Using herbicides to control aquatic pest
plants
Guidance on preparing an annual report
April 2015
TECHNICAL GUIDE
2
Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Background
The Environmental Protection Authority (EPA) has modified the approvals for herbicides containing
metsulfuron-methyl, haloxyfop-R-methyl, imazapyr isopropylamine or triclopyr triethylamine salt. These
substances can now be applied onto or into water as herbicides to control aquatic pest plants. Anyone
wanting to apply these herbicides onto or into water, including organisations such as councils or the
Department of Conservation, must first obtain a permission from the EPA under the Hazardous Substances
and New Organisms Act (HSNO) 1996.
A permission holder must provide the EPA with an annual report that outlines the activities that have been
undertaken when applying these herbicides to water bodies. This will provide transparency and provide the
public with information about operations involving the use of these substances.
An annual report must be provided to the EPA by 31 July each year and will cover the period 1 January–31
December for each calendar year. The annual report must provide details of all applications of the
substances onto or into water and must include:
 a map of all locations where the substances have been applied
 details of the spray operation by location, including application method used, quantity of the substance
applied, rates of application, frequency of application and the dates of application
 details (including results) of water sampling conducted to confirm compliance with Environmental
Exposure Limits (EEL).
 details of sediment testing conducted
 details of pest plant species targeted
 details of dissolved oxygen levels prior to application of the substance to any static water body
 details of pH testing conducted prior to application of substances containing metsulfuron-methyl
 details of engagement/consultation activities undertaken
 details of any incidents reported or complaints received in reference to the application of the substance
and details of any actions taken to remedy complaints
 an overall assessment of the outcome of each operation and any proposed follow-up spraying for the
forthcoming year.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Purpose of this guide
This document provides guidance on how to prepare and submit an annual report. Annual reporting
requirements are split into two sections that discuss the level of detail required. This will ensure permission
holders will provide the EPA with annual reports that are consistent in their scope, structure and content, and
will provide a reporting template for permission holders (refer to Appendix 1).
Permission holders are expected to provide the EPA with a summary of incidents and monitoring that has
been undertaken before and after spray operations. This document provides further guidance on when
monitoring is required and how permission holders are expected to report results of monitoring activities and
incidents.
The guide is split into two sections, these sections outline:
1. Annual reporting requirements
 Details of the operation
 Details of engagement
 Incident reporting
 Assessment of operation outcomes
2. Monitoring requirements
 What monitoring requirements are there
 How should data be presented
 How should measurements and samples be taken
 How should data be presented
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Section 1: Annual reporting requirements
Details of operations
An annual report to the EPA must contain a summary of all spray operations undertaken by a permission
holder during a calendar year. This summary should be provided at the beginning of an annual report and
the level of detail that should be included is detailed below.
What information must be provided?
A permission holder must provide the EPA with:
1. A map of all locations where herbicides containing metsulfuron-methyl, haloxyfop–R-methyl, imazapyr
isopropylamine or triclopyr triethylamine salt have been applied onto or into water.
2. A suggested method for mapping is to split the map into quadrats of areas treated rather than trying to pin
point each and every individual spray location.
The reason for this is that some operations may consist of multiple small spray applications along the
body of water. As such, it may be impossible and impractical to know how much is applied in every spot
application. Therefore, dividing the area into quadrats of treated areas enables the total volume in that
stretch of river or water body and amount of herbicide used to be calculated for that day.
3. The technical details of each spray event within an operation including the spray dates, as described
below.
What technical details must be provided?
A spray operation may consist of multiple spraying events. It is important that an annual report contains
information about each spray event and where these occurred.This section should identify:
 the dates of each spray event
 the location where a substance was applied
 the target pest plant
 the quantity of substance applied and the rate of application for each spray event
 the methods of application (for example, aerial spray or knapsack)
You should also record:

the name of the operator undertaking the application

GPS coordinates of location should be provided

the substance used (metsulfuron-methyl, haloxyfop–R-methyl, imazapyr isopropylamine or triclopyr
triethylamine salt) and its concentration

