Green infrastructure: urban water management framework for Paarden Eiland, Cape Town
Cities in South Africa are currently experiencing rapid urbanisation, especially Cape Town. Infrastructure development has long been a critical component with a large amount of money invested in the development of hard infrastructure. However, in light of excessive stormwater runoff, the increased deterioration of surface water resources, degraded water quality, and the rapid progression of climate change around the global, many cities including Cape Town have progressed towards more sustainable forms of infrastructure development. Discourse surrounding sustainable development often encourages the improvement of the quality of urban areas without compromising the carrying capacity of ecosystems. This is a fairly new model in South Africa, which challenges the underlying principles of conventional infrastructural design and management. There is particularly an enthusiastic interest in the promotion of green infrastructure as a water sensitive design strategy in the management of stormwater and surface water. Presently, drainage systems for urban areas in Cape Town are constructed using principles of hard infrastructure, which often consist of complex man-made networks of underground tunnels and pipes that gather and direct stormwater runoff towards a surface waterbody. However, the extensive development of drainage infrastructure has led to increased stormwater runoff volumes, flooding, and flows. Urban stormwater runoff is known to be one of main sources of pollution and degradation of waterbodies, which has in turn resulted in the degradation of other environmental assets. Therefore, the planning, design, and implementation of infrastructural solutions there is a need to move towards a more sustainable and water sensitive model, in order to remediate these problems. Green infrastructure in this respect offers an opportunity to better manage both stormwater and surface water in a more holistic, cost-effective, efficient and ecological sound manner. The main objective of green infrastructure urban water management is to mimicking the natural hydrological cycle through various stormwater management interventions, in order to achieve what conventional drainage systems currently do and beyond their existing capacity. This dissertation uses Paarden Eiland as a case study and experimental project site in order to assess and investigate how green infrastructure can be utilised to effectively manage stormwater runoff and surface water within a heavily developed urban area. It explores the potential benefits this method of management provides in comparison to a conventional infrastructural approach of management. This study also highlights some of the critical issues and barriers that urban practitioners need to take into account when implementing such systems. A green infrastructure urban water management framework and conceptual layout are presented in order to demonstrate potential green infrastructure tools and strategies that may be used in retrofitting heavily developed areas, as well as provide guidance on how spatial planning can be utilised as a tool in the planning, design, and implementation of green infrastructure as well as in overcoming identified financial, technical, and institutional barriers.
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School of Architecture, Planning and Geomatics