Specific Standards and Best Practices:
Stream Channel Maintenance

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Background

In addition to the fish and wildlife values that streams and channels sustain, they are also relied upon as drainage pathways. As such, maintenance activities are periodically required to ensure the ability and capacity of the channel to carry adequate flow is maintained. This section pertains only to works carried out by municipalities and BC Crown or its agents.

Stream channel maintenance refers to any of the following activities:

• Removal of debris, waste or garbage including discarded building materials, household waste, etc;
• Removal of sediment, vegetation, and and/or woody debris;
• Stream channel dredging; and
• Ditch maintenance.

Fish and other aquatic organisms need healthy places to live, feed and reproduce. For most species, these activities usually occur along stream banks and in nearshore areas of lakes. When you are proposing the removal of sediment, debris and/or vegetation from a stream or lake, you should be confident that the works are necessary and will serve a legitimate purpose.

In your notification to the Ministry of Water, Land and Air Protection, you will need to work with an appropriately qualified professional(s) to confirm that:

• The proposed works are necessary to alleviate actual or imminently potential flooding or other hazard that would result in the loss of life or property;
• The works will not result in the immediate or long term degradation of riparian or stream habitats, or fish and wildlife populations; and
• No alternative solutions such as strategically located sediment traps, off-line detention/retention ponds or increasing the watershed drainage density are available.

Objectives

Stream channel maintenance activities can cause temporary or permanent loss or alteration of instream or habitats, and can result in both temporary and permanent losses in riparian or streamside vegetation or channel stability. Extreme care must therefore be taken when conducting stream channel maintenance activities. The Ministry’s objective for the management of stream and channel clean up and maintenance is to prevent harmful impacts to water quality, riparian and aquatic habitats, and fish and wildlife species.

Standards for Stream Channel Maintenance

All stream channel maintenance works for which you are submitting instream works notifications or approvals must be compliant with the General Standards as listed in the Standards and Best Practices section of this document for:

• Compliance with Other Legislation;
• Land Ownership;
• Public safety;
• Completion of work;
• Protection of water quality;
• Protection of Species and Habitat; and
• Protection of other water users.

Specific Standards associated with this type of work (Water Act Regulation Section 44) authorize stream channel maintenance works completed as the following work types and under the following conditions:

Restoration or maintenance of a stream channel by British Columbia or its agents (Subsection 44(1)(g))

Restoration or maintenance of a stream channel by a municipality (Subsection 44(1)(h))

Mechanical or manual cutting of annual vegetation within the stream channel (Subsection 44(1)(i))

Mechanical or manual control of Eurasian watermilfoil and other aquatic vegetation (Subsection 44(1)(m))

Note:

Temporary diversion construction around or through a work site (Subsection 44(1)(x)) for works authorized under Section 44 is permitted providing that the worksite is no larger than the minimum area required, and

1. if pumps, pipes or conduits are used to divert water around or through the worksite,
    
   1. the pumps, pipes or conduits are sized to divert the 1 in 10 year maximum daily flow for the period of construction, and
       
   2. any pump or intake withdrawing water from fish bearing waters is screened in accordance with the Fish Screening Directive of the Department of Fisheries and Oceans (Canada), http://www.dfo-mpo.gc.ca/Library/223669.pdf
       
2. if cofferdams are used to isolate successive parts of the construction at the worksite,
    
   1. the cofferdams are designed by a professional engineer and constructed in accordance with that design, and
       
   2. the natural channel remaining outside of the cofferdams is adequate to pass the 1 in 10 year maximum daily flow during the period of construction, or
       
3. if ditches are used to divert flow around the worksite,
    
   1. the flow of water diverted remains within the stream channel,
       
   2. the ditches are designed and constructed to divert the 1 in 10 year maximum daily flow around or through the worksite and are protected from any anticipated erosion during the period of construction and use of the ditch, and
       
   3. the ditches are completely backfilled and the area returned as closely as possible to the natural state on completion of the works.

Best Practices

The best practices given here should be followed to ensure your proposed works comply with Provincial standards. They are designed to help you protect species and habitats, maintain adequate water flows, and maintain or improve existing channel characteristics through the way you plan and carry out your works.

• Only remove material needed to alleviate flood or debris flow risk. Retain, where possible, existing vegetation (instream & riparian) and other features such as: trees, bushes, shrubs, weeds or tall grasses along any stream bank; mats of floating vegetation from any section of the stream; overhanging vegetation; and natural, large woody debris that does not appear to be causing damage to the bottom. This includes the retention of large boulders.
• Maintain or improve existing channel complexity (i.e., mix of instream structure and overhanging vegetation).
• Do not disturb stream banks that can expose underlying soils, cause silt to enter the stream, and result in loss of fish habitat.
• Adhere to instream work windows: carry out instream clean-up activities during conditions of low flow, and when eggs and alevins are not present in the gravel, and there is the least risk to fish and wildlife populations and habitats.
• In some situations, removal of an object from the stream can cause more damage to fish and wildlife populations and habitats than would have resulted from leaving the object as it was. If the object is large (e.g., car or shopping cart), and is more than one-third buried in the stream substrates, its removal may result in a large amount of sediment being resuspended or discharged, or may result in significant changes to in-channel habitats. In these cases, such garbage, though unsightly, actually enhances habitat by performing a function similar to large woody debris.

To address the need for stream channel maintenance, those planning works (i.e., municipalities) should consider long-term solutions to flooding or debris flow risk(s) that are based on a solid understanding of the form and function of local watersheds and which eliminate or reduce stream and channel maintenance. These may include:

• appropriately constructed and licensed sediment traps in the stream (requires additional Water Act approval);
• the control or reduction of up-stream sources of sediment;
• increasing the overall drainage density in the watershed;
• the construction of off-line detention/retention facilities; and
• planting shade trees and shrubs to shade-out in-stream vegetation.

Operational Best Practices:

All individuals carrying out instream works should be made aware of and trained in the listed best practices. To comply with the Water Act Regulation’s Protection of Habitat (Section 42(1)) and Protection of Water Quality (Section 41) standards, you should follow these best practices:

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 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 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 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.

Stream Crossings | Stream Bank and Lakeshore Stabilization

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