Fish passage and instream structures

New Zealand has more than 50 species of native freshwater and sports fish. It’s important that instream structures such as culverts and weirs are designed to allow for fish passage, so that fish can move upstream and downstream between different river and stream habitats and complete their lifecycle.

Culverts, weirs, flap gates, fords and dams installed after 3 September 2020 must meet minimum reporting requirements such as height, width and location under the Essential Freshwater regulations.

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.

Regional Plan: Water for Otago rules

National Environmental Standards for Freshwater (NES-F) Regulations 

Apply for a resource consent

Go to the rules for specific in-stream structures:

Culverts
Weirs
Flap gates
Fords
Dams
Information requirements

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More information

Rules for culverts

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.

Rules for weirs

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.

Rules for flap gates

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.

Rules for fords

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.

Rules for dams

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.

Information requirements

The information specified in the regulations must be collected and provided to the relevant regional council, together with the time and date of its collection, within 20 working days after the activity is finished.

Reporting back to us

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.

 All Structures information requirements

a) the type of structure:
b) the geographical co-ordinates of the structure:
c) the flow of the river or connected area (whether none, low, normal, or high):
d) whether the water is tidal at the structure’s location:
e) at the structure’s location:
(i) the width of the river or connected area at the water’s surface; and
(ii) the width of the bed of the river or connected area:
f) whether there are improvements to the structure to mitigate any effects the structure may have on the passage of fish:
g) whether the structure protects particular species, or prevents access by particular species to protect other species:
h) the likelihood that the structure will impede the passage of fish:
i) visual evidence (for example, photographs) that shows both ends of the structure, viewed upstream and downstream.

Culvert information requirements

a) the culvert’s asset identification number, if known:
b) whether the culvert’s ownership is:

I. 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
II. held publicly by another person or organisation; or
III. held privately; or
IV. unknown:

c) the number of barrels that make up the culvert:
d) the culvert’s shape:
e) the culvert’s length:
f) the culvert’s diameter or its width and height:
g) the height of the drop (if any) from the culvert’s outlet:
h) the length of the undercut or erosion (if any) from the culvert’s outlet:
i) the material from which the culvert is made:
j) the mean depth of the water through the culvert:
k) the mean water velocity in the culvert:
l) whether there are low-velocity zones downstream of the culvert:
m) the type of bed substrate that is in most of the culvert:
n) whether there are any remediation features (for example, baffles or spat rope) in the culvert:
o) whether the culvert has wetted margins:
p) the slope of the culvert:
q) the alignment of the culvert:
r) the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the culvert:
s) if there is any apron or ramp on the culvert, the information required by regulation 68 for each of them.

Weir information requirements

a) the weir’s asset identification number, if known
b) whether the weir’s ownership is:

I. 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
II. held publicly by another person or organisation; or
III. held privately; or
IV. unknown:

c) the type of weir:
d) the weir’s crest shape:
e) the weir’s height:
f) the weir’s width:
g) the material from which the weir is made:
h) the type of bed substrate that is present across most of the weir:
i) whether there are any remediation features (for example, baffles or spat rope) in the weir:
j) whether the weir has wetted margins:
k) the slope of the weir:
l) the backwater distance from the weir, meaning the distance furthest upstream where the water level is influenced by the weir:
m) the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the weir:
n) if there is any apron or ramp on the weir, the information required by regulation 68 for each of them.

Flap gate information requirements

a) the flap gate’s asset identification number, if known
b) whether the flap gate’s ownership is:

I. 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
II. held publicly by another person or organisation; or
III. held privately; or
IV. unknown:

c) the type of flap gate:
d) the flap gate’s height:
e) the flap gate’s width:
f) the material from which the flap gate is made:
g) the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the flap gate:
h) if there is any apron or ramp on the flap gate, the information required by regulation 68 for each of them.

Dam information requirements

a) the dam’s asset identification number, if known
b) whether the dam’s ownership is:

I. 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
II. held publicly by another person or organisation; or
III. held privately; or
IV. unknown:

c) the dam’s height:
d) whether the dam has a spillway, meaning a structure used to control the release of flows from the dam into a downstream area:
e) the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the dam:
f) if there is any apron or ramp on the dam, the information required by regulation 68 for each of them.

Ford information requirements:

a) the ford’s asset identification number, if known
b) whether the ford’s ownership is:

I. 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
II. held publicly by another person or organisation; or
III. held privately; or
IV. unknown:

c) the ford’s length:
d) the ford’s width:
e) the height of the drop (if any) from the ford’s downstream end:
f) the material from which the ford is made:
g) the type of bed substrate that is across most of the ford:
h) the numbers of each other type of structure to which this subpart applies, or of wingwalls or screens, on the ford:
i) if there is any apron or ramp on the dam, the information required by regulation 68 for each of them.

Apron information requirements

a) The apron’s length
b) the height of the drop (if any) from the apron’s downstream end:
c) the material from which the apron is made:
d) the mean depth of the water across the apron:
e) the mean water velocity across the apron:
f) the type of bed substrate that is across most of the apron.

Ramp information requirements

a) The ramp’s length
b) the slope of the ramp:
c) the type of surface that the ramp has:
d) 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.

Need help?

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.  

More information

NIWA New Zealand Fish Passage Guidelines 
MfE Essential Freshwater: Fish passage factsheet