Source: Radio New Zealand
Damaged property from the landslide at Welcome Bay on 23 January. RNZ / Calvin Samuel
All four homes red-stickered in Tauranga’s Welcome Bay after a deadly landslide last month have had their safety restrictions eased.
The large slip hit neighbouring homes on Welcome Bay Road killing two people during the storm that hit the upper and eastern North Island.
Western Bay of Plenty District Council said yellow stickers had replaced the red.
“Given the land had dried out since the weather event, and the ‘additional weight’ on the land reduced, council’s consultant geotechnical engineers deemed the risk of imminent slip had reduced to a point where the properties could be accessed, under certain conditions,” it said.
Three homes had a Y2 type of sticker which allowed short-term access, and one had a more onerous Y1 which allowed access only to certain parts of a building.
It was up to the homeowners what to do next.
“Additional geotechnical investigations for affected properties will need to be undertaken by the homeowners in conjunction with their insurance companies, to identify a way forward to remove the hazards,” council duty controller Peter Watson said in a statement.
The council was not considering an inquiry, he said.
An [https://www.rnz.co.nz/news/national/585703/tauranga-city-council-votes-for-independent-review-into-fatal-mt-maunganui-landslide
independent inquiry] is going ahead nearby under Tauranga City Council into the Mt Maunganui campground landslide that killed six people, and the government may also do an inquiry.
Last month, local resident Dawn McNaughton said there were seven slips on her property on Welcome Bay Road. Supplied
No detailed survey of landslide risks
The history of landslides in the Welcome Bay area included a geotech study in 1980 that said: “Recent subdivisions in Welcome Bay should be examined by a geotechnical engineer as the area contains many inferred landslides, which may be reactivated by urban development.”
It was titled A preliminary assessment of geological factors influencing slope stability and landslipping in and around Tauranga city.
“The site of the fatal slip was not subdivided until the 1990s, with the building having been built in the year 2000, therefore it would not have been one of the subdivisions mentioned in the report,” Watson told RNZ on Tuesday.
The council had not carried out a detailed survey or assessment of landslide risks for the parts of Welcome Bay Road in the district, he said.
“We instead require that the stability of subdivisions on sloping ground … is assessed and demonstrated by an accredited geotechnical engineer or geologist as part of the resource consent process.”
Urban and lifestyle development areas that were known to be susceptible to land instability from studies done in 1981 and 2009 became a focus, but the Welcome Bay Road properties were zoned rural and not included in these studies.
The studies provided input for its district plan hazard maps, covering:
For the latter, “the scale at which this assessment was completed does not allow analysis on a site-by-site or individual subdivision scale”, Watson said.
The Geotechnical Society has a list of geotech studies in the area.
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand