The threat posed by lagarosiphon weed in Lake Wanaka means a combination of all available control methods must be used to stop the weed spreading, including a non residual herbicide, Lake Wanaka Guardians chairman Bill Hislop said.

"Having spent many months researching the facts, the Guardians are satisfied that the option to use herbicide is both necessary and safe," he said.

Contrary to a recent private advertisement in a Wanaka publication, the Guardians did not consider the use of herbicide, in conjunction with other methods, presented any risk.

"The herbicide planned to be used in Lake Wanaka has been used in New Zealand for more than 40 years in North and South Island lakes. Scientific studies have shown no long-term effects on the water, fish or people," Mr Hislop said.

No residue would be left in the lake, nor was the herbicide subject to spray drift as it would be applied as a gel.

"The same herbicide has been used in Lake Dunstan for two years and achieved good results. Its use has the full support of the Lake Dunstan Management Committee and is a permitted activity under the Otago Regional Council water plan," he said.

Control of lagarosiphon weed in Lake Wanaka is a joint effort involving the Guardians, Queenstown Lakes District Council (QLDC), Otago Regional Council, the Department of Conservation and Land Information New Zealand (LINZ).

QLDC Wanaka operations Manager Chris Hawker said other issues mentioned in the advertisement were covered by the normal weed management process.

All water supply intake from Lake Wanaka will be ceased prior to treatment and reinstated only after water testing is completely clear of any residue.

"With our reservoir capacity we have the luxury of taking the extra precaution of reassuring our community the water intake is completely unaffected," Mr Hawker said.

The Cromwell Community Board had confirmed that a new water bore in Cromwell, mentioned in the advertisement, was installed because of contamination during high rainfall. It was not related to the application of the herbicide in Lake Dunstan.

LINZ's Michael Mead said all agencies welcomed the opportunity to discuss the control programme with the community.

"At our recent open day in Wanaka, there was a good turn out and a positive response from the majority of people who attended," Mr Mead said.

Information about the methods used to control the weed could be easily accessed on the LINZ website and The Memorandum of Understanding between all the groups will be published on the LINZ and QLDC websites.

"It is very important that anyone considering this issue does so with all the relevant and factual information available, which is why all the agencies involved, participated in the open day," Mr Hawker said.

Application of the herbicide on Lake Wanaka would be widely publicised in advance through radio advertisements, public notices, a free-call number (0508 244746) and notification on LINZ's website at www.linz.govt.nz. Application was subject to weather and lake conditions.

ENDS

For further information please contact:

Guardians of Lake Wanaka chairman Bill Hislop 03 443 1285, Queenstown Lakes District Council Wanaka operations manager Chris Hawker 03 441 0499, LINZ representative Michael Mead 04 498 3516.

By: Kiri