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Snowy Mountains Hydroelectric Scheme

The largest engineering project Australia has ever seen lies within the boundaries of the Kosciuszko National Park in New South Wales and it is an absolute beast. The Snowy Mountains Hydroelectric Scheme incorporates 16 major dams, 9 power stations, 2 pumping stations, countless pipelines and aqueducts and roughly 225 kilometres (140 miles) of tunnels, all designed to funnel the precious water down from the Snowy Mountains to the Murray-Darling basin below and Australia’s thirsty irrigated agriculture industry as well as providing much-needed energy. 

This was a Megaproject of staggering proportions that took 25 years to complete and involved over 100,000 workers. In a country where water scarcity is still having an enormous impact, the Snowy Mountains Hydroelectric Scheme was able to utilize the natural elements to prove vital water to the local area. 

Australian Water Scarcity

If you can reach your mind back to the early days of 2020, before the word Covid had even really taken off, you may remember the horrifying images of the Australian bushfires. Great swaths were set alight as fires tore through huge patches of the country, adding up to an estimated 46,050,750 acres of burning land – that’s bigger than the whole state of Florida.

But while this was undoubtedly disastrous, this is not the longest-running and most severe ecological problem unfolding in Australia. You see, humans, plants and animals need water and unfortunately for Australia, it often doesn’t have enough – or at least, it’s not always in the right place.  

The land down under is perhaps not the ideal place to house a nation that currently has just over 25 million people, but it seems unlikely that they’re going to move any time soon. Water scarcity has been an issue for decades now, with numerous causes including a booming population, deforestation, overgrazing, extensive agriculture and of course the overriding threat of climate change.  

Australia has done its best to lower water consumption but it remains firmly in the top 10 most water-hungry nations of the world, consuming roughly 100,000 litres (22,000 gallons) of fresh water per person each year. Efforts have increasingly focused on maximising the water than the country does, and that brings us nicely back to the Snowy Mountains Hydroelectric Scheme.    

Background

Manipulating river flow to increase water levels isn’t new. As far back as the 1800s, the nearby Murray and Murrumbidgee Rivers had experienced some kind of human intervention, but for a long time, the Snowy River which winds through the Australian Alps had never been touched. Much of it eventually flows into the Pacific Ocean but takes with it a significant amount of melted snow and ice from the south-eastern New South Wales snowfields – water that could well be used elsewhere.

Shortly after World War II, a series of proposals emerged regarding the scheme. The first focused almost solely on irrigation, while the second incorporated a much broader use of the water and called for several dams and power stations. But the moment you start mentioning dams or diverting rivers, you’re always going to come up against opposition, and so was the case with the early design.

In 1948 a report by the Australian government was published which outlined a much more expansive plan than before that would focus on both irrigation and power generation, and a year later the Australian states involved and their main government finally came to a workable agreement and the vast project inched towards reality. 

The idea behind it was fairly straightforward. Melting snow and ice which accumulates in the Snowy Mountains travels down as water runoff and is captured by the various newly formed lakes and reservoirs below (sometimes travelling through purpose-built tunnels to get there). This water then passes through the dams and power stations creating electricity. The same water then continues out of the other side and down into the Murray and Murrumbidgee Rivers where it can be distributed through various irrigation channels to the agricultural industry desperate for water. So everybody’s happy, the farmers get their water and the home dwellers get their electricity.    

Construction Begins

One interesting fact about the Snowy Mountains Hydroelectric Scheme that we should probably start with was the extraordinary diverse nationalities included in the project. As many as 32 different nations were represented during construction, accounting for roughly two-thirds of the total manpower, many coming from Europe in search of a stable well-paid job. Considering construction began in 1949, just 4 years after the end of the war that had left Europe a smouldering wreck, it was common for groups who had been at war with each other a matter of years before, now working side by side.

Snowy hydro murray 1 machine hall floor
Snowy hydro murray 1 machine hall floor.By Ear1grey is licensed under CC-BY-SA

Much of the Scheme was modelled on the Tennessee Valley Authority, a similar venture in, you’ve guessed it, Tennessee. The United States even provided technical assistance and trained engineers for the project. 

In total, the Scheme covers an area of roughly 5,124 square kilometres (1,978 sq mi) – which is bigger than the whole of the Grand Canyon National Park. The first to go in was the vast network of roads and railways measuring some 1,600 kilometres (990 miles) in length to be used by the heavy machinery later in the project. Additionally, before any major construction work could be started, the thousands of workers employed on the project needed somewhere to live.

The result was the creation of seven different townships and over 100 separate camps. Two of these townships, Cabramurra and Khancoban have since become permanent towns, with Cabramurra holding the distinction of being the highest town in Australia. But where new towns appeared, others were lost or rather moved. One outcome of the Scheme was the vast reservoirs that appeared in the valley as a result of the damming. In total, they contain water equal to the volume of 13 Sydney Harbours and forced the relocations of several towns, including Adaminaby, Jindabyne and Talbingo. 

Dams

The project included 16 major dams all completed between 1955 and 1970. I’m not about to go through them all, but here’s a quick taster. The first was the Guthega Dam, a concrete gravity dam that stands at 34 metres (112ft) and stretches to a length of 139 metres (456 ft). It contains roughly 44,100 cubic metres (1,560,000 cu ft) of concrete and its two turbines have an installed capacity of 60 megawatts. 

