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Description
Woody plant encroachment is a worldwide phenomenon linked to water availability in semiarid systems. Nevertheless, the implications of woody plant encroachment on the hydrologic cycle are poorly understood, especially at the catchment scale. This study takes place in a pair of small semiarid rangeland undergoing the encroachment of Prosopis velutina

Woody plant encroachment is a worldwide phenomenon linked to water availability in semiarid systems. Nevertheless, the implications of woody plant encroachment on the hydrologic cycle are poorly understood, especially at the catchment scale. This study takes place in a pair of small semiarid rangeland undergoing the encroachment of Prosopis velutina Woot., or velvet mesquite tree. The similarly-sized basins are in close proximity, leading to equivalent meteorological and soil conditions. One basin was treated for mesquite in 1974, while the other represents the encroachment process. A sensor network was installed to measure ecohydrological states and fluxes, including precipitation, runoff, soil moisture and evapotranspiration. Observations from June 1, 2011 through September 30, 2012 are presented to describe the seasonality and spatial variability of ecohydrological conditions during the North American Monsoon (NAM). Runoff observations are linked to historical changes in runoff production in each watershed. Observations indicate that the mesquite-treated basin generates more runoff pulses and greater runoff volume for small rainfall events, while the mesquite-encroached basin generates more runoff volume for large rainfall events. A distributed hydrologic model is applied to both basins to investigate the runoff threshold processes experienced during the NAM. Vegetation in the two basins is classified into grass, mesquite, or bare soil using high-resolution imagery. Model predictions are used to investigate the vegetation controls on soil moisture, evapotranspiration, and runoff generation. The distributed model shows that grass and mesquite sites retain the highest levels of soil moisture. The model also captures the runoff generation differences between the two watersheds that have been observed over the past decade. Generally, grass sites in the mesquite-treated basin have less plant interception and evapotranspiration, leading to higher soil moisture that supports greater runoff for small rainfall events. For large rainfall events, the mesquite-encroached basin produces greater runoff due to its higher fraction of bare soil. The results of this study show that a distributed hydrologic model can be used to explain runoff threshold processes linked to woody plant encroachment at the catchment-scale and provides useful interpretations for rangeland management in semiarid areas.
ContributorsPierini, Nicole A (Author) / Vivoni, Enrique R (Thesis advisor) / Wang, Zhi-Hua (Committee member) / Mays, Larry W. (Committee member) / Arizona State University (Publisher)
Created2013
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Description
A fundamental gap in geomorphic scholarship regards fluvial terraces in small desert drainages and those terraces associated with integrating drainages. This dissertation analyzes four field-based case studies within the Sonoran Desert, south-central Arizona, with the overriding purpose of developing a theory to explain the formative processes and spatial distribution of

A fundamental gap in geomorphic scholarship regards fluvial terraces in small desert drainages and those terraces associated with integrating drainages. This dissertation analyzes four field-based case studies within the Sonoran Desert, south-central Arizona, with the overriding purpose of developing a theory to explain the formative processes and spatial distribution of fluvial terraces in the region. Strath terraces are a common form (Chapters 2, 3, 4) and are created at the expense of bounding pediments that occur on the margins of constraining mountainous drainage boundaries (Chapters 1, 2, 3). Base-level fluctuations of the major drainages cause the formation of new straths at lower elevations. Dramatic pediment adjustment and subsequent regrading follows (Chapter 3), where pediments regrade to strath floodplains. This linkage between pediments and their distal straths is termed the pediment-strath relationship. Stability of the base level of the major drainage leads to lateral migration and straths are carved at the expense of bounding pediments through an erosional asymmetry facilitated by differential rock decay between the channel bank and bed. Fill terraces occur within the Salt River drainage basin as a result of the integration processes that connect formerly endorheic basins (Chapter 4). The topographic, spatial, and sedimentologic relationship of the Stewart Mountain terrace (Chapter 4) points to a different genetic origin than the lower terraces in this basin. The high Stewart Mountain fill terrace records the initial integration of this river. The strath terraces inset below the Stewart Mountain terrace are a result of the pediment-strath relationship. These case studies also reveal that the under-addressed drainage processes of piracy and overflow have significant impacts in the evolution of drainages the lead to both strath and fill terrace formation in this region.
ContributorsLarson, Phillip Herman (Author) / Dorn, Ron I (Thesis advisor) / Schmeeckle, Mark (Thesis advisor) / Douglass, John (Committee member) / Cerveny, Randy (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Understanding agricultural land use requires the integration of natural factors, such as climate and nutrients, as well as human factors, such as agricultural intensification. Employing an agroecological framework, I use the Perry Mesa landscape, located in central Arizona, as a case study to explore the intersection of these factors to

