Masters Degrees (Geography)
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Browsing Masters Degrees (Geography) by Author "Barker, C. H."
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Item Open Access Aspekte rakende die ruimtelike ekologie van die rooijakkals (Canis mesomelas) as probleemdier in die Suid-Vrystaat(University of the Free State, 2010) Deacon, Francois; Barker, C. H.English: According to the Red Meat Producers’ Organisation, damage-causing predators annually catch small stock to a value of approximately R1,1 billion in South Africa. On most of the small stock farms in the Southern Free State, black-backed jackals, Canis mesomelas, are shot on sight and actively hunted to provide a safe environment for domesticated animals. The veld and habitats previously occupied by natural prey for these carnivores are now used for commercial farming practices. Carnivores are conserved in established formal protection and conservation areas within the ecosystem to lessen their contact with small stock. In South Africa the black-backed jackal successfully adapts to this farming environment with visible adaptation patterns. These behavioural patterns are influenced by the circumstances of the animal and variables within its environment. In the study area these fixed patterns of the black-backed jackal presumably annually repeat itself. This study researched these behavioural patterns of the jackal. For the first time, geographic information systems (GIS) are used in the research of the black-backed jackal. Since 2006, black-backed jackal regional data (of all jackals killed during hunting operations) was collected in a high depredation area in the Southern Free State. Data points collected from 1927 to 2009 were accordingly entered on electronic charts in ArcView. The total number of data points were obtained from 433 black-backed jackals killed, with the localities of 344 charted. The data is grouped into four sets: the first set, collected over 26 years, 1927 to 1953, consisted of 15 black-backed jackals; the second set, collected over 5 years, 1993 to 1997, consisted of 124 black-backed jackals; the third set, collected from 1999 to 2008, 10 years, consisted of 210 black-backed jackals; and the fourth set, from 2006 to 2009, four years, had a total of 84 black-backed jackals. Therefore, the number of black-backed jackals killed significantly increased, from 15 killed the first 26 years, to 418 over the last 16 years, within the same specific area. The increase in numbers of black-backed jackals removed from the area is used as indication of the increase in damage over the years in the study area. The average mass of 68 males, killed between 1993 and 1997, was 7.15kg and 63 females, 6.72kg. According to the 35 farmers in this specific area of the Southern Free State, the jackal problem is at present more under control than 30 years ago, which also applies to some other parts of the Southern Free State and South Africa. The reason for this can be ascribed to a better understanding of the animals and planning of hunting expeditions. In the late 1980’s, the average loss per farmer was ± 200 sheep per annum. At present, about 40 sheep on average are lost per farmer. The aim of this study is to further alleviate the damage-causing problem in the study area by making accurate predictions and planning to decrease losses. In the study area, peak losses are noted annually from August to October and March to May. The black-backed jackals mainly follow certain fixed movement patterns in the study area and breeding pairs seemingly react to the same stimuli from their direct environment. The same dens are repeatedly used and there is a clear relationship between the location of the dens and human activities. When a breeding pair is removed from an area, a new breeding pair will soon establish there. The processing of historic data leads to predictions on where the black-backed jackals will establish, where they will breed and where they will probably cause damage. It also predicts where they can probably be caught. This study shows a strong correlation between the physical nature of the environment and the black-backed jackals.Item Open Access An assessment of a technique to derive stream longitudinal profiles: a GIS approach(University of the Free State, 2012-05) Moolman, Juanita; Barker, C. H.English: The South African Water Act (Act 36 of 1998) (NWA, 1998) requires the calculation of the amount of water required for ecological sustainability in aquatic systems. Part of this process is the classification of slopes according to geomorphological class, which in turn requires, inter alia, the derivation of river longitudinal profiles from which to calculate these slopes. This has prompted the need to develop a method for obtaining these slopes that is fast and repeatable, and can be applied at both a national as well as sub-catchment level. Input data sets are required that are consistently available at a national as well as a sub-catchment level. This study will assess the results of using a semi-automated GIS procedure to derive longitudinal river profiles and slopes, based on nationally available data sets, in a test catchment. In recent years the use of Digital Elevation Models (DEMs) is replacing contour lines on topographic map sheets as the source of elevation inputs required to construct longitudinal profiles. The main question put forward is: can