Dannevirke dam repairs under way

Tararua District Council hopes to have the dam refilled as soon as possible.

Repairs for Dannevirke's impounded supply are now well under way and the Tararua District Council is hopeful it will be able to fill the dam "as soon as possible".

Infrastructure group manager Chris Chapman told councillors at a meeting last week that the company contracted to carry out the repairs had staff on site.

He said they had found multiple splits in the liner, but they were where they had been expected to be.

The leak in the impounded supply was first detected mid-July and it took council some time to locate the source of the leak.

Repairs started early last month, but wet weather had caused some delays.

"They do work in the rain," Chapman told councillors.

"But they can't weld those patches in the liner if it's raining. It does need to be dry."

A council spokesman said they were confident the repairs could be made over the next week.

Chapman said he understood a sample had been taken to determine what had caused the splits.

That sample had been couriered to Christchurch.

He said that he thought it was a rippling effect which had caused it.

"It is quite a rigid liner. So that ongoing wave action under the line is causing that constant moving."

That could not be confirmed until the results of the tests came back.

Councillor Kerry Sutherland asked if there had been any concern about degradation of the bank supporting the liner.

Chapman said any potential erosion or scouring had not been confirmed.

The area had been surveyed and council was looking at doing that regularly to monitor any indications of scouring.

The council spokesperson said they had not had to completely empty the dam so the repairs could be completed and it was currently around four metres full.

Water restrictions would remain in place for the immediate future and would be reviewed over the coming months.