing Archaeological Resources

Description

It is apparent that before emplacement of the dam gully degradation in terraces was restored by periodic alluvial deposition from river floods, but perhaps even more important is the redistribution of flood sands onto higher terraces by wind. Thus, we propose the term "restorative base-level hypothesis" to emphasize the dynamic…

It is apparent that before emplacement of the dam gully degradation in terraces was restored by periodic alluvial deposition from river floods, but perhaps even more important is the redistribution of flood sands onto higher terraces by wind. Thus, we propose the term "restorative base-level hypothesis" to emphasize the dynamic equilibrium between gully erosion and renewed deposition, a process that remains active in Cataract Canyon but is disrupted in Grand Canyon by the presence and operation of the dam.

We developed type geomorphic settings to develop a conceptual process model for the diverse small-catchment geomorphic system in Grand Canyon. Research findings explain how streams are able to cross broad, flat terraces given a rainfall event and how they become progressively more integrated with the river. The primary channelization processes are ponding and overflow, alluvial fan progradation, and infiltration and piping, all of which contribute to nickpoint migration. An understanding of these processes was essential to building the geomorphic model.

The predictive mathematical model quantifies erosional vulnerability by applying a hypothetical rainfall event of 25 mm/hour onto a catchment above a "pristine" terrace sequence. The principal driving factor for erosion is basin area. The principal resisting factor for erosion is terrace diffusion capacity, which is a function of terrace sand cross-sectional area and infiltration capacity. Several important modifying factors are applied to the basic model to determine relative vulnerability of each terrace to gully erosion. Vulnerability of the top terrace at each catchment is plotted against the measured amount of gully erosion in that terrace, providing a base line against which progressive changes in gully depth can be easily monitored in the future.

Field studies and research show that: (1) gully erosion of terraces has been severe during the past 20 years in Grand Canyon due to unusually high precipitation; and (2) sediment deprivation coupled with the lack of large annual floods has caused a reduction in restorative (depositional) factors. Continued measurement and documentation of geomorphic processes in catchments, particularly at type geomorphic settings, will further refine and verify the predictability of the model. We conclude that beach-habitat-building flows are essential for initiating natural restorative processes and that one of the most important processes in gully mitigation may be eolian reworking of newly deposited flood sands onto higher terraces. Prior to the construction of Glen Canyon Dam, gully-deepening and river/wind depositional processes were in dynamic equilibrium, allowing the preservation of ancient cultural sites for the past several thousand years.
ContributorsThompson, Kate S. (Editor) / Potochnik, Andre R. (Editor)
Created2000-02-18
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The Rise in Prevalence of Food Allergies

Description
The Centers for Disease Control and Prevention in the United States announced that there has been roughly a 50% increase in the prevalence of food allergies among people between the years of 1997 - 2011. A food allergy can be described as a medical condition where being exposed to a…

The Centers for Disease Control and Prevention in the United States announced that there has been roughly a 50% increase in the prevalence of food allergies among people between the years of 1997 - 2011. A food allergy can be described as a medical condition where being exposed to a certain food triggers a harmful immune response in the body, known as an allergic reaction. These reactions can range from mild to fatal, and they are caused mainly by the top 8 major food allergens: dairy, eggs, peanuts, tree nuts, wheat, soy, fish, and shellfish. Food allergies mainly plague children under the age of 3, as some of them will grow out of their allergy sensitivity over time, and most people develop their allergies at a young age, and not when they are older. The rise in prevalence is becoming a frightening problem around the world, and there are emerging theories that are attempting to ascribe a cause. There are three well-known hypotheses that will be discussed: the Hygiene Hypothesis, the Dual-Allergen Exposure Hypothesis, and the Vitamin-D Deficiency Hypothesis. Beyond that, this report proposes that a new hypothesis be studied, the Food Systems Hypothesis. This hypothesis theorizes that the cause of the rise of food allergies is actually caused by changes in the food itself and particularly the pesticides that are used to cultivate it.
ContributorsCromer, Kelly (Author) / Lee, Rebecca (Thesis director) / MacFadyen, Joshua (Committee member) / Sanford School of Social and Family Dynamics (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
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Does Inclusivity Really Matter? The Importance of Diversity and Inclusion in Farm-Based Internship Programs

