Where does the aqueduct go?

15 May, 2016

The Langford Gap Aqueduct is a convenient highway to be sure, but what is it doing there in the first place? I investigate the Kiewa Valley Hydro Scheme to find out.

Renewable energy is all the rage these days, so it surprised me to find out that Victoria’s biggest hydro power generators were first planned over 100 years ago.

One of the smaller companies that was swallowed up by the State Electricity Commission (SECV), that monolithic government entity which was responsible for generation, sale, and regulation in Victoria between 1921 and 1994 was the Victorian Hydro-Electric Company. It had been established in 1911 to develop power generation somewhere in what is today the Alpine National Park.

They decided that the Kiewa River was the best location in the area for a hydroelectric plant, and planned a modest scheme which would generate 30 megawatts — more energy than Melbourne required in those days. But they weren’t the only people who were campaigning to provide the capital with power.

Gippsland has extensive deposits of brown coal — coal with a high water content. Hydro power generation was cheaper to run than coal-fired generation, but even with the extra costs of building new plants next to the mines in the Latrobe Valley and the transmission wires up to Melbourne, the Gippsland plan still required half the capital expenditure of constructing the hydro power stations, so naturally that was the way that the state government went.The SECV soon bought out the Victorian Hydro-Electric Company, but for the next 15 years, works were limited to technical investigations and research.

Kiewa Hydroelectric Scheme

It took until 1937 for the SECV to start building their own hydroelectric scheme on the Kiewa River, and it was substantially more ambitious than the original proposal. Two large dams at Rocky Valley and Pretty Valley would provide water to five power stations providing 115 megawatts at peak times — although normally it would only operate at 50% capacity.

The plan was put into action, but World War Two soon came along to ruin everything. By 1945 (three years after the planned completion) only one power station was in operation, and demand for power had massively increased.

So SECV went back to the drawing board. The Rocky Valley Storage was to be expanded and complemented by a second dam —mdash; four times larger at Pretty Valley. The catchments of the two storage reservoirs would be enhanced through hundreds of kilometres of concrete-lined aqueducts from Spion Kopje, Mt Jim, Mt Niggerhead and The Fainters; while others would bring waters across the south face of Mt Bogong with matching aqueducts running across the northern face of Mt Nelse, and part of the Big River’s flow would be fed through a tunnel into the Kiewa as well.

Obviously, the combined power generation capacity was a much increased, to a total of 289 megawatts, and a sixth generator was added to the plan. All this extra construction meant that the village of Bogong needed replacing as the construction base, so another new town, Mount Beauty was constructed as more workers joined the project; at it’s peak, 4,000 people were employed on the construction.

Snowy Mountains Scheme

Beginning in 1949, the Snowy Mountains Scheme was a nearby project to divert snowmelt and other rainfall that should have flowed down the Snowy River, through East Gippsland and out into Bass Strait north, through the Great Dividing Range, and then down into the Murray-Darling System. It was the largest civil-engineering project in Australian history, and took 25 years to build. The redirected water is also used for power generation on its 800 metre journey to the bottom of the mountains.

Both of these two large public infrastructure projects both were getting a substantial amount of funding from the Commonwealth, so when funds started to dry up due to the financial crisis in the early 1950s, many State projects got the chop. The Commonwealth loans that were helping finance the Kiewa Hydro Scheme were cut off — although Victoria gained a larger share of the power from the Snowy Mountains Scheme to compensate.

So the Victorian Government was forced to scale down their plans on the Kiewa… only three power stations were constructed:

  • McKay Creek Power Station (No. 1)
  • Clover Power Station (No. 3)
  • West Kiewa Power Station (No. 4)

All three are fed from the Rocky Valley Storage, whilst most of the aqueducts were cancelled. Only Bogong Creek Aqueduct was constructed as originally conceived — with an accompanying tramway to assist in construction, and later inspections and maintenance work. “Our” aqueduct, Langford West is one of three that feeds into the Rocky Valley Storage.

The gigantic reservoir at Pretty Valley was scaled down to be only a minor weir that can only hold one day’s worth of water. It’s fed from Rocky Valley Storage and two rough aqueducts, while three of the planned six Power Stations were cancelled.

The much-reduced Kiewa Hydro Scheme was “completed” in 1960, with only 184 megawatts of capacity. It would remain half-built for another 50 years.

Later Developments

During the 2000s, plans were made by Southern Hydro, the company that had taken over management of the Kiewa Hydroelectric Scheme when the State Electricity Commission was broken up and privatised, to build the Bogong Power Station (No. 2.) No new dams were required, nor was any further water added to the Kiewa River’s catchment.

Building this new power station was the largest tunnelling project since the Melbourne City Loop during the 1980s. “Downstream” of Mackay Creek Power Station, the Bogong Power Station is located at Bogong Village and generates 140 megawatts of power. Things on the surface were largely undisturbed as tunnels are used to move the water from Mackay Creek Power Station, and most of the power station is underground. The removed earth was taken away and used by the shire to maintain local roads and seal the High Plans Road from Falls to Omeo.

The four power stations that make up the Kiewa Hydro Scheme now puts an average of 404 gigawatt-hours per year into the national power grid each year. And that’s why there’s an aqueduct.