Water-sensitive cities, by design

20 March 2018 | Story Kirsty Carden. Photo Roark Robinson. Read time 6 min.
Architectural image of the Water Hub in Franschhoek by Roark Robinson of MRA Architects.
Architectural image of the Water Hub in Franschhoek by Roark Robinson of MRA Architects.

Research at UCT is informing the design and development of water sensitive cities and the management of water cycles in urban environments.

A water-sensitive city is a sustainable city that uses water in a practical and aesthetically pleasing way using an approach termed water-sensitive design. Water-sensitive design differs from traditional planning methods that focus on water treatment and delivery infrastructure by including social, governance and engineering aspects to minimise the impacts of urban development on the surrounding environment.

As South Africa continues to face challenges of water scarcity and declining water quality, the relevance of this approach is increasing. It is thus being actively promoted as part of a suite of research projects by the South African Water Research Commission.

UCT researchers from the Future Water Institute have been involved in this initiative from the outset and have developed the framework and guidelines for water-sensitive design in South Africa. Future Water is also leading a project on developing and managing a community of practice for water-sensitive design, aimed at developing a critical mass of knowledge on the integration of planning activities for the adoption of water-sensitive design in South Africa, as well as the governance processes that we will need to facilitate this transition.

Future Water’s research projects have also investigated the feasibility of implementing technology options and approaches to water-sensitive design, including permeable pavements and sustainable sanitation options, as well as opportunities for recovering resources from urine, for example. Our research is ongoing into a range of alternative water sources for ‘fit-for-purpose’ uses. This means we match water of a certain quality to a use that is appropriate for that quality of water. The goal is to offset the growing demand for potable water – specifically using groundwater, stormwater, greywater and treated effluent – and links to plans to actively manage recharging the Cape Flats Aquifer.

Associated with this is work we are undertaking in the areas of water conservation and management of water demand, and on metering and leakage in water distribution systems. Focal points are stormwater harvesting, and the assessment and monitoring of sustainable drainage systems for surface water runoff; these form the basis of several different projects. Some of these systems are being demonstrated and experimented with at a facility under development at the Water Hub in Franschhoek, about 75 kilometres east of Cape Town, on the site of a decommissioned wastewater treatment works.

Our intention is to determine the extent to which robust, nature-based options for water treatment are capable of cleaning and polishing the water that is currently being discharged from the poorly-serviced settlements – that are typical in urban areas in South Africa – into urban stormwater and river systems. The aim is to produce, from these sources, water suitable for use in small-scale agriculture. An example of a nature-based tool that could be used of this purpose is a biofiltration cell, a chamber filled with media, such as aggregate stone or peach pips, on which micro-organisms grow and act as ‘cleansing’ agents for the contaminated water that flows through it.

A number of our other projects focus on water quality within our river systems in the Western Cape and its impact on human health, the environment and urban spaces, as well as the interaction between local communities and rivers.

Worldwide, evidence suggests that the philosophy of water-sensitive design offers a variety of choices in the management of scarce and often deteriorating water resources, and that it adds economic and environmental value to cities. In the South African context, our research is showing that water-sensitive design has the potential – through relatively modest interventions – to change the way in which water is managed to increase the sustainability and resilience of water systems.

By transforming urban areas in water-sensitive cities, we have the opportunity to connect spatial divisions through the development of waterscapes and ‘blue-green’ corridors, and ensure greater equity in terms of the availability of water services.

Dr Kirsty Carden is the research coordinator at the Future Water Institute based at UCT’s Faculty of Engineering and the Built Environment.
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