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Hydro canals to be drained for inspection

Monday 9 November 2009, 12:12PM

By Meridian

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OTAGO

The Pukaki and Ohau hydro canals, a key part of the South Island’s Waitaki hydro chain, are to be drained this week to allow inspection of the gate structure that controls the flow of water into the system from Lake Pukaki.

Meridian Energy, which operates the Waitaki system, says it is using Transpower’s planned outage of the inter-island power link as an opportunity to carry out the inspection.

Meridian spokesman Alan Seay says engineers are particularly keen to have a close look at the gate structure after observing deterioration of some of its concrete construction.

“The structure has been in place for 30 years, and it takes quite a pounding, so it’s inevitable that there’ll be some deterioration over that period. We’re keen to have a closer look so we can better determine the state of the structure and whether repairs may be necessary.”

The canal will be out of operation for five days, commencing Wednesday November 11. The 12.5km long Pukaki canal carries water from Lake Pukaki through to Ohau A power station, above Lake Ruataniwha.

The Ohau Canal is interconnected with the Pukaki Canal and carries water from Lake Ohau. The canals are designed to be dewatered and this has been done three times during their 30 year period of operation.

Meridian is working closely with Transpower and the industry to ensure that there is no risk of interruption to electricity supply.

The canal roads will be closed to the public while the inspection is in process.