Tag Archives: Tarraleah Power Station

Derwent River water passes via the township of Tarraleah

 

Earlier this year the entire town of Tarraleah was on the market for sale.  Refer article 1, article 2 , and article 3.

If you were to follow Derwent River water by walking from the western end of Lake Catagunya at the Wayatinah Power Station inland past the Wayatinah Lagoon to the Liapootah Power Station then follow the Nive River to the bridge next to the Tarraleah Power Station (with the Tungatinah Power Station on the other side of the bridge), you could look up the hill to see massive penstock pipes descending the hill from the township of Tarraleah above.

The water falling down these pipes is Derwent River water which has travelled via Tarraleah Canal 1 and Tarraleah Canal 2 after processing through Butlers Gorge Power Station at the foot of Clark Dam that holds back the waters of Lake King William.

I chose not to walk the route via the penstocks and Tarraleah township when walking from the mouth to the source of the Derwent River,  rather to follow the original river bed albeit a scatter of stones and limited water during the summer, between Wayatinah and Butlers Gorge Power Station.

However, knowing that Derwent River water flowed along the Canals and through the massive pipes, I did visit the township of Tarraleah during the period when it was advertised for sale. I was curious to see what the township of Tarraleah looked like (it had been many years since I last visited). Despite being centred within lush dense rainforest, thankfully no rain fell at Tarraleah and the sky was blue and the day sunny when I visited. I approached the town from the highway and followed the slightly snaking pipes.

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At the point where the pipes arrive at the top of the hill and are about to drop down the hill, I browsed public information boards and plaques.

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The views from the township were dramatic. I am forever in awe at the engineering achievements of the past.

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These days Tarraleah is a place that acknowledges its social history from the early days of Hydro Tasmania. I was amazed to see the row of freshly renovated houses each with their own array of pastel coloured paint finishes. Perfect location for a science fiction movie.  I felt there was something strange about its lollipop colours and perfection.

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Afterwards I travelled out of Tarraleah and down to the bridge over the Nive River. The Tarraleah Power Station was partly hidden in shadow from the afternoon sun. My eyes followed the pipes up the hill knowing the township was there on top.

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The Nive River accepts the Derwent River water after processing for electricity generation through the Tarraleah Power Station.  The water passes through a series of further management processes, and ultimately empties into Lake Catagunya and then continues its long journey towards the sea.

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I have heard rumours the Tarraleah township sold but I cannot find records supporting this.  I haven’t one idea how a buyer could get a return on an investment of $11 million at Tarraleah, so I will be very interested to hear what will happen to this piece of Tasmania’s history.

Tarraleah Canal No 1 walk – a surprising trickle

Blog followers may remember that at the start of my walk against Tarraleah Canal number 1, I was surprised to see an empty Canal.  Later in my walk I was even more surprised. After a few hours of walking, I stopped, looked, frowned, looked again and peered more intensely. A dribble of water was moving.  I blinked furiously.  Was I imagining that the water was running? No – the water was flowing.  Wow!  I was here on a day which next to nobody ever sees: a dewatered Canal and then one which is filling.  What a thrill.

In the photos below you can see that the water level is edging higher up in the Canal the closer I walked to my destination and the start of the Canal at the Clark Dam.

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The speed with which the water flows can be appreciated in the video.

Any person who decided to drop down into the empty Canal would have no way to clamber up and out over the deep smooth concrete sides and would be trapped.  If you fell in once water ran through the Canal, then the speed would quickly whizz you into the penstocks and before long you would be filtered out in tiny pieces at the Tarraleah Power Station before the water proceeded along at a crushingly powerful pace to create electricity.  I guess the remoteness and isolation prevent idiots from discovering this snaking gem – or maybe even idiots can appreciate the dangers.

