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Local atmospheric circulations and the mesoclimate of Durban.Preston-Whyte, Robert Arthur. January 1970 (has links)
Rapid urban and industrial growth along the Natal coast has occurred with little concern for characteristics of local climate. In general, industrial growth has taken place without taking into account the potential for pollution transportation during the winter season; urban areas have developed without consideration for the vital need in sub-tropical latitudes to maintain adequate mixing of the lower atmosphere. The apparent inadequacy in planning for climate has partly been due to a lack of understanding of the nature and characteristics of local wind systems. The motivation for this study stems , therefore, from the need to evaluate the influence of land-sea and topographically-induced wind systems upon certain aspects of weather and climate on the Natal coast. During summer, moist and relatively cool air is advected almost daily over the Natal coast by the sea breeze . Observations of spatial and temporal variations of these winds were made in the period 1963-69 from recording stations in the Durban area and along a 40-mile transect approximately normal to the coast at Durban. Comparable observations have not as yet been made in South Africa nor have there been a ttempts to examine the influence of sea breezes upon selected climate and weather phenomenon. In this latter connection the role of the sea br eeze is examined in two separate fields in this study, namely urban climatology and thunderstorm development. Climatic discomfort caused by the combined effect of high temperatures and humidities on the Natal coast, is at a maximum in urban areas . Since these areas are also highly populated , a need exists to evaluate the ability of the sea breeze to reduce urban temperatures by advection of cooler air over the area, by eddy diffusion of heat or by displacement of urban temperatures aw~ from poorly ventilated areas. Thus climatic discomfort in these areas may also be reduced. Detailed observations of the influence of the sea breeze, in particular, and wind in general, upon the spatial variation of temperature , humidity and human comfort were, therefore, undertaken in the Durban area. It is believed that this i s the first time an attempt has been made to describe the spatial distribution of a comfort index in an urban area. The results should be of interest to the a rchitect and town planner. The sea breeze, strengthened by gradient and valley Vlinds, is shown to penetrate at least 40 miles inland. In accordance with this , it is suggested that the inland invasion of marine air takes place in response to lowered pressure in adjacent inland areas in southern Natal and provides the moisture required to feed thunderstorms which develop in this area. These storms subsequently move towards the coast following the retreating convergence zone between winds with an onshore and offshore component of motion and reach Durban after sunset. Land breezes are best developed in winter. Observational techniques were similar to those employed in the sea breeze study and provide the only detailed examination of spatial and temporal variations of land breezes in South Africa. Until recently the nature and characteristics of topographically-induced winds in Natal were also a relatively unexplored feature of local atmospheric circulations. However, Tyson (1967) has examined local winds in certain Natal valleys and his prediction that mountain- plain winds reach the coast during the night is also examined in this study. While the relatively weak. and shallow land breeze may be of secondary importance when compared with the sea breeze, it would be a mistake to underestimate the importance of these winds upon certain aspects of coastal climate. In p~rticular the tendency for land breezes to initiate cloud and precipitation at night is examined while the potential for the transportation of atmospheric pollution by these winds is also briefly discussed. A study of the diurnal variation of precipitation at Durban reveals a high frequency of low intensi~ precipitation at night. The nature of this precipitation differs in both frequency and" amount from high intensity rainfall which is the product of thunderstorm and frontal activity. It is suggested in this study that the land breeze plays a dominant role in providing the buoyancy necessary to cause nocturnal drizzle precipitation from shallow stratus cloud. The thesis is divided into four parts. Part I examines details of the physiography, weather, climate, observati ~nal methods and analysis techniques. Because of the variability of weather on the coast of Natal that section is dealt with in more detail than would have been deemed necessary for a similar study inland. Without knowledge of the characteristics of the atmospheric circulation, the behaviour of local wind systems in relation to large scale systems could not be adequately discussed. In Part II land and sea breezes and topographically-induced wind systems are examined in detail. Emphasis is placed not only on the observational characteristics of these winds such as onset, depth, velocity gradient, surging, relation to gradient winds and dissipation but also on their relation to theoretical models of the relevant wind system. The influence of local wind systems upon selected climatic elements is dealt with in Part Ill. Characteristics of the diurnal variation of precipitation are examined in Chapter 6. Rainfall frequencies and amounts are shown to be highest in the first half of the night and a model is developed to explain the influence of land breezes and mountain-plain winds upon low intensity but high frequency nocturnal rainfall. High intensity but low frequency rainfall produced by thunderstorms also occurs soon after sunset and a further model is advanced to explain this phenomenon in relation to the sea breeze. The effect of air movement upon the spatial variation of temperature, humidity and a discomfort index in both summer and winter is examined in Chapters 7 and 8. The relationship between these elements has permitted the development of an empirical model to predict values across the city of mean midday summer and winter temperatures as well as discomfort index values. In Part IV the most significant aspeots relating to the study as a whole are summarised. In conclusion the potential f or the transport of pollutants by land breezes and topographically induced winds is briefly discussed as an aid to planning and siaple spatial models are given showing generalised air movement and ventilation characteristics in the Durban area and along the Natal coast. / Thesis (Ph.D.)-University of Natal, 1970.
