Herbicides are used by Council and its contractors. Herbicide use is minimised where possible for Council operations and only used where deemed necessary by Council staff and contractors.
Mechanical control, such as an excavator with a weed rake bucket, is used in drains to remove vegetation like watercress and monkey musk that can block flow.
Hand clearance, i.e. a person manually clearing weeds by hand is occasionally used.
Mulching of garden beds or other areas is used to minimise weed control and reduce the need for herbicide control.
Herbicides, for example glyphosate, triclopyr, aminopyralid and picloram, are used by Council and its contractors. This is mainly for weed control, such as spot spraying, ‘cut and paste’, drilling of woody stems, or spraying of weeds in drains when they are dry. A summary of herbicide usage by Council and its contractors in public spaces and near waterways is reported annually.
All herbicides and their uses are as approved by the Environmental Protection Authority.
- Road safety - to ensure visibility and prevent weeds from degrading road surfaces
- Biodiversity protection - enabling the establishment of native plantings and protecting native remnants from weed invasion
- Amenity- to maintain garden beds and other green spaces
- Flood mitigation – to prevent weed growth from blocking up drains, reducing the ability to deal with flood flows
Council is seeking to reduce the use of herbicide. One example is by planting of drain or river margins to provide shading, which can reduce the growth of nuisance weeds once shade has been established. The Waimakariri District Council Drainage Maintenance Management Plan outlines some methods to reduce herbicide dependence over time.
Waimakariri District Council maintains a ‘No Spray’ register for berms and other Council areas. Request to be added to this register by emailing roading@wmk.govt.nz. Note that you will be required to maintain appropriately any area that is not to be sprayed by Council.
The discharge consent CRC120402 issued by Environment Canterbury contains conditions to mitigate effects of spraying herbicide around drains, waterways and stockwater races. Works under this consent also follow the New Zealand Standard NZS 8409:2021 ‘Management of Agrichemicals’, the Waimakariri District Council Herbicide Spray Management Plan, and contractor-specific Standard Operating Procedures (SOPs).
Advice on herbicide usage to control weeds and other control techniques can be found at: