Please read the abstract in the section 00front of this document / Dissertation (MSc)--University of Pretoria, 2007. / Geology / MSc / Unrestricted

Philosophiae Doctor - PhD / The need to ensure groundwater security is vital, particularly in urban areas. Assessing the impact of land use and climate variables on groundwater quality can help improve sustainable management. The vulnerability mapping of groundwater contamination identifies high-risk areas. Using models and technologies that forecast the distribution of contamination risk over time and place can help prioritize groundwater monitoring. Based on such needs, the Cape Flats aquifer in Cape Town, South Africa, was chosen as the case study for assessing the potential for groundwater contamination risk in urban and coastal hydrogeological settings. The Cape Flats aquifer has been highlighted as an alternate water supply source to augment current supply sources in Cape Town. However, the shallow aquifer is under pressure from agricultural and industrial activities and long-term climate variables, among other factors.

High incidences of slope movement are observed throughout Cuyahoga River watershed in northeast Ohio, USA. The major type of slope failure involves rotational movement in steep stream walls where erosion of the banks creates over-steepened slopes. The occurrence of landslides in the area depends on a complex interaction of natural as well as human induced factors, including: rock and soil strength, slope geometry, permeability, precipitation, presence of old landslides, proximity to streams and flood-prone areas, land use patterns, excavation of lower slopes and/or increasing the load on upper slopes, alteration of surface and subsurface drainage. These factors were used to evaluate the landslide-induced hazard in Cuyahoga River watershed using logistic regression analysis, and a landslide susceptibility map was produced in ArcGIS. The map classified land into four categories of landslide susceptibility: low, moderate, high, and very high. The susceptibility map was validated using known landslide locations within the watershed area. The landslide susceptibility map produced by the logistic regression model can be efficiently used to monitor potential landslide-related problems, and, in turn, can help to reduce hazards associated with landslides.

Community health centers (CHCs) provide comprehensive primary care regardless of a patient’s ability to pay. Key policies in the last decade facilitated development of new CHC delivery sites, but the extent of change in geographic access to CHCs (CHC accessibility) is understudied. Furthermore, existing research on CHC accessibility relies on antiquated methods for measuring CHC accessibility despite the growing use of contemporary accessibility methods to study access to other types of health services. We conducted three studies that examined CHC accessibility using contemporary accessibility methods and publicly available data from the Health Resources and Services Administration, American Community Survey, Area Health Resources File, and the 500 Cities Project. The first study assessed CHC accessibility at the census tract level in 2008 and 2016, before and after implementation of policies that expanded CHCs, using the two-step floating catchment area method. It then investigated the association between indicators of CHC need and changes in CHC accessibility. The second study examined the association between CHC accessibility and primary care utilization. The third study investigated differential change in CHC accessibility for census tracts in a subset of Medicaid expansion states compared to census tracts in a subset of non-expansion states. We found that CHC accessibility substantially increased between 2008 and 2016, that spatial distribution of increases in CHC accessibility was not uniform, and that the two-step floating catchment area method could be successfully applied to reveal small area variation in CHC accessibility changes across states. We also found that CHC accessibility was positively related to primary care utilization, but moderated by extent of primary care provider supply and median household income in the surrounding area. Finally, we found that census tracts in Medicaid expansion and non-expansion states saw similar increases in CHC accessibility from 2008 to 2016. In the current health policy context, where gains in health coverage from the Affordable Care Act are in jeopardy of being scaled back, CHC accessibility is critically important. The findings of this work support the important role of CHC accessibility in primary care utilization and describe how CHC accessibility has changed in the last decade. / 2020-10-23T00:00:00Z

Historians have long recognized the tendency of communities to embrace tourism when extractive practices like agriculture, mining, and ranching fail as a dominant economic strategy. Jackson Hole, Wyoming, is a prime example of this phenomenon in the American West. From its origins as a Mormon farming community in the late-nineteenth century, the valley evolved into an extensively developed tourist mecca by the end of the next. While this industry was initially supported by hotel-dwelling auto tourists, by the 1960s wealthy second-home buyers began to descend on Jackson Hole, buying up scenic property and constructing vacation homes. Over the next few decades these neo-natives moved to the valley by the hundreds, initiating dramatic economic, physical, and social consequences which were a direct product of the pace, pattern, and location of development. This thesis explores that relationship, making extensive use of Geographic Information Systems (GIS) to identify spatial themes of development in an effort to enlighten historical themes of Jackson Hole's rapidly changing landscape. On a basic level, this process presents a local history of tourist development in Jackson Hole between 1967 and 2002, documenting where development occurred and the consequences and controversy that resulted. Its greater contribution, however, is methodological. The use of GIS as a tool of historical research is still in its infancy, and this project suggests another application of the technique involving the spatial integration of historical and contemporary data. Together, these contributions create an informative and inventive examination of Jackson Hole tourism that expands the potential of historical research.

