Fix for Nelson's Modellers Pond increases to more than $3m

Tuesday, 10 December 2019

The previous council voted to keep working on a concreting option as a fix for the modeller's pond, but already the costs are increasing.

Costs associated with fixing the weed-infested modeller's pond have crept up again like the algal blooms the project is battling, and is now estimated at more than $3 million.

The cost increase was included in the quarterly report to the Nelson City Council's sport and recreation committee meeting on Tuesday.

Councillor Matt Lawrey said in the meeting that seeing the figure made 'my eyes sort of bulge out of my head'.

'I checked that full year forecast total for the modellers' pond solution and it's $3.55 million. We've had a lot of big numbers thrown around with regards to the modellers pond over the last six years, but that's the biggest.'

The full year forecast cost of concreting the pond's base has been revised to include a higher contingency and could cost up to $3.55 million.

* Modellers Pond fix swamped with more than $1.7m in costs

* Councillors cast doubt on $1.2m plan to fix Tahunanui Modellers Pond**

The price tag is attached to the previous council's preferred solution to the persistent algae problem, concreting the base of the pond and having it manually cleaned out on the low tide. This solution this year was estimated to cost $2.37m, and was originally tabled in 2016 but discarded thanks to the then-expected high cost of $1.7m.

Nelson City Council property, parks and facilities asset manager Andrew Petheram said the latest figure of $3.55 was the largest figure, as a higher contingency had been added to the estimated cost, but the cost was not set in stone.

'It's based on the nature of the prices that have been coming in from consultants that we're dealing with,' he said.

'We felt we had to be up-front and put in a conservative price when we're considering projects.'

He said an accurate price couldn't be determined until the staff had a detailed design but the $3.55m figure, which included a 25 per cent contingency, was 'an upper end figure of what it could possibly be', and included estimated budgets for the 2020-2021 financial year.

Mayor Rachel Reese said that the increase was 'starting to get to a quite extraordinary amount', and indicated she was not comfortable with the estimated budget.

'I'd have to say to you as Mayor, when I'm looking at where funding is going to go for the annual plan … I'm going to signal to you, that will cause me great concern, as to whether that proceeds on that budget or not,' she said.

'It's quite simply getting to a very high number.'

Photos of the almost completely algae free modellers pond showed the diatomix was somewhat effective against algae, but unfortunately weeds were still an issue.

The concreting option, which would take 1,200 cubic metres of concrete to complete, is the latest in a decades-long effort to clear the pond of weed and algae once and for all. Over the years the council has poured hundreds of thousands of dollars into various attempts to clear the pond of ruppia weed and algae, from the high-tech biological control agent diatomix, down to scraping out the bottom of the pond with diggers.

Committee chair Tim Skinner said thanks to the discontinuation of the diatomix trial, a biological control that aimed to starve out the algae, the pond was 'back how it was'.

'The diatomix, that biological solution, seemed to be working quite effectively against the algae, the weed, ruppia, maybe not.'

Councillor Mel Courtney said he was being 'inundated' with people sending in photos of the pond and complaining about the algae, and said he had been recently himself and it was 'in a terrible state'.

Group manager of community services Roger Ball said that this would likely be a consistent problem over summer.

'Based on the very limited budget that's available for maintenance there, and how long a clean lasts, I regret that you will continue to see a state you won't be happy with, and people will comment to you,' he said.

'I have to let the council know that there's a very limited budget, the clean will only last, each time it is done, for a couple of days before it grows back again.'

The previous council decided to go ahead with the design work for the concrete option in an eight to five vote with then-councillor Luke Acland, and returning councillors Kate Fulton, Brian McGurk, Courtney, and Lawrey voting against it.

Reese was also initially against the decision, attempting to have it amended to explore other options, but supported the majority when all amendments failed.

The council is currently engaging with iwi to determine if support exists for concreting the pond's base.