Interim code of practice: temporary stream crossings

1 About this code of practice

This code of practice outlines national best practices for temporary stream crossings. For the purpose of this code of practice these may include fords, temporary clear span bridges (including Bailey bridges or log stringer bridges) and temporary winter crossings (i.e. ice bridges and snow fills). Temporary watercourse crossings are required to access infrastructure and property for construction and maintenance activities. They are employed for short term access across a watercourse by construction vehicles when an existing crossing is not available or practical to use. They are not intended for prolonged use (e.g., forest or mining haul roads).

The use of temporary bridges or dry fording is preferred over fording in flowing water due to the lower risk of fish injury and mortality, damaging the bed and banks of the watercourse, and sedimentation of downstream fish habitat.

Ice bridges and snow fills provide cost-effective access to remote areas when rivers and streams are frozen. Since the ground is frozen, ice bridges and snow fills can be built with minimal disturbance to the bed and banks of the watercourse.

There are however risks to fish and fish habitat associated with temporary stream crossings. These include the potential for: direct harm to stream banks and beds; release of sediments or other deleterious substances (e.g., fuel and lubricants); loss or damage of riparian vegetation; disruption of the sensitive life stages of fish; and injury and death of fish during wet fording. In the case of ice bridges and snow fills, blockage of fish passage during spring break up may also occur.

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 policy.

2 You can use this code of practice if:

• There are no shellfish listed under the Species at Risk Act, or critical habitat or residences of endangered or threatened aquatic species present in the work zone or thevicinity of the works, undertakings and activities. Consult our aquatic species at risk maps to determine where at-risk populations occur in Canada and where their critical habitat is located.
• There is no temporary or permanent increase in existing footprint below the ordinary high water mark (see definition below) if the riparian area is identified as part of the critical habitat of an aquatic listed species at risk.
• The work does not include realigning the watercourse, dredging, placing fill, grading or excavating the bed or banks of the watercourse.
• The crossing does not involve installation of a temporary culvert.
• You follow the measures in this code of practice and all other applicable Measures to Protect Fish and Fish Habitat.

2.1 Temporary bridges

• Installation of a temporary bridge does not include pile driving.
• The temporary bridge is no greater than one lane wide with no part of the structure placed within the wetted portion of the watercourse.
• The work does not include the placement of abutments, footings or armouring (e.g., rock and concrete) below the ordinary high water mark.
• The channel width at the crossing is no greater than 5 meters from ordinary high water mark to ordinary high water mark.

2.2 Fords

• Fording consists of a one-time crossing (over and back) in flowing waters, or a seasonally dry streambed ford.
• The channel width at the crossing is no greater than 5 meters from ordinary high water mark to ordinary high water mark.

2.3 Winter crossings

• Snow fills are constructed of clean snow, and will not restrict water flow at any time.
• Snow fills will not result in erosion and sedimentation of the stream or alteration (e.g., compaction or rutting) of the bed and bank substrates.
• Materials such as gravel, rock and loose woody materials are NOT used in the construction of ice bridges.

Request a project near water review when the works, undertakings and activities do not meet all of the criteria listed in this section.

3 Measures to protect fish and fish habitat

3.1 Protection of fish

• Plan in water works, undertakings and activities to respect timing windows to protect fish and fish habitat.
• Limit the duration of in-water works, undertakings and activities 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).
• Maintain an appropriate depth and flow (i.e. base flow and seasonal flow of water) for the protection of fish.

3.2 Protection of fish passage

• Maintain fish passage during all phases of works, undertakings and activities.
  • Avoid changing flow or water levels.
  • Avoid obstructing and interfering with the movement and migration of fish.

3.3 Protection of the riparian zone

• Use existing trails, roads access points or cut lines wherever possible.
• Avoid tree/shrub removal whenever possible.
• Avoid stockpiling of material on stream banks and riparian zones.
• Do not grade stream banks or approaches.
• Use methods to prevent substrate compaction (e.g., swamp mats, pads).
• Limit access to banks or areas adjacent to water bodies.
• Construct roads, access points and approaches perpendicular to the watercourse or water body.
• Prune or top the vegetation instead of grubbing/uprooting wherever possible.
• Limit grubbing on watercourse banks to the area required for the footprint of the works, undertakings and activities.
• Remove vegetation or species selectively and in phases.
• Restore stream banks and riparian vegetation affected by the works, undertakings and activities to their natural state (substrate granularity, profile, vegetation, etc.).
• Re-vegetate the disturbed banks and adjacent areas) with native species suitable for the site.

3.4 Protection of aquatic habitat

• Avoid disturbing or removing aquatic vegetation, natural wood debris, rocks, sand or other materials from the banks, shoreline or the bed of the water body.
• Ensure there is no temporary or permanent increase in existing footprint below the ordinary high water mark.
• Operate machinery in a manner that minimizes disturbance to the watercourse bed and banks.
• Maintain an appropriate depth and flow (i.e., base flow and seasonal flow of water) for the protection of fish habitat.
• Conduct in-water works, undertakings and activities during periods of low flow, or at low tide.

