Specific Standards and Best Practices:
Watercourse Channelization and Realignment

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Background

The channelization or realignment of a watercourse refers to any stream diversion activity that will permanently alter the direction or pattern of the watercourse’s path. Streams are often proposed for diversion to increase a property’s potential development yield or opportunity.

Generally, streams should never be diverted. There are many consequences of diversions that can be devastating to the stream and its aquatic life over the long term. The diversion of a stream is a very complex proposal that typically requires the involvement of many specialized qualified professionals, and requires addressing many complex issues involving, physical, biological and social constraints.

The following should be considered when proposing a stream diversion:

• The proximity of the stream and its' effects on adjacent properties and services before and after the proposed diversion. The value of adjacent properties can be greatly affected by changing the streams' proximity to them. The risk of flooding and erosion to properties and roads/services/utilities can also be greatly affected;
   
• Cost. A diverted and recreated stream should result in a net gain of fish habitat for the stream immediately after construction and in the long term. The costs for reproducing a natural fully productive fish habitat stream are substantial, and costs typically continue for years after the initial construction. Depending on the stream, the habitats supported, and the conditions in the area, a fish habitat stream can cost upwards of $10,000 per linear metre; and
   
• The long-term viability and maintenance of the stream. Streams are stable, dynamic organisms that support hundreds of different balanced aquatic and terrestrial life cycles. The path that streams follow is the most preferred and will need to change over time depending on the topography of the area. Restricting and fixing the path affects the ability of the stream to change or react to change and can limit its ability to support fish and wildlife habitats and populations. Also, a tendency with diversions is to force the channels path into fixed, tight unnatural turns, even to greater than 90 degrees. This substantially increases stream power and erosive forces in the turns, resulting in a need for substantial bank protection to keep the channel position fixed and the water moving in a direction that it doesn't prefer to go. This results in increased costly channel maintenance needs that continue in perpetuity.

Objectives

The Ministry’s objective for the management of alterations to watercourse channels and alignment is to prevent immediate and long-term harmful impacts to water quality, riparian and aquatic habitats and fish and wildlife species relating to the channelization or realignment activities.

Standards for Watercourse Channelization and Realignment

The federal Fisheries Act regulates fish and fish habitat in Canada. Section 35 of the Act prohibits the “harmful alteration, disruption, or destruction of fish habitat” (HADD) unless authorized by DFO. Stream diversions typically result in a HADD of fish habitat.

Channelization and realignment activities on a watercourse, because of their disturbance to instream habitat will require an approval pursuant to Section 9 of the Water Act.

Best Practices

Channelization, diversion and realignment activities are typically very damaging to environmental resources. These activities also require considerable attention to adjacent property rights and to stream design. They require substantial financial input. As such WLAP discourages these activities.

You should retain an appropriately qualified professional to assist with your proposal for works. Any proposal for watercourse channelization or realignment should consider the following:

Design Best Practices

The following describes the only situations or conditions where the diversion of a stream should be considered:

• There would be no significant immediate or long-term impacts to upstream or downstream riparian and aquatic habitats;
• There would be no significant immediate or long-term impacts to adjacent, upstream, or downstream properties, roads, services or utilities. Permission should be obtained for any actual or potential impacts;
• There would no impacts to upstream or downstream water rights;
• The newly created stream is designed, constructed, monitored and maintained by a team of appropriately qualified professionals, machine operators and other skilled construction staff that are specialized in the design, construction and maintenance of fish habitat streams; and
• The stream and associated riparian and in-channel habitats being recreated would result in significant immediate and long-term net gain in fish habitat. Net gains could occur if the majority of the existing channel to be diverted is heavily impacted from alteration and would be recreated to reproduce a natural fully productive condition, or if a significant portion of the existing channel were enclosed and would be opened up or daylighted and then recreated to reproduce a natural fully productive condition; or
• The stream is proposed to be relocated back to or near to its' original path prior to previous diversion; the recreated stream would result in less risk to the stream from maintenance requirements to protect properties, roads, services and utilities. The stream would be recreated to reproduce a natural fully productive condition, and the recreated stream would result in a significant immediate and long term net gain in fish habitat.

For further information regarding an application for a Section 9 Approval your proposed works, please contact Land and Water British Columbia: http://lwbc.bc.ca/

Operational Best Practices

These activities should only be undertaken if the above recommendations can be met, if so then the following operational best practices should be followed to ensure compliance with appropriate legislation.

