Tag Archives: electricity

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?

Panoramic views

I continued walking up and down the cleared land of the undulating landscape forever keeping as close to the Cluny Lagoon as practicable.

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And occasionally I deviated away from the river to capture the panorama.

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In addition, I felt compelled to take photos of the towers and wires which remind me that the water of the Derwent River is being used to generate electricity.  Cluny Lagoon exists to keep us electrified.

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Death and Lake King William

Fairly early in my walk along the eastern edge of Lake King William, when I neared the power transmission lines, signs such as the following were posted.

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I have no idea how close one must be to incur death, and therefore the concept of a ‘near approach’ is rather meaningless.  However, because I saw the 4WD track crossing under the power lines from time to time, I guessed that walking along these tracks wouldn’t bring on my early demise, well at least not from electricity jumping about. And so I live to tell tales.

Later in the walk when I approached another sign, the combination of the sign and the vista created a special message.

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The way my simple mind worked was this:  Lake King William is a man-made lake damming the burblings and gurglings of the infant Derwent River. The purpose of the Lake is to enable hydro-electricity power generation. The Lake drowned the native vegetation and dead trees are the result. The Danger sign alerts people to the danger of death from the electricity pouring through the wires overhead. The making of electricity kills and electricity itself is a killer.

As I walked, I thought a lot about the conservation needs of our forests and our contemporary way of life needs.

On the one hand, I can imagine the sorrow and despair that some will have when seeing the photos of the dead remains of old forests jutting out of the land as the Lake’s water level drops. I guess some people would wish this dramatic change to the original landscape never happened.

On the other hand, most people want to click lights on at night, recharge their technological devices, and have a refrigerator to keep their food cold and safe, run a washing machine, boil water and cook food. Without electricity (which is always generated using some natural resource), our contemporary lives could not continue. Hydro power is cleaner than coal power, and not dangerous like nuclear power.  If we must have electricity, which resource source should we use?  The creation of wind turbines changes landscapes and uses large quantities of processed mineral resources.  Equipment to support the gathering of solar power also uses processed mineral resources. If we choose to live as we have become accustomed, then ancient forests will be continue to be lost either directly or indirectly. There are very few who would give up the use of anything made from or using electricity.  I wonder if it is even possible to do so absolutely in first world and most third world countries.

Dunrobin Bridge over Meadowbank Lake

 

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Meadowbank Lake, a large spread of dammed water through which the Derwent River runs,  is located west of New Norfolk: an expanse of water which measures at least 15 kms in length.  Like many other dams and lakes on the Derwent, Meadowbank has been designed for electricity generation purposes.  The Meadowbank Power Station was commissioned in 1967. In a document The Power of Nature, Hydro Tasmania provides information about Meadowbank and the other electricity-generating lakes and stations across Tasmania.

The Dunrobin Bridge carries Dawson Road; a road which extends from the Lyell Highway, crosses Meadowbank Lake then continues on the western shore until it reaches Lake Repulse Dam.

The first Dunrobin Bridge over the Derwent River was built in the early 1850s. The National Library of Australia’s Trove repository of historic documents provides information from a 1910 copy of The Mercury newspaper: ‘Dunrobin Bridge was built over the Derwent, between the Ouse and Hamilton during the regime of Governor Denison. Governor Denison’s rule in Tasmania lasted from 1847 to 1855. It is a fine stone structure, and the cost is stated in the Legislative Council Journals of 1856 to have been £13,875. Its construction seems to have occupied six years, from 1850 to 1856. Dawson’s Road, which was named after the man who superintended its construction, went from Dunrobin Bridge…’ westwards.

In 1900, according to the blog Tasmanian Gothic , the bridge looked like:

Dunrobin Bridge

Dunrobin Bridge

The bridge was damaged during flooding in 1952 according to Linc Tasmania.

Dunrobin 1952

This site shows the remains of the bridge in 1963.