3.5 Protection of fish habitat from sedimentation

• Use only clean materials (e.g., rock, coarse gravel, wood, steel, snow) for works, undertakings and activities.
• Install effective erosion and sediment control measures prior to beginning works, undertakings and activities in order to stabilize all erodible and exposed areas.
  • Develop and implement an erosion and sediment control plan to avoid the introduction of sediment into any water body during all phases of the works, undertakings and activities.
  • Schedule work to avoid wet, windy and rainy periods (and heed weather advisories) that may result in high flow volumes and /or increase erosion and sedimentation.
  • Operate machinery on land in stable dry areas.
  • Regularly inspect and maintain the erosion and sediment control measures and structures during all phases of the project.
  • Regularly monitor the watercourse for signs of sedimentation during all phases of the works, undertakings and activities and take corrective action if required.
  • Use biodegradable erosion and sediment control materials whenever possible.
  • Keep the erosion and sediment control measures in place until all disturbed ground has been permanently stabilized.
  • Remove all sediment control materials once site has been stabilized.
  • Dispose of, and stabilize, all excavated material above the ordinary high water mark or top of bank of nearby waterbodies and ensure sediment re-entry to the watercourse is prevented.

3.6 Protection of fish and fish habitat from deleterious substances (including suspended sediments)

• Develop and immediately implement a response plan to prevent deleterious substances from entering a water body.
  • Stop works undertakings and activities in the event of a spill of a deleterious substance.
  • Immediately report any spills (e.g., sewage, oil, fuel or other deleterious material), whether near or directly into a water body.
  • Keep an emergency spill kit on site during all phases the works, undertakings and activities.
  • Contain any water with deleterious substances.
  • Ensure clean-up measures are suitably applied so as not to result in further alteration of the bed and/or banks of the watercourse.
  • Clean-up and appropriately dispose of water contaminated with deleterious substances.
  • Maintain all machinery on site in a clean condition and free of fluid leaks.
  • 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.
  • Dispose of all waste materials (e.g., construction, demolition, commercial logging) above the ordinary high water mark to prevent entry into the water body.

3.7 Additional measures for temporary crossings - general

• Locate temporary crossing site where streambanks are stable and where approaches have low slopes.
• Locate temporary crossing site where the stream is straight, unobstructed and well defined.
• Locate temporary crossing at a right angle to the stream.
• Ensure approach grades are kept to a minimum for at least 15m on each side of the crossing.

3.8 Additional measures for fords

• Locate fording site where stream substrate is stable or is a bedrock outcrop.
• Limit machinery fording of the watercourse to a one-time event (over and back).
• Conduct fording during periods of low flow.
• Stabilize approaches with non-erodible materials such as brush mats, corduroy or clean stone.
• Restore approaches and banks of the watercourse to its natural state.
• Do not skid or drag anything across ford.
• Do not use ford if the water depth is greater than the axle height of the vehicle.
• Do not manipulate material in the wetted portion of the watercourse while fording the watercourse.

3.9 Additional measures for winter crossings (ice bridges and snow fills)

• Construct snow bridges on large watercourses that have sufficient stream flow and water depth to prevent the ice bridge from coming into contact with the stream bed or restricting the water movement beneath the ice.
• Use only clean water, ice or snow to construct winter crossing.
• Construct approaches using clean compacted snow and ice to a sufficient depth to protect the banks of the watercourse.
• Do not exceed 10% of the instantaneous flow if withdrawing any water, in order to maintain existing fish habitat and flow under the ice.
• Screen intake pipes to prevent entrainment or impingement of fish.
• Use the interim code of practice for end-of-pipe fish protection screens for small water intakes in freshwater.
• Where logs are used to stabilize the approaches of an ice bridge or snow fill:
  • Do not leave logs or woody debris within the water body or on the banks or shoreline where they can wash back into the water body.
  • Ensure that the logs are clean and securely bound together so they can be easily removed either before or immediately following spring freshet.
• Maintain natural, under ice water flow where it occurs.
• Place notch in center of the ice bridge to encourage proper melting and reduce flooding, to ensure that fish passage is maintained.
• Remove compacted snow from the snow fills prior to the spring freshet.

3.10 Additional measures for temporary clear span bridges

• Ensure the single-span bridge structure, including approaches, abutments, footings, and armoring is built entirely above the ordinary high water mark.
• Design the bridge so that storm water runoff from the bridge deck, side slopes and approaches directly run off into a retention pond or vegetated area to prevent sediment and other deleterious substances from entering the watercourse.
• Design temporary bridges to accommodate any expected high flows of the watercourse during the construction period.
• Remove bridge crossing prior to the spring freshet, unless the crossing has been constructed above the annual spring high water level.

4 Notification

When making use of this code of practice, 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.

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 and/or the harmful alteration, disruption or destruction of fish habitat. Such notifications should be directed to the Fish and Fish Habitat Protection Program.

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

Ford

A shallow, stable crossing location that does not require alteration of the bed or bank of the watercourse.

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 so as 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).

Riparian zone

Area adjacent to streams, lakes, and wetlands that support a unique mixture of water tolerant vegetation from trees and shrubs to aquatic and herbaceous plants.

Temporary clear span bridge

Small scale bridge structures (e.g., Bailey bridge or log stringer bridge) that completely span the watercourse, do not alter the stream bed or bank, and are a maximum of one lane wide. The bridge structure (including bridge approaches, abutments, footings, and armouring is built entirely above the ordinary high water mark.

Winter crossings - Ice bridges and snow fills

These are two methods used for temporary winter access in remote areas. Ice bridges are constructed on large watercourses that have sufficient stream flow and water depth to prevent the ice bridge from coming into contact with the stream bed or restricting water movement beneath the ice. Snow fills are temporary stream crossings constructed by filling a stream channel with clean compacted snow, and are typically used for crossing smaller watercourses.