Waterbodies in Aotearoa New Zealand support a remarkable diversity of native freshwater fish, with nearly 60 species recognised.
Our freshwater fishes must be able to move freely in habitats to feed, migrate, spawn, and complete their life cycle. Instream structures, like culverts, weirs, and dams, can create barriers that block these fish from moving freely.
Ensuring proper fish passage protects our native biodiversity and keeps our waterways connected. All culverts, weirs and flap gates must meet minimum environmental conditions for fish passage and may need a resource consent.
While the new regulations do not apply to instream structures installed before 3 September 2020, it is still important to ensure those structures provide for fish passage. There are options for remediating or retrofitting structures to help fish passage.
The New Zealand Fish Passage Guidelines set out how to design instream structures that allow for fish passage.
Under national and regional rules, the installation, alteration, maintenance, and removal of some structures is a permitted activity – and therefore does not require resource consent – only if you can meet the specific requirements outlined below.
Fish Passage
Learn what fish passage is, how structures can affect fish movement, and practical guidance for designing, maintaining or improving crossings and other structures to keep Otago waterways connected.
NIWA Fish Passage Guidelines
Recommended standards for the design and restoration of instream infrastructure to provide for fish passage
Compliance NES notification
This page sets out the information you need to give us if you want to carry out activities permitted under National Environmental Standards (NES). Our compliance and consents teams can provide further guidance.
Fish passage requirements for structures installed on or after 3 September 2020 are generally managed differently from structures that already existed before September 2020.
This distinction exists because many older culverts, weirs, flap gates, and stream crossings were installed before modern fish passage requirements existed. Across Otago and the rest of New Zealand, many of these structures now create barriers that affect fish movement and freshwater habitat connectivity.
Current freshwater management frameworks generally focus on:
preventing new barriers from being created through fish-friendly design requirements for new structures; and
progressively improving existing barriers over time where practical and achievable.
New Structures
Key points:
- Fish passage should be considered early during project design.
- Poorly designed structures can create long-term barriers.
- Fish-friendly design is often easier and cheaper to incorporate during initial construction.
- Early planning can help avoid future compliance and remediation costs.
Structures installed on or after 3 September 2020 are generally managed as new structures under the NES-F and should be designed and installed in a way that allows fish and other aquatic species to move naturally through waterways.
Under current freshwater management frameworks, many new structures are expected to incorporate fish-friendly design principles from the outset. This helps prevent new fish passage barriers from being created and reduces the need for future remediation works.
Existing Structures
Key Points
Existing barriers are often prioritised based on ecological benefit and practicality.
Small remediation works can sometimes significantly improve fish passage.
Maintenance issues such as debris build-up and scour can also create barriers.
Not every existing structure requires immediate replacement.
Structures already existing before 3 September 2020, within Otago waterways, were installed before modern fish passage guidance and requirements existed. Some of these structures may now create barriers that affect fish movement and freshwater ecosystem health.
In many cases, existing barriers can be improved over time through remediation, maintenance, replacement, or small design changes that improve fish movement.
In many cases, fish-friendly structures are simply designed to allow water and fish to move through them as naturally as possible.
A good general rule is that a structure should aim to behave like a natural part of the stream rather than a barrier or artificial chute.
Fish passage issues often occur when structures:
create vertical drops;
increase water velocity;
reduce water depth; or
interrupt the natural stream bed.
Good fish-friendly design generally aims to:
maintain natural stream conditions;
maintain water depth;
reduce excessive water velocity; and
allow fish to move naturally upstream and downstream.
Incorporating fish passage into the initial design phase is often significantly easier and cheaper than retrofitting structures later.
For more detailed technical guidance, refer to the external resources below.
Many existing fish passage barriers can be improved through removal, replacement, remediation measures, maintenance works, or upgrades.
Where a structure is no longer required, removal may provide the most effective fish passage outcome. Where a structure remains necessary, replacement with a fish-friendly alternative may be appropriate. In many other situations, existing fish passage barriers can be improved through relatively simple remediation measures, maintenance works, or upgrades.
In some situations, small changes such as reducing outlet drops, improving water depth, removing debris blockages, installing baffles, embedding culverts, or adding rock ramps can significantly improve fish passage outcomes.
The most appropriate remediation approach will depend on the structure type, stream characteristics, fish species present, surrounding habitat, and practical site constraints.
If you are installing, altering, or maintaining a structure in a waterway, you must comply with national and regional rules.
All new structures (installed after 3 September 2020) must meet standards for fish passage such as height, width, location and reporting conditions under the National Environmental Standards for Freshwater. If these standards cannot be met, a resource consent is required.
The installation, alteration, maintenance, and removal of some structures is a permitted activity – and therefore does not require resource consent – only if the specific requirements are met in regional and national regulations.
The following national and regional rules apply if you are carrying out works to install or maintain a temporary or permanent culvert:
- Permitted activity conditions for culverts (NES-F Regulation 70).
- Permitted activity conditions for the erection or placement of any crossing (RPW Rule 13.2.1.7B).
- Permitted activity conditions for the use of instream structures (RPW Rule 13.1.1).
- Permitted activity conditions for maintaining instream structures (RPW Rules 13.3).
- Permitted activity conditions for diversions of water associated with work on instream structures (RPW Rule 12.3.2.3).
- Permitted activity conditions for discharges to water when working on instream structures (RPW Rule 13.5.1).
- Permitted activity conditions for the erection or placement of crossings (with a culvert) (RPW Rule 13.2.1.7B).
- Permitted activity conditions for activities in or near natural wetlands (NES-F Regulation 38).
If you cannot meet any of these requirements, you will have to apply for resource consent.
The following national and regional rules apply if you are carrying out works to install or maintain a temporary or permanent weir:
- Permitted activity conditions for weirs (NES-F Regulation 72).
- Permitted activity conditions for damming or diversion of water (RPW Rule 12.3.2).
- Permitted activity conditions for discharge of water or any contaminant to water (RPW Rules 12.C.1).
- Permitted activity conditions for the use of instream structures (RPW Rule 13.1.1).
- Permitted activity conditions for maintaining instream structures (RPW Rules 13.3).
- Permitted activity conditions for discharges to water when working on instream structures (RPW Rule 13.5.1).
- Permitted activity conditions for activities in or near natural wetlands (NES-F Regulation 38).
If you cannot meet any of these requirements, and the activity is not prohibited you will have to apply for resource consent.
The following national and regional rules apply if you are carrying out works to install or maintain a temporary or permanent flap gate:
- Consent requirements for passive flap gates (NES-F Regulation 74).
- Permitted activity conditions for damming or diversion of water (RPW Rule 12.3.2).
- Permitted activity conditions for discharge of water or any contaminant to water (RPW Rules 12.C.1).
- Permitted activity conditions for the use of instream structures (RPW Rule 13.1.1).
- Permitted activity conditions for maintaining instream structures (RPW Rules 13.3).
- Permitted activity conditions for discharges to water when working on instream structures (RPW Rule 13.5.1).
- Permitted activity conditions for activities in or near natural wetlands (NES-F Regulation 38).
If you cannot meet any of these requirements, you will have to apply for resource consent.
The following national and regional rules apply if you are carrying out works to install or maintain a temporary or permanent ford:
- Requirements to provide information to the regional council (NES-F Regulation 62 and 67).
- Permitted activity conditions for discharge of water or any contaminant to water (RPW Rules 12.C.1).
- Permitted activity conditions for the use of instream structures (RPW Rule 13.1.1)
- Permitted activity conditions for maintaining instream structures (RPW Rules 13.3).
- Permitted activity conditions for discharges to water when working on instream structures (RPW Rule 13.5.1).
- Permitted activity conditions for activities in or near natural wetlands (NES-F Regulation 38).
If you cannot meet any of these requirements, you will have to apply for resource consent.
The following national and regional rules apply if you are carrying out works to install or maintain a temporary or permanent dam:
- Requirements to provide information to the regional council (NES-F Regulation 62 and 66).
- Permitted activity conditions if damming in or within 100m of a natural wetland (NES-F Regulation 38(3)).
- Permitted activity conditions for damming or diversion of water (RPW Rule 12.3.2.1).
- Permitted activity conditions for maintaining instream structures (RPW Rules 13.3).
- Permitted activity conditions for diversions of water associated with work on instream structures (RPW Rule 12.3.2.3).
- Permitted activity conditions for discharges to water when working on instream structures (RPW Rule 13.5.1).
- Permitted activity conditions for activities in or near natural wetlands (NES-F Regulation 38).
If you cannot meet any of these requirements and the activity is not prohibited, you will have to apply for resource consent. Find out more about consent rules for larger dams.
When installing a structure in a waterway, you must provide information about the structure to us within 20 days of it being installed. Information must be provided for both permitted and consented activities.
- the type of structure;
- the geographical co-ordinates of the structure;
- the flow of the river or connected area (whether none, low, normal, or high);
- whether the water is tidal at the structure’s location;
- at the structure’s location;
- the width of the river or connected area at the water’s surface; and
- the width of the bed of the river or connected area;
- whether there are improvements to the structure to mitigate any effects the structure may have on the passage of fish;
- whether the structure protects particular species, or prevents access by particular species to protect other species;
- the likelihood that the structure will impede the passage of fish;
- visual evidence (for example, photographs) that shows both ends of the structure, viewed upstream and downstream.
