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Manapouri

Entry 404, on 2006-10-06 at 14:56:46 (Rating 1, Travel)

One of New Zealand's most impressive engineering achievements is the underground power station at West Arm on Lake Manapouri. Manapouri is a smaller lake about 20 kilometers south of Te Anau. A 45 minute journey across the lake from Manapouri township is necessary to get to the power station. On the way there is spectacular mountain scenery on every side, and we enjoyed sunny weather, although the air temperature was a bit low. Of course a dedicated photographer such as myself endured the cold so I could get the perfect photos!

The power station was completed in 1971 and is 178 meters underground, a 10 kilometer tunnel takes the water to the sea at Doubtful Sound after it has passed through the turbines. A rather precarious road, which is used by powerful busses with extra brakes goes over the same mountain the tunnel goes under. At Doubtful Sound there are cruises, bush walks, and wildlife viewing.

We arrived too late to do the full trip across to Doubtful Sound - but several of us had done it already anyway - so we took the shorter tour to the power station and back to Manapouri, which took about 3 hours in total.

At West Arm, the bus tour enters a tunnel which spirals down into the solid granite below the lake level. The machine hall - which is 111 meters long, 18 meters wide, and 39 meters high - has 7 turbines (producing 142,000 horsepower) and generators, which generate about 850 megawatts, and is mostly hidden beneath the floor - the machinery visible is just a small part of the turbine and generator system there. When we were there there was some work being done on the equipment from under the floor and it was possible to see how big the normally hidden machinery really is.

Its a strange feeling to know the surface of the ground, and the lake, is 178 meters above you, but you are actually at sea level with the nearest sea 10 kilometers through the rock. When the station was first built a lot of the modern tunneling equipment we have now wasn't available and the hardship and danger endured by the workers was significant. But they only lost 16 workers during the whole project.

One of those died as the result of a fight in the pub, another was accidentally blown up when he wandered around the road building site without anyone else knowing, but the most dangerous part was construction of the tunnel through to the sea. A photo shows the final blast which joined the two halves of the tunnel. It was witnessed by several dignitaries but the charge was a bit too much and the photo (taken with exquisite timing) shows all of their hard hats being blasted off by the explosion!

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