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An investigation into residential desegregation : a case study in the Durban Functional region.Naidoo, Reubendra. January 1996 (has links)
A number of mechanisms were used in the past to racially divide
South Africa's population, among them, the most notable being
the Group Areas Act. Apartheid was more than just the physical
separation of race groups. It was supported by an apparatus
designed to inequitably provide and distribute social amenities,
education, housing etc. In addition, it was a psychological
exercise designed to enforce the notion of white superiority on the
people. Now that the Group Areas Act has been repealed, the racio-spatial
patterns of the South African city are expected to change
as the doors of the previously prohibited residential areas become
"open" to all South Africans. The following dissertation is
concerned with the residential desegregation process. Its central
argument is that the practice of segregation stretches far beyond
the limits of the law. Informal processes will replace formal
legislation so that the segregation of the South African population
will continue. The main focus of the argument is that in the post-apartheid
period, disadvantages based on income will have the
same effect as the differences based on race did, in the old South
Africa. Affordability will play a major role in determining who gets
access to the housing stock in the "White" residential areas of the
old South Africa. Estate agents, the state, and the development companies will be
amongst the key actors in determining not only who gets access
to middle income housing but also in the new racio- spatial
patterns that are likely to develop in the residential areas of South
Africa's cities. Lastly, desegregation is about getting people of
different cultures, religions, and ethnic backgrounds together to
live as a single integrated community - a difficult task in a society
in which decades of separation have made us virtual strangers.
The study, which was conducted in the Borough of Queensburgh
and the Bellair-Sea View-Hillary areas,has revealed that ,as a
result of the reasons mentioned in the preceding paragraphs, the
rate of residential desegregation has been slow. Also the old
forms of segregation are being replaced by new forms in the
shape of ethnic pockets within the former "white" residential
areas. / Thesis (M.A.)-University of Durban-Westville, 1996.
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Residential desegregation in the Durban region : the case of Westville.Mpungose, Jabulani Everest. January 1996 (has links)
For many years blacks have been restricted from occupying housing in the suburbs and inner
parts of Durban. The Group Areas Act accommodated them in the rural and unserviced parts
on the periphery of the city. Townships were later developed for them as far away from the
city centre as possible. The scrapping of the Act in 1991 saw many of those people who
could afford housing in the city and in the suburbs moving into houses and flats in
predominantly white areas. The aim of this dissertation was to examine the process of
residential desegregation in a former white suburb. The study was conducted in Westville. a
middle- to upper-class residential area which is presently inhabited by both blacks and whites.
