Landslide stabilised, small lake a legacy?

A109 Light Utility Helicopter flight with mayor Gisborne City from the air in November 2023.

The landslide that created a lake at Mangapoike has been stabilised and Paparatu Road reopened.

The slip affected 25.8 hectares of land and created a lake about 50 metres deep. The lake rose at about 60cm a day.

Explosives were used last month to cut a two-metre-deep trench to release water from the dam formed on the Mangapoike River.

Workers enlarged the trench to improve the water flow and further reduce lake water levels, eliminating risks to the nearby bridge and farmland.

It had been a stressful few weeks since the slip, said Mangapoike Station owner Dan Jex-Blake.

“Now we know we won’t lose access to our farms. We don’t know the final outcome but we can see the positives.

“We’re hopeful we can have a permanent lake at the end of this, that will provide a habitat for rare and endangered wild life.

“It has been amazing to see how fast rare species such as dabchicks have adapted to life on the new lake.”

Gisborne District Council’s principle scientist Murry Cave said it was too soon to predict the end result but indications were the lake would remain at a safe level and no longer pose a risk to Mangapoike and Paparatu Stations.

Council staff worked with Hawke’s Bay Regional Council, Wairoa District Council and scientists from Auckland University throughout the response to the landslide.

The council will continue to monitor the situation over the next few weeks until long-term stability of the dam is established.

The lake built up behind the landslide dam now occupies about 33 hectares.

The public cannot access it.