Huge landslide forms hazardous lake
A large slip between Wairoa and Gisborne has created a large and growing lake that presents a ‘‘significant hazard’’.
Hawke’s Bay Civil Defence emergency management group was working with local authorities to monitor a growing dam of water and sediment on the boundary between Wairoa and Gisborne.
Hawke’s Bay Civil Defence Group manager Ian Macdonald said the large landslide had become a significant hazard and people were warned to stay away from it.
‘‘The landslide, likely triggered by a small, localised earthquake earlier this month, has resulted in [about] 80 million tonnes of material forming a large dam on a ... tributary to the Wairoa River.
‘‘The new lake is about 50 metres deep and rising. The area affected by the landslide is 25.8 hectares and the landslide is still moving. No water is currently leaking from the dam, but it is rising by about 60 centimetres each day,’’
The landslide and dam are on private property and in a remote area, but authorities want those living nearby and downstream to be aware of the hazard risk.
With Wairoa District Council, Civil Defence staff have been talking directly with potentially affected residents.
‘‘Downstream landowners and river users are strongly advised to keep out of the riverbed. The dam might fail at any time and there is a significant amount of water behind the landslide,’’ Macdonald said.
He said the only structures threatened were a woolshed and shearers’ quarters.
‘‘We’re working closely with Gisborne and Wairoa district councils, with support from Hawke’s Bay Regional Council to assess the risk of dam failure and develop an ongoing management plan,’’ Macdonald said.
Paparatu Rd in the area is closed to the public and appropriate signage has been installed. There is no date for when the road will reopen at this stage.