Future Water Institute wraps up six-year living lab project in Mitchells Plain

The second and final phase of an ecologically focused, novel initiative – Pathways to water resilient South African cities (PaWS) project – led by the University of Cape Town’s (UCT) Future Water Institute, has made good strides while operating as a living laboratory in Mitchells Plain on the Cape Flats.

The living laboratory, which forms part of the PaWS project, is situated in a stormwater pond in Fulham Road, Mitchells Plain, and got under way in 2019. The project was established in partnership with UCT’s Future Water Institute and the University of Copenhagen; and was set up in response to Cape Town’s 2017/2018 water crisis.

As the project prepares to wrap up later this year, UCT News sat down with the director of the Future Water Institute and South African principal investigator for the project, Associate Professor Kirsty Carden, for more on the initiative and their work at the stormwater pond.

Niémah Davids (ND): In a nutshell, tell us more about the PaWS project.

Kirsty Carden (KC): As partner universities, we responded to a call by the Danida Fellowship Centre in early 2018 with a Phase 1 concept note. We aimed to identify opportunities for integrating water supply alternatives within the urban water system, by implementing nature-based solutions within existing stormwater ponds as part of a bigger water sensitive design approach in Cape Town and Johannesburg. The idea was focused on investigating opportunities to build a resilient water supply system.

We were invited to submit a full proposal in August 2018, and soon thereafter we heard that we had been awarded funding for the project (from 2019 to 2022), and we subsequently applied for three more years of follow-on funding for the second phase. Our overall idea was to harness blue-green infrastructure (natural elements, parks, vegetation) combined with blue infrastructure (rivers, stormwater ponds, wetlands) to provide multiple benefits and to help us achieve water-sensitive futures. By doing this, we hoped to extend our initial study and generate knowledge on stormwater infrastructure network functions within a city; and how it can be designed, expanded and aggregated. We aimed to transform a monofunctional, neglected stormwater pond space into multifunctional blue-green infrastructure, and to carry out this transformation in collaboration with key local, city and civil society role-players.

ND: The project operates as a living laboratory in Mitchells Plain. What does this mean?

“A living lab is defined as a real-world, user-centred environment where people co-create and test innovative solutions, foster user-driven innovation and learn through collaboration and experimentation.”

KC: A living lab is defined as a real-world, user-centred environment where people co-create and test innovative solutions, foster user-driven innovation and learn through collaboration and experimentation. In our case, the stormwater pond is an experimental space that has been co-developed by the research team together with residents and other stakeholders. What we wanted is for our work at the stormwater pond to provide answers to a range of questions including hydrology (the movement of water), water quality, policy, local stewardship and engagement, as well as biodiversity and urban design, all of which are related to our overall study.

ND: What did it take to set it up?

KC: We hosted project kick-off meetings in Cape Town in May 2019, together with the research team from Denmark. These meetings were set up as learning labs and workshops with selected stakeholders from the municipality, consultants and non-governmental organisations (NGOs) to discuss the objectives of the project and initiate some of the co-design and research support processes.

We then went through several design iterations for the physical experiment in Cape Town, which involved retrofitting a selected stormwater detention pond with a nature-based solution (infiltration swale with a sandbag wall) to increase infiltration of incoming stormwater to the aquifer, while also improving its quality. We also held meetings with relevant officials from the City of Cape Town and their groundwater consultants about suitable pond sites.

Stormwater detention ponds are prevalent throughout the City of Cape Town (there are around 850 of them) and they are generally vacant, under-utilised spaces that are prone to vandalism, dumping or land invasions. They are also mostly dry, except when there has been heavy rain, in which case there may be some short-term ponding of water.

ND: Why Mitchells Plain in particular?

KC: Over 200 of the stormwater ponds across the city are situated in Mitchells Plain, above the Cape Flats aquifer. What this means is that there is lots of potential for experimenting with stormwater ponds in this area. We needed to find a pond that would serve our research purposes, including easy and safe access, suitable hydrogeology (including depth to water table to allow for stormwater infiltration), proximity to a local anchor (in our case a primary school) and no significant clay layer. After a process of assessment, we chose a pond in Fulham Road.

ND: What was the aim of this work and what impact do you hope it will have?

KC: We’d like for people to engage with and understand the water cycle better. We want them to understand that tap water and stormwater are all linked through the hydro-social cycle, where social structures and power relations influence how water is produced, managed and used, and how these, in turn, shape societal relationships with water.

“We’re also hoping to create a better understanding of stormwater systems and their value in urban areas.”

Importantly, we’re also hoping to create a better understanding of stormwater systems and their value in urban areas. These are spaces of opportunity and can also potentially provide a means for residents to engage with the city and to develop relations that improve historic perspectives. We want young people to understand the value of stormwater and blue-green spaces, and for neighbourhoods to find excitement in the variety of species, habitats and opportunities that such spaces can offer.

ND: After almost six years, what has your research revealed?

KC: There have been important findings in respect of the hydrological and water quality experiments – where the installation of the infiltration swale was found to significantly increase groundwater recharge, thus enhancing the potential for managed aquifer recharge.

There was also evidence of contaminant removal during stormwater infiltration, especially for ammonium, total organic carbon, total dissolved phosphate, aluminium and zinc, as well as nitrates. This highlights the possibilities for scaling up these systems into a broader stormwater harvesting programme at suitable sites across the city to assist with local water security.

ND: Have you found anything particularly interesting during this study period?

KC: Learning about the relationships among residents, between residents and the city, and between city departments has been very interesting. It has also started to paint a picture for, not only the importance of an engaged citizenry as we work towards implementing blue-green infrastructure, but also for governance processes at local government level, which need to be better integrated if the city’s water-sensitive vision is to be realised.

ND: Finally, how do you plan to use these findings to inform work in this area in the future?

KC: We are developing a compendium of case studies, applications and processes and these will be written up into a comprehensive toolkit that will form one of the project’s main outputs.

“This toolkit will address some of the gaps in knowledge and practice around the implementation and scaling of nature-based solutions for water management in South African cities.”

This toolkit will address some of the gaps in knowledge and practice around the implementation and scaling of nature-based solutions for water management in South African cities, and will be geared towards local government officials, consultants, technical specialists, NGOs and community groups. It will include details on how to repurpose the urban fabric; and how to plan, design, monitor and engage with repurposing of stormwater ponds.