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Once the Meadowbank Dam was built, the gorge behind gradually filled with water. The remnants of the old Dunrobin Bridge apparently remain beneath the current Meadowbank Lake.  I cannot find when the new Dunrobin Bridge was built.  Anybody know the date?

The photos of Chantale, Michelle and I show the current bridge across the northern section of Meadowbank Lake.

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At ground level, the Dunrobin Bridge curves across the Lake in a stunning simple arc.

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As I walked in the vicinity, time and again I was almost overwhelmed by the beauty of the landscape.

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Clark Dam

Clark Dam map

Late in October 2015, on the northern side of the Derwent River, I walked at Clark Dam built on Butlers Gorge, and then along a little of Lake King William. We know that in 1835, George Frankland followed the Derwent River in a southwesterly direction from Lake St Clair across huge plains until the gorge country commenced. The Clark Dam has been built at that junction, and over the decades the plains behind have been swamped with what is now known as Lake King William. The location is a place of extreme weather conditions, from blizzardly snows to ferocious and bitterly cold winds and to scorching sunny days, but always stunning.

Clark Dam is a massive piece of engineering in a beautiful but remote area of central Tasmania.

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Chantale’s aerial photograph below puts the Dam and Lake King William into context.

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Michelle’s photos below provide similar information.

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In 1952 a special tribute plaque was installed on the Dam: ‘The Hydro Electric Commission, Clark Dam, A Tribute, To those who conceived this project, who laboured on its construction, who made its accomplishment possible, a united effort to harness the forces of nature for the benefit of mankind.’

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Another plaque nearby records: ‘The Hydro Electric Commission, Clark Dam, Named in honour of his Excellency, Sir Ernest Clark,  G.C.M.G., K.C.B., C.B.E., Governor of this State, 1933- 1945.’

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My chauffeur for the day Andrew, remembered years ago he walked across the Dam wall but that is now impossible.

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This means it is impossible to change from one side of the Derwent River to the other at this point.  In the photo below despite the walkway beckoning a walker, it was impassably gated at the other end.

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The reminder that the Clark Dam is part of an electricity generating project is everywhere.

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Dams on the Derwent River

The potential of the volume of water passing down the Derwent River for hydro-electricity generation was seen over a century ago.  While a few power stations were built in the early decades of the 20th century, with an influx of migrants from war ravaged Europe in the 1940s-50s, the numbers of dams and power stations increased quickly.  Overall, many dams and approximately 30 power stations have been built across central Tasmania.

On my way to Lake St Clair, I will reach and walk past each of the following 7 markers along the River:

  • Meadowbank
  • Cluny
  • Repulse
  • Catagunya
  • Wayatinah
  • Tarraleah
  • Butlers Gorge

One of the Hydro websites provides detailed information about these and others which feed into the Derwent River catchment.  In addition, the site includes the diagram below.

Derwent dams

Another idyllic pathway on Stage 14 of my walk along the Derwent River

The world I entered on the pathway away from the Tynward Park sports ovals, was gentle in the autumn afternoon light. Almost a fairyland. A father fishing while his young daughter sat making drawings.  Blue wrens flitting. Seeding bull rushes sending creamy fluff across the path. Superb water reflections.

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The dramatic background was the walls of Derbyshire Rocks in startling view on the other side of the Derwent River.

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How lucky I felt to be able to walk in such a beautiful place, free of all worries.

The track started climbing up and away from the River.

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Black faced sheep grazed behind fences

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Powerful pylons carried electricity across country.

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I enjoyed the watery views with the backdrop of autumn toned trees and then, with excitement at 2.20pm, for the first time during the walk I saw the bridge in the distance over the Derwent River at New Norfolk.

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Not much later I came to a fork in the path, but neither track were signposted.  Where to from here?

Large information panels provided information about the nearby historic Turriff Lodge property (on which the black-headed sheep grazed), but nothing about which path went where.

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