- the culvert’s asset identification number, if known;
- whether the culvert’s ownership is;
- held by the Crown (for example, the Department of Conservation), a regional council, a territorial authority, the New Zealand Transport Agency, or KiwiRail Holdings Limited; or
- held publicly by another person or organisation; or
- held privately; or
- unknown
- the number of barrels that make up the culvert;
- the culvert’s shape;
- the culvert’s length;
- the culvert’s diameter or its width and height;
- the height of the drop (if any) from the culvert’s outlet;
- the length of the undercut or erosion (if any) from the culvert’s outlet;
- the material from which the culvert is made;
- the mean depth of the water through the culvert;
- the mean water velocity in the culvert;
- whether there are low-velocity zones downstream of the culvert;
- the type of bed substrate that is in most of the culvert;
- whether there are any remediation features (for example, baffles or spat rope) in the culvert;
- whether the culvert has wetted margins;
- the slope of the culvert;
- the alignment of the culvert;
- the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the culvert;
- if there is any apron or ramp on the culvert, the information required by regulation 68 for each of them.
- the weir’s asset identification number, if known
- whether the weir’s ownership is;
- held by the Crown (for example, the Department of Conservation), a regional council, a territorial authority, the New Zealand Transport Agency, or KiwiRail Holdings Limited; or
- held publicly by another person or organisation; or
- held privately; or
- unknown;
- the type of weir;
- the weir’s crest shape;
- the weir’s height;
- the weir’s width;
- the material from which the weir is made;
- the type of bed substrate that is present across most of the weir;
- whether there are any remediation features (for example, baffles or spat rope) in the weir;
- whether the weir has wetted margins;
- the slope of the weir;
- the backwater distance from the weir, meaning the distance furthest upstream where the water level is influenced by the weir;
- the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the weir;
- if there is any apron or ramp on the weir, the information required by regulation 68 for each of them.
- the flap gate’s asset identification number, if known
- whether the flap gate’s ownership is;
- held by the Crown (for example, the Department of Conservation), a regional council, a territorial authority, the New Zealand Transport Agency, or KiwiRail Holdings Limited; or
- held publicly by another person or organisation; or
- held privately; or
- unknown;
- the type of flap gate;
- the flap gate’s height;
- the flap gate’s width;
- the material from which the flap gate is made;
- the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the flap gate;
- if there is any apron or ramp on the flap gate, the information required by regulation 68 for each of them.
- the dam’s asset identification number, if known
- whether the dam’s ownership is;
- held by the Crown (for example, the Department of Conservation), a regional council, a territorial authority, the New Zealand Transport Agency, or KiwiRail Holdings Limited; or
- held publicly by another person or organisation; or
- held privately; or
- unknown;
- the dam’s height;
- whether the dam has a spillway, meaning a structure used to control the release of flows from the dam into a downstream area;
- the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the dam;
- if there is any apron or ramp on the dam, the information required by regulation 68 for each of them.
- the ford’s asset identification number, if known
- whether the ford’s ownership is;
- held by the Crown (for example, the Department of Conservation), a regional council, a territorial authority, the New Zealand Transport Agency, or KiwiRail Holdings Limited; or
- held publicly by another person or organisation; or
- held privately; or
- unknown;
- the ford’s length;
- the ford’s width;
- the height of the drop (if any) from the ford’s downstream end;
- the material from which the ford is made;
- the type of bed substrate that is across most of the ford;
- the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the ford;
- if there is any apron or ramp on the dam, the information required by regulation 68 for each of them.
- The apron’s length;
- the height of the drop (if any) from the apron’s downstream end;
- the material from which the apron is made;
- the mean depth of the water across the apron;
- the mean water velocity across the apron;
- the type of bed substrate that is across most of the apron.
- The ramp’s length
- the slope of the ramp;
- the type of surface that the ramp has;
- whether the ramp has wetted margins.
When you have your information ready, you can send it through using our compliance notification forms. You must provide information about the structure to us within 20 days of it being installed.
We have expert staff to provide localised assistance and advice regarding land management, consents and compliance.
If you think you may require a resource consent, please contact us. We can arrange for you to have a free pre-application meeting.
NIWA New Zealand Fish Passage Guidelines
The New Zealand Fish Passage Guidelines guidelines, developed by NIWA and the Department of Conservation in partnership with the New Zealand Fish Passage Advisory Group, set the foundation for improved fish passage management in New Zealand.
Essential Freshwater: Fish passage factsheet
This factsheet from the Ministry for the Environment, sets out the provisions relating to fish passage in the National Policy Statement for Freshwater 2020 and the National Environmental Standards for Freshwater.
Regional Plan: Water for Otago
The Regional Plan: Water for Otago (the Water Plan) assists us in managing Otago's water resources.
Fish passage regulations
Resource Management (National Environmental Standards for Freshwater) Regulations 2020—Passage of fish affected by structures
Te tono ki te whakaaetaka Apply for a consent
Find all the forms you need to apply for a consent, work with compliance, or work through our policy sheets.
Fish Passage
Learn what fish passage is, how structures can affect fish movement, and practical guidance for designing, maintaining or improving crossings and other structures to keep Otago waterways connected.
