Environment & Poverty Times
Construction and city planning
Urban planning and construction are cornerstones for human habitat. Both hold enormous potential for resource efficiency, with construction currently generating a substantial share of our waste burden. To house growing urban populations the need for more sustainable cities is increasingly urgent.
Reconstruction fables By Pablo Allard
On 3 May 2008 the 5,000 people living in the small but thriving town of Chaitén, Chile, were awakened by the fierce erup- tion of the neighbouring volcano of the same name. Neglected by geologists and dormant for more than 250 years, the small volcano sits just 3 miles north of the capital of Palena Province, a centre for connectivity and services for the isolated communities of the Chilean Patagonia. The danger of massive pyroclastic flows or the collapse of the dome forced the authorities to evacuate more than 7,000 people from the town and surrounding area in less than 48 hours. Despite the difficulties accessing the disaster zone, there were no fatalities.
During the early days of eruption the col- umn of incandescent ashes reached more than 12 kilometres high, covering the town and its surrounding hills with more than 60 centimetres of ash. But the disaster was not caused directly by the volcano, but by the river Blanco. Heavy rain washed most of the ash out after a few days clogging the river and forcing it to find a way through the city. The floods destroyed more than two-thirds of all properties and most of the infrastructure, including the regional airfield, while severely limiting operations in the port.
The Chilean Government responded rapidly, putting the Minister of Defence in charge of coordinating crisis management until a special authority, the Presidential Delegate on Chaitén was appointed in June, with a mandate to help displaced families with temporary accommo- dation and give each family a displacement bond worth about $1,000. The temporary loss of Chaitén meant that many small com- munities and a complete region would have to depend on Argentina to maintain commu- nications and connectivity, access to hospitals and services, literally splitting Chile in two and posing a complex geopolitical dilemma.
The volcanic eruption deteriorated and it be- came clear it would last longer than expected. By late July the river had destroyed most of town, small groups of Chaiteninos were allowed to return to town simply to recover whatever was left. A few decided to stay defy- ing the volcano and the Government’s call for complete evacuation. The Government responded very well in terms of evacuation and support for displaced persons, but made no plans for reconstruction or reloca- tion, since most of the Chaitén urban area was still subject to a high volcanic risk. In response to the call, the Cities Observatory (OCUC) – an urban and territorial intel- ligence unit at the Catholic University in Santiago – offered regional and national authorities its services for the creation of a special task force of more than 30 profes-
sionals that could rapidly analyse strategic scenarios and recommendations for recon- struction or relocation of the town.
Turning a catastrophe into an opportunity The eventual reconstruction or relocation of Chaitén poses a great challenge. But it is also an opportunity for a country like Chile to develop a response policy for its many natural disasters. Instead of treating the short-term emergency response as a cost, the idea was to consider its planning as an investment. The continuous volcanic activ- ity gave time to evaluate and consider mid and long-term scenarios while responding to disaster relief. This simultaneous vision is key if we consider Patagonia as one of the most sensitive and isolated areas in Chile and a world biosphere reserve.
Considering the geopolitical importance of the city within the region, and the visibility of its natural features, the future of Chaitén and Chilean Patagonia depends largely on the development of an eco-tourism industry, conservation, high-quality end- user services and sustainable production. Uncertainty over the future of the volcano provided a window of opportunity to define an adequate strategy, aligned with a clear development vision. Chaitén was also an opportunity to align four key issues defined by the Chilean Government as priorities for the future development of the country:
territorial equality, sustainability, innovation and country branding.
This new vision could be materialized in a sustainable low-impact development that makes efficient use of economic and natural resources a priority. This issue is particularly important in the Palena Region, where most human settlements still depend on Chile’s mainland for the majority of its services and provisions.
On the other hand, the small size of Chaitén allows for innovation in terms of sustainable urban planning and design. A small town of 5,000 has the right scale and components for self-sufficiency and low dependency on external services such as energy, water, waste management and goods. Its potential for replication is high, not only as a sustainable urban model, but also because it opens the way for new tools and capabilities that could allow developing countries to elaborate appropriate policies and contemporary approaches to planning small, remote towns.
By the time the Cities Observatory (OCUC) set up the task force, preliminary informa- tion showed that the level of destruction was so high that any potential scenario meant starting from zero, in terms of urbaniza- tion, infrastructure, energy provision and services. Starting from scratch lifted many
Aerial view of the town of Chaitén and its neighbouring volcano. Stephanie Rojas, OCUC.
Buildings – Eastgate building Harare, Zimbabwe
Efforts to improve resource efficiency in the building sector must consider construction materials and methods; energy consuming installations such as lights, fans, and pumps; and products that influence energy use, including windows and insulation.
Biomimicry principles, where nature is used as a model, were famously applied to the built environment in 1996 by architects and builders who modelled the Eastgate Building in Ha- rare (Zimbabwe) on the self-cooling system of termite mounds. The design derived from the observation of compass termites building wedge-shaped towers that always point north. This allows the broad sides of termite mounds to capture heat in early morning and late day while the point of the wedge exposes only a small surface to the mid-day sun. All surfaces contain
ventilation holes. As the air inside warms, it rises and exits through upper holes, creating an automatic draw of cooler fresh air through lower holes. The Eastgate Building uses a passive cooling system that operates on the same principles and is complemented by other features such as broad window overhangs.
Since it opened, the commercial structure with 5,600 square metres of retail space, 26,000 square metres of office space, and parking for 450 cars used an average of 90% less energy than other buildings of similar size – saving more than $3.5 million in air-conditioning costs alone.
Source: UNEP Yearbook 2009, chapter Resource Efficiency, pp 44-45.
| Page 2
| Page 3
| Page 4
| Page 5
| Page 6
| Page 7
| Page 8
| Page 9
| Page 10
| Page 11
| Page 12
| Page 13
| Page 14
| Page 15
| Page 16
| Page 17
| Page 18
| Page 19
| Page 20
| Page 21
| Page 22
| Page 23
| Page 24
| Page 25
| Page 26
| Page 27
| Page 28
| Page 29
| Page 30
| Page 31
| Page 32
| Page 33
| Page 34
| Page 35
| Page 36