The largest is the Eucumbene Dam which was completed in 1958. The dam wall contains 6,735,000 cubic metres (237,800,000 cu ft) of earth and the rockfill and is 116 metres (381 ft) high and 579 metres (1,900 ft) long. It also created the largest reservoir of the whole project with a capacity of 4,798,400 litres (1,267,600 gallons) and a total area of 35,930 acres – just slightly smaller than the whole of Washington D.C. And while we’re talking about the Eucumbene Reservoir, we might as well start talking about tunnels.

Quite amazingly, only 2% of the construction work done on the Scheme is visible from the air. 145 kilometres (90 miles) of tunnels and 80 kilometres (50 miles) of pipelines were built to divert water from the Snowy Mountains down into the reservoirs, and two of the longest terminate at or near the Eucumebene Reservoir. The 22.2 kilometres (13.8 miles) long Eucumbene-Tumut Haupt-tunnel diverts water from the Snowy River to the Tumut River, before dumping everything into Tumut Pond Reservoir. That’s impressive, but another one just about edges it out. The crown of the longest tunnel goes to the 23.5 kilometres (14.6 mi) long Eucumbene-Snowy Haupt-tunnel, with a circular diameter of 6.3 metres (21 ft) and which connects the Eucumbene River to the Snowy River. 

Power Stations

Then we have the seven hydroelectric power stations completed by 1974 and an additional three that have been built since. By far the biggest in terms of electrical output is the Tumut 3 power station – and yes, in case you were wondering there is a Tumut 1 and Tumut 2, but they pale in comparison to number 3. 

Tumut 3 was the first major pumped-hydro plant built in Australia when it was completed in 1973 and remains the largest of its kind to date. Water is pulled through six pipelines, each measuring 488 metres (1,601 ft) long and 5.6 metres (18 ft) in diameter, coming from the Jounama Pondage at the rate of 297 cubic metres per second (10,500 cu ft/s) before moving through the 6 Toshiba turbines generating a huge electrical output of 1,650 MW – enough to power over a million average homes. All in all, the nine power stations and the 33 turbines they include have a generating capacity of 4,100 megawatts (MW).    

The expansive project that is the Snowy Mountains Hydroelectric Scheme was officially completed on 21st October 1972 with the grand opening of the Tumut 3 power station at a total cost of A$820 million in 1974, which is around A$7.6 billion today. Over the 25 years, 121 people died during the various construction projects. The most serious incident occurred on 16th April 1958, when an elevator fell around 121 metres (400 feet) after the cable snapped, killing the 4 Italian employees inside.   

Impact

The immediate impact of the Snowy Mountains Hydroelectric Scheme has been quite remarkable. It provides 2,100 gigalitres of water a year to be used in Australia’s irrigated agriculture industry, which itself is worth around A$3 billion per year, around 40% of the gross value of the nation’s agricultural production. When you think that one gigalitre is a billion litres, you start to get an idea of the huge amount of water. As I’ve just mentioned, the power stations are throwing out a huge amount of electricity each year, which equates to around 4,500 gigawatt-hours of renewable electricity each year. 

But everything certainly isn’t all green and rosy. As you can imagine with large scale water diversion it has caused its fair share of environmental issues. When the Scheme was first set out the plan was to divert 99% of the natural water flow along the Snowy River into the vast network. However, it soon became apparent that this was causing severe knock-on effects further down the river, including erosion, the destruction of natural habit and an increase in salinity. 

Since then there has been plenty of debate and more than a little blind arguing about what percent of the natural water flow should be going down the Snowy River. Broadly speaking it has been climbing and in 2017, Snowy Hydro, the company that runs the entire system, announced that the target of 21% would soon be achieved. 

Snowy Hydro 2.0

But we might not be finished there, with Snowy Hydro 2.0 now on the horizon. A project that will link two existing dams, the Tantangara and Talbingo, through 27km (16.7 miles) of tunnels, while also providing a new underground power station, which will pump out an additional 2,000 megawatts. Snowy Hydro calls the project a win-win, which is probably a bit rich and should no doubt be taken with a pinch of salt, considering who it’s coming from.  

If all goes to plan, the new power station will begin generating power in 2025, with an estimated cost for the whole project of between $3.8 billion and $4.5 billion. But those are the low estimates. Others place the cost at closer to $10 billion and while preliminary work has already started on the project, there’s no doubt plenty of twists and turns left in this hugely expensive addition.  

The Scheme that Built Australia 

Australians are a proud bunch, in case you didn’t know already, and the Snowy Mountains Hydroelectric Scheme is one of their most celebrated engineering projects. And you can see why. While it may not be perfect it is undoubtedly a hugely impressive system. As I mentioned earlier in the video, Australia is not exactly blessed with an abundance of water but what was constructed in the Kosciuszko National Park is a perfect example of making the most of your situation.

But Australians also point to the Snowy Mountains Hydroelectric Scheme as one of the defining stages in the development of their country. Despite initial fears over competing nationalities during the building work, there was a surprising social harmony among the men who no doubt felt fortunate to have just escaped the horrors of Europe. Things weren’t perfect of course, but considering the proximity to the hellish days of World War II, it was notable.        

Many migrants who worked on the project settled in Australia after its completion and with it came what we consider modern Australia, a far more culturally diverse nation than it had ever been. The Snowy Mountains Hydroelectric Scheme not only provided huge amounts of renewable energy and water to places in real need of it, but it was also a project that altered the cultural makeup of the land down under.   

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