Tag Archives: Wayatinah Power Station

From Catagunya to Wayatinah – post 4 of 4

I took a series of forest photos most of which are blurred. I am adding some here to give you an idea of what parts looked like – sorry about the quality.

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20170424_111909.jpgThen the white shape of the Wayatinah Power Station appeared between the tree trunks.

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The closer I came to the Wayatinah Power Station the steeper the hills seemed. For vehicles travelling down the road, the final gradient requires a low gear in a 4WD. The drizzle on a day like the one on which I went, meant the clay and soil track surface was exceptionally slippery and dangerous for the inexperienced or inept.

Then I was out in the open again. This time looking down to Lake Catagunya past the Wayatinah Power Station.

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To my right, additional infrastructure punctured the sky.

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Further up the hill and connecting to the huge surge tank, the snaking length of wooden penstocks started.  See my earlier post for more information about wooden penstocks here. Can you remember the wonderful photos which Andrew took in this blog posting?  My photos are less detailed but still show the dramatic line of the penstocks.

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I ended the day with a thick coating of mud on my boots and a smile on my face. Yet another day offering me a memorable experience along the Derwent River. I am especially grateful for the extensive information and access provided by GL. Please note that private and corporate owners control access to this section of the Derwent River and the many gates are locked with an assortment of sophisticated processes. General public access is not available.

From Catagunya to Wayatinah – post 3 of 4

 

I followed a road aiming to intersect with the transmission lines ready to follow that towards Wayatinah to the extent it would be possible.  Massive heavily forested gullies made continued close access to Lake Catagunya (full of Derwent River water) impossible.

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Even the cleared area wasn’t clear enough for anyone to walk through on foot, although it was sufficiently clear to keep the power lines unaffected.

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When I stood on high, misty wisps reshaped distant hills and threatened to obliterate views of Lake Catagunya. Fortunately I could always see its glistening surface way below.

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On top of the second last hill before reaching Wayatinah Power Station, the western end of Lake Catagunya appeared through the clouds.

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Before long the metal pipeline streaming water into the Wayatinah Power Station became visible.

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Often the bush was amazingly quiet. This film  seems to be without sound. Only near the end can the faint crarking of a crow be heard.  This bush silence was an unexpected beauty of my day from Catagunya to Wayatinah.

From Catagunya to Wayatinah – post 1 of 4

Well over a year ago, one morning I walked through smoky air westwards into the Catagunya Power Station.  After a night camping, entwined by the thick atmosphere of a far distant bush fire and desperate for water, I was relieved to be received hospitably at the Station.  At that time I was thrilled by a guided tour of the building and its operation, however I never proceeded to walk the extra few hundred metres to look at the Dam wall holding back the large Lake Catagunya.  I was most grateful when many months ago, my walking proxy Andrew climbed the hills from Wayatinah Power Station to arrive at and photograph the Catagunya Dam.  A blog search using “Catagunya” as the term, will help you to locate those past stories plus a swag of descriptive photographs.

Recently, I was privileged to make the journey between the Catagunya and Wayatinah Power Stations and to experience that stimulating environment. Thanks to the generous assistance of GL from TasNetworks,  I was able to enter the locked Catagunya Road off the Lyell Highway, and travel the 8 or so kilometres to the Catagunya Dam.

The wall of the Dam curved magnificently and  the landscape-green Lake Catagunya spread impassively to the west. 20170424_104221.jpg

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Below I could see the old Derwent River bed as a rocky almost water free pathway.

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Bypassing the river bed, a massive Canal drained water from the Lake into the Power Station. It appeared as a giant marker on the landscape that seemed much wider and more substantial than the Tarraleah Canals that run from Lake King William and the Butlers Gorge Power Station further inland.    20170424_104148

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The apparently still Canal water was deceptive. Only on closer inspection could I see the dramatic gush of water moving underneath the left hand entrance at the end of the race.  Obviously electrical power was being generated in the Catagunya Power Station that day.

