Fish screens – what’s the story?

A fish screen is required whenever a water take could impact fish. They are designed to protect fish, including trout, salmon and native fish, by keeping them out of water takes. Water takes are used for irrigation, stock-water, community supplies or hydro-electric power generation. We often receive LGOIMAs on the subject; full LGOIMA responses can be viewed under the Compliance tab - 6 December 2017.

Update 4. 13/11/2019 - 2018/19 Summary report for fish screens released

Fish screen summary report released

We have released our 2018/19 fish screens summary report (PDF File, 776.43KB) on progress to date and our approach moving forward.

Fish screens have been a priority compliance activity for us since a decision of Council in April 2018. In May/June 2018, we conducted a pilot programme (read more about the programme in update 3) involving in-depth assessments of selected fish screens.

That programme indicated that most fish screens currently operating in Canterbury are likely to be non-compliant. Non-compliant fish screens either injure or kill native and sports fish or can result in them being unable to return to the waterway they had been in.

We intend to work with consent holders and industry on a proactive effort to ensure fish screens are upgrading over an appropriate timeframe so to achieve, at a minimum, compliance with the applicable consent conditions.

Key points from the report

The pilot programme in 2018 has highlighted:

  • A higher than anticipated number of issues with fish screen compliance and effectiveness. It appears that most fish screens in Canterbury may be non-compliant
  • Screen assessment of compliance and effectiveness is technically and legally complex
  • There are significant implications for industry in terms of the scale of upgrades likely to be required, and the related investment required by consent holders

As a result of the pilot, a number of activities have been undertaken, including:

  • We updated our monitoring procedures in line with Schedule 2 of the Canterbury Land and Water Regional Plan
  • The assessment process is more comprehensive with standard operating procedures and a moderation panel put in place to assist in decision making and to ensure consistency
  • Engagement with consent holders, stakeholders and industry
  • Development of a five-year programme that will address fish screens on over 95% of the consented surface water takes

The results of the programme to date will inform a package of improved solutions focusing on a greater role for industry and addressing the complex technical and legal issues highlighted.

New programme focus for 2019/20

Following the pilot from the previous year, we have redesigned our programme for 2019/20.

Key focus points

  • Addressing all consents in progress - ensuring action plans are in place to address compliance issues
  • Defining areas where industry resources can be utilised to resolve issues (instead of Environment Canterbury resources)
  • Development of a five-year programme that will address fish screens on over 95% of the consented surface water takes

Update 3. 20/09/2018 - Fish screen improvement campaign 2018/19

Why a campaign to improve fish screens?

From 2004 the Canterbury Land and Water Regional Plan stated that all diversions or water takes that meet the appropriate criteria must have a fish screen installed which is "kept functional at all times that water is being taken" (CLWRP, 2017:305). The underlying reason is to keep fish in our waterways.

In 2007 new guidelines for fish screens were developed by NIWA through a collaborative process initiated by Irrigation NZ, supported by the Sustainable Farming Fund (Ministry for Primary Industries), and these have formed the basis of consent conditions from 2008. These guidelines represent good management practice for fish screens.

From 2012 until 2017 the focus of regional implementation and compliance monitoring efforts within Environment Canterbury was on stock in waterways, dairy effluent, high-risk consents and water metering - the latter being an obligation directed from the National Water Metering Regulations. Fish screens were monitored, but at a lower level to these other priorities.

With the shift to Audited Self-Management of consents and technology improvements associated with water metering, the opportunity has arisen to allocate resources to a new priority.

Each year the council reviews its compliance monitoring priorities consistent with best practice as outlined in the Ministry for the Environment Best Practice Guidelines for Monitoring and Enforcement (p17) (PDF file 8.69MB). These guidelines recognise that Councils have limited resources and therefore must take a strategic and prioritised approach to compliance monitoring and enforcement activities.