the trade name of the substance.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Details of engagement activities
An annual report must provide details of notification and consultation activities carried out with local interest
groups.
Consultation
The EPA recommends that a permission holder provides opportunities for consultation with iwi, the wider
community and interested parties, if a spray operation is likely to directly impact these groups. If local iwi are
concerned at the potential effect of spray operations, consultation will enable the sharing of customary
knowledge and expertise that will help identify issues of significance and traditional sites that require
protection. Consultation may be a requirement of any resource consent.
In general, consultation is recommended when you are first proposing to applying a substance to an area.
Additionally, if the activity is to be on going all interested parties should be made aware of this. Subsequent
applications of the substance in the same operation programme should not require further consultation.
Notification of application should be sufficient to advise local communities in an area that spraying will be
undertaken.
What evidence of consultation should be provided?
If consultation has occurred, evidence must be provided in an annual report and could include:
 the names of the parties/local iwi spoken with and the date this occurred (unless parties don’t want to be
identified)
 how parties were contacted, for example, by email, phone or hui with iwi representatives
 responses received from iwi representatives and interested parties
 an explanation of how the permission holder has taken into account the concerns of interested parties,
which may include a description of any plans developed with interested parties (for example, a description
of a plan developed during consultation with irrigation users that manages risks to crops associated with
treated water).
Notification
All parties who may be directly affected, including those identified in a permission must be given written
notification at least five working days prior to each application of a substance onto or into water.
Notification requirements will be set out in any permission issued for the application of these substances
onto or into water. An annual report must demonstrate these requirements have been met.
What details must a notification provide?
A written notification must include:
 the name and location of the water body(s) that the substance will be applied to
 the date and approximate duration of each application
 the identity of the substance that is being applied
 the relevant restrictions on the use of water that will apply
 the name and contact details of the permission holder.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
A template for written notification is provided in Appendix 2. Written notifications can be sent via letter or
email.
What evidence of notification should be provided?
An annual report needs to incorporate evidence that demonstrates interested parties were notified. Evidence
provided in an annual report should include:
 the dates interested parties were notified
 a list of notified parties
 how interested parties were notified, for example, by letter or by email
 responses received from the notified parties.
Reporting of Incidents
Permission holders need to ensure incidents of unintended by-kills are reported to the EPA within one week
of the application of the substance. This excludes the by-kill of non-target plants that may be expected from
the herbicidal nature of the substance. A template for reporting incidents is provided in Appendix 3.
Annual reports must contain a summary of incidents. This should include:
 a list of each incident that occurred during the calendar year
 the time, date and location of each incident (including GPS coordinate)
 the species killed in an incident
 any actions that were taken to prevent further instances of by-kill
 the volume and type of substance used in the area where an incident occurred
 the name of the person and company that applied the substance.
If the permission holder receives complaints in reference to the application of a substance, this must be
included in the annual report. Actions taken to remedy the complaint must also be included. Details provided
in the annual report should follow the incident reporting requirements above.
Details of any monitoring undertaken
The level and type of monitoring required will depend on the substance being used and the nature of the
water body to which the substance is applied. Permission holders may be required to measure, sample and
analyse any of the following variables:
1. Dissolved oxygen levels, this is a requirement as per the controls
2. pH measurement
3. The concentration of the substances in the water to confirm compliance with Environmental Exposure
Limits (EEL).compliance with EELs is a control requirement
4. Biological communities and the persistence of the substances in the sediment.
If any monitoring has been undertaken then the permission holder must outline this in their annual report.