From vantage points near the Dam and the Canal I could see the Power Station building way below. Oh how tiny it seemed by comparison with the larger constructions. Yet when I had first approached and walked around it, the building seemed cavernous.

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More than anything I was as excited as a three year old having a birthday party with lots of surprises.  Recent rain had cleared the air of dust, the day was overcast and the fairy weight of moisture from low clouds kept the air moist. I kept breathing deeply, absorbing the cleanness of the air. Loving the damp air. Feeling cleansed. So profoundly happy to be back in the bush and walking besides my beloved Derwent River.

Between Wayatinah and Catagunya Power Stations- posting 6 of 6

 

The goal was achieved. It was great to have it done. I am very grateful for Andrew’s generosity of spirit and for his notes and photographs. The walk between Wayatinah and Catagunya Power Stations could be ticked off the list. But a long walk back to the Lyell Highway had to be faced before returning home. Andrew turned north for the 7 km walk on Catagunya Road. He passed a mix of open unfenced paddocks and distant plantations. The Cooma farmstead and outbuildings were the only marker that people had lived in the area.

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For a brief moment he thought he would have company. Andrew had been walking for a while when, in the distance on a straight stretch of road, he could just make out a couple of figures coming slowly towards him.  Someone to say g’day to and have a natter  – but  – on closer inspection they transformed into ambling sheep. After that, Andrew’s company all the way back to the locked gate was a rather large herd of very healthy looking quadrupedal steaks – which, with a spritely step, he kept ahead of. After some 7 hours of pleasant walking, this walk along the Derwent River was over.   There had been time for plenty of stops during the day to take photographs and to enjoy the surroundings.

Hydro Tasmania, TasNetworks and forestry related employees can drive over the convoluted maze of tracks between the two dams, but there are numerous locked gates and no general public access.  Even during the walking, many locked gates with serious double and complicated locks were seen. I have said in earlier postings that landowners and managers in the Derwent Valley and Central Highlands can recite histories of bad experiences with people entering their lands and not treating it appropriately or stealing their wood or livestock. It is a shame that a few people wreck it for the rest, and remove the opportunities for those who care for the land and the property of others and wish to explore more of our wonderful Tasmanian natural environment.

 

Between Wayatinah and Catagunya Power Stations- posting 2 of 6

Throughout the walk between the Wayatinah and Catagunya Power Stations, a number of creeks cut across the power line easement creating deep gullies with their own special environments of thick forests. In some spots these make progress slow.

Only the first creek had running and potable water. The other creek beds were dry and even if water had flowed, the extensive plantation forests or agricultural lands where chemicals are used, sit upstream so it would have been inadvisable to drink the water.

Long term readers know how on my walks I have been able to see the Derwent River (and its lakes and dams)  but in almost all cases I could not reach it to refill my water bottles.  The escarpments, rocks, steepness and dense vegetation to the water’s edge prevented access.  With that constraint plus finding dry creek beds, managing my water supply was always a challenge.  Water, water everywhere/over there but not a drop to drink!  Despite the weight of water, I strongly advise anyone walking inland in Tasmania in summer to carry plenty of water.

 

Between Wayatinah and Catagunya Power Stations- posting 1 of 6

Anticipating a comparatively easy and short day of walking, my proxy Andrew left Hobart at 7 am and drove westwards and inland along the Lyell Highway, until reaching Catagunya Road where he parked his vehicle at the locked gate.

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A friend drove him further along the highway, turned left just before the Liapootah Power Station and proceeded along the gravel surface of Long Spur Road towards the Wayatinah Power Station.

He arrived at the western side of the Station but needed to be on the eastern side to start this sector of the walk. Because it was not possible to cross over the Power Station outlet, and access through the Power Station is not permitted, Hydro tracks were followed to the most accessible part further away from the Lake Catagunya/Derwent River. Private vehicle access to the penstocks and beyond was prevented by a locked gate on the approach to the top of the penstocks, so the walk started there around 10 am. While it would have been possible to scramble beneath the penstocks, a detour to where the penstock began high up on the hill seemed like a good idea.

