Milestone for Ocean Outfall project
 One of the Council’s biggest and most important projects has reached a milestone, with New Zealand-based company McConnell Dowell Constructors Ltd awarded the contract to build the city’s ocean outfall pipeline.
Instead of traditional trench digging to lay the pipe, the company will use a boring machine to tunnel the landward section of the pipe route, from the oxidation ponds across the estuary and South Brighton Spit and through the surf zone.
Beyond the surf zone, the pipeline will be sunk into a dredged trench.
“This is an outstanding solution.” says Mayor Garry Moore. “Not only is it the best financially for the city, it is the most environmentally sound and least-disruptive solution for the local community and recreational users in the vicinity of the pipeline route.”
“This is a major milestone; we’re at the start of the final, even if long, stage in a massive project.”
A pump station, which is required as part of the ocean outfall at the oxidation pond end of the pipeline, was tendered separately and was awarded to Works Infrastructure Ltd.
The total expected cost of the project of $87.224 million is within 4 per cent of the estimated budget of $83.856m.
Mark Christison, the Council’s City Water and Waste Unit Manager, says to have tendered costs so close to what was budgeted is an excellent result given the size and complexity of the project and the recent construction market conditions.
McConnell Dowell recently completed construction of the Waimakariri ocean outfall and is now building the Clandeboye (near Temuka) and Tahuna (Dunedin) outfalls. “The company has a strong track record in this type of work and a sound local knowledge of Pegasus Bay,” Mr Christison says.
Preparation work for the pipeline, away from the construction area, has already begun. Construction on-site is expected to start in mid-December, at the city’s Wastewater Treatment Plant and South Brighton Park. On-site work for the pump station is expected to start in November.
Instead of the City’s treated wastewater being discharged into the Avon-Heathcote Estuary, the underground pipeline will take it from the oxidation ponds to 3km out into Pegasus Bay.
It is possible that the project will be completed at the end of 2008, nine months ahead of an Environment Court deadline to remove the discharge of treated wastewater from the estuary. |
