Waimea dam build on track, rock found at site – NELSON MAIL

Rock at the site of the right-hand plinth for the Waimea dam in the Lee Valley.

Bedrock has been found at the site of Waimea dam build in the Lee Valley, about 36km south-east of Nelson.

Waimea Water Ltd chief executive Mike Scott said the geology at the site was as expected, even better than expected in some spots.

“It’s early days but we’re pretty happy,” Scott said. “We’ve cleared the overburden and we’re on bedrock.”

Waimea Water is the council controlled organisation responsible for the construction, operation and maintenance of the dam.

Scott said engineers from Waimea Water, Damwatch, Jacobs and SMEC, of Australia, had inspected the site.

“They’re all pretty happy with it,” he said.

The geology has been identified as one of the major risks for the $104.4 million project. Bedrock is required to anchor the planned 53m-high concrete-face rockfill dam.

Scott said the team on site had started clearing the right-hand abutment “and this is all good rock; this is all ready to go”.

Some pockets of colluvium had been found – “rotten rock mixed with organic material, which is typically a very old landslide running up the gully”.

“We stabilised that and dug it out,” Scott said. “It was all expected and it’s in the budget.”

Excavation was under way for the left-hand plinth, which would be a 5.5m-wide leading edge of the dam, sealing it with the subsurface. “They are ready to start pouring concrete for the left-hand plinth.”

The rock was easy to see, shiny and hard. “You can hear them scrapping, the noise of the diggers scrapping away from across the gully.”

Waimea Water boss Mike Scott says the geology at the dam site so far is as expected “and in some areas, it’s better than expected”.

Scott said there was no reason to believe the project was not on budget.

“The reality is we’re slightly behind our forecast, just a fraction behind because we started two months later effectively but otherwise we’re on budget,” Scott said, adding the total was about $2m to $3m behind the forecast.

The project timeline remained the same.

“We’re still arguably two months behind … because we started two months late,” he said.

Work on site began in mid-March because the fire risk at the start of the year delayed mobilisation. “I still think we’ll catch it up.”

Scott’s comments came ahead of a project update he gave on Thursday to Tasman district councillors. During that update, Scott presented a slide showing 17 bores had been drilled in the area, the most recent in 2017. There had been no subsequent drilling to look for rock, despite some claims to the contrary, he said.
However, the contractor had had a rig on site to drill for explosives to blast through hard material that could not be dug out by an excavator.

“That’s a different sort of drilling,” Scott said.

In response to a question from Cr Mark Greening, Scott said three more bores were scheduled to be drilled later this year along the site of the planned spillway.

The left-hand abutment, which is almost ready for the concrete to be poured.

The inaugural annual report for Waimea Water was also presented and it showed a spend of $19.2 million on the dam project to June 30. Of that, $6.3m was expended prior to the final go decision on items such as land acquisition, design, procurement, early contractor involvement, consenting, the project office and governance.

However, outside the meeting Scott said $8.2m was the total pre-operating spend, which included insurance. The construction contract accounted for another $7.7m with ongoing operations swallowing up $2.9m. Earnings from interest income provided $300,000.

Overheads such as staff, directors and offices totalled $0.7m, Scott said.

An impression of how the dam is expected to look in the Lee Valley. The spillway is on the right.

The annual report shows directors’ fees of $134,000 plus “director services” of $324,000. A corresponding note about the director services says that prior to the recruitment of key management personnel, some directors performed “interim executive level services”.

Cr Anne Turley asked for details on the reasons for the additional fees.

Waimea Water board chairwoman Karen Jordan outlined the roles carried out by some of the directors between the signing of the deal and key staff starting work. Those roles, including interim chief executive, interim programme director and interim commercial director were taken on by some directors to meet commitments and avoid damages.

“For example, in the first week of operation we had about 15 key deliverables to meet our obligations on the schedule – our health and safety plan, our environment plan, vegetation plan, commitments of resource consents, all this stuff,” Jordan said.

Meanwhile, the Waimea Water team plans to hold a public meeting at Richmond Town Hall on September 25 to provide an update on the dam build and answer questions. The event is scheduled to be held from 7pm to 8.30pm and attendees are asked to email info@waimeawater.nz by September 22 to register and submit questions or topics of interest.

Link to the story on Stuff