Further details of monitoring are to be found in section 2.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Assessment of operation outcomes
Herbicides containing metsulfuron-methyl, haloxyfop-R-methyl, imazapyr isopropylamine or triclopyr
triethylamine salt have been identified as being the most effective way of controlling aquatic pest plants. To
provide transparency an annual report of operations must include:
 details of the pest plant species targeted by the operation
 an overall assessment of the outcome of each operation
 any proposed follow-up spraying for the forthcoming year.
An overall assessment of the outcome of an operation could be a comparison of the pest plant before and
after a substance has been applied.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Section 2: Monitoring requirements
Permission holders are required to provide a monitoring plan to the EPA within one year of the granting of
the permission. In the interim, permission holders are still required to comply with the controls that apply to
the use of these substances and this includes monitoring requirements. This section provides guidance on
how to report incidents related to the application of these substances to the EPA and how to fulfil the
monitoring requirements specified under HSNO. Whilst individual users may wish to undertake their own
monitoring , collaborative monitoring of sites is also acceptable and in that case a joint monitoring framework
should be submitted to the EPA for approval.
What monitoring requirements are there?
The use of all four substances to control aquatic plants should have some form of monitoring. There should
be at a minimum one site per substance. The level and type of monitoring required will depend on the nature
of the water body to which the substance is applied. For each substance, monitoring of a sensitive site or
worst case scenario is preferred over a degraded site as the data is more valuable. The following variables
should be measured:
5. The concentration of the substances in the water at a suitable distance downstream from the application
site to confirm compliance with Environmental Exposure Limits (EEL) compliance with EELs is a control
requirement
6. The persistence of the substances in the sediment
7. Dissolved oxygen levels, where required as per the controls
8. pH measurement, where required as per the controls
9. Biological communities in sediment
When the dissolved oxygen content of a site is less than 4 mg/l then only monitoring for EEL compliance and
sediment residue should be undertaken.
Recording of the site conditions is also recommended e.g. area treated, size of overall water body, flow rate,
depth, date. i.e. treatment area 60 m 2, river 3 m wide with a flow of 0.2 m 3/s, 1.2m depth 1/1/14.
Dissolved oxygen monitoring
Monitoring of dissolved oxygen levels is a requirement where large areas of a static water body will be
treated with a substance. This is because dissolved oxygen levels in static water bodies are more likely to be
depleted through the decomposition of dead plants than would be the case in flowing water. Dissolved
oxygen levels must be measured and reported if a permission holder intends to apply a substance to either:
more than 33% of a static water body in a single application, or if multiple applications occur, the treated
area exceeds more than 33% of a water body within a seven day period.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
To treat more than 33% of a static water body within a seven day period the average dissolved oxygen level
must be less than 4mg/L. An annual report must provide details of dissolved oxygen monitoring undertaken
prior to the application of a substance to any static water body.
If no monitoring of dissolved oxygen has been undertaken for the year, this needs to be justified in the
annual report.
pH monitoring
The results of pH monitoring undertaken prior to the application of substances containing metsulfuron-methyl
must be provided in an annual report. The annual report should also include details of pH testing undertaken
after the application of a substance containing metsulfuron-methyl onto or into water.
If no pH monitoring has been undertaken for the year, this should be justified why in the annual report.
Environmental Exposure Limits (EEL)
It is a legal requirement to ensure that set EELs are not exceeded. EEL values have been set to ensure
harm to the environment is mitigated. All four substances should be monitored for EEL compliance and
monitoring for environmental EELs should ideally occur before application to check what background levels
of these herbicides are.Samples should be collected, stored and transported in accordance with
internationally recognised protocols and analysed by International Accreditation New Zealand (IANZ)
recognised laboratories.
In the case of moving water bodies, water samples should be taken within 24 hours of application of the
substance, 100 metres downstream from the application area. For static water bodies, samples must be
taken at a point no more than 100 metres from the application area.
Sediment monitoring
Details of sediment testing must be included in the annual report. Sediment monitoring may include:

