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The effect of catchment land use on sediment input to SwartvleiBarker, Janet Alexandra January 1985 (has links)
Bibliography: pages 239-249. / The littoral aquatic plant community of Swartvlei declined after 1978, apparently as a result of increased lake water turbidity. To investigate the causes of this, land use and land management of the Swartvlei catchment area have been studied. Possible causes and the extent of accelerated runoff and sediment loss in different rainfall conditions were determined. Rainfall, water flow, Secchi disc and sediment load data are reviewed and the apparent relationship between them noted. Water samples were collected at 32 different sample sites to determine sediment loads. Samples were vacuum filtered through coarse and fine glass fibre filters and the results recorded in milligrams of sediment per litre of water. The quantity and duration of rainfall in the immediate pre-sampling period were recorded. Secchi disc transparency of Swartvlei water was recorded. Catchment land use and land management are described in four areas based on land use and geographical location. The naturally vegetated montane upper catchment area, the foothill plantation area, the agricultural areas on the tertiary plateau and the road reconstruction and recreation areas are considered separately. Land use and land management information was obtained from a literature review and study of topographical maps, orthophotographs, geological survey maps and aerial photographs. Flights over the area enabled confirmation of observations. Informal interviews with persons involved in catchment management, property-owners and roads authorities were conducted. Areas of accelerated sediment loss were determined and the magnitude of the problem noted. Results show that rainfall duration, intensity, quantity and distribution determine the effect of sediment-laden runoff on river and vlei water quality. Small storm events (< 50 mm) influence the water quality of tributaries particularly in the lower catchment areas. Storm events of > 50 mm influence the main catchment rivers and light penetration in Swartvlei at the river inflow points. Long-duration flood rainfalls bring about massive soil loss in the catchment and cause reduced light penetration over the entire surface area of Swartvlei. Most sediment originates from the lower sections of the catchment area where human activities are most intense. Natural vegetation acts as a protective barrier against soil loss and its removal and the lack of suitable runoff channels leads to greater sediment loss. Recommendations to reduce sediment loss are made. The topographical and soil characteristics of the area make it sensitive to soil loss, the significance of which has only been recognised recently. The socio-economic circumstances in the region and the present economic recession are limiting amelioration of the situation in this beautiful natural area.
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Conservation of private land by means of compensatory mechanisms and incentivesGlazewski, Jan January 1986 (has links)
Includes bibliography. / This report reviews the potential of financial incentives and compensatory mechanisms for achieving conservation goals on privately owned land in South Africa. Legal concepts, such as the notion of absolute ownership of property, are examined in the context of South Africa's historical and political circumstances to highlight how they have contributed to a highly individualistic attitude to land ownership in South Africa. The achievement of environmental objectives has relied largely on outright control of, and prohibitions on, the use of land. Incentives and compensatory mechanisms offer complementary methods of encouraging the diminution of ownership rights in private land for the public interest. A review of some foreign legal systems shows that compensation for the diminution of private rights in land is a grossly neglected area of South African law. It is found that attention should be given to the development of satisfactory principles of compensation as well as to the incorporation of incentives into South African legislation. It is concluded that the success of such recommendations is dependant on the fulfilment of certain administrative prerequisites, including the formulation of a national strategy for the conservation of private land in South Africa and the constitution of a formal body of experts to advise on compensation and incentive schemes.
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The use and disaggregation of survey data to study the cross-sectional and spatial distribution of multimorbidity and its association with socioeconomic disadvantage in South AfricaWeimann, Amy January 2016 (has links)
This study identified the need to provide a proof of concept of the use and disaggregation of existing health data in order to study the cross-sectional and spatial distribution of HIV, tuberculosis and noncommunicable disease multimorbidity and the association with socioeconomic disadvantage at a South African, Western Cape Province and urban/intra-urban scale for 2008 and 2012. This study was framed within a health geography context and draws attention to the reality of health variations which are influenced by place-based effects, including the surrounding social, cultural and economic structural factors and mechanisms that, together, constitute the social determinants of health. However, in order to identify and understand these variations in health, access to health data that is able to be disaggregated by key characteristic and spatial scales, is essential. Therefore, this study utilised existing health data from the National Income Dynamics Study, a longitudinal study with a sample of approximately 28 000 people, to perform secondary data analysis using a positivist approach to research. This study found that the coupling of geospatial and health data is able to produce new health information and the graphical representation of data provides unique insights in health variations. Secondly, the burden of disease is not consistent between spatial scales which suggests variations in epidemiological profiles between sub-national geographies, thereby supporting the argument for the need of data disaggregation. Finally, the cross-sectional analysis of this study found multimorbidity to be associated with age, socioeconomic deprivation, obesity and urban areas, while the spatial analysis showed clusters (hot spots) of higher multimorbidity prevalence in parts of KwaZulu-Natal and the Eastern Cape, which compared with the socioeconomic disadvantage spatial pattern. Therefore, this study provides an example of the research needed to provide information to support policy improvement and enable the urban planning and public health professions to work together.
