Abstract
Sustainable drainage systems (SuDS) imitate natural water management processes in catchments that have been degraded due to urbanisation. The aim is to reduce the quantity of stormwater runoff and improve water quality. Management of rainwater in the informal settlement of Diepsloot in Johannesburg is compounded by domestic wastewater discharged into the informal lanes. These lanes fall outside the mandate of the City of Johannesburg’s stormwater management system; hence residents need to rely on their own initiatives to address surface-water problems. This preliminary study investigated the introduction of SuDS to enhance existing surface-water interventions, as a low-cost flexible approach. Using action research methods, small-scale interventions were designed, constructed and refined by residents and researchers at two sites close to the Jukskei River. While the primary intention of the research was to reduce standing water in the public areas, water quality testing indicates that the SuDS reduced some pollutants. Nitrate and phosphate concentrations were slightly lowered through the introduction of permeable channels and soakaways, while these interventions had a moderate effect on chemical oxygen demand. The involvement of residents at the two sites was markedly different, reflecting divergent priorities and social dynamics. Spontaneous continuation of the SuDS system at one of the sites indicates successful knowledge and skills exchange. This study was of limited duration with only two sets of water quality tests; therefore, longer term monitoring is strongly advised to be able to give more robust assessment of this type of intervention.Keywords: SuDS, action research, water quality, informal settlements, Diepsloot
Highlights
In the City of Johannesburg, informal settlements are predominantly found on the periphery of the City on land that was formerly used for agriculture or pasturage (Harber, 2011)
The chemical oxygen demand (COD) results for samples taken before the Sustainable drainage systems (SuDS) intervention are higher than 75 mg/L at the outlets, posing environmental risks (DWAF, 1996b)
This study shows that pervious paving and soakaways can be installed for almost no cost with materials that would otherwise be contributing to the dumping
Summary
In the City of Johannesburg, informal settlements are predominantly found on the periphery of the City on land that was formerly used for agriculture or pasturage (Harber, 2011). Residents use cast-off carpeting or precast panels as a ‘paving’ solution to prevent soil erosion, especially at the entrances to dwellings (Carruthers, 2008; Mafunganyika, 2011). In this way, the natural surface-water regime is almost entirely replaced by impervious surfaces with a high runoff co-efficient (Carruthers, 2008). The level of cleanliness and hygiene within the individual households tends to be very high, but the impression to an outsider is of urban degradation (Richards et al, 2007; Mafunganyika, 2011)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have