Solar tsunami sirens close
New Zealand’s biggest tsunami siren network upgrade is rolling out across Northland this year. The $6.7 million (to date) four-year project funded by Northland ratepayers is the country’s first major regionwide project using new Danishdesigned solar-powered tsunami siren units. The 94-siren rollout is expected to be completed by October.
The new sirens are then expected to be in action from April next year, replacing the region’s current older style siren network and progressively installed since 2010.
More than 15,000 Northlanders shifted to higher ground on March 5, 2021, after an 8.1 earthquake in the Kermadecs in what was the event’s biggest regional tsunami evacuation nationally.
Northland currently has 205 existing sirens — New Zealand’s biggest tsunami siren network — that will be in action until the new Danishdesigned system kicks in.
Northland Civil Defence emergency management specialist tsunami projects Brendon Gray said the replacements would not mean loss of public safety.
“Even though the number of new sirens is less than half of the existing ones, due to the increased capabilities of the new sirens, all areas will see improved sound coverage from what they have currently,” Gray said.
“These upgraded sirens will provide timely alerts — even in situations where the current network wouldn’t be able to, such as during Cyclone Gabrielle where widespread power and mobile network outages impacted the region.
“Upgrading our siren network allows us to stay ahead of the curve. By meeting national and international standards for warning signals, we ensure our early warning system remains effective.”
Whangārei Heads currently has 18 sirens but that number will halve. In
Northland tsunami siren replacement project construction manager Tawanda Shiri with siren 21, taking shape at Whangārei’s Port Nikau.
the Bay of Islands, siren numbers will drop from 11 to eight in the Russell, Paihia and pua area.
Gray said the new sirens were light years ahead of the region’s current network. They had improved sound and functionality and their shape means their sound, which is louder than the existing network’s siren, will be distributed more widely and be less likely to be lost when strong winds carry it away before people have a chance to hear it.
Northland’s current tsunami sirens have a 108-118 decibel sound within one metre. The new sirens’ sound will be set to about 130 decibels.
“The sound will be able to travel much further and more clearly in all directions,” Gray said.
Gray said Northland’s existing tsunami siren network was put in place between 2010 and 2019, meaning the sirens were now reaching the end of their lives and expensive to maintain at up to 14 years old, .
Each new Danish siren unit costs about $60,000, compared with $2000 for existing sirens.
The new sirens will be erected on 8-metre-high poles. They will have north-facing solar panels, a back-up battery and control box and Ōabackup electricity connection.
Gray said a key plus for the new sirens was that they were not reliant on the region’s electricity network to function.
The new sirens are activated via the cellphone network or satellite if the phone network is out.
He said the new siren system also meant separate parts of the network could be individually activated, down to the level of a single unit if needed.