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  Partner: UNT Libraries
 Department: Department of Geography
 Collection: UNT Theses and Dissertations
Hurricane Storm Surge Sedimentation on the McFaddin National Wildlife Refuge, Texas: Implications for Coastal Marsh Aggradation

Hurricane Storm Surge Sedimentation on the McFaddin National Wildlife Refuge, Texas: Implications for Coastal Marsh Aggradation

Date: 2016-5
Creator: Hodge, Joshua Brian
Description: This study uses the storm surge sediment beds deposited by Hurricanes Audrey (1957), Carla (1961), Rita (2005) and Ike (2008) to investigate spatial and temporal changes in sedimentation rates on the McFaddin National Wildlife Refuge in Southeast Texas. Fourteen sediment cores were collected along a transect extending from 90 to 1230 meters inland from the Gulf Coast. Storm-surge-deposited sediment beds were identified by texture, organic content, carbonate content, the presence of marine microfossils, and Cesium-137 dating. The hurricane-derived sediment beds are marker horizons that facilitate assessment of marsh sedimentation rates from nearshore to inland locations as well as over decadal to annual timescales. Near the shore, on a Hurricane Ike washover fan, where hurricane-derived sedimentation has increased elevation by up to 0.68 m since 2005, there was no measurable marsh sedimentation in the period 2008-2014. Farther inland, at lower elevations, sedimentation for the period 2008-2014 averaged 0.36 cm per year. The reduction in sedimentation in the period 2008-2014 on the nearshore part of the marsh is likely due to reduced flooding in response to increased elevation from hurricane storm surge sediment deposition. These results provide valuable knowledge about the sedimentary response of coastal marshes subject to storm surge deposition and ...
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The Landscape Legacies of Gas Drilling in North Texas

The Landscape Legacies of Gas Drilling in North Texas

Date: 2016-5
Creator: Sakinejad, Michael C
Description: In North Texas, the Barnett Shale underlies large areas of the Dallas-Fort Worth Metroplex (DFW), which magnifies debates about the externalities of shale gas development (SGD). Continued demand for natural gas and expansive urbanization in DFW will cause more people to come in contact with drilling rigs, gas transport, and other urban shale gas landscapes. Thousands of gas wells within the DFW region occupy a large, yet scattered land surface area. DFW city planners, elected officials, and other stakeholders must deal with current and future urban growth and the surface impacts that are associated with gas development. This research examines how shale gas landscapes affect urban land uses, landscapes, and patterns of development in DFW. The study focuses on multiple fast growing DFW municipalities that also have high numbers of gas well pad sites. This study asks what are the spatial characteristics of gas well production sites in DFW and how do these sites vary across the region; how do gas well production sites affect urban growth and development; and how are city governments and surface developers responding to gas well production sites, and what are the dominant themes of contestation arising around gas well production sites and suburban growth?
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A New Lacunarity Analysis Add-In for ArcGIS

A New Lacunarity Analysis Add-In for ArcGIS

Date: 2016-5
Creator: Huang, Pu
Description: This thesis introduces a new lacunarity analysis add-in for ArcGIS
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The Study of Temporal and Spatial Variability of Degree Day Factor of Snowmelt in Colorado

The Study of Temporal and Spatial Variability of Degree Day Factor of Snowmelt in Colorado

