Otter plays super sleuth in Lake St Clair’s mystery of the deep
One of the nation’s great scientific mysteries has finally been solved, with a miniature sonar vessel confirming the true depth of Australia’s deepest lake in the Tasmanian central highlands. WATCH THE VIDEO>>>
One of the nation’s great scientific mysteries has finally been solved, with a miniature sonar vessel confirming the true depth of Australia’s deepest lake in the Tasmanian central highlands.
Equipped with advanced multi-beam technology and operated remotely, the 2m “Otter” allowed CSIRO’s high-tech mapping team to access parts of Lake St Clair considered too shallow for larger vessels.
Carved by ancient glaciers and an internationally renowned jewel of the Tasmanian Wilderness World Heritage Area, Lake St Clair has long been the subject of conjecture over its depth, with estimates ranging between 160m and 215m.
CSIRO hydrographic surveyor, Augustin Déplante, said stunning new, 3D views revealed the lake’s underwater cliffs, ravines and towering rock formations in high-definition, with pristine waterway’s depth confirmed as 163m.
This make the Tasmanian lake far deeper than any other in Australia, and deeper even than Bass Strait, which has a maximum depth of around 85m.
“Our mapping confirms that Lake St Clair is absolutely Australia’s deepest lake, with the next deepest lake being less than 100m deep,” Mr Déplante said.
“We found Lake St Clair’s deepest point is close to the western shore on the bend in the lake about 4km north of the visitor centre, but there are several areas where the lake depth reaches 150m.”
Also using the twin-hulled 8m research vessel, RV South Cape, to complete their eight-day mission amid wild Tasmanian weather conditions, Mr Déplante’s team mapped the lake using echosounders that employ noise pulses to measure the water depth.
CSIRO will share their 3D dataset with other stakeholders to increase understanding of the lake’s formation and underwater, and to improve navigation safety.
“The mapping is highly detailed and can identify objects as small as 50 centimetres in some places. Along the shoreline, it shows the trees that have fallen into the lake and, in deeper areas, has revealed several mysterious features on the lake bed, sparking curiosity about their origins,” Mr Déplante said.
“While the data does not confirm the presence of a Lake St Clair ‘Loch Ness’ monster, it does offer a powerful new tool for exploring the lake’s hidden depths.
“Importantly, the project provided us with the opportunity for cross-disciplinary training for our team and to integrate the latest technologies into our toolbox to enhance the capabilities we offer the research community.”
The project was led by CSIRO’s Engineering and Technology Program in Hobart, using Norbit multibeam systems provided by Seismic Asia Pacific.
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Originally published as Otter plays super sleuth in Lake St Clair’s mystery of the deep
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