1 Oct, 2014
Here are two important statistics from the UN:
- Firstly, that 60 per cent of the urban area of 2030 has yet to be built;
- Secondly, that in Asia, the majority of urban growth over the upcoming decades will take place in small and medium sized cities
Building resilient cities
Urban resilience means that urban systems and communities have the capacity to resist the effects of hazards, and if these hazards are too great, to accommodate and quickly recover from them. For cities to achieve this, a number of factors must be achieved. This can range from an economy based on resilient industries, to communities with resilient social bonds. UNISDR’s Making Cities Resilient campaign, for instance, outlined ten factors ranging from financing to policy. And while these lists are useful, no amount of community preparedness can off-set the glaring vulnerabilities of a city whose roads, infrastructure, utilities and housing stock are simply poorly built.
For poorly constructed cities, the basic fact of the matter, in my view, is that for long-term resilience a fair amount of rebuilding will be necessary. This would involve both retrofitting existing structures – where feasible – and demolition of other structures in order to frankly rebuild. If your dog gets rabies you put it down. And some stock just needs to get rebuilt.
Such rebuilding and retrofitting may not happen for decades and any city government must weigh its priorities. Disaster and climate change resilience for some is a long way down the municipal list of things to do.
Easiest to do through mainstreaming
Which is why secondary and smaller cities pose such an amazing opportunity, if we take the above statistics as the starting point. Secondary and smaller cities are currently being built and for a comparatively minor additional cost, urban resilience can be achieved via the building process itself.
The easiest way to achieve this is through mainstreaming disaster risk reduction and climate change adaptation into the policy, planning and programming processes of the municipal government. This means making decisions about where and how to build which take account of natural hazards and local vulnerabilities.
To do this, a risk assessment is usually undertaken or at minimum, risk information is collected. If the risk information indicates that a particular area of the city is prone to flooding, planners must steer development out of that area, or lay improved drainage systems and flood management canals or embankments. This is fairly straightforward. There is an added cost of course, but numerous studies show the long-term value of this from a cost-benefit point of view.
The additional cost is mainly due to an increase in the volume or quality of material used, though associated costs such as hiring more highly trained masons and engineers can also contribute. However, erecting more robust and resistant buildings is far cheaper than often anticipated. Usually strengthening involves improving the sub- and super-structure of the building, which is typically the cheapest component of the building, through the additional use of reinforcing steel, concrete and brick. In Asia, in general, this will only incur an additional 2-4 per cent to baseline building costs (PDF).
And this investment is worth it! The IFRC have undertaken cost-benefit analyses of investing in disaster risk reduction in various developing countries. Under cost-benefit analysis, if the ratio is 1:2 is means that the benefit of the investment is twice the cost – ie. the return on investment is double. Cost-benefit analysis shows overwhelming benefits of investing in disaster risk reduction (PDF, p. 15). Different disaster risk reduction measures have different benefits. Simple earth embankments along the edges of urban rivers, something that can be incorporated into land use and urban development plans in secondary cities, for example, can generate cost-benefit ratios of 1:2.4.
Mainstreaming, like all policy and planning, is future-oriented. It is a strategy that aims at making a better future. And while for secondary cities which are growing currently, mainstreaming is by far the most effective way to reduce risk and vulnerability, for already vast and sprawling megacities, mainstreaming may be less effective.
What to do with the big cities?
I’m not saying that the bigger cities are doomed, but we do have to be realistic about this. To what extent can Dhaka really expect to achieve urban resilience given the quality of its building stock currently? A seismic vulnerability assessment of Dhaka for example notes that (PDF, p. 5-1):
- 51 per cent of the city’s roads are built on soils which are prone to liquefaction
- most bridges are not built to common seismic-engineering standards
- 70 per cent of the rail system of the city is located in areas which are very prone to soil liquefaction
- most (57 per cent) of the utilities piping (water supply, sanitation etc.) are brittle, and therefore likely to break in the event an earthquake – as opposed to ductile pipes which can withstand some movement
- for residential houses, a majority are vulnerable due to the type, quality and age of construction.
Dhaka may in the future have the funds and regulatory capacity to really engage in full-scale urban resilience. However, given the current state of the city’s economy, governance etc. the reality is that this is unlikely to happen for a while.However, it is precisely in cities with low quality of building that retrofitting makes the most economic sense. In cities with high quality construction, the economic benefits of retrofitting are minimal. In Los Angeles, for example, a study shows that retrofitting houses for earthquakes using structural bracing would cost USD 14,000 per house, where as, given the likelihood of earthquake and other factors, the economic return on this investment, factoring in as many components as possible, is only around 1 per cent. In El Salvador, on the other hand, given an investment in retrofitting of USD 250 per house (adobe houses are cheaper to retrofit but more likely to collapse), the return on this investment sits at 29 per cent. Net benefits of retrofitting are highest where current building standards are lowest, concludes the study (PDF p. 11).
And so, my point: secondary cities should make the most of their options for resilience. Maybe this is like when people quote Wilde and claim youth is wasted on the young. But unless, secondary cities can capture their booming infrastructure and housing stocks, their utilities and transport systems and incorporate risk reduction and climate change adaptation measures, they run the longer-term risk of having to cover the costs of resilience at a later date – in say fifty years or so – at much higher costs. And while these retrofits will still be worth it then, many cities won’t have the capital to make such investments. Its best to attempt them now.
And with climate change, as the latest IPCC report of March 31st 2014 shows, set to worsen, the storms and the floods will not abate for a good while yet. It might be somewhat of a case of now or never.
Banner photo by NASA
Photo 1 by Martin Luff
Photo 2 by DVIDS
Photo 3 by Petronas