The wrecks of gold-mining dredges are being revealed in the Clutha River.
Low levels in the river are allowing four dredges to become more visible than usual.
The four dredges are Golden Treasure by Millers Flat, Gold Queen between Roxburgh and Millers Flat, Kohinoor by Coal Creek and Jubilee below Roxburgh.
Archaeologist Matthew Sole, of Alexandra, said at the height of the boom in gold dredging in the late 18th century, “we were recognised as the dredging capital of the world”.
By 1900 there were about 180 dredges in the Clutha River.
First the dredges could only work on river beds “but then they were able to design them so they could eat into the river banks”.
The dredging period went from the late 1880s right through to the 1950s and ’60s, Mr Sole said.
Gold recovery techniques were always improving, and dredges often revisited sites at later dates.
“Over that time there was a significant increase in the efficiency and gold recovery processes.”