The Wellington Lifelines Group, which comprises 20 utility operators and civil defence authorities from local and central government, released a report today examining the restoration of key infrastructure after a major rupture of the Wellington Fault.
Greater Wellington Chair Fran Wilde, who chairs the group, says the report is the result of six months’ work by members and shows progress in all critical areas of the region’s infrastructure.
“We’re by no means fully prepared, but every utility provider has either begun or is well into preparations for getting key services back on line after a serious rupture of the Wellington Fault,” she said.
“This report has taken a worst-case scenario - a Wellington Fault rupture measuring 7.5 on the Richter scale - and the work on this possibility puts us in a better position not just for ‘the big one’ but also for smaller earthquakes.
“It is important to stress that the chances of a quake of this magnitude in the near future are small. A major rupture is predicted to occur approximately every 840 years, and since the last one was 300 years ago, hopefully we have some time to build our resilience.
“As you’d expect, the report shows we are better organised in some areas of infrastructure than others, but doing a comprehensive audit of our efforts to date is vital to improving overall preparedness.”
A rupture of the size envisaged in the report could shift ground alongside the fault sideways by as much as five metres and lift one side by as much as a metre.
Ms Wilde said work had been going on across a host of different areas for some years, much of it unreported to the public. Strengthening work was invariably low-key and carried out in conjunction with routine maintenance work. A small but typical example cited was a programme to replace ageing cast iron mains pipes – both for water and gas – with flexible polyethylene piping.
She said the experience in Christchurch had brought home to everyone in quake-prone areas of the country just how important it was to invest today to save lives and property tomorrow.
“It’s an unfortunate fact, however, that unless you have a limitless budget there is no quick fix. The seismic strengthening of infrastructure is a huge and costly undertaking and must be approached in a methodical way over many years.”
She said Wellington faced particular difficulties because its topography funnelled roads, pipes and other key infrastructure into bottlenecks vulnerable to disruption.
“All our planning assumes that the disruption of one service would impede the recovery of others, so untangling the web of damage would be a big challenge. We might get off more lightly, but we’re not planning on it.”
Ms Wilde said the region’s residents and businesses should not be alarmed by the report because it sketched a scenario that had only a one-in-10 chance of happening in the next 100 years.
“Nonetheless, people should not be complacent. The length of time it would take to restore essential services underlines the importance of individuals taking responsibility for their own preparedness, whether at work or at home, as well as getting involved in Civil Defence efforts in the wider community.”
Living on a fault meant no amount of strengthening work could remove all risk, she said.
Jenny Rowan, chair of the Wellington Region Civil Defence Emergency Management joint committee, to which the report will be presented on Friday, said that residents needed to take heed of the report and understand its implications for them and their families.
“This report raises the bar for individual responsibility and preparedness,” she said. “People and organisations need to be aware of the catastrophic disruption of a major earthquake and ensure that their planning takes it into account. A few bottles of water scattered round the house are no longer enough.”
The Wellington Lifelines Group will continue to monitor and co-ordinate planning and quake-strengthening work in the years ahead.
Media inquiries: Fran Wilde, mobile: 021 888 075
The aftermath of a 7.5-magnitude rupture:
- Wellington would be cut off for four months or more by damage to the main routes in – State Highways 1 and 2 – and the linking roads – Akatarawa Road and State Highway 58. The rail link would be cut for the same length of time.
- Most of the region would be without gas for nearly three months and without power and water for at least three weeks.
- Telecommunications services would be out for 10 days (though that assumes roads are passable and there are supplies of fuel for generators and vehicles).
- Restoring sewage systems would take several months.
- Food, fuel and materials to a cut-off Hutt Valley might have to be barged to Seaview Marina or Petone beach. (Barges might also be needed to supply Wellington, Porirua and Tawa.)
- Helicopters based at Paraparaumu airport would be extensively involved in ferrying light supplies to the region.
- The port’s cranes might be physically damaged or without power, and restarting operations immediately would require ships with their own cranes, but supplies could also come from roll-on, roll-off vessels or mobile cranes. The port would be central to the supply of materials to a cut-off city.
- Wellington airport’s runway would incur some damage, but helicopter and military aircraft should be able to use it within hours.
- Restoring physical links between the hospital, CBD, port and airport (for high-priority supplies and evacuations) would be a key task of authorities, search and rescue operations being the top priority.
Key upgrading work:
Significant seismic-strengthening projects completed, under way or planned include:
- A $10m upgrade of embankments at the Te Marua lakes, which hold on average 21 days’ supply for the metropolitan area.
- Strengthening of water pumping stations and other bulk water infrastructure.
- Investigation of options to supply Wellington and Porirua with water till system reinstated, including construction of emergency ponds and storage tanks.
- Replacement of critical water pipelines with more resilient materials.
- Installation of shut-off valves, activated by seismic shocks or excessive flow, at main water reservoirs.
- Identifying alternative water sources such as mobile tankers and bores to provide emergency water.
- Examination of options to dispose of toilet waste till sewage systems back on line, including portable toilets to hospitals and welfare centres.
- Replacement of five kilometres of power distribution cabling in Wilton at a cost of $9 million.
- Extensive upgrading of power transmission equipment at Haywards substation.
- A 10 to 15-year programme of strengthening electricity substations, based on an approved priority-ranking system.
- Storage of temporary power transmission towers in Palmerston North, which could be brought by helicopter to Wellington if roads are blocked.
- Completion of a decade-long programme of improvements to Ngaio Gorge Road to enable it to better withstand earthquakes, thereby providing a potentially vital corridor after a disaster.
- Completion of strengthening work, including retaining wall improvements, to Churchill Drive, Churton Park, making it another potential strategic recovery corridor.
- Work to begin on reinforcing the walls of Mt Victoria Tunnel.
- Funding allocated to begin construction before 2015 of the MacKays to Peka Peka section of the Kapiti Expressway and to investigate improvements between Petone and Grenada and between State Highways 2 and 58 to make them more earthquake resistant
- After 2015, major investment is planned to build Transmission Gully, the Peka Peka to Otaki Expressway and a second Mount Victoria tunnel.
- Renewal of railway tracks and other structures in line with latest earthquake design standards, plus contingency plans are in place to bring in emergency bridging and other repair materials.
- Formation of all telecommunications providers in Wellington into a group to co-ordinate and improve their responses during emergencies. One initiative is a review of vulnerable points in the fibre optic network.
- Enlarging the fleet of portable generators to be used to power cellphone sites. This also includes getting more powerful models.
- Improvements to the region’s emergency-response capability by the Wellington Region Emergency Management Office, along with emergency-response planning by Lifeline Group members.