Monday 7th March - Doubtful Sound - Part 2

Mike and Liz Downing
Wed 30 Mar 2011 09:15
More photos of the trip back up Doubtful Sound from the sea, and the Manapouri Hydro Power Station built deep underground in the middle of a mountain.
One the way back we headed up one of the several arms of the Sound, Hall Arm, to see Commander Peak
and stopped, turning everything off, including engine and generator, to listen to the sounds of the
NZ wilderness.
Just more beautiful views!
We're back on land now and in the coach on our way back through the mountains and temperate
rainforest, heading for the Wilmot Pass.
These huge tunnels (there are 2) are the 6-mile long tailraces where the water escapes into Deep Cove in
Doubtful Sound after passing through the power station turbines.
The 1.2 mile road tunnel spirals down within the mountain to the generator hall 700ft down. Glad there
were no earthquakes today (no matter how safe they say it is!).
The huge power station machine hall, 700ft underground in the mountain. The photo below gives the
size of this hall. There are 7 generators and Manapouri is the largest hydro power station in NZ.
This is how it works - simple really, and all down to gravity. Just funnel water from the high lake
through pipes down to turbines situated in the mountain below and dump the used water in the
Sound below that. Only miles of tunnels and halls to carve out of solid granite!
The water descends into the power station here in Lake Manapouri (called penstocks).
Pylons take the power 106 miles to an aluminium smelter on the coast.