Understanding agricultural land use requires the integration of natural factors, such as climate and nutrients, as well as human factors, such as agricultural intensification. Employing an agroecological framework, I use the Perry Mesa landscape, located in central Arizona, as a case study to explore the intersection of these factors to investigate prehistoric agriculture from A.D. 1275-1450. Ancient Perry Mesa farmers used a runoff agricultural strategy and constructed extensive alignments, or terraces, on gentle hillslopes to slow and capture nutrient rich surface runoff generated from intense rainfall. I investigate how the construction of agricultural terraces altered key parameters (water and nutrients) necessary for successful agriculture in this arid region. Building upon past work focused on agricultural terraces in general, I gathered empirical data pertaining to nutrient renewal and water retention from one ancient runoff field. I developed a long-term model of maize growth and soil nutrient dynamics parameterized using nutrient analyses of runoff collected from the sample prehistoric field. This model resulted in an estimate of ideal field use and fallow periods for maintaining long-term soil fertility under different climatic regimes. The results of the model were integrated with estimates of prehistoric population distribution and geographical characterizations of the arable lands to evaluate the places and periods when sufficient arable land was available for the type of cropping and fallowing systems suggested by the model (given the known climatic trends and land use requirements). Results indicate that not only do dry climatic periods put stress on crops due to reduced precipitation but that a reduction in expected runoff events results in a reduction in the amount of nutrient renewal due to fewer runoff events. This reduction lengthens estimated fallow cycles, and probably would have increased the amount of land necessary to maintain sustainable agricultural production. While the overall Perry Mesa area was not limited in terms of arable land, this analysis demonstrates the likely presence of arable land pressures in the immediate vicinity of some communities. Anthropological understandings of agricultural land use combined with ecological tools for investigating nutrient dynamics provides a comprehensive understanding of ancient land use in arid regions.
ContributorsKruse-Peeples, Melissa R (Author) / Spielmann, Katherine A. (Thesis advisor) / Abbott, David R. (Committee member) / Hall, Sharon J. (Committee member) / Kintigh, Keith W. (Committee member) / Arizona State University (Publisher)
Created2013
ContributorsChang, Ruihong (Performer) / ASU Library. Music Library (Publisher)
Created2018-03-29
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Description
Four Souvenirs for Violin and Piano was composed by Paul Schoenfeld (b.1947) in 1990 as a showpiece, spotlighting the virtuosity of both the violin and piano in equal measure. Each movement is a modern interpretation of a folk or popular genre, re- envisioned over intricate jazz harmonies and rhythms. The

Four Souvenirs for Violin and Piano was composed by Paul Schoenfeld (b.1947) in 1990 as a showpiece, spotlighting the virtuosity of both the violin and piano in equal measure. Each movement is a modern interpretation of a folk or popular genre, re- envisioned over intricate jazz harmonies and rhythms. The work was commissioned by violinist Lev Polyakin, who specifically requested some short pieces that could be performed in a local jazz establishment named Night Town in Cleveland, Ohio. The result is a work that is approximately fifteen minutes in length. Schoenfeld is a respected composer in the contemporary classical music community, whose Café Music (1986) for piano trio has recently become a staple of the standard chamber music repertoire. Many of his other works, however, remain in relative obscurity. It is the focus of this document to shed light on at least one other notable composition; Four Souvenirs for Violin and Piano. Among the topics to be discussed regarding this piece are a brief history behind the genesis of this composition, a structural summary of the entire work and each of its movements, and an appended practice guide based on interview and coaching sessions with the composer himself. With this project, I hope to provide a better understanding and appreciation of this work.
ContributorsJanczyk, Kristie Annette (Author) / Ryan, Russell (Thesis advisor) / Campbell, Andrew (Committee member) / Norton, Kay (Committee member) / Arizona State University (Publisher)
Created2015
ContributorsASU Library. Music Library (Publisher)
Created2018-02-23
ContributorsWhite, Aaron (Performer) / Kim, Olga (Performer) / Hammond, Marinne (Performer) / Shaner, Hayden (Performer) / Yoo, Katie (Performer) / Shoemake, Crista (Performer) / Gebe, Vladimir, 1987- (Performer) / Wills, Grace (Performer) / McKinch, Riley (Performer) / Freshmen Four (Performer) / ASU Library. Music Library (Publisher)
Created2018-04-27
ContributorsRosenfeld, Albor (Performer) / Pagano, Caio, 1940- (Performer) / ASU Library. Music Library (Publisher)
Created2018-10-03
ContributorsASU Library. Music Library (Publisher)
Created2018-10-04
ContributorsCao, Yuchen (Performer) / Chen, Sicong (Performer) / Soberano, Chino (Performer) / Nam, Michelle (Performer) / Collins, Clarice (Performer) / Witt, Juliana (Performer) / Liu, Jingting (Performer) / Chen, Neilson (Performer) / Zhang, Aihua (Performer) / Jiang, Zhou (Performer) / ASU Library. Music Library (Publisher)
Created2018-04-25