Notice of Weed Spraying in Lake Benmore

22 August 2013

Property owners and users of Lake Benmore, including for recreation, are advised that the herbicide diquat, will be applied to control lake weed (Lagarosiphon) in the Ahuriri Delta, Ahuriri Arm, Sailors Cutting and Neck in Lake Benmore.

The spray operations may involve the discharge of harmless tracer dye during and/or prior to the spray operations. The dye is used to mimic the discharge of herbicides in order to obtain information about the dilution and dispersion characteristics after it has been sprayed on the target weeds. The key adverse effect of the use of the dye will be the temporary visual impact of the dye plume in the water. The dye is harmless, there will be no adverse effects on the aquatic ecology of the water body, and the dye will continue to be diluted until it is no longer visible. 
 
The work is scheduled to begin from Monday 26 August 2013 and may continue intermittently to Friday 20 December 2013, as weather and water conditions permit. Treatment will not take place during weekends or on public holidays.
 
As a precautionary measure only, Land Information New Zealand advises users not to take water from Lake Benmore to consume or for irrigation purposes from the vicinity of the treatment area, until 24 hours after treatment has been completed.
 
Warning signs will be placed at authorised public boat ramps during treatment and will be removed 24 hours after treatment.
 
A helicopter and boat will be used to apply the herbicide when weather and lake conditions are suitable.
 
The treatment works on Lake Benmore are a joint venture between Meridian Energy Limited and Land Information New Zealand.
 
A copy of Land Information New Zealand’s full annual control works programme is available at www.linz.govt.nz, under “Crown Property”.  Further information is available from Boffa Miskell Ltd during office hours on 0800 638 943, by writing to PO Box 110, Christchurch, or emailing marcus.girvan@boffamiskell.co.nz.