Christchurch, New Zealand, which experienced an earthquake in 2011, is being rebuilt and construction will go on for another five or six years.
As a resident, David G. Wareham, Associate Dean (International) of the College of Engineering at the University of Canterbury, Christchurch, had shown scant interest to the phenomenon or the engineering techniques to tackle earthquakes till it struck. “But then it happened in my backyard,” he said. It was then he began studying how the city managed to return to normalcy.
Prof. Wareham, who has specialised in Applied Sciences, is in India to deliver a series of lectures. On Monday, he shared his experiences with the students of the Indian Institute of Technology, Madras, saying that though the country was in the seismic zone and its expertise in earthquakes was much sought after, he had never been drawn in to it. But after the disaster, he began studying the city’s system, especially after the sewage treatment system collapsed.
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“Christchurch is not prone to earthquake; its occurrence was one in 2,000 years. We had the second highest ‘g’ forces ever recorded in terms of an earthquake,” Prof. Wareham recalled. The city experienced 14,000 aftershocks, damaging 10,000 homes and 1,200 commercial structures.
“The earthquake ripped our sewage pipes apart and there was deposition of silt. The pipes could carry sewage but not silt and that affected the biological processes in the sewage treatment plants,” he explained.
The population did not have access to toilets. The government divided the affected zones into “one where the pipes could be fixed and the other where the ground was badly damaged”.
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As many as 38,000 chemical toilets, with the facility to treat waste, were placed in areas where pipes could be fixed and in the severely damaged areas portable toilets were placed. The treated waste was let into the sewage system. It took six months to restore 50 per cent of the sewage system. “By two years, 90 per cent of the system was operational,” he said.
Christchurch has a 15-year reconstruction plan costing 13 billion Australian dollars. Every week, around $100 million (approximately Rs. 500 crore) is being spent to rebuild the city.
On how the Christchurch experiences could help Chennai in case of another flood of last December’s proportions strikes, he said: “Every disaster is unique. Every city has an emergency management for business continuity. What you need is exercised simulation, mock-like scenarios. You have to have forecast and training sessions.”