Date: 2016-5
Creator: Pokhrel, Pranav
Description: Snowmelt is one of the major sources of surface water supply and ground-water recharge in high elevation areas and can also cause flooding in snow dominated watersheds. Direct estimation of daily snowmelt requires daily snow water equivalent (SWE) measurements that are not always available, especially in places without monitoring stations. There are two alternative approaches to modeling snowmelt without using direct measurements of SWE, temperature-based and energy-based models. Due to its simplicity, computational efficiency, and less input data requirement, the temperature-based method is commonly used than the energy-based method. In the temperature-index approach snowmelt is estimated as a linear function of average air temperature, and the slope of the linear function is called the degree-day factor (DDF). Hence, the DDF is an essential parameter for utilizing the temperature-based method to estimate snowmelt. Thereby, to analyze the spatial properties of DDF, 10 years DDF from the entire state of Colorado was calculated for this research. Likewise, to study the temporal properties, DDFs for 27 years from the White Yampa water basin and the Colorado Headwaters water basin were calculated. As a part of the spatial analysis, the calculated DDFs were correlated with spatial variables (slope, aspect, latitude and elevation) and a ...
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Decoding the Formation of a Retail Giant: the Evolving Geography of Costco’s Store Network

Decoding the Formation of a Retail Giant: the Evolving Geography of Costco’s Store Network

Date: December 2015
Creator: Testa, Peter
Description: Although Costco operates over 580 warehouse stores throughout North America, their location strategy remains relatively unexamined in the economic geography literature. A cursory examination of Costco’s network makes it clear that the firm chooses to locate primarily in the suburbs of major cities, where income levels are somewhat higher than the national average. However, what is not clear is the extent to which other demographic and geographic factors adequately account for Costco’s store locations, and what strategy underlies the geography of the firm’s warehouse stores, especially in relation to its distribution network. This research studies Costco in order to decode the location strategies that have guided the company’s North American and international expansions. The investigation attempts to identify key elements of Costco’s multinational retail network, including this network’s evolution over time. This paper seeks to benefit both retail business and public policymakers by highlighting elements of Costco’s location strategy that have contributed to the firm’s success.
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The Influence of Local Forage Variability on White-tailed Deer (Odocoileus Virginianus) Body Size at Fort Hood, Texas

The Influence of Local Forage Variability on White-tailed Deer (Odocoileus Virginianus) Body Size at Fort Hood, Texas

Date: December 2015
Creator: Eddins, Amy C.
Description: Nutritional quality and availability is thought to regulate geographic patterns of variability in animal body size due to phenotypic plasticity. The purpose of this study is to determine how vegetation quality, abundance and population density influence white-tailed deer (Odocoileus virginianus) body size on a subregional spatial scale at Fort Hood, Texas. Harvest and census records are used to test the hypothesis that white-tailed deer exhibit phenotypic plasticity (e.g. larger body size) in response to differences in vegetation quality and availability. Results from these analyses suggest that forage quality and abundance alone is not a main driver of white-tailed deer body size. Analysis of deer population density (generally) resulted in an inverse relationship with body size. Areas with high quality forage and low population density support larger deer while areas with low quality forage and high density support smaller than average deer. The few exceptions occur in areas exhibiting poor quality forage and low population density or high forage quality and high density. Results from this study suggest that continued overcrowding of deer within isolated areas may eventually lead to efficiency phenotypic conditions producing smaller sized deer. These results could prove useful in interpreting deer population responses to harvest management. For ...
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Influence of the Choice of Disease Mapping Method on Population Characteristics in Areas of High Disease Burdens

Influence of the Choice of Disease Mapping Method on Population Characteristics in Areas of High Disease Burdens

Date: December 2015
Creator: Desai, Khyati Sanket
Description: Disease maps are powerful tools for depicting spatial variations in disease risk and its underlying drivers. However, producing effective disease maps requires careful consideration of the statistical and spatial properties of the disease data. In fact, the choice of mapping method influences the resulting spatial pattern of the disease, as well as the understanding of its underlying population characteristics. New developments in mapping methods and software in addition to continuing improvements in data quality and quantity are requiring map-makers to make a multitude of decisions before a map of disease burdens can be created. The impact of such decisions on a map, including the choice of appropriate mapping method, not been addressed adequately in the literature. This research demonstrates how choice of mapping method and associated parameters influence the spatial pattern of disease. We use four different disease-mapping methods – unsmoothed choropleth maps, smoothed choropleth maps produced using the headbanging method, smoothed kernel density maps, and smoothed choropleth maps produced using spatial empirical Bayes methods and 5-years of zip code level HIV incidence (2007- 2011) data from Dallas and Tarrant Counties, Texas. For each map, the leading population characteristics and their relative importance with regards to HIV incidence is identified ...
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Small Town Retail Change in East Texas: an Analysis of Retail Growth, Decline, and Spatial Reconfiguration