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Assessing intra-seasonal land surface change and long term trends in the succulent Karoo biome using coarse resolution satellite and interpolated rainfall surfacesRoberts, Jonathan Wesley January 2005 (has links)
Includes bibliographical references (leaves 132-151). / The Succulent Karoo is a biodiversity hot spot situated along the west coast of southern Africa. While it is predominantly recognized as a west coast vegetation type its borders stretch as far east as Steytlerville in the Little Karoo. The area contains the largest number of endemic succulent species in the world and harbors nearly 10 percent of the of the total number of succulent species worldwide. Furthermore, spring mass-flowering events draw thousands of tourists to the region, providing welcome input to the local economies. The floral diversity is however, under threat from various environmental forces. These forces include inappropriate land use practices resulting in Land Degradation and the ever-present threat of Climate Change.
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Analysis of land-cover change in the Kogmans River (H3) secondary catchment : impact of land degradation and river management on flood severityRogatschnig, Daniel January 2005 (has links)
Includes bibliographical references (leaves 111-124). / This study aims to understand what role the landscape, and the management thereof, played in the March 2003 floods in the Kogmans River catchment. The Kogmans River (H3) secondary catchment is situated in the Klein (Uttle) Karoo region of the Western Cape, approximately 170km east of the city of Cape Town.
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Towards an integrated solid waste management strategy for the Robben Island MuseumSidzumo, Nolubabalo January 2000 (has links)
Bibliography: leaves 104-109. / This study assesses the process of solid waste management, from generation to disposal, on Robben Island. The major objectives of this research were the following: * To assess the quantity and the type of solid waste generated on Robben Island; * To investigate the areas where waste is generated; * To assess current waste management practices that are undertaken on Robben Island; and * To assess the level of understanding, the attitudes and the behaviour of people working and residing on Robben Island with regards to waste management issues. As a popular tourist destination site, the researcher took into consideration during the investigation that, waste quantities generated on Robben Island might vary from season to season depending on the number of tourists visiting the island per season.
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Barriers to flood risk adaptation a case study of cross-scale collaboration in the informal settlement of Graveyard Pond, PhilipiOrangio, Christina January 2012 (has links)
Includes abstract. / Includes bibliographical references. / This study provides insight into the barriers of adapting to urban flooding as well as how flooding is responded to in informal settlements in order to increase adaptive capacity to future climate change. There is a growing concern over the increase in extreme events expected as part of climate change.
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Investigating the relationships between wheat-specific rainfall characteristics, large-scale modes of climate variability and wheat yields in the Swartland region, South AfricaKloppers,Pierre-Louis January 2014 (has links)
Includes bibliographical references. / Wheat producers in the South Western Cape (SWC) of South Africa need to cope with biophysical and socio-economic systems exposing farmers to a multidimensional decision- making environment. The rain fed wheat production in the Swartland region is highly susceptible to the interannual variability of winter rainfall. Producers, therefore, need relevant climatic information to identify ways to improve profitability and to make sound economic decisions. Seasonal forecasting has the potential to provide wheat producers with invaluable information regarding the climatic conditions. However, due to the complex nature of the atmospheric dynamics associated with winter rainfall in South Africa, seasonal forecasting models have been found to have very little skill in predicting the variability of winter rainfall. Such a shortfall has created a gap for which this study has attempted to bridge. This study aimed to investigate the relationship between wheat-specific rainfall characteristics, large-scale modes of climate variability and wheat yields in the Swartland region to assess whether these relationships could provide useful climatic information to the wheat farmers. Six wheat-specific rainfall characteristics (total rainfall ; number of wet days ; number of ‘good’ rainfall events; number of heavy rainfall events; percentage ‘good’ rainfall ; and the number of dry dekads ) on various time scales (winter; seasonal; monthly and dekadal) were correlated against wheat yield records over a 17 year period from 1994 to 2010. From this analysis, the distribution and timing of the rainfall throughout the wheat growing season (April to September) emerged as an important determinant of wheat yield. An accurate statistical wheat prediction model was created using farmer stipulated rainfall- wheat yield thresholds. Three teleconnections (El Niño-Southern Oscillation [ENSO], Antarctic Oscillation [AAO] and South Atlantic sea surface temperatures [SSTs]) represented by eight climate indices (Nino 3.4 Index, Ocean Nino Index [ONI], Southern Oscillation Index [SOI], AAO index, Southern Annular Mode Index [SAM], South Atlantic