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- All Subjects: Nature
- Creators: Schmeeckle, Mark
- Creators: Smith, Andrew
Description
Ephemeral streams in Arizona that are perpendicularly intersected by the Central Arizona Project (CAP) canal have been altered due to partial or complete damming of the stream channel. The dammed upstream channels have experienced decades long cycles of sediment deposition and waterlogging during storm events causing the development of "green-up" zones. This dissertation examines the biogeomorphological effects of damming ephemeral streams caused by the CAP canal by investigating: (1) changes in the preexisting spatial cover of riparian vegetation and how these changes are affected by stream geometry; (2) green-up initiation and evolution; and (3) changes in plant species and community level changes. To the author's knowledge, this is the only study that undertakes an interdisciplinary approach to understanding the environmental responses to anthropogenically-altered ephemeral stream channels. The results presented herein show that vegetation along the upstream section increased by an average of 200,872 m2 per kilometer of the CAP canal over a 28 year period. Vegetation growth was compared to channel widths which share a quasi-linear relationship. Remote sensing analysis of Landsat TM images using an object-oriented approach shows that riparian vegetation cover gradually increased over 28 years. Field studies reveal that the increases in vegetation are attributed to the artificial rise in local base-level upstream created by the canal, which causes water to spill laterally onto the desert floor. Vegetation within the green-up zone varies considerably in comparison to pre-canal construction. Changes are most notable in vegetation community shifts and abundance. The wettest section of the green-up zone contains the greatest density of woody plant stems, the greatest vegetation volume, and a high percentage of herbaceous cover. Vegetation within wetter zones changed from a tree-shrub to a predominantly tree-herb assemblage, whereas desert shrubs located in zones with intermediate moisture have developed larger stems. Results from this study lend valuable insight to green-up processes associated with damming ephemeral streams, which can be applied to planning future canal or dam projects in drylands. Also, understanding the development of the green-up zones provide awareness to potentially avoiding flood damage to infrastructure that may be unknowingly constructed within the slow-growing green-up zone.
ContributorsHamdan, Abeer (Author) / Schmeeckle, Mark (Thesis advisor) / Myint, Soe (Thesis advisor) / Dorn, Ronald (Committee member) / Stromberg, Juliet (Committee member) / Arizona State University (Publisher)
Created2014
Description
Human endeavors move 7x more volume of earth than the world’s rivers accelerating the removal of Earth’s soil surface. Measuring anthropogenic acceleration of soil erosion requires knowledge of natural rates through the study of 10Be, but same-watershed comparisons between anthropogenically-accelerated and natural erosion rates do not exist for urbanizing watersheds. Here I show that urban sprawl from 1989 to 2013 accelerated soil erosion between 1.3x and 15x above natural rates for different urbanizing watersheds in the metropolitan Phoenix region, Sonoran Desert, USA, and that statistical modeling a century of urban sprawl indicates an acceleration of only 2.7x for the Phoenix region. Based on studies of urbanization’s erosive effects, and studies comparing other land-use changes to natural erosion rates, we expected a greater degree of urban acceleration. Given that continued urban expansion will add a new city of a million every five days until 2050, given the potential importance of urban soils for absorbing anthropogenically-released carbon, and given the role of urban-sourced pollution, quantifying urbanization’s acceleration of natural erosion in other urban settings could reveal important regional patterns. For example, a comparison of urban watersheds to nearby non-urban watersheds suggests that the Phoenix case study is on the low-end of the urban acceleration factor. This new insight into the urban acceleration of soil erosion in metropolitan Phoenix can help reduce the acute risk of flooding for many rapidly urbanizing desert cities around the globe. To reduce this risk, properly engineered Flood Control Structures must account for sediment accumulation as well as flood waters. While the Phoenix area used regional data from non-urban, non-desert watersheds to generate sediment yield rates, this research presents a new analysis of empirical data for the Phoenix metropolitan region, where two regression models provide estimates of a more realistic sediment accumulation for arid regions and also urbanization of a desert cities. The new model can be used to predict the realistic sediment accumulation for helping provide data where few data exists in parts of arid Africa, southwest Asia, and India.
ContributorsJeong, Ara (Author) / Dorn, Ronald I. (Thesis advisor) / Schmeeckle, Mark (Committee member) / Walker, Ian J. (Committee member) / Arizona State University (Publisher)
Created2019
Description
Spending time outdoors can have a positive impact on the physical and mental health of individuals. These physiological and psychological benefits were comprehensively reviewed, accompanied by a brief history of these views in American society and how modern programs are promoting outdoor activity. Some of the populations targeted in this research include children, veterans, the elderly, and the clinically ill. A guidebook for Arizona outdoor adventures \u2014 containing original landscape photography \u2014 was created to encourage ASU students to explore local hikes, campsites, and other outdoor opportunities near the city of Phoenix. Each entry contained a brief description of the area or trail, along with the distance from the ASU Tempe campus and information on the length and difficulty of the hike, if applicable. A section at the end of the book was aimed at education readers on basic outdoor survival protocol, as many people venture into the wild with very little understanding of the dangers associated with their activities. A website was made that mirrors the guidebook, but was intended to be a more accessible method of sharing our information. The final component of the project involved maintaining a social media account over the course of the year, allowing us to expand our reach to people beyond ASU and this community. Over the course of the project, the account gained a large following, and several posted photos went on to be featured on prominent regional accounts. By combining the four components described previously, several resources were created for people, particularly students attending ASU, to gain a better understanding of the outdoor adventures available to them, and the benefits that spending time surrounded by nature can have.
ContributorsSwitzer, Hannah (Co-author) / Weinstein, Casey (Co-author) / Smith, Andrew (Thesis director) / Lefler, Scott (Committee member) / Kozakiewicz, Scott (Committee member) / Harrington Bioengineering Program (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
With the overall health of the environment rapidly declining \u2014 mostly due to human behaviors, solving the problem of nature deficit disorder and getting more children interested and aware of nature could be paramount to improving the environmental health of our planet. In this study, the relationship between children's learning and emotion is explored. Pre- and post-tests were given to children attending a week-long summer freshwater ecology camp; their knowledge of and emotional connection to different ecological concepts were measured. Two separate ecosystems were tested \u2014 a freshwater ecosystem that was taught over the course of the week, and a marine ecosystem for comparison. Increases in knowledge and emotion were seen in every freshwater ecosystem concept. Additionally, the knowledge and emotion scores were correlated, suggesting a positive relationship between them. The marine ecosystem did not show improvements in concrete knowledge, but showed increases in abstract learning, indicating that the abstract concepts learned about the freshwater ecosystem were able to transfer to the marine. Overall results show the ability of a hands-on learning experience to foster an emotional connection between a child and the subject matter. However, long-term studies are needed to track the relationship between children and their knowledge of and emotional connection to the subject matter.
ContributorsMossler, Max Vaughn (Author) / Pearson, David (Thesis director) / Smith, Andrew (Committee member) / Berkowitz, Alan (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / School of Life Sciences (Contributor)
Created2013-05