Language selection


Code of practice: Culvert maintenance

On this page:

1.0 About this code of practice

This code of practice outlines Fisheries and Oceans Canada (DFO)’s national best practices for the maintenance of existing culverts. A culvert is a closed conduit or tunnel used to convey water under a road or railroad. Culvert maintenance is often necessary to extend the life of the structure and ensuring it is functioning as designed. When a culvert no longer functions as designed, there is a risk that fish passage, natural flows and channel integrity will be compromised. It is good practice to ensure that culverts are maintained in good condition such that these impacts do not occur.

For the purposes of this code of practice, culvert maintenance includes:

This is a front view of a properly installed culvert. The Culvert is embedded and water flow is at an appropriate level to allow for fish passage. The road bed is on top of the culvert, and both inlet and outlet ends have reinforcement material (rock) placed around them to ensure stability and reduce erosion.

You can protect fish and fish habitat (including aquatic species at risk, their critical habitat and residences) when proceeding with culvert maintenance by following the measures listed below. When implemented correctly, this can mitigate risks to fish and fish habitat associated with culvert maintenance, which can include:

DFO is responsible for the conservation and protection of fish and fish habitat across Canada. Under the Fisheries Act, no one may carry out works, undertakings and activities that result in the harmful alteration, disruption or destruction (HADD) of fish habitat, or the death of fish, unless it has been authorized by DFO. DFO's approval under the Species at Risk Act is also required if an activity affects an aquatic species at risk, any part of its critical habitat or the residences of its individuals.

The purpose of this code of practice is to describe the conditions under which the code can be applied to your project and the measures you are required to implement in order to prevent harmful impacts to fish and fish habitat and avoid contravention of the Fisheries Act and the Species at Risk Act. If you cannot meet all of the conditions and implement all of the applicable measures listed below, your project may result in a violation of the Fisheries Act and the Species at Risk Act and you could be subject to enforcement action.

If you are uncertain about whether this code of practice is applicable to your project, it is recommended that you consult our website or a qualified environmental professional to determine if other codes of practice should also be implemented, or if further review by DFO may be necessary. For any remaining questions, please contact the Fish and Fish Habitat Protection Program office located in your area. It remains your responsibility to comply with the Fisheries Act and the Species at Risk Act.

It is your duty to notify DFO if you have caused, or are about to cause, the unauthorized death of fish by means other than fishing/harmful alteration, disruption or destruction of fish habitat. Such notifications should be directed to the Fish and Fish Habitat Protection Program office located in your area.

This code of practice does not remove nor replace the obligation to comply with the requirements of any other federal, territorial, provincial or municipal regulatory agency including guidance regarding species and habitats managed by these jurisdictions.

It is good practice to notify nearby Indigenous communities of the works, undertakings and activities.

A project review by DFO is not required when the project activities meet the description in section 1 and the conditions in section 2, and when the measures to protect fish and fish habitat set out in section 3 of this code of practice are applied. Request a project review if your project does not meet all of these requirements.

2.0 Conditions

The following conditions describe when this code of practice can be applied:

As a condition of this code of practice, please submit a notification form (PDF, 50 KB) to your regional DFO office 10 working days before starting work. Notification forms will inform the continuous improvement of the codes of practice over time.

You must download and save this PDF form to your computer before filling it out. How to download and open a PDF form.

3.0 Measures to protect fish and fish habitat

3.1  Protection of fish

3.2  Protection of fish passage

3.3  Protection of the riparian zone

Side view of a riparian zone. There are three distinct zones in the diagram: the aquatic zone, riparian zone, and upland zone. In the aquatic zone there is aquatic vegetation growing on the bed of the water body that is either fully submerged under water, or partially emerging, from the current water level. The riparian zone includes vegetation such as sedges and rushes, and shrubs and trees. The upland zone, furthest from the water's edge, includes vegetation such as: trees (evergreens), shrubs, and grasses.

3.4  Protection of aquatic habitat

3.5  Protection of fish and fish habitat from sediment

3.6  Protection of fish and fish habitat from other deleterious substances

3.6.1  Develop a prevention plan

3.6.2  Implement a response plan

4.0 Glossary

Affected area: The area within which all of the proposed project impacts are likely to occur either directly (i.e., project footprint) or indirectly (i.e., downstream or other surrounding areas).

Aquatic species at risk: Any aquatic species listed under schedule 1 of the Species at Risk Act as endangered, threatened, or extirpated.

Deleterious substance: Any substance that, if added to water, would degrade, alter, or form part of a process of degradation/alteration to the quality of that water so that it is possibly rendered deleterious to fish, fish habitat, or to the human use of fish that frequent that water. For example: fuel, lubricants, paint, primers, rust, solvents, degreasers, antifreeze, uncured concrete, creosote, chlorinated water, herbicides, etc.

Harmful alteration, disruption or destruction (HADD): Any temporary or permanent change to fish habitat that directly or indirectly impairs the habitat's capacity to support one or more life processes of fish.

Ordinary high water mark: The usual or average level to which a body of water rises at its highest point and remains for sufficient time to change the characteristics of the land. In flowing waters (e.g., rivers, streams) this refers to the "active channel/bank-full level" which is often the 1:2 year flood flow return level. In inland lakes, wetlands or marine environments it refers to those parts of the water body, bed and banks that are frequently flooded by water so as to leave a mark on the land and where the natural vegetation changes from predominately aquatic vegetation to terrestrial vegetation (excepting water tolerant species). For reservoirs this refers to normal high operating levels (i.e., full supply level).

This is a cross section of flowing waters, for both rivers and streams, with banks on both sides of the water body. Terrestrial vegetation is drawn in the form of trees, shrubs, and grasses and are located on land above the ordinary high water mark.

This is a cross section of the area where water meets land for a lake, wetland, or marine environment. Aquatic vegetation can be found growing on the bed of the water body and are either fully submerged, or partially emerging, from the current water level.  Trees, shrubs, and plants are shown at and above the ordinary high water mark of the shoreline which is depicted by a dotted line slightly above where the water meets land.

Riparian vegetation: Occurs adjacent to the water body and directly contributes to fish habitat by providing shade, cover and areas for spawning and food production.

Riparian zone: Area located between a water body's ordinary high water mark and upland area.

Qualified Environmental Professional (QEP): A person who is experienced in identifying and assessing potential impacts to fish and fish habitat generated from various works, undertakings or activities conducted in or near water, and implementing management measures to avoid and mitigate them. QEPs possess a post-secondary degree or diploma in biological, geophysical or environmental sciences and are often referred to as:

Date modified: