Revised tsunami evacuation zones for Waimate District

New tsunami modelling for the Mid and South Canterbury coastlines has today seen a rollout of revised tsunami evacuation zones, with minor impact in the Waimate District.

As part of a programme of tsunami modelling for the wider Canterbury coast, Environment Canterbury (ECan) commissioned the Institute of Geological and Nuclear Sciences to complete multiple scenario tsunami modelling for the Mid and South Canterbury coastline.

The report’s findings have led to small changes to the existing tsunami evacuation zones in the Waimate District, which overall have reduced in size. The new red tsunami evacuation zone, which is the area most likely to be affected by a tsunami, including beaches, lagoons, and river mouths, remains the same as the old red zone. The orange tsunami evacuation zone, which includes low lying coastal land that could be flooded in a large tsunami, has been reduced in many places.

Most notably, Makikihi east of State Highway 1 and Waitaki Huts, along with areas of farmland between Otaio and Morven Beach, have been removed from the orange zone as the modelling showed no inundation of these areas, even in a ‘worst case’ tsunami. The orange zone has been increased slightly at Otaio and the old St Andrews Golf Course. The orange zone now crosses State Highway 1 at these locations whereas previously the orange zone was entirely east of State Highway 1.

Commenting on the review, Waimate District Council Regulatory and Compliance Group Manager Jonts McKerrow said it had been almost a decade since Waimate’s tsunami evacuation zones had been established, initially drawn in 2012.

“The report has shown us that in most areas the tsunami evacuation zones remain the same or have been reduced. For our district, the tsunami hazard remains relatively low compared to many other parts of New Zealand because there are no known significant tsunami sources close to the Waimate coastline, the shape of the coastline itself and the presence of coastal cliffs in some areas,” McKerrow said.

“Despite this, and the changes to the orange zone, the messaging remains the same and is as important as ever. If you’re in a red or orange zone and you feel an earthquake that is long or strong, get gone. There may not be time for an official warning, so once the shaking stops head immediately inland, and out of the tsunami evacuation zones.”

If a tsunami is coming from further away, and there is time for an official warning, people will be told which zone(s) to evacuate.

McKerrow’s advice for anyone wanting to know if they reside within the revised tsunami evacuation zones, is to head to the tsunami evacuation zone webmap on Canterbury Maps ecan.maps.arcgis.com/apps/minimalist/index.html?appid=591062afb6b542abb247cc8d15a64855, and enter their address.

“It’s important that people know where the zones are and if they are located within one. If you live or work in a tsunami evacuation zone, it is important that you have an evacuation plan and know what to do in case of a tsunami. You need to think about the route you would take to evacuate and where you would go.”

In the coming months, tsunami information boards formerly located at Galletlys Road, Hook Beach, Waihao Box and Glenavy will be replaced with new boards, detailing the revised tsunami evacuation zones. Plans are also underway to host a public meeting early next year, though details are yet to be confirmed.

For more information on tsunamis,click HERE.