Harvesting stormwater to supplement water demands has attracted a growing interest in South Africa as concerns over the security of the country's water supply increase. Whilst stormwater harvesting has been shown to offer a viable alternative water resource, there are often concerns about its storage requirements due to space constraints in urban areas. Stormwater ponds offer a potential solution to these concerns. Since stormwater ponds are typically designed for the sole responsibility of attenuating the periodic peak stormwater flows that are associated with large storm events, they often remain underutilised. By introducing Real Time Control (RTC) systems to operate stormwater pond outlets, ponds could potentially be used to store stormwater. This could increase the benefits that stormwater ponds provide as well as offer a viable alternative water resource. To investigate the economic viability of harvesting stormwater from existing stormwater ponds, a case study was performed on a representative urban catchment – the Diep River subcatchment, located in Cape Town, South Africa. The catchment contains seven stormwater ponds, which could be retrofitted for harvesting purposes. Sixteen different stormwater harvesting scenarios were developed that modelled various non-potable demands in the vicinity as well as different storage and harvesting arrangements, created using RTC strategies, of the catchment's existing ponds. These scenarios were modelled using an assortment of modelling tools which include: a catchment stormwater model; water distribution network models; and a Life Cycle Cost Analysis (LCCA). The economic viability of harvesting stormwater from the Diep River subcatchment's stormwater ponds was most susceptible to the cost of the system's water distribution infrastructure. Consequently, stormwater harvesting was most economically viable if used to supply toilet, clothes washing and irrigation demands to residential properties situated in close vicinity to the system's harvesting pond as this minimised the extent of the water distribution network. The results also revealed that distributing storage amongst ponds situated throughout the catchment is an effective method of increasing the volume of stormwater a stormwater harvesting system could yield without reducing its economic viability. However, this is on the condition that the system only extracts stormwater from the most downstream pond in the catchment. Importantly, the study also revealed that the attenuation of peak flows of large storm events (up to 1-in-20 year return period), achieved when harvesting stormwater from the existing stormwater ponds would be comparable to what the ponds currently provide. The study concluded that harvesting stormwater from existing stormwater ponds is potentially viable. It also demonstrated an effective method to maximise a catchment's storage capacity using distributed storage. For stormwater harvesting to be viable however, stormwater should be used to supplement a large percentage of non-potable end-uses and requires significant uptake amongst catchment residents.

It is the purpose of this thesis to evaluate a few selected gas chromatographic materials for the separation of odorants produced by an actinomycete culture under laboratory conditions. Also to compare the results obtained with concentrated solutions of a surface water containing similar odors under natural conditions.

This dissertation examines the development of Cape Town's water supply between 1840 and 1920. The thesis examines the effect that the augmentation water supply had on municipal politics and the development of the municipality of Cape Town. It is argued that the high cost of water supply, arising out of Cape Town's geographic situation, had a major impact on its municipal government. In the nineteenth century the dominant class was divided between merchants who wanted water and the rentier classes who had to pay for it. In the subsequent political struggle for control of the municipality, the working class, which supported the rentier class were alienated. As a result, they resisted municipal improvement, delaying a solution to the water problem until the twentieth century. Chapter One examines the period from 1840 to 1900 where water supply was related to attempts to bring about municipal and sanitation reform. While this succeeded, by the late 1890's ratepayers reacted against excessive municipal spending, ultimately to the detriment of planned water schemes in the hinterland. Chapter Two argues that in the period between 1900 and 1910 businessmen attempted to link water supply to the unification of the municipalities of the Cape Peninsula. This resulted in a struggle between the city and the suburbs for over the control of the water resources of the hinterland. Chapter Three examines municipal unification in 1913 and the repercussions it had for water supply. The focus falls on a municipal referendum in 1917 in which the class divisions of half a century were a factor in the choice of a hinterland water scheme. The dissertation concludes that water is important for explaining class divisions in municipal politics. It is suggested that the impact of water on municipal history is not unique, but in Cape Town's experience it was prolonged and intense. A further conclusion is that it affected the process of municipal unification between 1902 and 1913, shaping the form of the modern city. A wide range of sources were used including municipal archive material and government reports and commissions. Newspapers and cartoons have been used extensively as they were instruments in the struggle for reform. Comparisons are drawn with the experience of overseas cities in an attempt to provide a coherent model for understanding the place of water supply in urban history. The dissertation represents an attempt to provide a better understanding of Cape Town's history during this period and therefore relates municipal history to wider political, economic and social changes taking place. It also complements recent histories on sanitation, race and municipal politics which fall in this period.

