Protecting our water supply during Auckland Council’s Hūnua Ranges pest control operation

Update: Tuesday 1 November
All samples have now been analysed by Landcare Laboratory who have confirmed no 1080 has been detected in the water. All additional samples taken following the weekend’s heavy rain also confirm no 1080 has been detected. We’re now in the process of returning our Wairoa and Mangatawhiri dams to service.

Update: Monday 31 October
All samples taken for 4-8 hrs, 20-24 hrs, and 40-48hrs have come back 'undetected'. Due to the heavy rain over the weekend, extra samples were taken yesterday. We will also be sampling today and tomorrow.

Update: Friday 28 October
The 1080 drop was carried out yesterday. Wairoa and Mangatawhiri Dam were taken out of service before the drop and will remain out of service until all samples confirm no 1080 is detected in the water.

Wairoa and Mangatawhiri dams water testing results
Wairoa Dam 

	Sample point 1	Sample point 2	Sample point 3	Sample point 4
Pre-1080 drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
4-8 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
20-24 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
40-48 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓

Mangatawhiri Dam

	Sample point 1	Sample point 2	Sample point 3	Sample point 4
Pre-1080 drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
4-8 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
20-24 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
40-48 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓

Update: Friday 21 October
Auckland Council will be progressing 1080 operations on Tuesday 25 October. Our team will isolate Wairoa and Mangatawhiri Dams on Tuesday morning prior to the operation commencing.

Update: Monday 17 October
Auckland Council has cancelled the operations previously planned for tomorrow (Tuesday) due to high winds. As the wind is expected to worsen later in the week, it is unlikely that application to block two will progress this week. Operations are also unable to take place over this coming labour weekend. Wairoa and Mangatawhiri Dams will not be taken out of service this week.

Cosseys and Mangatangi dams water testing results
Cosseys Dam 

	Sample point 1	Sample point 2	Sample point 3	Sample point 4
Pre-1080 drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
4-8 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
20-24 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
40-48 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓

Mangatangi Dam

	Sample point 1	Sample point 2	Sample point 3	Sample point 4
Pre-1080 drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
4-8 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
20-24 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓
40-48 hours after drop	Undetected ✓	Undetected ✓	Undetected ✓	Undetected ✓

 
Update: Tuesday 20 September
Cosseys and Mangatangi will be back in service tomorrow, Wednesday, having returned all 'undetected' results.

Update: Monday 19 September
Results for the 40-48 hour samples
All results for samples collected at Cosseys and Mangatangi Dam are below the detection limit. The duplicate samples will be flown to Christchurch and hand delivered to the Landcare Laboratory. This will ensure the quickest possible analysis of the duplicate samples.

Update: Saturday 17 September
The 20-24 hour samples are all below the detection limit
This morning, the third round off samples were collected from Cosseys and Mangatangi Dams. When we receive the results for these 40-48 hour samples, we can assess return to service. Results from the samples being analysed at Watercare Lab are expected within the next 24 hours. Results of the duplicate samples being analysed by Landcare Lab in Christchurch are not expected until Tuesday.

Update: Friday 16 September
Second round of samples analysed
The second round of water samples were successfully collected from Cosseys and Mangatangi Dams. We have received the certificate of analysis for the samples collected yesterday. All results are below the detection limit.

Update: Thursday 15 September
Hunua 1080 application begins
The second phase of this season's pest control operation in the Hunua Ranges parkland, neighbouring Department of Conservation administered land reserves and some private land, has begun.

Aerial application of bait containing sodium fluoroacetate, 1080, began this morning within the first block of the 21,500 hectares of forest covered by the operation.

The Hunua Ranges, Waharau and Whakatiwai regional parks and tracks within the neighbouring Mangatawhiri and Vining reserves (DOC land) are all closed to the public. The park will remain closed while a track clearance programme is carried out.

Water supply reservoirs in block one of the treatment areas were isolated from the public water supply ahead of the toxic bait application commencing. 

These will not be returned to service until a comprehensive water monitoring programme has been completed with consecutive samples showing no 1080 has been detected.

Other safety measures around the water supply include exclusion zones around and no flying over the reservoirs.

Following the operation, visitors to the park and reserve lands should observe information and warning signs. Dogs and young children are particularly at risk from 1080 poisoning.

Dog owners are advised to avoid taking animals into the operational area until the caution period is over and warning signs are removed, a minimum of six months.

Those who choose to bring their dogs to areas of the parks (where dogs are allowed) or near to the operational area should supervise them closely to prevent scavenging of carcasses and consider muzzling the dog if off-lead. It is a general requirement for dogs being walked within the parkland to be always on lead.

For more information, including park closure details, see www.aucklandcouncil.govt.nz/hunuaproject or phone 09 301 0101.

Update: Wednesday 14 September
Cosseys and Mangatangi dams to be taken out of service during Auckland Council's first pest control application
Our Cosseys and Mangatangi dams will be taken out of service this evening ahead of Auckland Council's pest control operation in the Hūnua Ranges, planned for tomorrow. Once the 1080 drop is complete, a stringent water quality testing regime will be carried out over several days. The dams will only be returned to service when consecutive samples at multiple locations within each dam confirm no 1080 is detected in the water.

Our water sampling plan incorporates recommendations by Landcare Research and was reviewed by the Auckland Regional Public Health Service.

Testing will be carried out by Watercare Laboratory Services, an IANZ accredited lab with IANZ-approved test methodology for 1080. To provide additional assurance, a number of duplicate samples will also be tested at the Landcare Research Laboratory.

The Ministry of Health sets a Provisional Maximum Acceptable Value for 1080 of 0.0035mg/L for sodium fluoroacetate (1080). The Auckland Regional Public Health Service has set a maximum of 0.00175mg/L for drinking water.

We will only return our dams to services once the level of 1080 is below the detectable limit.