New Zealand prime minister Helen Clark opened the 10km long second Manapouri tailrace tunnel at Deep Cove, Fiordland, at the end of May this year. The event comes some 15 months later than planned following engineering difficulties on the scheme.
The tunnel, built by a JV between Fletcher Construction, Dillingham Construction and Ilbau, cost US$129M, about US$11.8M over budget, according to the client, Meridian Energy chief executive Keith Turner.
The project employed more than 200 tunnellers at the peak of construction who worked “underground in very tough conditions – cold, wet, water pouring out of the roof,”said prime minister Clark, concluding, “this project is a world class engineering achievement which has global environmental significance.”
The additional tunnel, constructed through extremely challenging geology by a 10m diameter Robbins TBM, means the Manapouri power station is finally operating at full capacity. The event comes 30 years after the controversial scheme helped topple the government of the day, headed by Keith Holyoake. This followed widespread opposition to the hydro scheme which included building a dam on Lake Manapouri that raised water levels by 30m, drowning islands in the lake and flooding the shoreline.