Very little has been achieved during the first five decades of development and application of what is now known as environmental law, in terms of slowing the global rate of biodiversity loss and ecosystem degradation. A major factor in this lack of effectiveness has been, perhaps, too narrow a focus on individual elements that exist within ecosystems, rather than on the health of the ecosystems themselves. Additionally, very little attention has been paid to maintenance of the integrity of the many types of connections that exist between the different components of ecosystems, notably aquatic ecosystems. These components are connected not only by water, but also by a variety of ecological connections and pathways ¾ here termed 'hydroecological connectivity' (HEC). These connections are not only important in terms of providing abiotic and biota corridors between components, but they also act as conduits which can translocate pollutants from one location, over vast distances, throughout a fluvial ecosystem, consequently impacting virtually all areas of human life and nature. This thesis outlines the science underpinning the first connectivity-based water law regulation, the American Clean Water Rule (CWR) and analyzes a set of legal challenges to this Rule. Barring one instance, no substantive merit was found for any of the disputed claims. Furthermore, this thesis identifies the transferability of the Rule to South Africa. It was possible to empirically substantiate the merit of the single instance that lacked appropriate qualification in the CWR. The importance of HEC is elucidated in this work using the example of headwater streams which, in aggregate, comprise 79 per cent of the aggregate length of the mapped rivers in South Africa. Also provisionally evaluated is a brightline distance, lateral to fluvial watercourses, within which water resource components that are likely to be connected to the mainstem will be found. This provides a guideline for HEC-directed administrative decision making. A connectivity-based approach to water resource governance will require limitations on some land uses on portions of land that is likely to be perceived as terrestrial but which, in fact, forms part of an aquatic ecosystem. This requirement raises obvious implications for property ownership and expropriation. Here the principles of the public trust, already legislatively expressed in South African water law, provide an institutional legal framework that renders 'public' any lands which form part and parcel of the integrity an aquatic ecosystem. The public trust doctrine anchored the reform of the post-apartheid water law of South Africa. It was introduced in a transformative and emancipatory approach to the democratisation of the nation's water resources and the restoration of water equity. This work provides the first historico-legal and comprehensive perspective of the genealogy and intentions for, the public trust in South Africa, and distils out the principles which the trust embodies. An example protocol is developed which shows how the trust principles underpin the formulation of guidance for determinations of beneficial water uses. Recommendations are made regarding the operationalization of the currently moribund South African public trust in water and highlights the role of the public trust as an effective and reformatory tool of water law. In summary this work is a translational and transdisciplinary example of aquatic science into environmental law. The complex and challenging concept of HEC is communicated in plain language and then its perceived weak point ¾ the need to isolate areas of land which form part of the aquatic resource and incorporate these within the trust res ¾ is construed using the principles of the public trust doctrine. Simultaneously the potential of the public trust to offset obstacles to environmental protection, such as the need for reformed guidance for administrative decision making, has been highlighted. On this model the public trust enfolds an ecosystem-directed HEC approach into a transformative and normative governance package which is integrative, adaptive, multi-disciplinary and proactive.

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This thesis has been damaged by water. Unfortunately, it is the only physical copy available and therefore we cannot improve the quality of this scan.

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