Tauranga's 20 year tsunami siren debate continues

The community's 20-year fight for tsunami sirens has hit another road block. Photo / George Novak

Tsunami sirens for Mount Maunganui and Pāpāmoa have been talked about for nearly 20 years but, despite having funding, the council wants to remove them from its work programme.

In 2019 Tauranga City Council approved a budget for the sirens, something then-councillor Steve Morris was "really pleased" about.

Morris has advocated for sirens for at least 12 years and thinks they should be a priority as a secondary warning system.

Council has just finished consulting on the use of tsunami sirens as part of 2021-31 Long-term Plan.

The cost of the sirens is $3.9 million with an ongoing cost of $209,000 per annum, according to the council.

Morris said this was a small price for "critical, potentially lifesaving infrastructure".

"I think it's a matter of priorities.

"The first thing is to actually understand what a siren is for and that is as a backup to the primary mechanism, which is the natural warning signs, and not to get bogged down in the bureaucratic arguments about it."

Former Tauranga City councillor Steve Morris. Photo / George Novak

Council emergency management manager Paula Naude said there were pros and cons to tsunami sirens.

"International evidence shows us that the risks associated with community reliance on a siren to know when to evacuate can be more dangerous than no siren," she said.

"The best and most reliable warning system for local source tsunami in New Zealand is the natural warning."

The natural warning is if an earthquake is long or strong people should evacuate and not wait for an alert.

"There have been advances in knowledge, data and technology since sirens were first discussed for Tauranga," Naude said.

"Based on the best available information, it is no longer considered that sirens are the safest solution for our community."

Emergency Management Bay of Plenty director Clinton Naude said the BOP Civil Defence Emergency Management Group did not regard sirens as an effective or a reliable alerting mechanism in local source tsunami events and there were no sirens in the region currently.

The Bay of Plenty CDEM group includes seven councils: Bay of Plenty Regional, Tauranga City, Western Bay of Plenty, Whakatāne, Kawerau, Ōpōtiki and Rotorua Lakes councils.

Clinton Naude said some disadvantages of tsunami sirens were local source tsunamis could arrive within minutes, so there may not be time for an official warning.

"Sirens may also be damaged by the earthquake itself and therefore cannot be activated," he said.

"Sirens are known to cause complacency, which undermines the most reliable warning system for local source tsunami - the natural warning itself."

He said if evacuation was needed alerting systems included the emergency mobile alert, radio, television, social media and loud hailers.

Despite the other systems available, Morris said there was still community support for sirens.

"What we found with Mount and Pāpāmoa residents in particular, is that they wanted, an addition to the text message system and knowing the early warning signs," he said.

"They wanted to be alerted via public siren system as well."

In 2012, the Pāpāmoa Residents and Ratepayers Association set up temporary air raid sirens and conducted its own tests.

Morris was chairman at the time. He said the sirens were widely heard in Mount Maunganui and Pāpāmoa.

He said this "really annoyed" the council of the day, but it showed sirens could be widely heard.

Current association chairman Philip Brown said the association thought sirens were essential.

Papamoa Residents and Ratepayers Association president Philip Brown. Photo / Talia Parker

"We've always asked for them," he said.

"We always thought they are part of the mix of getting the warnings across and the evacuation message across, we've never deviated on that.

"The fact that there are other high tech solutions coming along, we think sirens are a great complementary fit."

When asked what he thought of removing sirens from the council's work programme, Brown replied: "Do they want to kill people?"

He said there were limitations to the emergency mobile alert.

"Not everyone has a cell phone, not everyone hears their cell phone.

"Not everyone wakes up for their cell phone, but with a continuously sounding tsunami siren they will wake up."

He said there was no quick inland escape route for people in Mount Maunganui and Pāpāmoa so people needed as much warning as possible.

Plans to install sirens along the Western Bay of Plenty coastline were launched in 2005 after the 2004 Boxing Day tsunami in Indonesia.

In 2006, 10 sirens were tested between Waihi Beach and Pukehina, however, "black spots" were discovered where the sirens couldn't be heard.

Both Tauranga City Council and Bay of Plenty Civil Defence Emergency Management were unable to say if this resulted in sirens being installed due to a lack of "sufficient information".

Morris wants to see action on siren installation rather than more consultation.

"The dithering and dragging out has gone on way too long in my view."

• Local Democracy Reporting is Public Interest Journalism funded through NZ On Air