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Stream channel morphology is influenced by gradient (topography), basin catchment area, surficial and bedrock geology, channel substrate, amount of precipitation (average and extremes) and human and animal activity (beaver and man-made dams or other impoundments). The distance that suspended and bedload sediment is transported along a watercourse is a function of particle size, water velocity and channel configuration. The smaller the particle size and steeper the gradient, the further it travels. Two classes of particles can affect fish habitat adversely: Silt and clay (diameter 62 microns) are readily suspended and travel farther than sand and coarser particles (diameter 62 microns), which are more likely to settle within a short distance of the crossing. Typically, it is the deposition of particles from the water column and the movement of bedload that can compromise aquatic habitat suitability for resident fish.
Elevated total suspended solids (TSS) and accelerated bedload movement can affect water quality, as well as alter channel morphology and streambed composition (Anderson et al. 1996). With traditionally trenched crossings, altered channel cross-sectional characteristics can arise following excavation and backfilling. In addition, particles carried by water are abrasive and their movement can physically erode channels (Anderson et al. 1996). If TSS levels remain elevated for a prolonged duration (days or weeks) during certain periods of the year, primary productivity of a watercourse can be inhibited downstream of the crossing.
Depending on the amount and type of substrate affected, and the duration of the effect, bedload movement can reduce substrate porosity, pool depth and riffle area. All three aspects can have negative consequences for fauna living downstream of the crossing. Reduced depth compromises a pool’s ability to overwinter fish and can render it less suitable as a rearing and foraging habitat for
Interruption or disruption of surface flows during open trenched watercourse crossings can produce areas immediately downstream that are dewatered and/or shallower than before the onset of the crossing. Habitat loss and/or mortality of fish and benthic invertebrates can occur due to stranding or reduced flow volumes. If suitable mitigation measures are not implemented, the timing, degree and duration of the disruption in streamflow dictates the consequences to aquatic resources downstream.
1.2.1 Effects on Fish Populations
In general, fish populations that inhabit coldwater watercourses are more sensitive to changes in TSS than those resident in cool or warm water habitats (Scott and Crossman 1973). Generally, fish populations that inhabit larger, slower flowing watercourses at lower elevations have evolved to tolerate higher suspended sediment concentrations. Since larger watercourses typically remain turbid for longer periods of time, resident fish such as burbot, walleye, sauger, goldeye and sucker have adapted accordingly (Anderson et al. 1996).
Elevated TSS can affect fish individually through altered behaviour and/or physiology or, more generally, at the population level. Behavioural and physiological responses in fish are linked. In general, fish exposed to elevated levels of suspended sediment for extended periods experience biological (population) and physical (individual) stress. The degree of response is species and life-history stage specific (i.e., egg, fry, juvenile, adult), and dictated by the magnitude and duration of exposure to the sediment plume.
Behavioural responses experienced by fish exposed to elevated TSS include suspension of territorial behaviour, depressed feeding rate and stimulated cough reflex. On experiencing discomfort, fish will move out of a sediment plume to ease the physical discomfort associated with gill abrasion if possible. Reduced feeding rate occurs in response to decreased instream visibility associated with elevated turbidity, TSS and stress in addition to reduced food supply. Increases in territoriality associated with movement out of the channel elevates biological stress both at the individual and population level as fish compete for less turbid territories, or establish new ones elsewhere within the system.
Physiological effects in fish exposed to elevated TSS are associated with stress, which can weaken an organism’s immune system. Over extended periods, depressed feeding rates can be manifested in lower growth rate. Damaged gill filaments impair respiration, lead to elevated stress, changes in blood chemistry,
Elevated sediment concentrations can affect fish further downstream of the crossing location at the population level through increased egg mortality, decreased hatching success and loss of suitable spawning substrate. Like eggs, fish larvae have limited mobility and cannot avoid sedimentation of substrate or elevated TSS. Failed recruitment from eggs to larvae to juveniles ultimately affects annual production of a population within a watercourse. Similarly, loss of suitable spawning habitat as a consequence of sedimentation can adversely affect fish populations that rely on clean substrate for spawning and juvenile rearing.
