Whispering Wall at the Barossa Reservoir: In the Barossa Valley Region of South Australia

It was once the highest dam in Australia, and its bold new design made the Americans sit up and take notice. This is the hundredth anniversary of the retaining dam of the Barossa Reservoir, better known as the "Whispering Wall", and its story begins about thirteen kilometres away in the early town of Gawler. Through nineteenth century water came from a well South Parra River, but as quality dropped fears an epidemic rose, search for reservoir site was on.

The solution was novel. Into the Mt Lofty Ranges, the Yettie Creek gorge would be dammed - with a concave concrete dam bending its back against the pressure of hundreds of tons of water stacked up to twenty seven metres (nine stories) at the wall. The scheme got the nod in 1899, and by the winter of that year the construction workers were on the job in the creekbed. In just over two years, they'd "topped off" this modern marvel of its time.

Mind you, the Gawler folk didn't hang about. As water rose behind the dam, the waterworks department reckoned there was enough to turn on the tap on the last day of 1901, and so it just squeezed into Australia's Federation celebrations.

Most visitors to the Whispering Wall don't worry too much about what is upstream of the curved concrete. Up a steep hillside above the water, Kooringal Bed and Breakfast residents enjoy a beautiful panorama over the water reserve with thick scrub and tall gumtrees running right down to a brilliant blue strip. A wander through the grounds reveals a stretch of just over two kilometres of reservoir up the Yettie Creek gully.

As with all our water reserves, this one doubles as a precious patch of protected bush. This beginning of the Barossa Range is still covered with the original scrub of pink gums and native pines. There is plenty of bird life on the water, too, as Nature enjoys a breather here.

With no obvious catchment creeks, where does all the water come from? Through a tunnel. It comes more than two kilometres through the range from a weir on the South Para River. The conduit was cut by horsepower, literally...one local horse spent nine months working in there a century back without once seeing the light of day.

The supply comes from the South Para Reservoir, the original and picturesque Warren Reservoir up towards Mt Crawford, and now it's supplemented by a feed of Murray water into that system as well.

It calls itself the Gateway of the Barossa. Williamstown is an attractive old timber community, and it has seen two nearby towns come and go. First, the Barossa Goldfields in the 1870's, and then as the twentieth century dawned, the Barossa Waterworks township rose about where the old caretaker's cottage now stands just back across the picnic ground from the Whispering Wall. About four hundred workers - many of them with wives and children - lived in tents and galvo-and-canvas huts here. When the dam construction was wound up in 1903, all that remained was auctioned off and the town was gone.

The daringly designed dam wall was begun in 1899. It is more than ten metres thick at its base, and it tapers up to just the width of a narrow pathway at the top. They flew the concrete (mixed on site) in by flying fox and added "plums", as they called them. They were big quartz boulders blown from the sides of the gorge. Higher up, forty tons of old Gawler horse tram tracks were laid in for added strength.

With an SA Water guide on hand, we took the Postcards camera right up to the wall at the bottom. The marks of the timber formwork used to shape the curved wall are still clearly evident a century later. Hermann Heinze used to set the boards in place - he'd jumped ship and picked up a job here in here in the gully. But he was caught smoking on the job and was sacked. Trouble was, no one else knew how to do the work, and so they brought him back - hangover and all - from the Sandy Creek pub.

The Barossa Reservoir now feeds water to Gawler and the Munno Para and Elizabeth regions via a new filtration plant. The dam, however, is famous for its audio-bounce from one side of the wall to the other. We asked Ilsa from Holland to talk very quietly to her back-packer partner Frank 144 metres away at the opposite lookout...

"Can you hear me Ok?"

"Yes, it's very clear, it's amazing"

Their voices were heard so clearly because of a parabola effect. The wall is one sector of a perfect circle, and the soundwaves bounce in a series of straight jumps along it to the other end.

The idea of this tall thin concrete dam curved against the pressure of the water was radical at the time. It attracted international attention and featured in Scientific American. The design came from the Irish-born Alexander Moncrieff - as a government engineer, he was remarkable. He never took a holiday in forty-two years and he left a considerable legacy...

Fort Glanville and Fort Largs, the Port Augusta to Oodnadatta railway line, four lighthouses including KI's Capede Conedic and a whole lot more. This, however, was his crowning glory.

"The Barossa Reservoir's boldness of design deserves to rank with the most famous dams in the world". So said the American Engineer's News. Famous then and now. As Williamstown Historical Society celebrates its hundredth anniversary throughout the year, come and have a picnic soon at the Whispering Wall.

Barossa Reservoir
Via Yettie Road, Williamstown
(follow signposts from main street)

Information:
Barossa Wine and Visitor Centre
66-68 Murray St,
Tanunda, South Australia, 5352
Freecall 1800 812 662

Kooringal Homestead Bed and Breakfast
PO Box 171
Cockatoo Valley, South Australia, 5351
Ph. (08) 8524 6196
Mobile: 0419 862 776