SuDS in Diepsloot

Creation of new green areas, Ecological restoration of ecosystems

Diepsloot is highly susceptible to flooding due to its location in the Jukskei River floodplain. The area is also densely populated, fully covered with impervious surfaces and has very little green space, all characteristics that exacerbate flood risk. As such, the goals of the intervention were the following: 1. To adopt a green infrastructure (GI) approach – a holistic urban planning approach deliberately incorporating natural and man-made ecological systems into infrastructure planning and development in a similar way to traditional grey infrastructure. The scope is to help restore biodiversity and the provision of ecosystem services. 2. To address issues related to erosion and flooding, specific during summer thunderstorms - this places severe stress on formal and informal stormwater systems and regularly results in flooding, an aspect of particular concern in informal settlements where the dwellings are vulnerable to collapse. 3. To address the phenomenon of rapid densification that led to the removal of vegetation, straining therefore the natural ecosystem of the area. 4. To create a sustainable drainage system that will also help with the improvement of the water quality in the area. (1,2,3)

The research team, including a resident who is a member of a local community plumbing organisation, carried out a broad survey to identify surface water ‘hotspots’. A 600 m stretch of the south bank of the Jukskei River was selected, representing one of the least formal parts of the settlement. The resident team member did a door-to-door survey to assess householders’ interest in the project. From this, 2 sites were chosen, each with 4 to 8 households. The chosen sites are located within the river floodplain, in which years of illegal dumping have created a berm between the flowing water and dwellings. Both sites had rudimentary drainage constructed by residents, which leads through the dumpsites before percolating into the river. The elements chosen were simplifications of standard SuDS, namely previous channels, semi-vegetated channels, soakaways and a miniature bio-retention area. A bio-retention pond was built from broken brick to create a porous base, and water-tolerant indigenous vegetation was planted on the periphery of the paving. Each day’s work was then evaluated on the subsequent work-day in discussion groups of 4 to 8 residents, which explored adaptations to previous work. (1,2)

• Non-government organisation/Civil Society
• Researchers/University
• Citizens or community groups
• Marginalized groups: Socio-economically disadvantaged populations (e.g. low-income households, unemployed)