The problem of water scarcity is a top concern for South African cities. Cape Town is currently experiencing a drought that has led to a water supply crisis with the city declared a Disaster Area. This declaration has enabled the city to access funds for accelerated construction of several small desalination plants and the drilling of the Cape Flats and Table Mountain aquifers to augment water supply. Johannesburg is a historically water-scarce city, relying on Inter-Basin Transfers (IBT’s) from Lesotho for water and like Cape Town, recurring droughts are resulting in uncertainty in water supply. Desalination and IBT’s are indicative of both cities’ continued path-dependence on centralised, hard water infrastructure whose negative environmental impacts also in light of projected climate change is increasingly recognised.

Water management is an essential part of urban sustainability. However existing centralised water provision models are increasingly viewed as ill-suited to address prevailing problems including climate change and resource pressures. There are increased calls for adaptive urban water governance to address the environmental and socio-economic uncertainties confronting urban water systems.

’Sustainable urban Water management’

Sustainable urban water management (SUWM) is an umbrella term for various nature-based approaches to water management that take a total urban water cycle view through the integration of built water infrastructure with green infrastructure in a decentralised manner. Approaches that link storm-runoff and wastewater to water supply are also known as Water Sensitive Urban Design (WSUD), Sustainable Drainage Systems (SuDS); they help to return urban rainfall-runoff processes to natural hydrological cycle flows, by reducing runoff volumes and peak flows, improving infiltration, and reducing pollutant loads.

Improved water supply

There is a need to explore under-exploited water resources such as stormwater harvesting and managed aquifer recharge with treated sewage effluent that can simultaneously augment water supply and enhance urban resilience. However, the quality of stormwater in South African cities is generally poor due to infrastructure deficits, with point and non-point source pollution in runoff flows. Harnessing SWH and MAR with treated effluent would be more feasible if the quality of runoff being infiltrated or stored is improved through pre-treatment with green infrastructure options such as swales, biofiltration cells and constructed wetlands. These elements also offer cities the benefits of flood risk management and improved biodiversity, opportunities for food production through edible green infrastructure and increased liveability.

Improved water governance

Whilst there is consensus within the urban water fraternity on the need for a shift to more adaptive approaches, how such transformations in the design, implementation and governance can be realised remains unclear, particularly in the highly compartmentalised infrastructure sectors typically found in South African cities.

Recognising the economic, environmental, technological and governance challenges in the South African urban water sector, the South African government developed the Water Research Development and Innovation Roadmap. One focus area is the unlocking of water supply alternatives such as SWH and groundwater through the use of WSUD approaches. There is a need for assessing the technical feasibility of these alternatives and the governance implications of hybridising built water infrastructure with nature-based solutions. The project will also contribute to the achievement of SDG’s 6, 9, 11, 13 and 17 of ensuring access to drinking water and integrated water resources management; promoting urban resilience to climate change and cooperative governance for sustainable development. It will also support the national priority of increased urban green infrastructure and facilitating engagement and coordination between stakeholders in the management of human settlements.