Imagine if you and your work colleagues were commenting on your boss over a hundred metres away and the boss heard every word. That's how the Whispering Wall, near Williamstown was discovered, so the story goes. Construction workers working on one side of the dam were reportedly criticising their boss who was working on the other side, 144 metres away. The acoustic ability of the dam became the cause of their early retirement!
Whispering Wall attracts many tourists who travel to the Barossa Reservoir to test out the wall for themselves. Damming the Yettie Creek Gorge, part of the northern Mount Lofty Ranges, formed the reservoir. Constructed from large stones and reinforced with tram rails, 400 workers, whose families set up camp nearby during construction, were involved in constructing of the 36-metre high dam wall. The dam holds back 4.5 mega-litres of water, which is sourced from a weir through a tunnel over two kilometres away. The tunnel was cut using a single horse over a nine-month period.
Main Dam Looking West . 18 February 1902 SA Water
Led by Irish-born engineer, Alexander Moncrieff, the dam initially gained notoriety for being the first arched and highest dam to be constructed in Australia. The thin arch of the retaining wall was considered innovative, attracting international attention including being featured in Scientific American. Today the reservoir is famous for the ability to transmit sounds, known as whispering gallery waves, across the dam wall.
Workers on the Barossa Reservoir Project c1899 SA Water 19595
Take a walk across the dam wall and have a quiet conversation with someone on the other side; it is an interesting phenomenon known as the parabola effect. The rigid and flawlessly curved surface of the dam wall, allows sound waves to travel unobstructed from one end to the other. A fact the workers may have found useful, before they lost their jobs!
Access to the reservoir, together with picnic, toilet and car parking facilities, is available between the opening hours of 8am to 5pm,. A variety of birdlife is attracted to the reservoir and surrounding native vegetation in the protected park area. Pink gums and pine trees surround the small caretakers hut at the bottom of the dam and the waterfall, which can be seen from the dam wall.
Whispering Wall is one of many man-made whispering galleries across the world including Grand Central Station in New York and St Paul's Cathedral in London, where whispering gallery waves were first discovered by Lord Rayleigh, a physicist, in the late 1870s.
Displays of old SA Water equipment. Photo: Hazel Cochrane
Big kids and little will enjoy checking out some of the equipment used by SA Water, formerly E&WS, in the management of water in South Australia. Located in the car park, visitors can wander through an assortment of gates, signs, tubes and even an overnight hut used by meter readers who must have spent many cold nights in those small tin sheds.
Monument remembering Captain Thomas Lawson and his wife Catherine, early land owners in the area. Photo: Hazel Cochrane
The rock monument near the abandoned building in the car park, is in memory of Captain Thomas Lacey Lawson and his wife Catherine Constance Lawson, who purchased and farmed the land under the current Barossa Reservoir site in 1845.
The Whispering Wall is a fascinating site to visit and can be accessed from Whispering Wall Road, off Yettie Road, about 5km from Williamstown.