The main scope of this project is to rebuild and deploy web applications that will help share historical artifacts related to the Santa Ana watershed. This project is designed to give a consistent user interface and add extra tools to enhance the functionality of existing applications at the Water Resources Institute (WRI) at California State University San Bernardino (CSUSB). The purpose of this project is to migrate all applications to a single server and update the applications using ArcGIS Server 9.2. Also to give a consistent look to the applications and to make them user friendly.

The Agricultural Nonpoint Source model (AGNPS) is a single-event grid-based model used for simulating runoff, sediment and nutrients from agricultural areas. This study involved using geographic information system (GIS) spatial data and functionality to improve the spatial and temporal assignment of parameter values for the AGNPS 5.0 model and incorporated methods for representing urban fringe land uses and their nonpoint source (NPS) pollution contributions in model inputs. Auxiliary procedures for modeling with AGNPS were developed both for enhancing input into the model and for enhancing modeled output. On an event basis, one procedure automated the creation of complex-formatted AGNPS 5.0 model input files using GIS as a spatial data manager. One pair of alternative procedures were developed to automate the assignment of parameter values on an event basis. One procedure used typical average annual parameter values, and the second assigned parameter values using adaptations of existing time-dependent relationships. On a monthly basis, a sequencing procedure was created to perform multiple runs with the model for a list of storms while updating parameters for each event and aggregating monthly modeled spatial output. Another pair of alternative procedures were developed to facilitate the simulation of monthly output from AGNPS modeled events. The first of these aggregated event output for all storms in each month, while the second supplemented the aggregated output with baseflow and septic system loads. The study area was the 6,500 ha urbanizing Bull Run watershed in northern Virginia, which was modeled as 14,621 cells. Databases were assembled and 109 selected storm events within a 16-year period were modeled using the above procedures. Event data were added together, where necessary, to correspond with observed data from composite-sampled intervals. Output from the two event parameterization procedures were compared with monitored loads calculated for 89 composite periods, while output from the two monthly simulation procedures were compared with monthly monitored data for 23 complete months. The monitored-modeled comparisons were considered inconclusive. Evidence strongly suggested that the rainfall records from a rain gauge outside the watershed did not correspond well with monitored runoff. The average runoff produced with the AGNPS model from the 109 selected storms amounted to 40.7% of rainfall, consistent with the calculated long-term average of 38% for the Bull Run watershed. A nonpoint source pollution index was developed to utilize monthly modeled total nitrogen, total phosphorus, and suspended sediment. Individual rating curves were developed to separately transform loads and concentrations of each pollutant into sub-index values. The maximum sub-index from each parameter was added together and averaged for the index. The index was calculated at the watershed outlet from monitored data, and in a spatially-distributed fashion along all streams from simulated output. / Ph. D.

Indiana University-Purdue University Indianapolis (IUPUI) / Geographic technologies can be used to visualize and analyze data patterns that may go unnoticed from other approaches. The purpose of this project was to provide examples of how GIS and cartographic methods are being used to help facilitate communication and inform management processes for a complex statewide medical education system administered by the Indiana University School of Medicine, the largest medical school in the United States. The IU School of Medicine has nine regional campuses located around the state in addition to numerous partnering hospitals where medical students are trained. We illustrate geographic examples of various stages of medical student education from admissions, through campus assignments and clinical rotations, to residency training. These geographic processes are being used to inform reaccreditation processes as well as assisting administration with recruitment/retention strategies, statewide planning, and analysis in a complex medical education system.

Eurasian watermilfoil (Myriophyllum spicatum) habitat was predicted at multiple scales, including a lake, regional, and national level. This dissertation illustrates how habitat can be predicted for M. spicatum using publically-available data for both presence and environmental variables. Models were generated using statistical procedures and quantative methods to determine where the greatest likelihood of presence was located. For the single lake, presence and absence data were available, but the larger-scale models used presence-only methods of prediction. These models were paired with a Geographic Information System so that data could be visualized on a map. For the selected lake, Pend Oreille (Idaho), spatial analysis using general linear mixed models was used to show that depth and fetch could be used to predict habitat, although differences were seen in their importance between the littoral and pelagic zones. For the states of Minnesota and Wisconsin, Mahalanobis distance and maximum entropy methods were used to demonstrate that available habitat will not always mean presence of M. spicatum. The differing approaches to management in these states illustrated how an aggressive public education campaign can limit spread of M. spicatum, even when habitat is available. Bass habitat appeared to be the largest predictor of M. spicatum in Minnesota, although this was due to the similar environmental preferences by these species. Using maximum entropy, on a national level, presence of M. spicatum appeared to be best predicted by annual precipitation. Again, results showed that habitat is colonized as time permits, and not necessarily as conditions permit.

In this study Geographic Information System (GIS) technology was integrated with remote sensing techniques in order to determine the potential for nonpoint source pollution in the Lake Palestine and Cedar Creek Reservoir watersheds of North Central Texas. The Universal Soil Loss Equation was used to determine soil erosion potential from the watersheds, and export coefficients were used to estimate nutrient loadings into the reservoirs.