In April 2018 the council added Fish Screens to its compliance priorities for 2018-19. In addition to compliance monitoring, the Fish Screen Improvement Campaign will include: educating consent holders on best practice, encouraging voluntary upgrades to older fish screens (in excess of compliance obligations) and efforts to build capacity within the engineering industry (to support fish screen upgrades).

Gathering intelligence for the campaign

Following a council decision to prioritise fish screen improvement, staff from the Service Delivery and Regional Support groups commenced the development of the Fish Screen Improvement campaign. This work included:

  • analysis of consents databases to identify and categorise consents for potential inclusion in the campaign;
  • consultation with stakeholder groups (including iwi, Fish & Game, Irrigation NZ); and
  • the completion of a four-week pilot study, which studied (among other things): resources required for monitoring; developing Standard Operating Procedures and training materials; assessments of both fish screen compliance (against consent conditions) and effectiveness (against best practise guidelines).

The screens selected for inclusion in the pilot were chosen to cover a wide range of technically different screen types and consented volumes, and included both pump and open channels.

However, it should be noted that while the study looked at a range of screens, it did not comprise a fully representative sample of all fish screens. For example, fish screens included within the pilot were not representative of the range in consented water volumes and those with consent conditions from prior to 2008 were overrepresented.

Notwithstanding the above, the pilot highlighted the following:

  • While some of the compliance issues could be rectified with maintenance, some had several issues to resolve, before they would be compliant.
  • "Compliance" and "Effectiveness" are not the same thing. Many of the fish screens had older consent conditions, which are not at the standard of current best practice guidelines. Even if these screens are fully compliant, they are unlikely to be effective.
  • Designing and installing an effective fish screen is both technically difficult and expensive (especially for larger takes). Several consent holders discussed the potential to work with neighbours to amalgamate their abstraction points, so they could invest in single, superior fish screens. Many screens were operated by companies which have additional steps to secure shareholder funding for new investment in fish screens. Given these factors, it is recognised that upgrading major fish screens takes time.
  • In addition, there is limited capacity within the engineering support industry to assist with fish screen design and installation. In some instances, consent holders had sought to upgrade their screens but had been unable to find service providers to assist them.

The 2018-19 Fish Screen Improvement Campaign

With the intelligence learnt through the pilot, a comprehensive Fish Screen campaign for 2018-19 has been developed.

The goal of the 2018-19 Fish Screen Improvement Campaign is to "improve the standard of fish screens to ensure more fish are retained in a healthy state in our rivers".

Key components of the campaign will be:

  • communication and engagement (informing consent holders of their requirements and best practice);
  • compliance monitoring (meeting with consent holders to assess the effectiveness and compliance of their screens);
  • working with consent holders on action plans to resolve non-compliances, and to encourage upgrades to best practice (even if this is beyond current consent conditions); and
  • supporting industry to increase capacity and improve technology and services to improve fish screens.


Given the scale of fish screens that need to be monitored under the new Standard Operating Procedure, it is essential that a prioritisation exercise determines which sites should be visited first.

Environment Canterbury will focus on monitoring 50 consents in the 2018-19 season (including working with consent holders to develop appropriate action plans to address issues).

While 50 consents represent a small number of the 922 consents with fish screen conditions, a careful selection of consents to monitor will enable a significant proportion of surface water takes to be included.

Cumulative water take (L/S)

Figure 1 shows that 85% of consent water volume comes from 50 consents

This graph shows that 85% of consent water volume comes from 50 consents

In addition to considering water volume, Environment Canterbury has also consulted with iwi, DoC and fishing interest groups (incl. Fish and Game) to get their input into the consents which should be included in the 2018-19 campaign. These groups will provide advice on the consents with the largest environmental and cultural impact.


The campaign, which is due to start in September, will be reviewed after the first year. Throughout the year, Environment Canterbury staff will be regularly contacting consent holders with action plans to monitor their progress in addressing issues. The progress made by consent holders will be included in quarterly reporting to council. Quarterly reports will also be made available publicly.