Thanks to Tim, a Hydro Tas mechanical engineer who was working at the Butlers Gorge Power Station (Clark Dam) on the day of my walk and who was kind enough to drive me back home to Hobart, I know Hydro Tasmania had deliberately ‘dewatered’ the Canal in order to complete maintenance work at the Butlers Gorge Power Station and at the Tarraleah Power Station.  Obviously tonnes of water pressing through while someone changes a valve or whatever, means the job won’t get done.  While Canal number 1 was dewatered, Canal number 2 a little further inland was running full with water in order for the Tarraleah Power Station to continue to generate electricity.

When I met Tim at the end of my walk, I learned he was responsible for the final maintenance and the rewatering. On his mobile phone he had taken photos and a short video of the first cylindrical gush of water – he was as excited as I. The power of the water was obvious.  A perfect picture of a powerhouse for generating electricity.

I learned that it would take the Canal two hours to reach full capacity between Clark Dam and the Tarraleah Power Station.  I had seen all stages: the Canal empty and later with a dribble across the bottom.  Then the closer I came to Clark Dam the higher the water reached up the Canal walls.  By the time I reached the start of the Canal near the Dam, the water level was at its highest but for some reason I don’t have photos after a certain point back down the road – frustrating.  I know my feet were hurting and I was plodding with determination to reach the end.  I suspect that I lost focus on maintaining a photographic coverage of the whole distance. Maybe someone will want to drive a couple of hours up there with me one day so I can get those additional photos.

Tarraleah Canal No 1 walk – what is the ‘real’ Derwent?

Will the real Derwent River please stand up!   Where should a person walk if they are ‘walking the Derwent’?

Since the Clark Dam was built in 1952, the Derwent River has not flowed from the area now known as Lake King William downstream across its original bed, until closer to Hobart.  Instead the Tarraleah Canals number 1 and 2 accept Derwent River water from Clark Dam/Lake King William at Butlers Gorge in central Tasmania.  These canals channel the water to penstocks that feed the Tarraleah Power Station.  Electricity is generated and then the water flows on to create more electricity at Liapootah then Wayatinah Power Stations.  Eventually the water empties into Lake Catagunya.

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The old Derwent River bed is stony.  Along its length between Clark Dam and the bridge at Wayatinah, seepage from the steep hills creates pools of water.  There is sufficient water, although limited, to create a continuous running flow between the stones.  At the end of Spring the river bed looking upstream from Wayatinah was as follows:

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Michelle’s photo shows another view.

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In January the water level had dropped and the river bed looked like …

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Similarly, between the bridge over the Derwent River bed at Wayatinah and the river’s meeting with the Florentine River, and downstream almost to Lake Catagunya, the river is often a stony bed with limited flow.

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Upstream from the junction of the Florentine and Derwent Rivers, upstream from the Wayatinah Power Station, I walked on the river bed where I could.

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To ‘walk the Derwent’ should one follow the original river bed or the Canals or a mix of both?

Since Tarraleah Canal number 1 runs more or less parallel to the old river bed and is usually located under 500 metres from that river bed, I chose to walk next to the Canal along the section before it turned inland to travel to Tarraleah Power Station. I rather liked the idea of staying as close to the original Derwent River course rather than following man-made deviations. However this ‘walkingthederwent’ project does raise the question as to what constitutes the ‘real’ Derwent River. Does it exist any longer? And therefore, is it possible to walk the Derwent?

Tarraleah Canal No 2

Derwent River water from storage in Lake King William travels overground via a number of canals towards Tarraleah Power Station.

The water pours down a carefully calibrated though seemingly slight gradient at an exceptionally fast rate. When I stopped at a canal crossing walkway, I could see the concreted sides offered no purchase if you fell in; there were no hand-holds to grasp. Clearly, if you found yourself in that water, you would never get out and soon find yourself tumbling through the penstocks before reaching the Power Station. At some point you would drown.

Listen to our estimation of the situation.

Watch this video to hear the rush.

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This canal cuts a significant swathe through the landscape roughly one to two hundred or so metres away from the Derwent River, as noted in Chantale, Michelle and my aerial photos.

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