The United States has the highest teen birth rate among western industrialized countries and the highest levels of pregnancy among adolescents (Alan Guttmacher Institute, 1994). While the rate of teen births is high throughout the country, considerable variations exist between and within regions. Texas is one of the 5 leading states with the highest teen birth rates to mothers less than 18 years of age. This research provides a detailed analysis of births to mothers aged between 10 and 19 years in North Central Texas counties. Due to the modifiable area unit problem and to provide a finer geographical scale of analysis, teen births in Dallas County zip codes were examined as a special case study. Statistical and Geographic Information System (GIS) analysis reveal that race/ethnicity, education and income are significant factors in teen births in the region. Single parent households and receipt of public assistance were not statistically significant. Suggestions for reducing vulnerability to teen births are presented.

Retail geography is a field of study that is growing in significance and importance within the academic, business, economic, and governmental realms. This study's main focus is on the changing retail environment with regards to business location and function within a small Midwestern city. The research focuses on Port Huron, Michigan because of the growth and shift of the retail community within the city over the past twenty years. The study specifically examines the changing influence and roles of Port Huron's central business district and of Birchwood Mall a retail development opened on the urban area's north end in 1990. The study uses the chi-squared, ANOVA, and cross tabulation statistical tests to analyze the changing geography of retail functions in the city. These statistics are used along with relative entropy equations to distinguish areas of high diversification, changing area functions, and common locations for multiple retail types.

Archaeologically site catchment analysis produces valuable information regarding prehistoric subsistence strategies and social organization. Incorporating archaeological data into catchment analyses is an effective strategy to develop regional models of prehistoric site selection and settlement patterns. Digital access to data permits the incorporation of multiple layers of information into the process of synthesizing regional archaeology and interpreting corresponding spatial patterning. GIS software provides a means to integrate digital environmental and archaeological data into an effective tool. Resultant environmental archaeology maps facilitate interpretive analysis. To fulfill the objectives of this thesis, GIS software is employed to construct site catchment areas for archaeological sites and to implement multivariate statistical analyses of physical and biological attributes of catchments in correlation with assemblage data from sites. Guided by ecological, anthropological and geographical theories hypotheses testing evaluates patterns of prehistoric socio-economic behavior. Analytical results are summarized in a model of prehistoric settlement patterns in North Central Texas.

Jamaica has an abundance of freshwater resources, however, a lack of infrastructure makes treated, piped water inaccessible in many areas. Through literature reviews and site visits, this thesis is an analysis of how the people and land, and money and policy, interact with one another in relation to Jamaica's freshwater resources and water infrastructure. Special attention is given to the island's type-example Cockpit karst geology; tourism, mining, and farming's relation to this karst; types of water delivery systems in rural southern Trelawny's Cockpit Country; southern Trelawny residents' perceptions of the water situation; and policy and development goals in the context of Jamaica and southern Trelawny. I hope to bring attention to the unique social, geologic, and developmental context of water in Jamaica, and more specifically to garner attention for major water infrastructure improvements in south Trelawny. A number of recommendations for improvements with policy and infrastructure are made.

This research project concerns changes in hydrology resulting from urbanization of the upper sub-basin of the White Rock Creek Watershed in Collin and Dallas Counties, Texas. The objectives of this study are: to calculate the percent watershed urbanized for the period of 1961 through 1968 and the period of 2000 through 2005; to derive a 1960s average unit hydrograph and a 2000s average unit hydrograph; and, to use the two averaged hydrographs to develop a range of hypothetical storm scenarios to evaluate how the storm response of the watershed has changed between these two periods. Results of this study show that stormflow occurs under lower intensity precipitation in the post-urbanized period and that stormflow peaks and volumes are substantially larger compared to the pre-urbanized period. It is concluded that changes in watershed surface conditions resulting from urbanization have lowered the precipitation-intensity threshold that must be surpassed before storm run-off is generated.

Integrating decision analytical techniques in geographic information systems (GIS) can help remove the two primary obstacles in spatial decision making: inaccessibility to required geographic data and difficulties in synthesizing various criteria. I developed a GIS model to assist people seeking optimal residential locations. Fuzzy set theory was used to codify criteria for each factor used in evaluating residential locations, and weighted linear combination (WLC) was employed to simulate users' preferences in decision making. Three examples were used to demonstrate the applications in the study area. The results from the examples were analyzed. The model and the ArcGIS Extension can be used in other geographic areas for residential location selection, or in other applications of spatial decision making.

This thesis is a contribution to the work of the Texas Environmental Observatory (TEO), which provides environmental information from the Greenbelt Corridor (GBC) of the Elm Fork of the Trinity River. The motivation of this research is to analyze the short-term water dynamic of soil in response to the substantial rainfall events that occurred in North Texas in 2007. Data collected during that year by a TEO soil and weather station located at the GBC includes precipitation, and soil moisture levels at various depths. In addition to these field measurements there is soil texture data obtained from lab experiments. By comparing existing water dynamic models, water balance equations were selected for the study as they reflect the water movement of the soil without complicated interrelation between parameters. Estimations of water flow between soil layers, infiltration rate, runoff, evapotranspiration, water potential, hydraulic conductivity, and field capacity are all obtained by direct and indirect methods. The response of the soil at field scale to rainfall event is interpreted in form of flow and change of soil moisture at each layer. Additionally, the analysis demonstrates that the accuracy of soil characteristic measurement is the main factor that effect physical description. Suggestions for model …

Population estimation in inter-censual years has many important applications. In this research, high-resolution pan-sharpened IKONOS image, LiDAR data, and parcel data are used to estimate small-area population in the eastern part of the city of Denton, Texas. Residential buildings are extracted through object-based classification techniques supported by shape indices and spectral signatures. Three population indicators -building count, building volume and building area at block level are derived using spatial joining and zonal statistics in GIS. Linear regression and geographically weighted regression (GWR) models generated using the three variables and the census data are used to estimate population at the census block level. The maximum total estimation accuracy that can be attained by the models is 94.21%. Accuracy assessments suggest that the GWR models outperformed linear regression models due to their better handling of spatial heterogeneity. Models generated from building volume and area gave better results. The models have lower accuracy in both densely populated census blocks and sparsely populated census blocks, which could be partly attributed to the lower accuracy of the LiDAR data used.