Measures of the biological diversity or species richness in sediments before and after a substance is
applied.

The persistence of the substance in the sediment before and after subsequent applications of the
substance.

It is recommended that samples are taken prior to spraying to account for possible background
levels of herbicide in the environment.

Repeat measurements should be taken at subsequent applications of the substance and control
sites should be sampled in order to isolate any impacts of the substance.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
How should measurements and samples be taken?
Dissolved oxygen levels, pH, sediment biology and the concentration of substances in sediment are likely to
vary throughout an application area. To account for this natural environmental variability, random samples
should be taken over a representative sample of the application area to ensure statistically relevant data.
At each randomly selected site within the application area, replicate measurements or samples should be
taken to ensure the data is consistent and statistically relevant.
Water samples for EEL monitoring should be taken at the following time periods after application. 0, 1, 7, 24
days.
Samples for persistence in sediment monitoring should be taken prior to the application to take account for
any background herbicide in the environment and then again 24 days later. If the substance is present at
levels above the minimum level of detection at that time further monitoring is required to report when
substance concentrations fall below detectable levels.
How should data be presented in an annual report?
Results from any monitoring of dissolved oxygen, pH, sediment and concentration of the substances in the
water must be supplied to the EPA as part of an annual report. Results should:

be summarised in tabular form and be a compilation of the raw data

be presented as means with standard errors

include the sample sizes

include analysis method

include storage method
The following section provides details of the information that should be included in an annual report.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Appendix 1: Annual Report Template
Every person or organisation that holds a permission to apply herbicides with the approval codes
HSR000373, HSR002431, HSR000063, HSR100098, HSR100054, HSR008025, HSR007690, HSR000232,
HSR000242, HSR000238, HSR000245 or HSR000521 must produce an annual report of their activities. The
report must show the name and address of the reporting person or organisation and could be on an
organisations letter headed paper.
Reports should follow the following structure:
Name of permission holder and postal address:
Postal address:
Street number and name:
in New Zealand
Suburb:
Town/City:
Postal code:
Permission register number:
Report prepared by: (Name / Position / Contact Details)
Report checked/approved by: (Name and position)
1. Details of operations
1.1. Map of locations
A permission holder is required to provide a map of their region that highlights where spray operations were undertaken.
1.2. Description of operations
This sub-section should provide a summary of each operation undertaken during a calendar year. This should be presented in a table
format like the example provided below:
Title of operation and weed plant targeted: (eg. Whangape stream alligator weed control)
Date of
application
Name of
water
body/GPS
coordinates
Substance
applied/trade
name
Area
of
water
body
treated
Quantity
applied
Rate of
application
Application
method
5/1/13
Whangape
stream
Metsulfuron –
methyl
1190
m2
0.010 kg
ai
0.084 kg
ai/ha
Knapsack
6/2/13
Whangape
stream
Metsulfuron –
methyl
595 m2
0.005 kg
ai
0.084 kg
ai/ha
Knapsack
April 2015
Operator/company
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
2. Details of engagement activities
2.1. Evidence of notification
A permission holder must notify all the people and organisations identified in a permission before each application of a substance.
Annual reports require a list of the parties notified, details of notification and when the notification occurred.
An example is presented below:
Details of notification before substance was applied to name of site on the application date:
Parties notified
Detail of notification
Timing
Relevant territorial authority (city or
district council)
Letter
1 February 2013
The name of every holder of a resource
consent to take water for water supply
purposes within one km downstream of
application area
Letter
1 February 2013
The name of every local iwi runanga
representative
Phone calls / letter
30 January to 1 February 2013
2.2. Evidence of consultation
Permission holders should consult with iwi and other parties that may be directly affected by a spray operation at the earliest
opportunity. Evidence of the consultation process should be provided in an annual report. A tabular summary of consultation procedures
should be presented as follows:
Details of consultation before substance was applied to name of site on the application date:
Parties consulted
Detail of notification
Timing
Actions taken to remedy
concerns
The names of local iwi
runanga representatives
Hui to discuss the presence
of inanga and traditional
sites of importance
1 February 2013
Follow up meetings to
discuss changes to operation
area
The name of every holder of
a resource consent to take
water for water supply
purposes within one km
downstream of application
area
Letter
1 February 2013
10 February 2013 - Letters
received from consent
holders are responded to
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
3. Incident reporting
3.1. Incident reporting
A permission holder needs to provide the EPA with a summary of the incidents that occurred during the 12 month reporting period. Each
summary must include details of the incidents reported or complaints received in reference to the application of a substance and details
of any actions taken to remedy complaints. Details of each incident should include:

the date and time of the incident

the location

the operation date

the substance used in the operation and

the name of the operator and company
4. Assessment of operation outcomes
To demonstrate the efficacy and critical nature of the use of these substances to control aquatic pest plants, permission holders are
required to provide an overall assessment of their operations undertaken and any proposed follow-up spraying for the forthcoming year.
Operations should be summarised in chronological order and must include the identification of the aquatic pest plant species targeted.
The summary could also outline:

the percentage cover of the aquatic plant before application

the percentage cover after application at an appropriate interval.
5. Monitoring requirements
3.2. Additional monitoring
If monitoring is undertaken in your area then evidence of dissolved oxygen monitoring must be provided to the EPA where a substance
has been applied to more than 33% of a static water body within a seven day period. The pH should also be measured where the
substance applied contains metsulfuron - methyl as the active ingredient. If sediment testing of biological communities and water
sampling to confirm EEL compliance has been undertaken these details must also be listed. Results from any monitoring should be
presented in a tabular summary similar to below.
Details of monitoring undertaken before and after the application of name of substance to name of treatment site.
Pre-application / date
Oxygen mg/L (no. of
samples)
pH (no. of samples)
2.1 +/- 0.4 mg/L (n =
26)
7.5 +/- 0.02 (n = 32)
Post application /
date
7.4 +/- 0.07 (n = 32)
EEL µg/L (no. of
samples)
N/A
0.00021 +/- 0.0001
µg/L
NOTE
1. n = the number of measurements or samples taken
2. Measurements of dissolved oxygen and date should be presented as the mean +/- standard error.
April 2015
Sediment testing
N/A
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Appendix 2: Example of notification letter
On a company letterhead with your contact details
Name of person
Address
Postcode
Date
Dear Occupant
Re: Notification of application of [name of substance] to treat [target pest plant]
We are writing to notify you of our intention to apply [name of substance] at [name of location] on [date]. The
spray operation will be carried out between the hours of [
] and [
]. Signage will be erected on the
day of application before the operation starts. These signs will be located at public access areas within
100 m of the application area and will state:
 Do not swim.
 Do not gather food from the waterway (including fish).
 Do not take water for consumption.
It is important that you adhere to these restrictions while signage remains in place. We will contact you to
inform you if there are any changes to the spray operation.
Please contact us on [provide a contact phone number or email address] if you require any further
information.
Yours sincerely
signature of person in charge of operation
Name
April 2015
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Appendix 3: How to report incidents
Notifying the EPA about incidents
An organisation or person who holds a permission to apply the substances to control aquatic pest plants must ensure that any incidents
of accidental by-kills of non-target organisms are reported to the EPA within a week of the application of the substance.
The report must include the time, date and location where the incident occurred.
Sample incident notification form:
Name of person reporting the incident:
Organisation:
Phone:
Email:
Postal address:
Street number and name:
in New Zealand
Suburb:
Town/City:
Postal code:
Permission register number:
Description of incident
Date incident
occurred
Time
Site/place where
incident
happened and
GPS
coordinates
Description of incident
Substance
used in
operation prior
to incident
Name of
operator
and
company
Additional information:
Possible reason(s) for incident:
Appendix 4: Interpretation
Consultation: Discussing the details of an activity with a person(s) and taking into account any concerns
that they may have prior to commencing the activity.
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Using herbicides to control aquatic pest plants Guidance on preparing an annual report
Environmental Exposure Limit or EEL: An environmental exposure limit (EEL) establishes the maximum
concentration of an ecotoxic substance that is legally allowable in a particular environmental medium (eg,
water, soil or sediment).
Incident: Incidents are events that may have resulted from non-compliance with regulatory requirements
and/or may have caused adverse effects to human health and safety, or the environment. Incidents also
include accidental by-kill.
Notification: Formally notifying a person(s) of an activity that is about to commence
b before using certain substances a person (or organisation) must obtain a prior permission from the EPA
Sensitive site: Sensitive sites includes but is not limited to, aquatic farms, water ways used for crops
irrigation, drinking water, ecologically important sites
spray application: each individual application of spray e.g. spot spraying
spray event: all spray applications within a defined area on a given day
spray operation: spray programme to treat each target area. May consist of multiple of spray events over a
number of days.
April 2015
Level 10, 215 Lambton Quay, Wellington 6011, New Zealand