river longitudinal profiles and slopes generated from a DEM and based on 1:500 000 mapped river lines adjusted to within 50m of 1:50 000 mapped river lines, be used as effectively as river longitudinal profiles extracted from 1:50 000 mapped contours and based on 1:50 000 mapped rivers lines? Primary catchment X, situated in eastern South Africa, is used as the test area for this study. River channels in this catchment represent a range of slopes, from steep mountains streams to flat lowland rivers. The assessment is undertaken on 109 rivers identified at 1:500 000 scale in primary catchment X. These river lines are based on those originally scanned and vectorised from 1:500 000 topographic map sheets. These lines are available at a national level, have been connected to form a continuous network and horizontally adjusted to improve locational accuracy to within 50m of the river lines on 1:50 000 topographic map sheets (DWAF, 2003; DWAF, 2006). Profile elevation values extracted from three medium to low resolution Digital Elevation Models are examined in this study. This study compares slopes based on the elevation values extracted from DEMs according to adjusted 1:500 000 river lines, to those extracted from contour lines on 1:50 000 topographic map sheets according to 1:50 000 scanned river lines. These input data sets and any limitations associated with them are discussed. A semi-automated method used to extract and compile the elevation and distance values required to construct longitudinal profiles and the statistical tests and procedures used to compare elevation and slope values, are also described. Comparisons are formed around two reference scenarios. In the first elevations are extracted at the intersections of river lines with 1:50 000 scanned contour lines. The second reference scenario uses these same derived longitudinal profiles, but divided into five sets of equal horizontal intervals: 100m, 200m, 300m, 400m and 500m. Finally, the conclusions that can be drawn form these results, together with any recommendations for either improving or even replacing the data sets and methods described in this study, are presented. It is found that, that when comparing slopes derived from 1:50 000 contour line elevations to those based on DEM elevations, steep slopes tend to be more underestimated by the DEM than flatter slopes. More than 90% of profiles based on contour intervals and more than 90% of slopes derived at 500m horizontal distance intervals show no significant difference between slopes. It is finally suggested that the adjusted 1:500 000 river lines available from DWA (DWAF, 2003; DWAF 2006) combined with elevations from medium to low resolution DEMs can be used as a substitute for 1:50 000 river line and contour linebased profiles. It is also suggested that the automated GIS procedure used to extract and combine these values can be applied in other areas where the 1:500 000 river lines and medium to low resolution DEMs are available.Item Open Access The construction of a Geographic Information System (GIS) model for landfill site selection(University of the Free State, 2007-11) Thoso, Makibinyane; Barker, C. H.In the past decade, locating landfill site has been recognized as a significant planning problem and has subsequently received much attention from researchers in the planning sector. In particular, the siting of landfills is becoming more of an issue due to the prevalent “not in my backyard” (NIMBY) and “not in anyone’s backyard” (NIABY) concerns from the public. The purpose of this study, after identifying important criteria for siting landfills, was to develop a user-friendly landfill site selection model using a Geographic Information Systems (GIS) framework. Due to unavailability of electronic spatial data for Lesotho, Bloemfontein area was used as a test case. The model is tested in Bloemfontein with the intension to be applied in the city of Maseru as soon as the spatial data become available. The three main objectives were to develop GIS criteria for locating the landfill, identify possible sites that were suitable for this type of development and evaluate the effectiveness of these GIS methods used in the study. Production of constraint and factor maps took place. Afterwards, final suitability map was created using ArcGIS analysis tools. The optimum suitability map indicated that there were more optimal sites found within Bloemfontein city. The results discovered in Bloemfontein city using the GIS-based study revealed that although highly suitable areas were limited, a site was still able to be chosen under the predefined parameters. The site is not located on, or near, any environmental interest areas and is located a significant distance away from streams and urban areas, which minimizes social conflict and environmental impacts. The site is also located close enough (1-2km) to major road (N8) to Kimberley from Bloemfontein city and railroad, which ensures that economic costs of implementation are minimal. The selected region has a slope less than 12%, which are both an infrastructural advantage and a means of minimizing environmental impacts. Furthermore, the landfill is located in an area within 22 kilometres of the Bloemfontein study area. Since the site is located in a highly suitable area, environmental, social, and economic concerns have been met. Ultimately, the study proposes an acceptable landfill site for solid