Dipole Index [SADI], South Western Atlantic SST Index [SWAI] and South Central Atlantic SST Index [SCAI]), were correlated against wheat yield data over a 17 year period from 1994 to 2010. The relationships between the three teleconnections and wheat yield in the Swartland were established. Teleconnection-wheat yield correlations were found to be limited, with regards to the application of this information to farmers, due to the lack of a comprehensive understanding of the dynamics of how the three teleconnections influence the local climate and, therefore, the wheat yield in the Swartland. The eight climate indices, representing the three teleconnections, were correlated against the six wheat-specific rainfall characteristic indices from each of the three study areas over the period from 1980 to 2012. The state of ENSO during the first half of the year was shown to be correlated with rainfall characteristics during both the first (April to July) and second (July to September) halves of the wheat growing season; however, these correlations differ ed in their sign. Correlations suggested a negative phase of AAO was associated with above normal rainfall throughout the year across the Swartland region. Sea surface temperatures in the central South Atlantic during March to October showed significant negative correlations with rainfall during the latter half of the wheat growing season (July to October) across the Swartland region. This study presented evidence supporting the plausibility and validity for the use of the state of large-scale modes of variability in the prediction of wheat-specific rainfall characteristics and aggregated yields in the Swartland region. This has the potential to provide useful information to wheat farmers in the Swartland to aid in their decision making process
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Spatio-temporal effects of projected climate on future crop suitability over West AfricaEgbebiyi, Temitope Samuel 14 September 2020 (has links)
Future climate is projected to deviate from present-day by unprecedented measure, hereafter climate departure, with direct consequences on food security. West Africa, one of the hotspots for climate departure globally, has suffered significantly from climate change impacts via extreme events with large impacts on food production. A better understanding of the impact of climate departure on crop growth suitability and planting season is still unknown and is highly needed in West Africa, owing to its high vulnerability and low adaptive capacity. This thesis developed a methodology aimed at defining the cropping system to investigate the projected timing of climate departures from historical variability and their impact on crop growth suitability over West Africa. For the study we used 4 statistically downscaled Global Climate Models, GCMs at station level for the period 1951- 2100 under RCP8.5 across the three AgroEcological Zones (AEZs) of West Africa for eight crops, cassava, maize, mango, orange, pearl millet, plantain, pineapple and tomato. Climate variables minimum mean monthly temperature and total monthly precipitation were used as input crop suitability model, Ecocrop to develop a new approach to define and characterise cropping systems departure from their normal regime, called crop-climate departure (CCD), to better understand the timing of future changes in crop suitability. Also, the concept of CCD was defined, tested and applied in West Africa for five different crops types, using 10 GCMs downscaled by regional climate model, RCA4 as input into crop suitability model Ecocrop. The downscaled GCMs were also employed to examine the impact at the different global warming levels, 1.5, 2.0 and 3.0oC on crop suitability over West Africa. Using the GCMs at station level, we develop the concept of crop-climate used in characterizing the suitability of different crop across the three AEZs of West Africa. The result highlights the constraint, a reduction in suitable area, of growing cassava and pineapple only in the Guinea zone by mid and end of century. In contrast, there is an observed and projected opportunity, increase in suitable areas, of growing maize in southern Sahel by the end of the century while mango remains suitable across the three West African AEZs. The application applying the concept crop-climate departure on different crop types showed in decrease suitable areas for most crops by the end of century with horticultural, cassava and cereals respectively are the crops mostly affected. The changes in crop-climate relationship suggests a future constraint in crop suitability could be detrimental to future food security over West Africa. Finally, our findings from the impact of different global warming levels, 1.5. 2.0 and 3.0oC highlights the potential of sustained suitability for all the crops and improved food security under 1.5oC global warming for all the six crops but a contrast under 3oC over West Africa except for cowpea and groundnut. Our findings for cowpea and groundnut showed an increase suitable area into the southern Sahel with increasing global warming level. The study holds great value at regional scale where improved preparedness and regional cohesion could make the difference in making decision for a food secure Africa. Further studies to explore associated short and long-term adaptation options to changes in crop-climate relationship are recommended.
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How natural are 'natural disasters'? : vulnerability to drought in Southern Namibia communal areasFara, Katiuscia January 2000 (has links)
Bibliography: leaves 37-41
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