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The Study of Temporal and Spatial Variability of Degree Day Factor of Snowmelt in Colorado (open access)

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

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 …
Date: May 2016
Creator: Pokhrel, Pranav
System: The UNT Digital Library
Zooarchaeology and Biogeography of Freshwater Mussels in the Leon River During the Late Holocene (open access)

Zooarchaeology and Biogeography of Freshwater Mussels in the Leon River During the Late Holocene

The Leon River, a small-medium river in central Texas, is highly impacted by multiple impoundments, enrichment from agricultural runoff, and decreased dissolved oxygen levels. This degraded river contains sixteen unionid species, two of which are both endemic to the region and candidates for the federal endangered species listing (Quadrula houstonensis and Truncilla macrodon). While there is a short historical record for this river basin and a recent modern survey completed in 2011, zooarchaeological data adds evidence for conservation efforts by increasing the time depth of data available and providing another conservation baseline. Zooarchaeological data for the Leon River is available from the two Late Holocene archaeological sites: 41HM61 and the Belton Lake Assemblages. Data generated from these assemblages describe the prehistoric freshwater mussel community of the Leon River in terms of taxonomic composition and structure. By comparing this zooarchaeological data to the data generated by the longitudinal modern survey of the Leon River, long term changes within the freshwater mussel community can be detected. A conceptual model is constructed to evaluate how robusticity, identifiability, and life history ecology affect unionid taxonomic abundances in zooarchaeological data. This conceptual model functions as an interpretive tool for zooarchaeologists to evaluate forms of equifinality …
Date: May 2015
Creator: Popejoy, Traci Glyn
System: The UNT Digital Library
Assessing the Role of Smaller Format Retailers on the Food Desert Landscape in Dallas, Texas (open access)

Assessing the Role of Smaller Format Retailers on the Food Desert Landscape in Dallas, Texas

Many policy and business decisions regarding food deserts in the U.S. are based on the United States Department of Agriculture (USDA) definition of a food desert. This definition only includes large/national chain grocery retailers, based on the assumption that these major retailers are the only affordable sources of food contributing to balanced diets. As alternative distribution channels, including smaller stores, start to include groceries in their product offering, the need to consider the role of other businesses in the food retailing environment should be addressed. This thesis assesses the role of smaller format grocery retailers (small local grocers, convenience stores, gas stations, dollar stores, and drug stores) in shaping the food desert landscape in Dallas, Texas. The analysis evaluates the products offered in these stores, and then identifies the difference these stores make when included in the USDA analysis. This was done by collecting in-store data to determine the variety of products offered, the affordability of those products, and the overall healthfulness of the store. In addition, the gaps in supply and demand were identified in the USDA-defined food deserts in order to identify the impact any smaller format retailer may have. The findings suggest that, overall, smaller format retailers …
Date: May 2013
Creator: Regan, Amanda D.
System: The UNT Digital Library
The Landscape Legacies of Gas Drilling in North Texas (open access)

The Landscape Legacies of Gas Drilling in North Texas

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?
Date: May 2016
Creator: Sakinejad, Michael Cyrus
System: The UNT Digital Library
An Analysis of UNT Commuting Patterns (open access)

An Analysis of UNT Commuting Patterns

Academic institutions have recently organized to address their campus' greenhouse gas emissions. Along those lines, the University of North Texas (UNT) pledged to minimize the campus' environmental impact, and conducted a transportation survey in May 2009. The analyses confirm that commuting to campus was the second highest source (29%) of UNT's greenhouse gas emissions, following purchased electricity (48%). Students, faculty and staff drive over 89 million miles per year, 84% of which comes from students. Forty‐two percent of student driving trips originate in the primary and secondary core areas surrounding Denton, which are partially served by buses. However, because these core areas are in close proximity to the campus, they contribute only 8% of the total student driving distance. Beyond the Denton core, the inner periphery of Denton County contributes another 22% of driving mileage. Students living in the outer periphery (outside Denton County) contribute the remaining 70% of total driving distance, and carpooling is currently their only alternative.
Date: May 2010
Creator: Waskey, Susan L.
System: The UNT Digital Library
Geoarchaeological Analysis of Two New Test Pits at the Dmanisi Site, Republic of Georgia (open access)

Geoarchaeological Analysis of Two New Test Pits at the Dmanisi Site, Republic of Georgia

This thesis presents the results of geoarchaeological investigations conducted at two new test pits, M11 and M12, at the paleoanthropological site of Dmanisi during the 2012 field season. This research is important for understanding the site formation processes occurring along the north-south axis of the Dmanisi site and how that affects the chronostratigraphic sequence and interpretation of archaeological materials here. With these excavations we can build a stronger interpretation for how broader areas of this site formed and changed both geologically and archaeologically. The geologic results of this study indicate that changes in sediment deposition and development episodes can affect interpretations of how long these sediments accumulated, how likely bones are to preserve, as well as how secondary gravel deposition can influence several archaeological interpretations. The archaeological results suggest that there could have been changes in occupation intensity between the stratum A and B phases although different rates of sediment deposition and surface stability could affect such artifact accumulations. In addition, during the stratum B phase there appears to be little change in artifact procurement behaviors and reduction characteristics by these hominins. The overall results of this research indicate that geologic factors should be addressed and cautions should be taken …
Date: May 2013
Creator: Zack, Winston S.
System: The UNT Digital Library