Wayatinah’s penstocks consist of two massive parallel pipes that carry water from the tunnel bored through from Wayatinah Lagoon. The pipes are approximately 1.2 km long and are made entirely of timber – coopered like gigantic continuous barrels. To keep it all together they are tightly bound with steel straps which keep the joints snug, save for the occasional trivial leak. Interestingly, inserted into the walls of the pipes every 50 metres of so, is a fire hose outlet (obviously the timber pipelines are not only protected from the inside!).  DSC01655e.jpg

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The walk began by heading around the top of the penstocks where they emerge from the tunnel.

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There is an impressive view down the length of the penstocks to where they disappear around a distant bend for the final approach to the Wayatinah Power Station.

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On the far side of the penstocks a good track leads down to the huge surge tank near the entrance to the power station. The glorious panoramic photo below distorts the view so I have also included a Google Earth aerial shot so you can understand the situation.

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Past the surge tank but before the Power Station, a power line easement heads east, then south east, over a series of ridges and gullies to Catagunya Power Station. The forest next to the track leading to the easement was open with healthy eucalypts, dogwoods and some wattle trees sprinkled across the landscape. The day’s walk was a combination of traversing hills and gullies, and the next photo gives an appreciation of one of the more gentle hills.

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Because of the steep and scrubby terrain, it was not viable to access or follow against the edge of Catagunya Lake (Derwent River) at water level. Instead, following the power line ‘clearing’ was the smart alternative.

Once serious walking along the transmission line ‘clearing’ began, it was obvious that sections had not been slashed in a long while. The going was irregular with patches of scrubby low level vegetation and fallen logs to negotiate so that, occasionally, Andrew walked off to one side for a clearer route. The next photo shows an example of a less straightforward area along the easement under the power lines, and helps to explain why deviating from this line made sense during the walk.

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Did you know not all penstocks are constructed using steel?

This post provides a background on an extraordinary feature of the walk between Wayatinah and Catagunya Power Stations along the Derwent River.   It is about one of the great surprises of this  ‘walking the Derwent’ project and, as such, reminds me that even the most ordinary of explorations can unearth new discoveries (for those not familiar with an industry – in this case, the industry involved with penstocks).

Okay okay okay I know some readers will have rolled their eyes wondering what a penstock is.  A penstock is a very large pipe that is laid downhill through which water falls at high speed to an electricity generating power station.  Refer to photos in some of my earlier posts such as: Derwent River water passes via the township of Tarraleah .

My typical experience of penstocks, as conduits for water gushing into electricity generating power stations, is of massive steel structures.  I suspect this would be the expectation for others who have seen Tasmania’s penstocks only from the vantage point of our highways.  For people like me, the wooden penstocks feeding Wayatinah Power Station are astounding and therefore I thought it would be of value to undertake some research and learn more. Andrew’s photo below shows the wooden penstocks emerging from an underground tunnel and sloping down towards the Wayatinah Power Station.

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The questions which come to mind include, are there any other wooden penstocks in Tasmania, what wood is used, when were they built, why weren’t they built with metal, who built them, how effective are they, and what is their life span. In my research a constant term was ‘stave’. A stave is a narrow length of wood with a slightly bevelled edge to form the sides of barrels, tanks and pipelines, originally handmade by coopers.

After a little research I now know that wooden penstocks are not unique to Tasmania and have been built in a number of countries including Britain, Canada and the USA. For example, wooden penstocks were built for hydroelectric facilities in Lincoln County, Wisconsin, USA as shown in this article.  This web site contains a great deal of construction and other information which I imagine is similar to that for Tasmanian wooden pipelines, and therefore worth reading. The photo below, from that website, shows redwood penstocks at the Thomson Hydroelectric Station in eastern Minnesota, Wisconsin.