Description
Current farming demographics in the United States indicate an aging and overwhelmingly white group of farmers, stimulating the need for engaging a younger and more diverse population. There is an opportunity to engage these populations through farm-based internship and apprenticeship programs, which are immersive programs on small-scale, sustainable farms. These…

Current farming demographics in the United States indicate an aging and overwhelmingly white group of farmers, stimulating the need for engaging a younger and more diverse population. There is an opportunity to engage these populations through farm-based internship and apprenticeship programs, which are immersive programs on small-scale, sustainable farms. These programs are unique in providing hands-on training, housing, meals, and a stipend in return for labor, presenting a pathway to social empowerment. The potential outcomes of increasing diversity and inclusion in farm programs are absent from the research on the benefits of diversity and inclusion in other work environments, such as the corporate setting. This paper presents the results of a study aimed at determining levels of diversity and inclusion in United States farm-based internship programs, and the viability of these programs as an effective opportunity to engage marginalized young people in farming. The study of 13 farm owners and managers across the U.S. found that the participants are focused on fostering education and training, environmental benefits, and a sense of community in their respective programs. All participants either want to establish, or believe they currently have, an inclusive workplace on their farm, but also indicated a barrier to inclusivity in the lack of a diverse applicant pool. Future recommendations for removing that barrier and involving more young, diverse interns include increased outreach and access to these programs, the use of inclusive language, and further research.
ContributorsLascola, Dania (Co-author) / Biel, Braden (Co-author) / Cloutier, Scott (Thesis director) / MacFadyen, Joshua (Committee member) / School of International Letters and Cultures (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
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Diagnosing a silent epidemic: the historical ecology of metal pollution in the Sonoran Desert

Description
This research investigates the biophysical and institutional mechanisms affecting the distribution of metals in the Sonoran Desert of Arizona. To date, a long-term, interdisciplinary perspective on metal pollution in the region has been lacking. To address this gap, I integrated approaches from environmental chemistry, historical geography, and institutional economics to…

This research investigates the biophysical and institutional mechanisms affecting the distribution of metals in the Sonoran Desert of Arizona. To date, a long-term, interdisciplinary perspective on metal pollution in the region has been lacking. To address this gap, I integrated approaches from environmental chemistry, historical geography, and institutional economics to study the history of metal pollution in the desert. First, by analyzing the chemistry embodied in the sequentially-grown spines of long-lived cacti, I created a record of metal pollution that details biogeochemical trends in the desert since the 1980s. These data suggest that metal pollution is not simply a legacy of early industrialization. Instead, I found evidence of recent metal pollution in both the heart of the city and a remote, rural location. To understand how changing land uses may have contributed to this, I next explored the historical geography of industrialization in the desert. After identifying cities and mining districts as hot spots for airborne metals, I used a mixture of historical reports, maps, and memoirs to reconstruct the industrial history of these polluted landscapes. In the process, I identified three key transitions in the energy-metal nexus that drove the redistribution of metals from mineral deposits to urban communities. These transitions coincided with the Columbian exchange, the arrival of the railroads, and the economic restructuring that accompanied World War II. Finally, to determine how legal and political forces may be influencing the fate of metals, I studied the evolution of the rights and duties affecting metals in their various forms. This allowed me to track changes in the institutions regulating metals from the mining laws of the 19th century through their treatment as occupational and public health hazards in the 20th century. In the process, I show how Arizona’s environmental and resource institutions were often transformed by extra-territorial concerns. Ultimately, this created an institutional system that compartmentalizes metals and fails to appreciate their capacity to mobilize across legal and biophysical boundaries to accumulate in the environment. Long-term, interdisciplinary perspectives such as this are critical for untangling the complex web of elements and social relations transforming the modern world.
ContributorsHester, Cyrus M (Author) / Larson, Kelli L (Thesis advisor) / Laubichler, Manfred D (Thesis advisor) / MacFadyen, Joshua (Committee member) / Arizona State University (Publisher)
Created2019
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From “Open Country” to “Open Space”: Park Planning, Rapid Growth and Community Identity in Tempe, Arizona, 1949-1975