The severe shortages of land and housing, accompanied by the continuing unrest in the
townships and changes in the family size and needs. influenced the migration of blacks to
Westville. This migration started as early as 1987 despite the legal. financial and racist
impediments prior to the repeal of the Group Areas Act in 1991. Most of the black
households in Westville bought their houses through the estate agents. Income was the main
criterion to determine whether blacks qualified for the purchase of property. Most of the
buyers who qualified for loans and could afford to pay for services in the suburbs were those
with more than one income earner per family. The process of residential desegregation was
enhanced by the positive attitudes of the households towards their neighbourhood. The
positive demographic and biracial social interaction among all residents also played an
important role in the integration process. Problems were experienced when some whites
showed signs of prejudice which emanated from the clash of cultures. such as blacks
slaughtering cattle and Muslims sacrificing animals. Although the abolition of the Group
Areas Act in 1991 was not wholeheartedly accepted by all whites. they were gradually
accepting the right or blacks to choose any residential neighbourhood in which they wished
to live. / Thesis(M.A.)-University of Durban-Westville, 1996.
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Assessment of soil erosion in the Mfolozi catchment, Kwazulu Natal implications for land reform.Ramokgopa, Raphaahle. January 1996 (has links)
The Mfolozi, the second largest catchment in KwaZulu Natal, is already severely degraded over substantial areas. Its mean annual sediment load is extremely high and deposits on its floodplain have caused very serious financial losses. Previous studies in the catchment have attributed its soil loss to poor land use practices by peasant farmers. There is a concern that this production will be substantially increased by land use changes incumbent on the land
reform programme. In order to ensure that this programme does not lead to increased degradation and exacerbate associated environmental and socio-economic problems, this study identified both subcatchments and land types that are highly susceptible to erosion and already highly eroded. An unpublished map showing the location of 19 categories of erosional forms and three categories of extreme relief features was available for use. The density (and areal
extent in the case of badlands) of each of these forms within each of the 16 possible land types within each of the 43 subcatchments, was obtained and related to their dominant physiographic variables. The findings revealed that the catchment is not as severely or extensively eroded as suggested by previous studies. A substantial portion of the former Natal areas, mostly targeted for reallocation, have however, been shown to be unsuitable for this purpose. / Thesis (M.A.)-University of Durban-Westville, 1996.
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An investigation into some aspects of the relationship between diabetes mellitus and male sexual dysfunction.Pillay, Veniela. January 1990 (has links)
This investigation reports the effects of diabetes mellitus
on some aspects of the male reproductive system. When
compared to non-diabetic controls, human diabetics indicated
a 35% reduction in gross sperm motility, a 13% decrease in
progressive sperm motility and a 49% reduction in rapid
sperm motility. Sperm viability also decreased by 35% in
this group. Semen carnitine and acid phosphatase levels were
elevated by 47% and 13% respectively, whilst the circulating
testosterone level decreased by 20%. Semen pH and volume,
sperm concentration and sperm morphology did not differ
significantly between the diabetic and non-diabetic control
patients. Circulating LH, FSH and prolactin, as well as
seminal zinc, fructose and citric acid levels were found to
be similar in the two groups.
In a human infertility group, the number of morphologically
normal sperm was 46% lower in comparison to the control
group. Gross sperm motility decreased by 21%, progressive
motility by 11% and sperm viability by 9%. Carnitine
concentration in semen was 38% higher and fructose levels
27% lower than that of the control group. There were also
significant reductions in circulating testosterone and LH
levels (16% and 28% respectively). other parameters
investigated, but which were not significantly different
from the control, were semen pH and volume, sperm
concentration, seminal zinc, acid phosphatase and citric
acid concentrations, and circulating FSH and prolactin
levels.
streptozotocin-induced diabetic rats maintained on insulin
for 90 days, were also assessed for testicular function.
Extracts from the cauda epididymis indicated a 39% decrease
in sperm motility and a 19% reduction in viability. Unlike
the human diabetics, a 59% reduction in sperm number per
cauda was also noted, together with an 86% rise in
morphologically abnormal sperm. Measurements of the
accessory organ weights indicated a 44% loss in prostate
weight only. The testicular weight and testicular cell size
and number did not differ significantly between the two
groups. Circulating testosterone levels also remained
unchanged. Reduced fecundity in these animals was displayed
by the reduction in the number of pups sired.
