CSIRO Maps Tasmania's Deepest Lake Revealing Dramatic Features

Researchers from the CSIRO have confirmed that Tasmania's Lake St Clair is Australia's deepest lake, reaching a depth of 163 metres at its deepest point. This was achieved through the use of advanced multi-beam sonar and LIDAR technology, which allowed for the first high-resolution 3D mapping of the lake.

Previous depth estimates, dating back to the 1860s and 1965, ranged from 160 to 215 metres, but the recent research has definitively established Lake St Clair's true depth, nearly double that of Bass Strait.

Hydrographic surveyor Augustin Deplante stated this mapping ends speculation regarding the lake's size, noting that the next deepest lake is less than 100 metres deep. The detailed mapping process revealed dramatic underwater features including underwater cliffs, deep ravines, and towering rock formations.

Notably, objects as small as 50 centimetres were identified, including fallen trees along the shoreline and mysterious features on the lake bed. While this research does not confirm the existence of a Lake St Clair 'Loch Ness' monster, it provides a powerful tool for further exploration.

The mapping team faced wild weather over eight days to complete the survey, utilizing multi-beam sonars that measure water depth with sound pulses, alongside LIDAR technology. A remotely operated vessel named the Otter was also deployed for mapping in shallow areas.

Historical surveys of Lake St Clair utilized outdated methods, such as lead lines in the 1860s and single beam sonar in 1965, which both had significant limitations. CSIRO plans to share the 3D mapping data to support understanding of the lake's underwater habitats, enhance safe navigation, and inform future scientific research.

Deplante expressed hope that this research method could be applied to other waterways in Tasmania, potentially benefiting rare species like the spotted handfish in the River Derwent. This 3D mapping not only contributes to marine biology and ecosystem health studies but also enhances our understanding of freshwater environments.

The findings will be instrumental in guiding future conservation efforts in the region.