Description
Tempe experienced rapid growth in population and area from 1949 to 1975, stretching its resources thin and changing the character of the city. City boosters encouraged growth through the 1950s to safeguard Tempe’s borders against its larger neighbor, Phoenix. New residents moved to Tempe as it grew, expecting suburban amenities…

Tempe experienced rapid growth in population and area from 1949 to 1975, stretching its resources thin and changing the character of the city. City boosters encouraged growth through the 1950s to safeguard Tempe’s borders against its larger neighbor, Phoenix. New residents moved to Tempe as it grew, expecting suburban amenities that the former agricultural supply town struggled to pay for and provide. After initially balking at taking responsibility for development of a park system, Tempe established a Parks and Recreation Department in 1958 and used parks as a main component in an evolving strategy for responding to rapid suburban growth. Through the 1960s and 1970s, Tempe pursued an ambitious goal of siting one park in each square mile of the city, planning for neighborhood parks to be paired with elementary schools and placed at the center of each Tempe neighborhood. The highly-publicized plan created a framework, based on the familiarity of public park spaces, that helped both long-time residents and recent transplants understand the new city form and participate in a changing community identity. As growth accelerated and subdivisions surged southward into the productive agricultural area that had driven Tempe’s economy for decades, the School-Park Policy faltered as a planning and community-building tool. Residents and city leaders struggled to reconcile the loss of agricultural land with the carefully maintained cultural narrative that connected Tempe to its frontier past, ultimately broadening the role of parks to address the needs of a changing city.
ContributorsSweeney, Jennifer (Author) / Thompson, Victoria (Thesis advisor) / Gray, Susan (Committee member) / MacFadyen, Joshua (Committee member) / Smith, Jared (Committee member) / Arizona State University (Publisher)
Created2019
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Children of the Mother Road: Route 66, Regional Transformation, and Community Identity in Northwestern Arizona, 1882-1989

Description
This dissertation explores the role transportation infrastructure played in regional and community development in northwestern Arizona from 1882 to 1989. Transportation infrastructure undergirds the economic viability and development of most American regions and communities. In northwestern Arizona, following a process familiar throughout the American West, the initial construction of railroad…

This dissertation explores the role transportation infrastructure played in regional and community development in northwestern Arizona from 1882 to 1989. Transportation infrastructure undergirds the economic viability and development of most American regions and communities. In northwestern Arizona, following a process familiar throughout the American West, the initial construction of railroad transportation infrastructure fundamentally transformed the area from sparsely populated space to an industrialized region centered on railroad created townsites. Although critical to regional development and growth, U.S. Route 66 was added well after the initial railroad period. In total, regional transformation occurred in four phases: Railroad, Route 66, I-40, and post-bypass. For regional residents, Route 66 was the most important phase transforming railroad created spaces into functional communities. Yet, despite maturing as communities, each of these towns also struggled with the same racial and class divides as the larger nation. From the early railroad period, through WW2, tourism was present in the region, but an ancillary part of the economy focused on visiting environmental attractions like the Grand Canyon. After WW2, it became more important as regional industrialism faded and traffic levels rose on Route 66. However, as long as Route 66 remained a primary highway, tourism retained its focus on the environment. As much as the construction of transportation infrastructure provided initial access to the region and founded towns, the later regional highway and railroad bypasses cut-off many of these communities from the source of their economic livelihood. Regional towns lucky enough to be integrated into the new interstate highway system like Kingman profited and grew; towns bypassed by the interstate and railroad withered and were forced to reinvent themselves to survive. This post-bypass reinvention took the form of a non-environmental focused mythic tourism connected to an emerging national Route 66 nostalgia movement that envisioned the lost Route 66 as representative of a better, more authentic America. The association with the national Route 66 nostalgia myth successfully attracted tourists but came at the cost of regional communities losing a more realistic understanding of their past and becoming disassociated from their previous community identity.
ContributorsMilowski, Daniel (Author) / Jones, Christopher (Thesis advisor) / Lim, Julian (Committee member) / MacFadyen, Joshua (Committee member) / Arizona State University (Publisher)
Created2021