Warning as hydro dams spill water

16:00, Jan 04 2013
lake pukaki
RARE SIGHT: Meridian Energy has been forced to spill water from Lake Pukaki, above, after heavy rains along the Upper Waitaki River catchment.

A close eye will be kept on campers, as well as the ageing Kurow bridges, as water flows at hundreds of cubic metres per second (cumecs) through the Waitaki hydro system.

More than 500 millimetres of rain fell in South Canterbury over the last week, swelling the hydro lakes to close to capacity. State-owned generator Meridian Energy has begun controlled spilling at lakes Benmore and Pukaki, and expected to continue to do so over the next few days.

Spokeswoman Michelle Brooker said water was flowing at more than 900 cumecs through the lower Waitaki, with that expected to rise to 1100 cumecs.

"We've been keeping a close watch on the situation, and informing the public and campers about the high flows," Ms Brooker said.

There was also 575 cumecs of flow at the Aviemore spillway, she said.

Environment Canterbury duty flood controller Chris Fauth said there had been a lot of rain over the last week, but recent forecasts suggested the worst of it was over.


"The Rangitata was running close to 2000 cumecs on Wednesday evening, that has dropped to 480, and we expect it to return to about 100 cumecs over the next day, which is about the usual rate for this time of year," he said.

Mr Fauth said people camping in the lower Waitaki should be careful to get to "high and dry" ground.

"People should be mindful that the levels could rise pretty rapidly over the next day or so," Mr Fauth said.

ECan and consultancy firm Opus would also keep an eye on the 132-year-old twin bridges at Kurow. Mr Fauth said if the river flows in the lower Waitaki exceeded 1200 cumecs, the bridges could be closed.

The ageing bridges have been plagued with closures in recent years, although the New Zealand Transport Agency confirmed $17 million funding towards the upgrade in October last year.

Meanwhile, Genesis Energy spokesman Richard Gordon said the de-watering of the Tekapo canals would occur shortly after the shutdown for extensive repairs began on January 14, with the preparations in full swing.

The Timaru Herald