Interim code of practice: Routine maintenance dredging

1 About this code of practice

This code of practice outlines national best practices for routine maintenance dredging. Routine maintenance dredging occurs at least once every 10 years and involves the mechanical removal of accumulated sediment from the bed of a waterbody with clamshell buckets, draglines, backhoes or suction dredges. Routine dredging helps to maintain the design depths of navigation channels, harbours, marinas, boat launches, docking sites and port facilities that contribute to tourism, recreation and the transportation of goods.

Some potential impacts to fish habitat from routine maintenance dredging could include but are not limited to: sedimentation of aquatic habitat, change of aquatic habitat and vegetation, change in riparian zones and accumulation of deleterious substances.

This code of practice provides useful information on the measures to follow to ensure that fish and fish habitat are protected. This code applies to routine maintenance dredging only and does not apply to new dredging projects or to the expansion of a previously dredged area.

A project review by DFO is not required when the conditions and measures set out in this code of practice and all applicable measures to protect fish and fish habitat are applied.

This code does not remove or replace the obligation to comply with all applicable statutory and regulatory requirements of the Fisheries Act, or other federal, provincial, or municipal legislation and policies.

2 You can use this code of practice if:

• there are no SARA-listed shellfish, or critical habitat or residences of freshwater endangered or threatened aquatic species present in the work zone or the affected area except where exempted in the recovery strategy for that species. Consult our aquatic species at risk maps to determine where at-risk populations occur in Canada and where their critical habitat is located
• you performed analysis on the polychlorinated biphenyls (PCB) content of the substrate to be dredged, within the last 5 years and you were not required to apply mitigation measures over and above best management practices for dredging
• you are dredging in an area that has been dredged within the past 10 years
• your project does not include propeller wash dredging
• you are not temporarily or permanently increasing the existing footprint of the dredge and disposal areas
• you dispose of dredged material and stabilize it on land following provincial legislation or you dispose of dredged material in an approved Marine Disposal and Dumping Site
• you incorporate the applicable measures in this code of practice and all other applicable measures to Protect Fish and Fish Habitat

Consult our Projects near water review webpage when the works, undertakings or activities do not meet all the criteria listed in section 2.

3 Measures to protect fish and fish habitat for routine maintenance dredging

1 Timing windows

• Plan in water works, undertakings or activities to respect timing windows to protect fish including their eggs, juveniles, spawning adults and/or the organisms upon which they feed and migrate
• Conduct in-water work, undertaking and activity during periods of low flow
• Limit the duration of in-water work, undertaking and activity so that it does not diminish the ability of fish to carry out one or more of their life processes (e.g. spawning, rearing, feeding, migrating)

2 Dredging

• Limit impacts of fish habitat components to those approved for the work, undertaking or activity
• Limit the amount of dredged material removed for depth require for navigation
• For water-based operations, avoid placing vertical spuds or other anchors into sensitive fish habitat areas outside the footprint of the dredge area (e.g. eelgrass or kelp beds, saltmarshes, shellfish harvesting areas and known spawning areas)

3 Limit impacts on riparian vegetation

Limit impacts on riparian vegetation to those approved for the work, undertaking or activity.

• Limit access to banks or areas adjacent to waterbodies
• Prune or top the vegetation instead of grubbing/uprooting
• Limit grubbing on watercourse banks to the area required for the footprint of work, undertaking or activity
• Construct access points and approaches perpendicular to the watercourse or waterbody
• Remove vegetation or species selectively and in phases
• Re-vegetate the disturbed areas with native species suitable for the site

4 Limit impacts on habitat components

• Salvage, reinstate or match habitat structure (e.g., large wood debris, boulders, instream aquatic vegetation/substrate) to its initial state
• Restore stream geomorphology (i.e., restore the bed and banks, gradient and contour of the waterbody) to its initial state
• Replace/restore any other disturbed habitat features and remediate any areas impacted by the work, undertaking or activity

5 Ensure proper sediment control

Develop and implement a sediment control plan that minimizes sedimentation of the waterbody during all phases of the work, undertaking or activity.

• Operate machinery on land in stable dry areas, or from barges or on ice
• Use methods to prevent substrate compaction (e.g., swamp mats, pads)
• Where applicable, put in place site isolation measures (e.g., silt boom or silt curtain) to contain suspended sediment generated by dredging activities
• Schedule work to avoid wet, windy and rainy periods (and heed weather advisories)
• Inspect and regularly maintain erosion and sediment control measures and structures during all phases of the project
• Use biodegradable erosion and sediment control materials whenever possible
• Remove all exposed non-biodegradable erosion and sediment control materials once site is stabilized
• Monitor the watercourse to observe signs of sedimentation during all phases of the work, undertaking or activity and take corrective action

6 Deleterious substances

Develop a response plan that is to be implemented immediately in the event of a release or spill of a deleterious substance and keep an emergency spill kit on site.

• Stop work, contain sediment-laden water or other deleterious substances and prevent their further migration into the watercourse
• Report any spills of sewage, oil, fuel or other deleterious material, whether near or directly into a water body
• Maintain all machinery on site in a clean condition and free of fluid leaks to prevent any deleterious substances from entering the water
• Wash, refuel and service machinery and store fuel and other materials for the machinery in such a way as to prevent any deleterious substances from entering the water

4 Project notification

Please submit a Notification Form (PDF, 50 KB) to your regional DFO office to help us improve this fish and fish habitat protection guidance over time.

5 Contact us

If you have questions regarding this code of practice contact the Fish and Fish Habitat Protection Program located in your region.

6 Glossary

Affected area

Area within which potential impacts from works, undertakings or activities are likely to occur.

Navigation channels

Channels in the sea, lake or river bed that are wide and deep enough to accommodate vessels passing through to, or accessing a harbour, marina, boat launch or a port facility.