With the global population of urban dwellers expected to rise to 5 billion in 2030, it is now crucial that cities grow in a sustainable manner in order to relieve pressure on resources and infrastructure.

This is according to green building consultant Marloes Reinink of Solid Green. “Cities today face numerous challenges, but at the same time they are nodes of opportunity to move green design beyond the scale of individual buildings.” She adds that the impacts of unsustainable development include a rise in global temperatures, the urban heat-island effect, a lack of resilience to natural disasters, air and noise pollution, concerns around food and water security, and increasing socio-economic inequality.

Urban sprawl

According to Reinink, one of the biggest challenges is suburban sprawl. This is characterised by isolated residential developments, separate business parks and islands of retail with big parking lots that are mainly accessible by car, despite 80% of the population being pedestrians. This disconnected way of urban planning takes up valuable land space that could be used for agriculture, increases pressure on resources, and requires extensive transport infrastructure. And, according to an American study by The Smart Prosperity Institute on the cost of sprawl, it is almost three times more expensive to maintain these wide-spread sprawl areas than high-density, inner-city living areas.

Well-designed cycle and pedestrian path around Cape Town Stadium (Credit: Zendré Compion)

On a personal level, people have to spend more on transport and waste a lot of time sitting in traffic – thus missing out on vital physical activity which, in turn, may lead to health issues and higher medical expenses.

Learning from the Past

Reinink highlights a number of strategies to create sustainable cities that are both in line with New Urbanism principles and draw on the lessons of historical cities that evolved over time – resulting in compact, connected, mixed-use and walkable neighbourhoods.

• Compact, mixed-use precincts: Taking the idea of a 20-minute neighbourhood, developments should comprise a good mix of uses that are all connected so that residents can easily walk or cycle to where they need to be.
• Human scale: Probably the most important objective is to plan for the end user by designing to a human scale, with a focus on sidewalks with ground-level activity where people feel safe walking. This would exclude big open parking lots, closed facades along walkways, and multi-lane roads in predominantly pedestrian areas.
• Activate street edges: Design for vertical mixed use (commercial and residential), with restaurants, retail and leisure activities encouraging pedestrian movement at street level, connected by safe, shaded pedestrian walkways and places for social interaction.
• Mixed-mode transport infrastructure: Providing cycling lanes, continuous sidewalks and connections to suitable public transport could significantly change people’s behaviour, just as the Gautrain did. Reinink observes, “In Gauteng in general we have extremely low densities, which makes it really difficult for public transport to work efficiently, but that is beginning to change.”
• Integration and connectivity: Most malls and offices in South Africa are very difficult to access on foot or by bicycle. Rather, these retail and commercial opportunities should be integrated with the surrounding neighbourhoods through interconnected blocks and multiple pedestrian entrances and exits.
• Create walkable cities: Urban planner Jeff Speck has identified four characteristics of a walkable city: (1) users should have a reason to walk (close amenities); (2) the walk must be safe (continuous sidewalks); (3) it should be comfortable (shading); and (4) the route should be interesting (providing access to shops, public art/furniture and rest areas).

Sustainable Precincts

The new Green Star SA Communities tool has recently been launched, with Solid Green consulting on four of the thirteen projects that will be piloting the tool – Oxford Parks, Sandton Gate, Metro Precinct and Menlyn Maine.

Menlyn Maine Pegasus (Credit: Boogertman+Partners.)

The Green Star Communities vision is to: enhance liveability while creating opportunities for economic prosperity; foster environmental responsibility; and embrace design excellence while demonstrating visionary leadership and strong governance. The tool looks at the shared attributes of Infrastructure, Buildings, the Public Realm, People, Ecology, Economy, Governance, and Services.

Reinink concludes:

While several high-density, self-sustaining city developments have been developed, such as Melrose Arch, Waterfall Estate, Menlyn Maine and Oxford Parks, we need to ensure that these developments are connected and that there will be a sustainable means of transport between these developments to ensure the sustainable growth of our cities. Walkable cities are healthy cities, and we have to look more pragmatically at how we can adjust to make cities function in a more sustainable way.

Bryant Park, NYC (Credit: Zendré Compion)