Orewa’s tsunami risk exposed


Orewa has again been named the community with by far the highest potential exposure to tsunami in Auckland.

According to Cr John Watson, this puts it in a prime position to access Auckland Council funding that has been allocated for public alerting systems, such as tsunami sirens, in the Long Term Plan.

A report commissioned from the Institute of Geological and Nuclear Sciences (GNS) by Auckland Civil Defence & Emergency Management was presented to the Civil Defence & Emergency Management Group Committee last month. It listed the top 20 most exposed communities to tsunami in Auckland’s orange and red tsunami evacuation zones. Number one was Orewa, with a potential 6521 people exposed under the study’s modeling. This is followed by Browns Bay, with 3597 people exposed. Also included in the top 20 is Silverdale Central at number seven, with 1543 people exposed and Stanmore Bay East, with 1236.

The findings were not surprising, given a report by GNS and the National Institute of Water & Atmospheric Research in 2010 that demonstrated that Orewa and surrounding areas had one of the highest risks of inundation on Auckland’s east coast.

However, Cr Watson, who is deputy chair of the committee, says the latest report will influence how funding is allocated.

“Council has $2.72 million of capital funding in its budget for public alerting systems. If any of that is to be divvied up, then Orewa is going to be at the top of the list,” he says.

Local boards will now be consulted and their feedback and Civil Defence’s recommendations will come back to the committee.

Cr Watson says that local boards should make a strong plea that the funding be used in areas of most acute vulnerability.

He supports the installation of tsunami sirens in Orewa as one of the most effective means of mass notification.

“While new warning technologies continue to evolve, sirens have many advantages. They can be controlled from a central trigger point and have the potential for rapid notification while voice capable sirens can provide both a ‘heads-up’ that something is occurring and instruction,” he says.

The GNS report is linked to this story at localmatters.co.nz