SA Water has been draining the Warren Reservoir, on the South Para River near Williamstown, for five weeks in order to carry out an $8 million valve upgrade.

But the receding waters this week revealed the Second South Para Bridge, not seen since it was submerged by the reservoir more than 100 years ago.

The 1890-built, 20-metre bridge spanned the South Para River within the original family property of the reservoir’s namesake, John Warren.

SA Water manager Peter Seltsikas said the 133-year-old bridge was “generally intact” and a “rare and unexpected sight”.

“The discovery only came to light when the local Williamstown & Districts Historical Society reached out to inform us that one of their members recalled a bridge had become slightly visible during the 1960s drought,” he said.

“After the tip off, we conducted sonar testing while the reservoir was at 16 per cent capacity and detected a structure at the bottom of the water resembling a bridge.

“We have since learned it was originally built on the family property of John Warren – a former councillor and member of the Legislative Council, who the reservoir is named after – with the entire structure fully resurfacing for the first time since it was flooded by the reservoir’s filling.”

Seltsikas said the bridge deck, pylons and substructure appeared to be mainly intact.

“Despite it no longer carrying a horse and cart over the old river, it’s helped provide habitat and shelter for the reservoir’s fish as we’ve caught a large number in and around the bridge during our relocation activities,” he said.

More than four tonnes of the reservoir’s native fish and turtles have been relocated to the nearby South Para Reservoir.

Watch the time lapse video of the reservoir draining:

[solstice_jwplayer mediaid=”vJrgcP0x” caption=”Video supplied: SA Water” /]