Monitoring

• Construction activities should be monitored full-time during start-up and any instream works or sensitive activity, otherwise on a daily basis to the completion of the project. The environmental monitor(s) must be an appropriately qualified professional(s) and will be provided with written authority to modify and/or halt any construction activity if deemed necessary for the protection of fish and wildlife populations or their habitats. A sign should be posted listing the monitor’s company name and phone number at the entrance to or immediate vicinity of the job site.
• Forward a copy of this document listing standards and best practices for your works, and all appropriate plans, drawings and documents to the contractor/crew supervisor and keep it readily available at all times at the site while the work is proceeding.
• Hold a pre-construction meeting between the environmental monitor and the contractor undertaking the work on the site to ensure an understanding of the mitigative best practices for the project.
• Within 60 days of completion of this project the environmental monitor will complete and submit a minimum of one (1) copy of a monitoring report consistent with the recommended standard format to his/her client;

For more information see Appendix I: Monitoring.

Timing of Works (Subsection 42(1)(a))

• If works are scheduled for fish-bearing streams or if fish presence in the watercourse in not known, complete in-channel or bank work during the instream reduced risk work window approved for your region. To find out what the timing window requirements are for your area, contact your regional MOE office.
• Be advised that for certain fish and amphibian species at risk, there may be no window of least risk. Please contact your local WLAP office for more information.
• Only clear vegetation for worksite access and stream crossing right-of-way within the vegetation clearing timing window.
• Only undertake works during favourable weather and low water conditions.
• Complete the works as quickly as possible once started

For more information see Appendix II: Timing of Works.

Deleterious Substance Control/Spill Management (Subsections 41(a)(b) & 42(1)(d))

• Prevent the release of silt, sediment or sediment-laden water, raw concrete or concrete leachate, or any other deleterious substances into any ditch, watercourse, ravine or storm sewer system. The recommendations for sediment and erosion control outlined in the Land Development Guidelines for the Protection of Aquatic Habitat (Chilibeck et al, 1992) can also be used for reference.
• Ensure equipment and machinery is in good operating condition (power washed), free of leaks or excess oil and grease. No equipment refueling or servicing should be undertaken within thirty (30.0) metres of any watercourse or surface water drainage
• Ensure all hydraulic machinery to be used instream uses environmentally sensitive hydraulic fluids which are non-toxic to aquatic life, and which are readily or inherently bio-degradable
• Keep a spill containment kit readily accessible on-site in the event of a release of a deleterious substance to the environment. Train on-site staff in its use. Immediately report any spill of a substance toxic to aquatic life of reportable quantities to the Provincial Emergency Program 24 hour phone line at 1-800-663-3456
• Do not use treated wood products in any construction below the high water mark of the stream channel to prevent the release of preservatives toxic to fish.

For more information see Appendix III: Deleterious Substance Control/Spill Management.

Concrete Works (Subsections 41(e) & 42(d))

• As concrete leachate is alkaline and highly toxic to fish and other aquatic life, ensure that all works involving the use of concrete, cement, mortars, and other Portland cement or lime-containing construction materials (concrete) will not deposit, directly or indirectly, sediments, debris, concrete, concrete fines, wash or contact water into or about any watercourse. Concrete materials cast in place must remain inside formed structures.
• A CO₂ tank with regulator, hose and gas diffuser must be readily available during concrete work to neutralize pH levels should a spill occur. Train staff in its use.
• Provide containment facilities for the wash-down water from concrete delivery trucks, concrete pumping equipment, and other tools and equipment.
• Report immediately any spills of sediments, debris, concrete fines, wash or contact water to 1-800-663-3456. Implement emergency mitigation and clean-up measures, like use of CO₂ and removal of the material immediately.
• Completely isolate all concrete work from any water within or entering into any watercourse or stormwater system.
• Monitor the pH frequently in the watercourse immediately downstream of the isolated worksite until completion of the works. Emergency measures will be implemented if downstream pH has changed more than 1.0 pH unit, measured to an accuracy of +/- 0.2 pH units from the background level, or is recorded to be below 6.0 or above 9.0 pH units.
• Prevent any water that contacts uncured or partly cured concrete during activities like exposed aggregate wash-off, wet curing, or equipment washing from directly or indirectly entering any watercourse or stormwater system.
• Isolate and hold any water that contacts uncured or partly cured concrete until the pH is between 6.5 and 8.0 pH units, and the turbidity is less than 25 nephelometric turbidity units (NTU), measured to an accuracy of +/- 2 NTU;

For more information see Appendix IV: Concrete Works.

Isolation of the Work Area (Subsections 42(b) & 44(x))

• Isolate your work area from all flowing water, but do not cut off flow to downstream portions of the stream at any time during construction.
• Temporarily divert, enclose or pump the water around the work site. Ensure the point of discharge to the creek is located immediately downstream of the work site to minimize disturbance to downstream populations and habitats;

For more information see Appendix V: Isolation of the Work Area.