Collectively these results indicate that diabetes adversely
affects the male reproductive system. The profile of the
human diabetes group was similar to that of a group of
infertile males, indicating a severe loss in reproductive
potential in these patients. The results obtained from the
streptozotocin-induced diabetic rats complimented the
investigation on human diabetics. The animal studies further
indicated reduced fecundity and a compromised accessory
organ function, as suggested by the weight loss of these
organs. / Thesis (M.Sc.)-University of Durban-Westville, 1990.
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A socio-spatial study of recreation in Metropolitan Durban.Franke, Alison Frances. January 1985 (has links)
No abstract available. / Thesis (M.A.)-University of Durban-Westville, 1985.
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Investigation on solid waste management in townships : case study of Umlazi, Durban.Njoko, Lindokuhle Lucrecia. January 2003 (has links)
Today environmental degradation is perceived to be a global phenomena, since the Earth Summit of 1992 gained phenomenal interest among the international community. Consequently there was a major interest among conservationist, environmentalist and other disciplines to write about the alarming rate at which natural resources are being polluted and over utilized and eventually depleted. This is evident when one looks at land, air, water pollution, and deforestation and soil erosion. Human dependence on these resources, most of which are non-renewable, compounded by growth in popUlation numbers will inevitably impact the quality oflife of the global community. Most developing Urban areas in South Africa and formal residential areas where waste removal services are supposed to be available, are characterised by solid waste being illegal dumps on open spaces, streets etc. The heaps of waste have become breeding grounds for insects and pests. The odour emanating from these sites together with potential for diseases can have serious implications on the health of residents as well as aesthetic nature of the environment. It is not yet understood why such situations exists within formal serviced areas. This provided the motivation for the investigation. The purpose of the study was to investigate solid waste management practices in a forn1al residential area of Durban namely Umlazi and its negative impact on the human and natural environments. The effect of the social dimensions of households on solid waste practices was investigated in order to examine relationship between socio economic and current waste practices. Current perceptions, attitudes and solid waste practices of households were assessed to explain the influence of socio economIC factors in the planning and operations of solid waste management systems in townships. Questionnaires relating to the problem were administered to the residents ofUmlazi. The results indicated that the waste collection system is characterised by inefficiency. The study revealed that attitudes and perceptions, educational status and income are significant factors that contribute to effective waste management processes. The analysis of data for domestic solid waste showed that the evaluation of both the social demographic and solid waste generation rates is crucial in understanding why such inefficiency in formally serviced areas exists. This in turn could provide guidelines on the possible roles that households can play in the planning and implementation of domestic solid waste. Amongst others the consumption patterns, knowledge about waste management practices and preferences for service provision were interpreted. Based on the findings of this study and the review of related literature, it is concluded that attitudes and perceptions of residents need to change. Residents need to become responsible for caring for their environment and a different mind set towards solid waste is needed. Appropriate policy backed by legislation and enforceable regulations must underpin the strategic alternatives selected to deal with waste management in the purban Metropolitan Area (DMA). Policy legislation and regulations at the local level must be fitting with those set at national and provincial levels of government. The planning of integrated waste management should be a consultative process in which partnerships are encouraged between the DMA authorities and communities who will benefit from the waste management plan. The public and private organisations that handle waste in the municipality should be seen as part of the solution, not a problem, of waste management. Effective waste management should be appreciated as a public good from which benefits such as opportunities for employment, resource recovery, safe disposal of hazardous waste, reduced pollution and community development projects can spring. / Thesis (M.A.)-University of Durban-Westville, 2003.
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An investigation into solid waste management practices in residential areas the case of the Phoenix township.Rajpal, L. January 2002 (has links)
The rapid population growth accompanied by urbanisation and industrialisation has
resulted in a dramatic increase in the volume of waste being generated by modem
societies. This has led to a growing awareness of the serious threats that these wastes
pose to the environment. Thus, it has been acknowledged that one of the many
environmental challenges confronting authorities in Metropolitan Durban is The
Management of Solid Wastes. A number of researchers have found that inadequate and
inefficient waste management practices are heavily impacting on the human and natural
environment.