1.2.2 Additional Consequences of Watercourse Crossings
Loss of riparian vegetation associated with clearing and/or grading of the banks to access a watercourse crossing can affect all life-history stages of fish. Clearing of riparian areas can locally raise water temperature within adjacent nearshore shallow areas reducing their attractiveness as incubation, rearing, foraging and escape habitat for selected species. Loss of instream and overhead cover as a result of right-of-way construction can reduce the habitat quality for resident fish populations. Cleared rights-of-way can become persistent sources of sediment to a watercourse if they are not suitably reclaimed. Introduction of sediment and increased water temperature can compromise water quality and the integrity of downstream aquatic habitat.
Crossings can create movement barriers that reduce fish distribution and abundance. It is common for contractors to place excessive amounts of riprap over a pipeline, which can obstruct fish movement during periods of low flow.
Furthermore, clearing and grading of rights-of-way at watercourse crossings can increase fish mortality indirectly, since improved access for anglers can expose previously remote sections of a watercourse to harvest.
The use of explosives can result in harm to fish habitat and/or mortality or injury of resident fish and invertebrates through damage to internal organs and crushing, as a consequence of the pressure wave associated with blasting. Mortality is influenced by factors such as water depth (i.e., in shallow water much of the blast energy is released above the water), as well as the type and amount of explosive detonated, but tends to be limited to the immediate vicinity of the crossing. In addition, an accidental release of hazardous materials (e.g., hydraulic fluid) from equipment or a fuel spill into a watercourse or within the riparian right-of-way, can lead to stress or fish kills at and downstream of the crossing.
Disruption of instream groundwater upwelling through sedimentation or disturbance to groundwater flows can adversely affect spawning habitat for salmonids and overwintering habitat.
1.2.3 Natural Watercourse Dynamics Natural storm and flood events can destabilize streambanks, create landslides within riparian zones and alter flow regimes within watercourses. It is the intensity and frequency of these events that ultimately influence channel morphology and the abundance, distribution and composition of resident fish and fish habitat. Natural flushing and stabilization of the system after an event permits recolonization and settlement of fish and benthic invertebrate populations within affected reaches. Watercourses are inherently dynamic and their fish populations have adapted to cope with natural catastrophic events. Landslides and floods both can contribute large quantities of sediment, however, both typically occur when flows are high and dilution of sediment levels facilitates their tolerance by fish populations and transport downstream.
The cumulative effects of human activities within watercourses and riparian areas can magnify the outcome of a storm or flood event and prolonged, unnatural events can stress fish populations. Consequently, when designing pipeline crossings of watercourses, it is important to acknowledge the degree of existing development in the area in conjunction with fish presence, distribution and habitat suitability for spawning, incubating, rearing, foraging, resting and overwintering at and immediately downstream of a proposed crossing.
1.3 Objectives for Watercourse Crossings
The overall goals and objectives of regulatory agencies for pipeline associated watercourse crossings are similar across Canada. However, there may be substantial variation in the construction techniques allowed as well as environmental protection and mitigation measures that are required for project approval among the various jurisdictions. The main guiding principle for all agencies across Canada, however, parallels the DFO guiding principle of "no net loss" of productive capacity of fish habitat.
The regulatory requirements for the construction, operation and abandonment of pipeline associated watercourse crossings in Canada vary according to the jurisdiction in which a project is being built. Each watercourse crossing may be subject to federal, provincial and territorial review. Many jurisdictional agencies have Codes of Practice, guidelines and policies regarding watercourse crossings, and require application for permits, authorizations and licenses.
Sections 2.1 and 2.2 describe the federal, provincial and territorial regulatory framework. