The lake formed by the dammed Kaiwhata River remains largely unchanged since Monday. PHOTO/SUPPLIED

GIANINA SCHWANECKE
gianina.schwanecke@age.co.nz

There’s been little change at the lake formed after a large landslide damned the Kaiwhata River almost two weeks ago.

Two residential households evacuated last weekend have returned home, while authorities wait to see how the wet weather will impact the new dam.

Earlier this week, a small channel had appeared to be helping break down the dam wall, but Thursday’s solid rainfall had topped it up, said Kummerstein farm manager Marty Byl.

He said the water in the dam seemed to have risen a “little bit” on Thursday, with an estimated 20mm of rain falling on Wednesday night.

The water was not carving through the dam wall but around it, he said.

“It’s not going over the dam but it’s going around it through the trees. It’s not scouring away anything.”

Representatives from GNS Science and local authorities met residents on Wednesday to explain the data they had collected and detail the possible outcomes for the dam.

Infrastructure, services and regulatory manager Dave Gittings said there were a lot of variables which made it difficult to predict exactly what would happen to the dam.

This included everything from a “catastrophic failure”. in which the dam broke suddenly, to a gradual breakdown of the walls with water flowing along the river.

“It’s dependent on the weather and the make-up of the dam and how the water flows,” he said.

“Ideally what we’d like to see is the rainfall increase so that the dam tops over and starts to gouge out a pathway, allowing for a slow release [of the water in the lake].”

Gittings advised members of the public eager to check out the new natural feature to stay away and reminded them that a section of Kaiwhata Rd remains closed.

“Stay away from the area. You can’t see anything but a flooded road. You can’t see the dam so there’s no point in going there.”