Darren's Diaries for Water Power

Diary 3 - Thursday 11 September 2008

Field Trip Name: Water Power Field Trip Place: Diary number of total: 3 of 4 Weather: Dry with low cloud lifting Where's Darren: Hydro Power Station

Hi everyone, Darren here.

There is a saying that you should not measure your life by the number of breaths you take but instead by the number of times your breath is taken away. You can tick the column for the second one today. When we came The early morning sun breaks through the cloud over and Doubtful Sound appeared through the trees six over the West Arm of . Image: Heurisko Ltd hundred metres below, our breath was most certainly taken away.

Another early start saw us on the Z-boat in the morning darkness and on our way across the lake again. As we arrived the morning sun was doing its best to break through the clouds. We took a morning stroll to a beach opposite the power station. Looking back across the water you could clearly see the intake block, switchyard and control building of the power station. We tried to visualise the machine hall 200m below. Walking back we came across an old turbine that now stands near where tourists get off the boats that bring them here. It was fun climbing inside it and looking out through the blades. Look at the panorama image.

Back at the control building we met up with John Twidle who is the Team Tracy Island or Manapouri Hydro Power Station? Leader of Maintenance and Operations here at Manapouri Hydro Power Either way it's FAB. Image: Heurisko Ltd Station. John seems to know everything there is to know about the power station and along with Paul Lloyd provided excellent answers during our morning audioconference with Room 1 at Ilam School. John and Paul also starred in a videoconference soon afterwards with Wellington Girls' College. The Year 9 students were actually inside Meridian's offices in Wellington at the time and kept John and Paul on their toes with their questions.

Today we wanted to follow the water flow from Lake Manapouri, through the power station, and out into . We began with a visit to the intake block where the water enters the power station. Paul explained to us in a video about the penstocks and how the water falls deep into the John, Paul but not Ringo during our audioconference with Ilam School. Earth to the turbines below. You cannot actually see the turbines Image: Heurisko Ltd operating because they are underwater but remember our visit to the bottom of the penstocks yesterday?

To get to see the water leave the power station we needed to travel along a very special road. The 20km long Wilmot Pass Road was built between September 1963 and November 1965. It was built to link Deep Cove in Doubtful Sound with the power station site and at the time was the most expensive road built in (at $80 dollars per metre). The road crosses the 670m high Wilmot Pass through dense bush and was used to transport the equipment and machinery used in construction from the wharf at Deep Cove to the power station. It is a shingle road but is well maintained and John offered to drive us. Of course we hopped, skipped Doubtful Sound viewed from the top of Wilmot and jumped at the chance. Pass. Image: Heurisko Ltd

The road climbs steeply from Lake Manapouri and someone with a sense of humour has slightly altered the "Danger Ice" signs. Check out Webster's update to see this. The road is lined with steep sided mountains covered with thick bush. The occasional waterfall can be seen with their origin high above us. Just after crossing the highest point John pulled over to the left and we jumped out and had what is known as "a special moment". Doubtful Sound could be seen far below us but did not

1 of 3 seem real - a truly stunning view. After getting our breath back we continued our journey stopping halfway down so that John could show us the effects of a huge earthquake five years ago. A huge section of hillside had come crashing down changing the course of a waterfall along the way. Watch the video to find out how the power station (and John's home in Te Anau) was affected.

As we approached sea level we took a slight detour to see the tailrace tunnels emerge from their 10km journey through solid rock. The second tunnel is the easier to see of the two with the original tunnel almost completely submerged in the river they have created. Why two tunnels? Where did all the waste rock go? Paul answers these questions in a video for you. Big earthquakes happen here. Note the part of the hillside that came away during a 7.1 shake five Deep Cove was not too much further. It is at the eastern end of Doubtful years ago. Image: Heurisko Ltd Sound and we spent some time on the wharf trying to guess how deep it actually is. Why is it called Doubtful Sound? Well, it was named by Captain James Cook in 1770 because he was "doubtful" that if he entered the fiord he would be able to sail out again. It is connected to the sea but as a lot of freshwater enters the cove, mainly from waterfalls in this high rainfall region but also of course from the power station, a strange thing happens. The freshwater forms a layer up to 20m deep on top of the salt water because it is less dense. The water is black and still. Hardly any light can get the layer of fresh water to the salt water underneath and so because of this, a lot of deepwater fish, plants and other marine life live unusually close to the surface. The exit of the second tailrace tunnel. We drove back over the pass and as we approached the power station Image: Heurisko Ltd John took a slight detour to take us into the 2km long tunnel down to the machine hall. Remember, yesterday we took the lift. Like the rest of the power station the road tunnel has been carved out of a rock called gneiss. We came across a fault in the rock which was easy to see due to a different rock type that has formed along the fault due to the huge pressures. Watch the videos to hear John tell you all about the tunnel. It was quite a sobering moment to come across a plaque that named the 16 people that were killed during the construction of the power station. All too soon we were back on the surface.

Today's competition clues: The wharf at Deep Cove, Doubtful Sound. You are 1. I am part of Doubtful Sound looking back towards the Wilmot Pass. Image: Heurisko Ltd 2. I am where the water from the power station ends up

3. I am not shallow

The competition prize is a fantastic Power House DIY kit for your class courtesy of Meridian. Remember you will also need the clues from Wednesday and Friday.

See you in the morning.

Darren (and Webster)

It's not my fault! Image: Heurisko Ltd

The plaque inside the tunnel recording the names of the 16 people who lost their lives during the construction of the power station. Image: Heurisko

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We're back at the surface again. Image: Heurisko Ltd

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