9 December 2016

MEDIA RELEASE: More Goose Bay residents can return to their homes

Following further research by GNS scientists, another eight Goose Bay properties can be reoccupied from today. This is in addition to the 12 properties reoccupied last week. However, further work needs to be done to ensure the safety of the other eight properties plus the campground before they can be occupied.

Kaikōura District Council Mayor Winston Gray told Goose Bay residents at a meeting this morning that the safety of the residents and their families was of primary concern in coming to this difficult decision.

The safety concerns mean that each of the remaining eight properties plus the campground will be given a yellow placard, which means there will be restrictions on entering their homes and properties. Supervised entry will be allowed but people won’t be allowed to live there.

Goose Bay evacuations have occurred because of the risk to life and safety posed by a large landslip across Ote Makura Stream, which has created a small lake behind the dam.

“The scientists have shown it’s too dangerous to re-occupy the remaining evacuated properties in Goose Bay until further research is done and a number of safety measures are in place. These will take a little longer to develop,” Winston Gray said.

The measures could include heavy rain warnings and the development by each evacuated property owner of a property-specific evacuation plan.

Mayor Winston Gray told the residents he understood how tough it had been for them not being able to return to their homes. “That’s why we’ve worked closely with the scientists and others to make sure at least some Goose Bay residents can be back in their homes right now. We’ve done our best to find a balance between practical needs and people’s personal safety.”

GNS Science engineering geologist Chris Massey outlined to residents the further work carried out in the last week to identify the risk to residents should the dam fail. This included Lidar photography and LINZ mapping, and work showing what was likely to occur should water build up in the lake from a significant rain event in the catchment behind the stream.

“The dam itself contains some 140,000 cubic metres of landslip material, and the lake behind the dam contains 10,000 to 20,000 cubic metres of water. So it is obviously a very big dam, comparatively much larger than the lake. If the dam fails due to undercutting, it is mostly debris and fill that will travel down the river rather than water. However, in a large rainstorm (e.g. rain on snow melt) the dam may fail by overtopping and the debris would be more mobile and travel further down the stream and potentially inundate a larger area,” Chris Massey said.

“Water is currently flowing steadily through the base of the dam which means the level of

the dam could be self-regulating under current conditions and is unlikely to change – unless there is heavy rain in the catchment upstream behind it,” he said.

Mr Gray said residents could access temporary accommodation in the meantime if they needed it.

Last week, 12 property owners were advised they could return as an initial assessment by GNS showed their properties were clear of any potential landslide or debris flow. There is no change to the status of these properties. Today’s announcement means that 20 of the 28 properties are now occupied.

ENDS

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