Browsing by Author "Van Zyl, Amore"

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    System dynamics modelling as policy decision support for retaining and recycling water within the urban water system to address water scarcity – the case of the City of Cape Town
    (Stellenbosch : Stellenbosch University, 2019-12) Van Zyl, Amore; Jooste, J. L.; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.
    ENGLISH ABSTRACT: Water scarcity is a worldwide phenomenon, identified as the number one global risk, that if neglected, can result in social and economic collapse. The City of Cape Town is one The results found that rainwater harvesting and decentralised wastewater reuse did not significantly decrease the water supply stress in the City. However, the effective reuse of greywater lowered the water stress experienced, while combining several intervention actions simultaneously had the most success in reducing water supply stress in the City. Furthermore, the model presented expected oscillatory behaviour due to the system’s reaction to constraints on water allocation. Finally, as time progress the impact of interventions declined, indicating that continuous evaluation and intervention actions are required to balance the growing demand. such urban region experiencing ongoing water shortages in conjunction with several other urban regions in South Africa. Subsequently, the need for innovative and sustainable solutions, to address the growing water deficit, has become essential to assure sustainable water resources for the future. The City is predominantly dependent on traditional water resources from the Western Cape Water Supply System that are vulnerable to climate change and rising water demands. Therefore, alternative sources of water serve to diversify the water resources for City consumption. Using an integrated approach to alleviate water stress in the City, value can be extracted from within the water system. Retaining and reusing water in the system and reducing water consumption are interventions that align with circular economy principles to zero waste for value generation. However, legislation aimed at extracting value from the urban water system need to be tested and evaluated to ensure sustainability in the City’s economic, social and environmental sectors. The urban water system is a complex system with interconnecting elements. To avoid unexpected outcomes as a result of implemented changes, a holistic approach to water management is required. Literature found system thinking to be a suitable approach for evaluating policy changes in complex water systems, providing insight and understanding to decision-makers. To develop a decision support model that represent the real-world system behaviour, technical and census data as well as case study research was used to link causal behaviour by constructing equations and stock-and-flow diagrams. The constructed system dynamics model, once validated, allowed for the development of policy scenarios. These scenarios tested the impact of utilising rainwater harvesting, greywater reuse and decentralised wastewater treatment plants together with consumption restrictions to alleviate water supply stress in the City over the period 2001-2040.