Although formal townships are supposed to have adequate waste removal services, many
of these townships are characterized by wastes being disposed of in streets, open spaces,
streams etc. In the light of above, the aim of this study was to assess the Solid Waste
Management Practices in the Phoenix Township. Questionnaires relating to the problem
of Solid Waste Management Practices were administered to the residents of the Phoenix
community. The study identified factors that contributed to the detrimental impacts on
the physical and human environment.
The study revealed that the current waste management practices (which encompassed the
generation, storage, collection, disposal and waste reduction options) are characterized by
inefficiency. Furthermore, it was evident, that this inefficiency impacts negatively on the
physical and human environments, of which the major impacts are the illegal dumping in
the Phoenix area. Therefore, recommendations were made consulting both the residents
and local authorities with regards to combating or curbing the problems relating to Solid
Waste Management Practices / Thesis (M.Sc.)-University of Durban-Westville, 2002.
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Soil conservation policy in South Africa, 1910-1992 : the human dimension.Cooper, Amanda. January 1996 (has links)
The overwhelming focus of documentary sources indicate that traditional approaches to
land degradation and soil erosion in South Africa have focussed on the physical
dimension of the problem and the development of practical solutions to its reduction.
This study was undertaken from the viewpoint that this emphasis has resulted in the
neglect of other (for example, socio-political) aspects of soil erosion and that such
neglect has exacerbated the soil erosion problem manifest in South Africa. An
examination of the 'human dimension' of soil erosion in South Africa was therefore
undertaken through an analysis of soil conservation policy and legislation promulgated
to effect policy objectives between 1910 and 1992. Acknowledging that the policy
environment is influenced by factors within the economic, political, historical and
perceptual (all human) environments, as well as the natural environment, this study
attempts to integrate information relating to each of these parameters within the overall
framework of South African soil conservation policy. Particular emphasis is placed on
the role of environmental perception in the decision-making process, together with the
critical influence of intervening variables found to be operative within the perceptual
environment as represented in the South African context.
In the absence of substantive empirical data, this study posits a number of a priori
assumptions regarding the extent and causes of soil erosion, support for which was
initially derived from the extensive literature sources reviewed for the study. The basic
premise of this study is that soil erosion persists in South Africa, and despite
considerable government and public inputs and participation, and the existence of a
legislative machinery created specifically to address the problem, progress in promoting
soil conservation through implementation of specific measures has been slow.
Following a review of soil conservation policy and legislation up to 1992, it is further
submitted that factors other than legislative inadequacies could account for this problem
and therefore warrant particular and thorough investigation.
To this end, this work firstly describes the physical context within which South African
soil erosion occurs, followed by a brief appraisal of socio-economic and political
variables which together have shaped contemporary perceptions regarding the nature,
extent and causes of soil erosion in the country. A comprehensive review of relevant
policy and legislation in the period 1910-1992 was then undertaken by reference to
published and unpublished sources. The evolution of soil conservation policy in the
country was charted through reference to relevant legislation and parliamentary debate.
The temporal variation in the relative success of the policy and legislative enactments
was measured by reference to relevant indicators.
The adequacy of South African soil conservation (as indicated by four key legislative
enactments formulated to specifically address soil erosion) was evaluated using key
elements of the World Soils Policy as a baseline. Analysis of the Forest and Veld
Conservation Act of 1941, the Soil Conservation Act of 1946, the Soil Conservation
Act of 1969 and the Conservation of Agricultural Resources Act of 1983, revealed a
clear evolutionary progression in which successive acts sought to build upon successes
and minimise the weaknesses of previous efforts. This analysis reveals marked
temporal variability in the extent to which each element is addressed and explores the
multi-environmental (political, social, historical, economic and perceptual) constraints
on attainment of all goals. This assessment permitted the compilation of, what the
author has termed the South African Policy Environment Model, which takes the form
of a working hypothesis.
This hypothesis was subsequently tested utilising the 103 responses obtained from a
postal questionnaire survey directed at 242 scientists, policy developers and
extensionists (representing a 43 per cent return), that is, those persons who either
currently or during the study period, were actively involved in the development of soil
erosion research and/or the implementation of conservation policy objectives.