Small Town Retail Change in East Texas: an Analysis of Retail Growth, Decline, and Spatial Reconfiguration

Date: December 2015
Creator: Whitaker, Carl W.
Description: In recent years, small towns have experienced declining levels of retail activity attributable to a variety of factors. Previously conducted research identifies a number of these factors such as changing population dynamics, continuously evolving retail practices, locational factors, and an assortment of other macroeconomic factors. Although retail decline is common for many small towns, there are some small towns that have been able to maintain their viability in an ever-changing economic climate. The primary purpose of this research is to better understand what spatial and socio-economic characteristics contribute to retail growth and decline in a series of small towns. This research highlights a selection of small towns across a 14 county area within east Texas. The selection of small towns includes a number of towns with an increasing number of retail establishments as well as a number of towns with decreasing retail establishments over the 14 year study timeframe. Contained within this research is a discussion of small town economic and retail development, as well as findings regarding spatial and socio-economic characteristics as they relate to retail growth and decline in small towns. This research finds that locational characteristics do have an effect on retail growth and decline. The research ...
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Archaeological Site Vulnerability Modeling for Cultural Resources Management Based on Historic Aerial Photogrammetry and Lidar

Archaeological Site Vulnerability Modeling for Cultural Resources Management Based on Historic Aerial Photogrammetry and Lidar

Date: August 2015
Creator: Helton, Erin King
Description: GIS has been utilized in cultural resources management for decades, yet its application has been largely isolated to predicting the occurrence of archaeological sites. Federal and State agencies are required to protect archaeological sites that are discovered on their lands, but their resources and personnel are very limited. A new methodology is evaluated that uses modern light detection and ranging (LiDAR) and historic aerial photogrammetry to create digital terrain models (DTMs) capable of identifying sites that are most at risk of damage from changes in terrain. Results revealed that photogrammetric modeling of historic aerial imagery, with limitations, can be a useful decision making tool for cultural resources managers to prioritize conservation and monitoring efforts. An attempt to identify key environmental factors that would be indicative of future topographic changes did not reveal conclusive results. However, the methodology proposed has the potential to add an affordable temporal dimension to future digital terrain modeling and land management. Furthermore, the methods have global applicability because they can be utilized in any region with an arid environment.
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Efficiency of Nitrate and Phosphorus Removal in a Working Rain Garden

Efficiency of Nitrate and Phosphorus Removal in a Working Rain Garden

Date: August 2015
Creator: Strong, Patrick
Description: Rain gardens are low impact developments designed to mitigate a suite of issues associated with urban stormwater runoff. The site for this study was a Denton City rain garden at the Denton Waste Water Treatment Plant. Nitrogen and phosphorus removal was examined in light of two overflow events comprised of partially treated wastewater from an upslope anaerobic digester pond. Nitrate removal efficiency was examined across differing dry spell intervals of 5, 8, and 12 d, displaying a moderate negative correlation (r2 = 0.59). Continued phosphorus removal capacity was assessed, showing phosphorus removal in cases where P was in excess of 0.8 mg/L, reflecting an equilibrium phosphorus concentration. A high expanded shale component in the soil media (25%) was likely a factor in the continued removal of phosphorus. Overall the rain garden proved to be a large source of nitrate (+425%) and total nitrogen (+61%) by mass. The study showed that while the rain garden intercepted a large volume of partially treated wastewater during the overflow events, preventing it from reaching a nearby creek, the mitigation of an acute event has extended to a chronic one as nitrogen is gradually processed and flushed from the system as nitrate.
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