Salvage of Fish and/or Wildilfe (Subsection 42(1)(e)

• Complete a fish and amphibian salvage for works prior to the start of works if any portion of the wetted channel will be isolated and/or dewatered. An appropriately qualified professional(s) must complete the salvage. It is the responsibility of the salvage crew to obtain the necessary permits required by the British Columbia Fisheries Regulations or Canada Fisheries Act prior to conducting the salvage activities;

For more information see Appendix VI: Salvage of Fish and/or Wildlife.

Sediment Control (Subsections 41(a)(b)(c) & 42 (1)(c)(d)(f))

• Ensure material, such as rock, riprap, or other materials placed on the banks or within the active channel or floodplain of the watercourse, is inert and free of silt, overburden, debris or other substances deleterious to aquatic life.
• Ensure machinery works from the bank of the stream and not in the stream channel to minimize impacts and to better enable mitigation of sedimentation.
• Minimize the disturbance to existing vegetation on and adjacent to the stream banks.
• Place sediment control measures before starting any works that may result in sediment mobilization.
• Construct any ditches, water bars or water diversions within the work area so they do not directly discharge sediment-laden surface flows to the stream. Divert such flows to a vegetated area where flows can slowly infiltrate.
• Remove excavated material and debris from the site or place it in a stable area above the high water mark or active floodplain of the stream, as far as possible from the channel.
• Protect this material from erosion and reintroduction to the watercourse by using mitigating measures including, but not limited to covering the material with erosion blankets or seeding/planting with native vegetation.
• When material is moved off-site, dispose of it in such a manner as to prevent its entry into any watercourse, floodplain, ravine, or storm sewer system;

For more information see Appendix VII: Sediment Control.

Vegetation Management (Subsections 41(c) & 42 (f)(g))

• Limit vegetation clearing for access and at your work area.
• Consider other options when contemplating the need to remove vegetation. It is very often not the best choice for fish and wildlife habitat and species.
• Wildlife trees are important for many wildlife, bird, and amphibian species. You should avoid vegetation activities that will impact trees used for nesting or roosting. Section 34(b) of the Wildlife Act prohibits the your interference with bird nests, young, or eggs. This means that a wildlife tree containing an active nest, or a nest of species listed under the Act (i.e., raptors or species at risk), even outside of the breeding season, may not be felled.
• If you are proposing to top or remove trees, have the trees within the riparian area assessed by an appropriately qualified profession who is also a Wildlife Danger Tree Assessor to determine the presence and nature of the hazard.
• Where the danger can be removed by topping or removal of the dead limb this should be undertaken in preference to removal of the entire tree.
• Where the entire tree must be removed then the tree replacement criteria should be applied.
• Also in consideration of the importance of large woody debris to the stream/fish habitat and the importance of large diameter trees to wildlife populations, the stub of the trees should be retained where it is deemed safe to do so.
• Fall or top all trees so that the branches do not enter the stream channel. If any branches do inadvertently end up in the channel they should be removed offsite to where they will not enter the channel during high flows. Removal of limbs from the channel must be completed in a manner that will not disturb aquatic organisms.
• Fall the tree across the stream when falling across the stream cannot be avoided because of safety reasons (faller safety, buildings etc) and all methods of tree removal have been considered but cannot be safely employed. Removal of the felled tree must be completed in a manner that does not damage the banks and the bed of the stream. If possible, leave and anchor the trunk as large woody debris to be left within the riparian zone.
• Fall the tree away from the channel unless there is an immediate threat to life and limb and remove the material within the instream work window.
• Equipment used for vegetation removal should comply with this document’s listed best practices for deleterious substance control.
• Danger trees/limbs prior to the instream window to allow works to be scheduled within the timing window.

For more information see Appendix VIII: Vegetation Management.

Restoration of the Site (Subsections 41(a)(c) & 42(1)(c)(f)(g))

• Grade disturbed areas to a stable angle of repose upon completion of the work. These areas should also be revegetated to prevent surface erosion and subsequent siltation of the watercourse.
• Protect disturbed soil areas on the banks and areas adjacent to the stream from surface erosion by hydroseeding with a heavy mulch, tackifier, seed mix; by installing erosion blankets; and/or by heavily revegetating;
• Plant native trees, shrubs, and herbaceous plants that are appropriate to the site conditions to revegetate and replace impacted riparian vegetation.
• Restore all in-channel or active floodplain habitats that have been disturbed during the completion of works to a condition that is enhanced from their original state. The restoration will be consistent with a no-net-loss of fish and wildlife habitat
• Remove any remaining sediment and erosion control measures (i.e., silt fence). Ensure all equipment, supplies, and non-biodegradable materials have been removed from the site.
• Complete post-construction multiyear monitoring to ensure your revegetation meets full survival.

For more information see Appendix IX: Restoration of the Site.

Beaver and Beaver Dam Management | Other Types of Instream Work

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