In spite of the apparent effort by the South African government to address soil
conservation, contemporary opinion (according to documentary evidence) suggests that
the policies formulated have failed to attain soil conservation goals and reduce the
manifest extent and rate of land degradation in the country. This study broadly
concludes that such inefficacy of policy may be ascribed to:
1. lack of importance ascribed to soil
2. national level control
3. non-uniformity in application of law
4. inadequacies in the implementation of policy
5. paucity of information on real nature and extent of problem
6. perceptions in an uninformed environment.
The study furthermore submits that images concerning the realities of soil erosion are
shaped by perceptual filters and the value systems of individuals active in the soil
conservation arena, or more specifically, key players' perceptions regarding the causes,
extent and nature of the soil erosion problem, are what underpin and ultimately give rise
to the relative effectiveness of soil conservation strategies.
This study identifies a multiplicity of factors which operate within five dynamically
interative environments (the political, economic, historical, perceptual and natural
environments) considered influential in shaping the temporal (and spatial) variation in
the policy environment represented in this study. This examination of the
multidimensionality of soil erosion has led to the conclusion that in addition to the
problems broadly outlined above, soil erosion is also a problem of:
1. accountability;
2. focus;
3. priorities and government commitment;
4. situational incompatibility;
5. misinformed perceptions; and
6. timing.
It is submitted that lack of recognition of these inter- and intra-environment dynamics
could account for the relative inefficacy of soil conservation policy to promote the
sustained adoption of conservation practices. Such factors will in the past have been
overlooked due to the neglect of the 'human dimension' of the problem in South Africa
in the period under review.
It is believed that the measure of consensus derived from the results of this study,
reflects contemporary realities concerning the status of soil conservation in the country,
at least amongst those individuals most intimately involved in the development,
formulation and administration of soil conservation policy. As such it provides an
appropriate foundation upon which to base future policy decisions and more
importantly, to derive optimum compliance with conservation norms and standards of
practice amongst land users.
Only by recognising the multidimensionality of the soil conservation policy
environment and its components, can the past inefficacies be overcome. It is submitted
therefore that for South Africa to meet its challenges of the 21st century concerning the
conservation and sustainable utilisation of soil, the priority of policy developers must
be - the expedient adoption of a multi- and interdisciplinary approach to agricultural
resource management, with particular emphasis on its 'human dimension' . / Thesis (Ph.D.)-University of Natal, Durban, 1996.
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Subsurface soil erosion phenomena in Transkei and southern KwaZulu- Natal, South Africa.Beckedahl, Heinrich Reinhard. January 1996 (has links)
Subsurface erosion forms has been regarded as a unique exception to the more
common surficial erosion forms such as rills and gullies, and have therefore been viewed as being of little consequence consequence for the total annual soil loss within any given region. A total of 148 subsurface erosion system occurring at 66 sites in Southern KwaZulu-Natal and Transkei were analysed morphologically to determine the
significance of subsurface erosion within this region, to assess the extent to which
the observed phenomena may be explained by current theories.
Based on morphological criteria related to the dimensions of the subsurface erosion
phenomena, it has been shown that there are five distinct -subsurface erosion systems
namely scree slope systems; gully- sidewall systems; anthropogenically induced
systems; system associated dispersive soils, seepage systems. It was further
found that, under certain circumstances, the sediment lost through surficial erosion can be increased 77% by subsurface erosion and the subsurface erosion is spacially to particular slope units which are defined on the basis of the dominant geomorphic processes.
Although soil chemistry, in particular dispersion related to the exchangeable Sodium percentage and the Sodium Absorption Ratio, is an important factor in facilitating
subsurface erosion, other factors are also important as scree slope systems for
example occur in soils which are completely non-dispersive. It has been possible to
demonstrate that there is a statistically' significant correspondence between the spatial orientation of
inter-ped surfaces the orientation of bedrock joints. This correspondence has enabled the explanation of how the well documented phenomenon of structurally controlled drainage basins may develop._ This correspondence has enabled the explanation of how well documented phenomenon of structurally
controlled drainage basins may develop. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1996.
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