The purpose of this study was to determine the effects of attendance at a senior center on the well being and quality of life of grandparents that were rearing grandchildren. Using convenience sampling, grandparents (N=130) who were rearing grandchildren were given a self administered demographic data survey along with an attendance at a senior center questionnaire, the Quality of Life Scale, the Well Being Scale by Liang, the UCLA Loneliness Scale, the Caregiver Burden Scale, and the Role Satisfaction Scale. An initial MANOVA (F 7, 69 = 2.72, p < .01) suggesting that senior center attendance affect the measures as a set was conducted and then a series of one way ANOVAs were carried out to test the hypothesis that attending a senior center has an effect on the dependent variables: well being, quality of life, role satisfaction, caregiver burden, loneliness, current health, and heath one year ago. Subsequently, a hierarchical regression analysis was conducted to find out whether frequency and quality of attendance of a senior center predicted quality of life, caregiver burden, well being, loneliness, and role satisfaction, controlling for the demographic data. The results of the MANOVA showed that the dependent variables: quality of life, caregiver burden, …

Geographic information systems and remote sensing software were used to analyze data to determine the area and volume of the proposed Fastrill Reservoir, and to examine seven alternatives. The controversial reservoir site is in the same location as a nascent wildlife refuge. Six general land cover types impacted by the reservoir were also quantified using Landsat imagery. The study found that water consumption in Dallas is high, but if consumption rates are reduced to that of similar Texas cities, the reservoir is likely unnecessary. The reservoir and its alternatives were modeled in a GIS by selecting sites and intersecting horizontal water surfaces with terrain data to create a series of reservoir footprints and volumetric measurements. These were then compared with a classified satellite imagery to quantify land cover types. The reservoir impacted the most ecologically sensitive land cover type the most. Only one alternative site appeared slightly less environmentally damaging.

Forest encroachment is understood to be the main reason for prairie grassland decline across the United States. In Texas and Oklahoma, juniper has been highlighted as particularly opportunistic. This study assesses the usefulness of three remote sensing techniques to aid in locating the areas of juniper encroachment for the LBJ Grasslands in Decatur, Texas. An object based classification was performed in eCognition and final accuracy assessments placed the overall accuracy at 94%, a significant improvement over traditional pixel based methods. Image biomass was estimated using normalized difference vegetation index (NDVI) for 1 meter resolution IKONOS winter images. A high correlation between the sum of NDVI for tree objects and field tree biomass was determined where R = 0.72, suggesting NDVI sum of a tree area is plausible. However, issues with NDVI saturation and regression produced unrealistically high biomass estimates for large NDVI. Canopy height model (CHM) derived from 3-5m LiDAR data did not perform as well. LiDAR typically used for digital elevation model (DEM) production was acquired for the CHM and produced correlations of R = 0.26. This suggests an inability for this particular dataset to identify juniper trees. When points that registered a tree height where correlated with field …

Rapid Bioassessment Protocols integrate a suite of community, population, and functional metrics, determined from the collection of benthic macroinvertebrates or fish, into a single assessment. This study was conducted in Dallas County Texas, an area located in the blackland prairie eco-region that is semi-arid and densely populated. The objectives of this research were to identify reference streams and propose a set of metrics that are best able to discriminate between differences in community structure due to natural variability from those caused by changes in water quality due to watershed impacts. Using geographic information systems, a total of nine watersheds, each representing a different mix of land uses, were chosen for evaluation. A total of 30 metrics commonly used in RBP protocols were calculated. Efficacy of these metrics to distinguish change was determined using several statistical techniques. Ten metrics were used to classify study area watersheds according to stream quality. Many trends, such as taxa presence along habitat quality gradients, were observed. These gradients coincided with expected responses of stream communities to landscape and habitat variables.

This study is a test of a methodology to predict changes in elevation and shoreline position of coastal wetlands in Trinity Bay, Texas, in response to projected sea level rise. The study combines numerical modeling and a geographic information system. A smoothing technique is used on a United States Geographical Survey (USGS) digital elevation model to obtain elevation profiles that more accurately represent the gently sloping wetlands surface. The numerical model estimates the expected elevation change by raster cell based on input parameters of predicted sea level rise, mineral and organic sedimentation rates, and sediment autocompaction rates. A GIS is used to display predicted elevation changes and changes in shoreline position as a result of four projected sea level rise scenarios over the next 100 years. Results demonstrate that this numerical model and methodology are promising as a technique of modeling predicted elevation change and shoreline migration in wetlands. The approach has potential utility in coastal management applications.

Assessing the impact of climate variability on water resources is one of the difficult tasks in planning the future growth of North-Central Texas. This study defined twelve extreme climate scenarios. Data from each scenario was input to a hydrological model (HEC-HMS) to calculate watershed runoff to Lake Ray Roberts. Model parameters are determined using Geographic Information System (GIS). The water balance was calculated for current and future water demand and resulting change in the volume and level of this reservoir. The results indicate certain climate scenarios decrease in volume. Thus, local governments should plan alternative water management strategies during droughts.