The Otago Regional Council says its proposed training works on the Shotover River would cost up to $2 million and be met by targeted ratepayers within the Wakatipu.
Queenstown Lakes Mayor Clive Geddes told councillors at an extraordinary meeting yesterday the flood mitigation work proposed by the Shotover Delta Steering Group was not flood protection measures, but river management, with side benefits to the airport's runway safety extension and the district council's disposal of wastewater project.
Mr Geddes said concerns had been raised by the Department of Conservation previously about the change in the braided characteristics of the Shotover River and noted the "sensitive relation" between rainfall, the delta and Lake Wakatipu evident over the past four days.
"This isn't going to stop floods. It'll hopefully stop the floods from getting any worse," he said.
District councillors gathered to consider reports on flood mitigation at the Shotover Delta and heard from regional council chairman Stephen Cairns and chief executive Graeme Martin.
"The idea is to clean out the delta so that in high flood it will have a wide area to deposit sediment," Mr Martin said.
"That will allow for less of a build-up of obstruction on the Shotover and Kawarau Rivers."
Mr Martin said the excavation would be to a shallow depth across a wide area to restore the river to a braided state, "but not lower than it has been over the last 50 years".
Asked by Cr Cath Gilmour how long it would take to excavate about one million cubic metres of gravel from the river, Mr Martin said it depended on other projects by members of the delta steering group, but "the quicker the better".
Willow removal on the delta, investigations of training and public utility works for the delta, and public consultation on funding were included in the regional council's 2008-09 annual plan.
The activities were funded from a targeted rate applied to the Wakatipu special rating district, although the regional council has not decided how to fund works beyond the financial year, including the construction and maintenance of the training works.
The Lakes District had been split into Wakatipu and Wanaka districts by the council for targeted rates because of the disparate burden of river work, Mr Martin said.
The regional council would negotiate with other parties on cost-sharing for parts of the proposed training line.
It would develop funding options and consult the public over the constellation and maintenance of the training line and river works as part of the 2009-19 long-term council community plan.