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The website answered some of my questions: “Why wood? First and foremost, keep the wood thoroughly wet and it will not rot. If there is an issue, it has to do with the quality of the metal bands. Expansion joints are not required as the wood absorbs the water and expands. Steel restraining bands are used and the wood will expand against those. The metal bands are used only to provide strength. Even when they corrode and lose their strength, the wood will hold together and the bands can be easily replaced. The carrying capacity exceeds that of metal pipe, in large part because the interior walls remain smooth and do not form tubercles. The wood components are easily transported to the sites, which can be remote. No massive hoisting apparatus is needed. They do not require concrete foundations, but “float” on the gravel. The wood is easy to bend, so the contractors can follow a more natural contour; for example, bending around curves. There is no need to cover them. The wood has natural insulation. They can last for 40-50 years. Simple carpentry can be used for repairs. Assembly is easy.

Why do we see so any leaks? Leaks do occur at the end of a stave, at what is called the butt-joint, most often when combined with a breakdown or severing of a steel band at that point. In addition, steel plates are sometimes placed in the slots at each stave end, and these steel plates can corrode. Also, some erosion can occur at the end of a stave, and develop into a hole. In this instance, the steel band in that area might corrode and sever, and the pressure of the water inside might break off a section of the stave, however small. Metal corrosion also sets up a mild acidic condition. The acid can degrade the wood. There can be a breakdown in the staves when the water pressure inside varies a lot. You will seldom see wooden penstocks for example in positions where turbines can vary the water pressure output in large degrees. This creates what is known as the hammer effect which can beat up a wooden penstock quickly. It’s best to try to keep the inside water pressure as even as possible. This said, small leaks can self-repair as the wood expands. Even large breakdowns in the staves can be repaired. In most instances, the leaks are tracked closely and there is very little risk of a catastrophic failure. “

The hole in a penstock and the story of its repair speedily within one week for the Jackson Hydro Station in New England, USA can be seen here. Another rupture coverage, this time in Quebec, Canada is covered here.  I was surprised when this website included photos of other wooden penstocks around the world including a photo of one of Tasmania’s wooden penstocks.  It looks remarkably like Wayatinah’s penstock, and there are outbuildings in view and some dates as well.  Perhaps a blog reader can make a more accurate identification.

It seems there are only two Tasmanian power stations being supplied by water flowing down wooden penstocks: Lake Margaret Power Station (not on the Derwent River) and Wayatinah Power Station.   Wikipedia  explains the situation in relation to the Lake Margaret Power Station here. For more information refer to the fact sheet for Upper Lake Margaret Power Station, the fact sheet for the Lower Lake Margaret Power Station, and a  note regarding Innovation and heritage feature in Lower Lake Margaret redevelopment. Photos of the pipeline can be seen in Lake Margaret Power Scheme A Conservation Management Plan. I found the photos on pages 11 and 19 particularly helpful with pinpointing the location.

In relation to the wooden penstocks feeding the Wayatinah Power Station,  a You Tube video is worth watching. Page 25 of the booklet ‘The Power of Nature’ includes a photo of the woodstave penstocks at Wayatinah. Other informative photos of dams and power stations and penstocks associated with other parts of the Derwent River are also presented.  Most are glamour shots taken from excellent locations and, after the gritty often basic photos which I have taken, these make the extraordinary engineering feats look even more magnificent and significant. This website offers the following information:  “Wayatinah is the sixth station on the Nive/Derwent cascade and is downstream of Liapootah HPP. Water is supplied from a small storage lake called Wayatinah Lagoon and diverted into a 2 km tunnel to two 1.3 km low-pressure wood stave pipelines. Finally, water drops 56 m through three steel penstocks to the powerhouse.”

Now the scene is set for the story of the walk between Wayatinah and Catagunya Power Stations.