(Post by Kerry Bobbins, of the Gauteng-City Region Observatory).
Functioning as a living infrastructure alternative, green infrastructure (GI) is the natural life support system that provides services for society and the environment. GI is described as the interconnected set of natural and planted trees, wetlands, parks, open spaces, grasslands and woodlands and man-made grey-green design solutions such a green roofs, bioswales and constructed wetlands.
Considered to be a forgotten component of many urban landscapes, GI provides important services for urban areas. These can include air filtering, micro-climate regulation, noise reduction, rainwater drainage, sewage treatment and recreational and cultural spaces (Bolund & Hunhammar, 1999).
A range of theoretical and applied studies on the benefits of GI have started to permeate the policy and planning landscapes of cities around the world. This is because city managers and planners strive to find more sustainable alternatives for addressing growing urban mandates with limited budgets. GI is increasingly being recognised for its potential in designing cost effective solutions for existing urban-based challenges such as pollution, flooding, poor air quality and heat island effects. GI has also become an attractive concept for creating sustainable urban design through supporting high-density urban development, climate change adaptation, sustainable communities, micro-climate control and biodiversity (Mell, 2008).
While a GI planning approach is being taken up in the planning of many cities around the world, it is finding very little purchase in South African cities. This is because GI is not considered to be a viable infrastructure alternative and this is further inhibited by the way infrastructure projects are commissioned and how budgets are allocated. More specifically, traditional built infrastructure is perceived to be low a risk solution for meeting developmental needs while grey-green engineered solutions and the extension of green networks, are perceived to be high risk with no standard design procedures.
With limited budgets and capacity, South African cities arguably have the most to gain from a GI planning approach. This is because the multi-functional nature of GI has the ability to meet a number of local infrastructural and developmental challenges associated with inequality and poor living and working environments.
For example, Johannesburg and Pretoria struggle to address the stark inequalities that still exist in the provision and access to basic services and a broad set of environmental challenges associated with mine waste, biodiversity loss and land degradation. A GI planning approach can be easily applied in these cities as they are already considered to be highly transformed landscapes and they have a rich and diverse set of green assets both natural and man – made. The largest share of land cover in the GCR is planted and natural grasslands, followed by cultivated land and trees. These features create opportunities for extending the existing networks of GI and integrating the concept of GI into city planning. An example of this is illustrated in Lancaster City, Pennsylvania (EPA, 2014). Here, additional infrastructure was required to manage increased storm water runoff. Instead of implementing traditional built infrastructure, a local park called Brandon Park was redeveloped using GI practices. The uptake of GI rather than a traditional infrastructure approach led to the avoided capital costs of $982,476 and has resulted in additional benefits that are estimated to be worth $5,827 per annum, which include reduced pumping and treatment costs and energy-related, air quality and climate change benefits.
The uptake of a GI planning approach in Johannesburg and Pretoria requires a shift in the way traditional urban planning programmes are carried out. Key to unlocking the benefits of a GI planning approach is a co-ordinated governance shift toward utilising green assets to complement traditional built infrastructure. This can be initiated through project level interventions, which can expose city officials, planners and engineers to the opportunities associated with GI and the benefits that can derived for society and the environment.
Kerry Bobbins is a researcher at the Gauteng City-Region Observatory, a partnership between the University of Johannesburg, the University of the Witwatersrand, Gauteng Provincial Government and organised local government.
Bolund, P. & Hunhammar, S., 1999. Ecosystem services in urban areas. Ecological Economics, Volume 29, pp. 293 – 301.
United States Environmental Protection Agency (EPA), 2014. The economic benefits of green infrastructure: A case study of Lancaster, PA., Lancaster, Pennsylvania: EPA printer
Mell, I. C., 2008. Green infrastructure: concepts and planning. FORUM Ejournal, pp. 69 – 80.
United Nations Human Settlements Programme (UN-Habitat), 2014. The state of African cities: Re-imagining sustainable urban transitions, Nairobi: UN-Habitat.
Main image by Kerry Bobbins.
Read older posts from this section