In my last post I discussed the risks to cities highlighted by Hurricane Sandy. In New Zealand earthquakes pose risks of similar scale. I suggested that the unpredictability of such extreme events should place the highest priority on readiness, response, and recovery.
This leaves mitigation as a second order but still essential priority in emergency management. Long-term mitigation revolves around land use strategies (where people live and work) and urban form (how cities are shaped around them). This post shows just how far removed from effective mitigation planning, and in particular the Auckland Plan, lies.
Does reshaping cities lower the risk
Many cities have committed to indirect mitigation by focusing on moderating global warming by promoting urban form that might lower dependence on fossil fuels. The prescription for this is increasing dwelling and workplace densities and putting more people on public transport.
In a slow growth environment such policies can only take effect at the margin: urban form for the next 50 years is largely shaped by what is already here. And even if they eventually do reduce warming and sea level rise, these policies increase vulnerability in the meantime.
Let’s look at this claim with respect to Auckland.
First, the Auckland hazardscape
Based on records and fault mapping, Auckland has the lowest risk of serious earthquakes within New Zealand – although they cannot be ruled out.
But the city sits on a volcanic field of some 50 vents and several explosion craters. The last significant eruption took place 600 years ago. The return period may be as short as several hundred years. It makes sense that long-term plans take into account the hazards associated with volcanic activity if only by ensuring lifelines – roads, infrastructure networks – are resilient, buildings robust, and city and town centres have adequate open space and corridors to provide for public sanctuary and movement.
Auckland’s maritime geography poses the most immediate threat. Auckland lies on an isthmus incised by two harbours and penetrated by estuaries and streams. Its main street is a drained swamp, much of the CBD is on reclaimed land. And while some attention has been paid to tsunami risk, the most likely risk may be from the sort of inundation New York suffered under Sandy.
Given global warming and seal level rise, storm surges are likely to increase in intensity and severity. In Auckland in early 2011, for example, a combination of high tides and low pressure inundated the waterfront, including downtown.
How well is Auckland prepared?
I explored various documents to understand Auckland’s capacity to respond. An Auckland engineering lifelines group is examining the likely impact of different events on networks and collaborative responses to the risks raised. This is very much a work in progress.
The office of Civil Defence and Emergency Management has a well-developed strategy for response but still relies on others for mitigation. Here are some of the risks it identifies:
· Auckland’s infrastructure is vulnerable because networks (power, gas, water) are supplied by external sources and Auckland’s geography creates delivery ‘chokepoints’;
· Auckland utilities depend on external agencies for service;
· Increasing urban density lifts the potential consequences of hazards;
· Auckland has approximately 1,800km of coastline where development exposes communities to a wide range of hazards.
What does the Auckland Plan offer?
The Auckland Plan the city’s blueprint for the next fifty years, is probably the best place for promoting initiatives to mitigate the effects of extreme events. So what does it say?
Chapter 8 talks about limiting emissions and promoting energy efficient to reduce global warming. But that’s it. Unfortunately, nothing in the Plan relates land use to the hazards Auckland faces.
Planning for disaster
Worse, the Plan promotes urban form likely to increase the vulnerability of many residents and businesses to extreme climatic (and other) events. A commitment to focusing public and private investment downtown and tripling the population there is a particularly high risk policy.
Housing more people in more multi-unit, multi-storey buildings in the confined area of the CBD promises to increase turmoil for households and business located there when power fails and the lifts don’t work , water supply and sanitation services are disrupted, when there are gas outages , and telecommunications falter. Given the age and capacity of infrastructure in the city centre, these outcomes are all possible if not likely, and could be prolonged under extreme storm conditions.
Getting people out and getting emergency services and supplies in would be a nightmare. Focusing the rail network on the underground Britomart station 120m from the water's edge is particularly short-sighted. Flooding there would disrupt the city’s entire passenger service. Increasing intensity of development on arterial roads and around ageing centres won’t help much, either, compounding already congested routes. Nor will further development of the already inundation-prone eastern arterial road and rail link, much of which crosses a causeway just metres above sea level.
|Central Auckland - Key Transport Links|
One response to such threats is to build defences. Architects Stephenson and Turner have looked carefully and creatively for mitigation solutions for Auckland. They have considered initiatives, experiments and research internationally. Their report favours a resilience-based response, one that might protect the CBD by softening the shoreline, or make use of protective maritime structures, and reverse engineers an urban retreat from the edge, or a combination of such measures.
|Options for Adaptation, Auckland CBD|
Rethinking our plans
Rethinking the current approach to Auckland’s growth remains an imperative if we really do accept global warming and sea level rise are part of our future. We should drop 20th century thinking about compact cities, rethink the CBD, and rethink city form. If we cannot do this, then we will continue, Canute-like, to pretend that we can hold back the waters with little more than wishful thinking when the reality is that retreat in one form or another is the only action that will truly acknowledge the rising tide of risk. The most effective urbanism in the 21st Century may be that which embraces the desirability – and sustainability -- of decentralised urban form.