A thundering torrent of water has been passing through the Clyde Dam over the weekend - enough to fill more than 33 Olympic-sized swimming pools every minute.

Contact Energy, which operates the hydroelectrical dam on the Clutha/Mata-Au River, has been releasing water after weather-warning levels of rain fell late last week in the Otago headwaters.

Acting head of hydro generation Blair Croall said the river catchment was full, prompting “managed controlled spills and flushing through the spillway and gates” at the dam.

In recent days 1,400 cubic metres of water per second has passed through the dam.

“They happen once or twice a year at this capacity,” Blair said.

“We’re expecting controlled releases will continue until river levels stabilise.”

After any heavy rain event, the energy company works with local authorities and environmental regulators to ensure flows are safe and well-communicated, he said.

“These controlled releases are carefully managed and help maintain safe river levels, protect communities, and support the health of the river.”

Power generation continues during spilling.

“The dam is designed to handle high flows safely while keeping electricity supply running,” Blair said.

Otago Regional Council said on Friday (October 24), while rain had eased, Lakes Whakatipu and Wānaka and Glenorchy Lagoon remained under watch, expected to peak on Saturday morning at the lower end of earlier predictions.

The authority continued to monitor lake and river levels throughout the long weekend.

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