waste, taking Bloemfontein as the test study area. This research will contribute in developing Lesotho’s spatial database of environmental and social information to assist in the formulation of environmental policy. It is also expected that such municipal GIS when planned and implemented efficiently with sufficient public awareness and support would be instrumental in bringing reforms at the local and national level, realizing a major improvement without much capital investment.Item Open Access An evaluation of the spatial variability of sediment sources along the banks of the Modder River, Free State Province, South Africa(University of the Free State, 2005-05) Tsokeli, Raboroko David; Barker, C. H.The study focuses on the characteristics of the Modder River in the Free State. The Modder River plays an important role in supplying water for domestic, agricultural and industrial uses in the Bloemfontein, Botshabelo and Thaba Nchu areas. According to present (2001) estimates by the Centre of Environmental Management of the University of the Free State, the Modder River is exploited to its full capacity owing to the construction of dams. As the name of river suggests, the Modder River is said to have high sediment loads. In Afrikaans, modder means mud. The drainage pattern of the Modder River reveals well-developed dendritic drainage on the eastern part of the catchment and an endoreic drainage pattern on the western part. This study aims to evaluate the spatial variability of sediment sources along the main course of the Modder River as well as assess the possible role of fluvial geomorphology in river management. The study is based on the hypothesis that the high sediment load in the Modder River main course is caused more by riverbank processes than by the surface of the basin. Helicopter and fieldwork surveys were carried out in order to obtain the required materials (variables). The spatial variability of bank-forming material, vegetation cover, type and channel form were investigated in order to realise the aim of this study. The channel form of the Modder River indicates a decrease in sediment loads since the channel form shows some shrinkage immediately below the Krugersdrift Dam. The Modder River transports less and less sediments downstream as a result of a high number of constructed dams. Dams are barriers that create discontinuities in the channel system. Observations of the characteristics of the banks of the Modder River reveal that these banks are resistant to erosion owing to the luxuriant vegetation growth and low stream power because of the channel gradient. A question arises as to whether the Modder River really has such high sediment loads as its name suggests. Given the current state of the Modder River, high sediments are highly localised at certain sections of the stream. The transfer of sediments from one part of the river to another depends on the availability of sediment sources in space and time.Item Open Access The influence of climate variability on flood risk in the //Khara Hais municipality (Upington area): a GIS-based approach(University of the Free State, 2009-11) Jacobs, Kirsten Jacobs; Barker, C. H.English: The climate of the continents and the world is controlled by complex maritime and terrestrial interactions that produce a variety of climates across a range of regions and continents. Climate influences agriculture, environment, water and even the economy of countries all over the world. The climate of the world varies from one decade to another and a changing climate is natural and expected. However, there is a well-founded concern that the unprecedented human industrial and development activities of the past two centuries have caused changes over and above natural variation. Climate change is the natural cycle through which the earth and its atmosphere accommodate the change in the amount of energy received from the sun. A hazard is a physical situation with a potential for human injury, damage to property, damage to the environment or some combination of these. It is important to distinguish between the terms disaster and hazard. A disaster is seen as a serious disruption of the functioning of a community or society, causing widespread human, material or economic losses which exceed the ability of the affected community to cope, using its own resources. Disasters can be either natural, for instance a flood, or human induced, such as a nuclear accident. Disasters may furthermore be classified as slow-onset disasters, such as a drought, or sudden disasters, such as an earthquake . The word risk is one of the most notable examples of words with multiple and disparate meanings that may not be commonly acknowledged. Risk may have a technical meaning, referring to a chance or probability, such as risk from exposure, a consequence or impact, an example being the risk from smoking, or a perilous situation like a nuclear power plant that creates a risk. This study examines the influence of climate variability on flood risk in the //Khara Hais Municipality in the Northern Cape. The area that was investigated included the entire Orange River and Vaal River catchment areas where monthly rainfall data, as well as runoff data were used to produce a flood model for predicting a flood event within a two-month period, giving enough warning time to farmers and the inhabitants of the areas that may be influenced by this flood event. Maps were