Green as the new grey: A spatial planning perspective on the use of raingardens in stormwater management in Johannesburg, South Africa

Abstract

Global climate change causes a change in rainfall patterns and an increase in downpours that results in flash floods. Floods are responsible for more deaths than any other thunderstorm related hazards. The purpose of this study is to explore green infrastructure as an alternative to traditional grey stormwater management systems by focusing on Water Sensitive Urban Design (WSUD) with specific reference to raingardens to create a more sustainable, resilient and regenerative urban stormwater management system. The research context of the study is the City of Johannesburg Local Municipality, located in the Gauteng Province, South Africa. Taking into consideration that Gauteng is the province with the highest population in South Africa and in December of 2022 more than three hundred and thirty-nine (339) people have been impacted by floods, the need to investigate alternative methods to manage stormwater is a pressing issue. However, scholarship about the utilisation of green infrastructure in terms of stormwater management is limited from a South African perspective, especially from the field of Urban and Regional Planning. This study uses a qualitative approach and singular in-depth case study design in to obtain an in depth understanding of the current stormwater management system within Johannesburg. To execute the research, a comprehensive literature review has been conducted about three underpinning theories that form the theoretical framework for the study including sustainability theory, resilience theory and regenerative theory. For the empirical part of the study, two methods were employed to generate data. Firstly, a document analysis has been conducted, to investigate the relevant policies, legislation, and frameworks. Secondly, digital semi-structured interviews have been conducted to obtain in-depth information on three aspects: (i) the current stormwater management system; (ii) the sustainability of the current stormwater management system, and (iii) possible solutions / future considerations for stormwater management in Johannesburg. Interviews have been analysed by means of thematic analysis from the verbatim transcriptions. The findings of the study include findings from the literature review, document analysis and empirical investigation. Main findings from the literature review relates to the interconnection of ecosystem services, nature based solutions and green infrastructure, and the importance of the concepts in terms of sustainable developments. Therefore, WSUD is seen as a solution to address stormwater runoff. The document analysis indicates that there is a need to increase the amount of ecosystem services. From the empirical study, three main themes emerge about the management of stormwater in the case of the City of Johannesburg. Themes and sub-themes include: (i) main theme one; the lack of a proper stormwater management system. Sub-themes include that the stormwater management system of Johannesburg is ineffective, low-costdevelopments are not serviced with stormwater management systems, and the custodian of stormwater management. (ii) Main theme two relates to the current unsustainability of the stormwater management system. Sub-themes: the quality of stormwater in Johannesburg; and the challenges of implementing and maintaining the stormwater management system of Johannesburg. (iii) Main theme three relates to the potential solutions / future considerations for stormwater management. Sub-themes: the restructure of stormwater management governance; and green infrastructure as a strategic solution for mitigating stormwater. These themes indicate that there is a need to shift from grey traditional stormwater management systems to a green sustainable stormwater management system. A shift has been made on international, national, and local level towards sustainable development regarding stormwater management. However, although sustainable development is propagated and green infrastructure acknowledged in the Johannesburg Spatial Development Framework, the most recent stormwater management plan has remained a focus on traditional grey stormwater management practices.