November 26, 2019
Private Bag 92250,
The use of Foamstream V4 for weed management in the road corridor
In April 2019, Community Facilities (CF) took over the management of green assets within the road
corridor on behalf of Auckland Transport (AT), which still retains responsibility for the road corridor.
The CF supplier Ventia has requested to use the Environmental Protection Authority (EPA) approved
product Foamstream V4 to manage weeds in the kerb and channel in three local boards; Kaipatiki,
Upper Harbour and Devonport & Takapuna.
AT has raised the following concerns on the use of the product and its potential impacts on
stormwater (SW). Therefore, CF communicated them to Healthy Waters (HW). In particular, AT has
requested feedback regarding:
• mobilization of Polycyclic Aromatic Hydrocarbons (PAHs) by Foamstream V4 and the
potential impact on SW.
• Foam discharges in SW network
Mobilization of PHAs: Based on the available information including an independent assessment,
product demonstrations and previous Auckland Council (AC) research regarding PHAs in SW, the
impact of the application of Foamstream V4 in the road corridor cannot be considered as significant
impact on SW.
Foam discharges in SW network: The quantity of foam being discharged in stormwater is also
considered as negligible as most of it remains on the weeds and dissolves within 15-20 minutes after
the application. A general control measure that the supplier should follow is that Foamstream V4
can never be applied during rainfall
in order to minimise the risks.
Additional recommendations: AC call centre staff will be provided with information on the product
through iknow. Any further questions from the public on the foam and its use can be directed to the
weed management team at the address [email address]. Suppliers have found when speaking
to the public about the product there has been positive support for the use of alternative weed
management products. Ventia should use informative signage on their trucks and at the area of
application. Ventia employees should be advised to direct any public concerns to weed management
Foamstream V4 use: Christchurch Council (CCC) currently uses Foamstream V4 in the road
corridor. After contacting CityCare it has been confirmed that the product was approved for use by
CCC through a contract manager as an alternative to the use of herbicide, both plant-based and
synthetic, to manage weeds on 140km of road corridor for the last three months. There has been no
reported impact on the SW. Moreover, Foamstream V4 is a patented process which is already being
used by municipalities around the world across North America and Europe.
HW considers that Foamstream V4 can be trialed in the Kaipatiki, Upper Harbour and Devonport &
Takapuna road corridor over the next three months, as HW Lifecycle Teams will have the opportunity
to observe and identify any potential impact related to the product use.
135 Albert Street | Private Bag 92300, Auckland 1142 | aucklandcouncil.govt.nz
09 301 0101
Head of Lifecycle Management
Healthy Waters I Infrastructure and Environmental Services