Looking ahead

The 2018-19 compliance monitoring campaign is a significant effort by Environment Canterbury to lift the standard of fish screens towards current best practice. However, it is noted that the current best practise guidelines (NIWA 2007) have some deficiencies and there is a desire amongst a number of parties to improve them.

In 2017 the Regional Committee of the Canterbury Water Management Strategy (CWMS) reformed a Fish Screen Technical Working Group (FSTWG) to investigate technical issues. This group is reviewing the current good practice guidelines and may commission new research. Environment Canterbury is a member of the Technical Working Group, which is working to improve industry capability and address technical challenges.

While the FSTWG is not involved in the compliance monitoring aspects of the Fish Screen Improvement campaign (as this is an Environment Canterbury responsibility), there is an active dialogue between the groups on technical matters. These discussions have not only assisted in the development of Environment Canterbury's campaign but will assist in improved standards of fish screening in the future.

Update 2. 29/05/2018 - Council sign off

Council has signed off a fish screen compliance monitoring campaign to be included in the 2018-19 programme of work.

To inform the 2018-19 programme, a four-week pilot (which started in May) will assist Environment Canterbury to structure the programme in the most cost-effective manner and ensure officers are fully trained and prepared for the programme.

The pilot will also indicate the level of fish screen compliance, identify any common issues and assess the effectiveness of the fish screen against current best practice.

Once the pilot is concluded and the results assessed, a wider programme of monitoring fish screens will be rolled out across the region.

The monitoring of fish screen consent conditions is a normal part of compliance monitoring and the standard monitoring charges will be applied.

Update 1. 16/04/2018 - Winter fish screen monitoring programme

Winter fish screen monitoring programme

Environment Canterbury has developed a fish screen compliance monitoring programme as we head into winter. Our monitoring programme will run from May through winter. We don't tend to monitor pump fish screens during the summer because they are often in use and, as such, in the water so critical design aspects (overall size, aperture size and condition) can be very difficult to assess.

Preliminary work undertaken between November 2017 and March 2018 to enable this work has included:

  • analysis of consents databases to review the number and type of consents with fish screen conditions;
  • revised training of Resource Monitoring Officers on fish screen compliance monitoring; and
  • the development of the compliance monitoring programme to run for the remainder of the financial year (to 30 June 2018) and into the coming financial year (1 July 2018 to 30 June 2019).

This programme of work is scheduled to commence from late April.

Guidelines for fish screens

In Canterbury there are around 1,400 consents that abstract water from our rivers. These consents must have an effective fish screen, be fit for purpose and not cause detrimental effects on the environment.

The guidelines for fish screens were released in 2007. They were prepared by NIWA in consultation with Irrigation NZ, Environment Canterbury, Fish and Game New Zealand, the Department of Conservation, Fish and Game, the Jet Boat Association and Whitewater NZ.

The guidelines were prepared to provide practical advice on fish exclusion for larger water takes between 500L/s and 10,000L/s. However, they still provide practical advice for smaller and larger takes. We aim to monitor all surface water consents which take greater than 100L/s once per year to ensure their fish screens are working properly.

How do we test the efficiency of the screens?

We expect screens are built to the design criteria in the 2007 guidelines, rather than running an efficiency test after the screen has been built. All fish screens are expected to meet the following seven criteria:

  1. Locate to avoid fish exposure
  2. Sufficiently low water velocity through outlet
  3. Sufficiently high-water velocity across structure
  4. Provide a fish bypass (escape route)
  5. Connect the bypass to a safe exit
  6. Any screening material openings small enough to exclude fish
  7. Needs to be capable to operate as designed.

Most large consents (>10,000L/s) require the consent holder to develop an efficiency test to demonstrate they are working after construction. This test needs to be developed in consultation with the Department of Conservation and Fish and Game, before being approved by Environment Canterbury.