produced to show the high and low rainfall amounts in the these two catchment areas where randomly selected years and months were taken, as well as showing the one-month and two-month periods before these selected dates. Examples of the highest rainfall recorded, which was in 1988, the medium amount in 1977, and the lowest amount in 1997 were selected. Furthermore, five other such examples were taken to examine the rainfall and climate variation between the years and months ranging from 1950 to 1999.Item Open Access ‘n Ruimtelike-analitiese ondersoek na seisoenale reënval- en temperatuurpatrone oor suidelike Afrika(University of the Free State, 2014-07) Van der Walt, Adriaan Johannes; Barker, C. H.English: Changes in climatic variability and extremes of weather and climate events have received increased attention in the last few years. Many studies have been done on climate trends, especially for precipitation and temperature, compared to the time before the issue of climate change became more prominent during the 1980s. Since then, one of the biggest motivations for such studies is to establish if and how global warming might have influenced the climate on a global as well as regional scale. Southern Africa is predominantly semi-arid region with generally a high inter-annual rainfall variability and pronounced seasonal cycle. Climate variability and long-term change thus pose serious challenges for southern Africa. The main aim for this study is to investigate the seasonal trends of rainfall and surface temperature from 1950 to 1999 and to compare these seasonal trends with yearly trends. Rainfall and temperature data of the 1 946 Quaternary catchments in South Africa, Swaziland and Lesotho were used as input data. Correlation coefficients were determined and mapped using Geographic Information Systems ArcMap. HotSpot analysis was used to calculate the Getis-Ord Gi* statistic (Z score) for each feature in the data set. Results show more pronounced trends in rainfall and surface temperature during the different seasons.Item Open Access ‘n Ruimtelike-analitiese ondersoek na seisoenale reënval- en temperatuurpatrone oor suidelike Afrika(University of the Free State, 2014-07) Van der Walt, Adriaan Johannes; Barker, C. H.English: Changes in climatic variability and extremes of weather and climate events have received increased attention in the last few years. Many studies have been done on climate trends, especially for precipitation and temperature, compared to the time before the issue of climate change became more prominent during the 1980s. Since then, one of the biggest motivations for such studies is to establish if and how global warming might have influenced the climate on a global as well as regional scale. Southern Africa is predominantly semi-arid region with generally a high inter-annual rainfall variability and pronounced seasonal cycle. Climate variability and long-term change thus pose serious challenges for southern Africa. The main aim for this study is to investigate the seasonal trends of rainfall and surface temperature from 1950 to 1999 and to compare these seasonal trends with yearly trends. Rainfall and temperature data of the 1 946 Quaternary catchments in South Africa, Swaziland and Lesotho were used as input data. Correlation coefficients were determined and mapped using Geographic Information Systems ArcMap. HotSpot analysis was used to calculate the Getis-Ord Gi* statistic (Z score) for each feature in the data set. Results show more pronounced trends in rainfall and surface temperature during the different seasons.Item Open Access Optimising interpolation as a tool for use in soil property mapping(University of the Free State, 2014-01-31) Mtshawu, Babalwa; Barker, C. H.Inverse distance weighting (IDW) and kriging are robust and widely used estimation techniques in earth sciences (soil science). Variance of Kriging is often proposed as a statistical technique with superior mathematical properties such as a minimum error variance. However, the robustness and simplicity of IDW motivate its continued use. This research aims to compare the two interpolation techniques (Inverse Distance Weighting and Kriging), as well as to evaluate the effect of sampling density on mapping accuracy of soil properties with diverse spatial structure and diverse variability in a quest to improve interpolation quality for soil chemical property mapping. The comparison of these interpolation methods is achieved using the total error of crossvalidation and validation statistics. Mean Prediction Error and Root Mean Square Error are calculated and combined to determine which interpolator produced the lowest total error. The interpolator that produced the lowest total error portrays the most accurate soil property predictions of the study area. The finding of this study strongly suggests that the accuracy achieved in mapping soil properties strongly depends on the spatial structure of the data. This was clearly visible, in that, when the subset training data set was decreased, the total error increased. The results also confirmed that systematic sampling pattern provides more accurate results than random sampling pattern. The overall results obtained from the comparison of the two applied interpolation methods indicated that Kriging was the most suitable method for prediction and mapping the spatial distribution of soil chemical properties in this study area.