Lake seen as water answer

Hundreds of millions of dollars might be spent transforming Canterbury's Lake Coleridge for hydro power and irrigation storage, TrustPower says.

The plan has been discussed by the Government, and Cabinet ministers will be briefed further this week.

Discussions have included the obstacle of a water conservation order on the Rakaia River that bans water takes above the Rakaia Gorge.

Fish & Game says any threat to the order will be vigorously opposed.

The plan was light on detail yesterday, but TrustPower community relations manager Graeme Purches said the company was sure power generation and irrigation on the lake would be profitable.

"We have run a bunch of scenarios and done the sums on the scenarios and they all stack up," he said. "We're pretty keen to pursue it."

The infrastructure would cost "hundreds of millions of dollars", he said, and include a network of canals to service the central plains.

TrustPower bought the Coleridge power station from the old Electricity Corporation in 1998.

Purches said the plan had not progressed to a detailed level, but should the proposal get the go-ahead "we would be getting down the track of consenting fairly quickly".

Parties consulted included irrigation company Central Plains Water (CPW) and dairy giant Synlait.

Purches said the Government would probably not contribute funding, but it had indicated possible legislative support.

CPW Trust chairman Pat Morrison said that between TrustPower and the trust there was the "perfect setup" of power generation and irrigation.

"We're very keen to work with them, but we'd need the co-operation of the Government in particular."

CPW had previously ruled out Coleridge as a storage option because of the water conservation order, he said. "That's obviously a Government decision."

North Canterbury Fish & Game chairman Martin Clements said retention of the order was important.

"Fishermen in this region have lost so much with the advent of intensive agriculture, particularly irrigated agriculture, and the ability to compromise downward any further is really not something that we want to contemplate," he said.

Green Party co-leader Russel Norman said the Rakaia conservation order was a "national park for rivers".

"They're not going to get it without a fight."

Raising the lake's level could cause problems with sediment and reed-bed growth, he said, while massive irrigation could cause the contamination of lowland streams and groundwater.

The lake has emerged as the frontrunner to become a pilot scheme for the Canterbury Water Management Strategy – an attempt by the Canterbury Mayoral Forum to resolve the region's contentious water-allocation problems.

Strategy chairman and Ashburton Mayor Bede O'Malley said Coleridge was the pragmatic choice as a pilot study, but the Hurunui River was also being considered.

He said the ban on water takes through the Rakaia water conservation order might be moved from the gorge bridge to the Wilberforce River, above the lake. The problems were "not insurmountable".

O'Malley said he would brief ministers on the water strategy, including the plans for Lake Coleridge, on Thursday.

Water Rights Trust chairman Murray Rodgers, a member of the strategy's steering group, said talks had centred on Coleridge being used, with a possible dam at Lees Valley to boost the irrigation of Canterbury farmland.

"I would not be opposed to it [the Lake Coleridge plan], provided all aspects of the scheme, including the use of water, are sustainable," he said.

The Canterbury Mayoral Forum expects to confirm the strategy, including a possible Canterbury bill for its legal framework, on November 4.

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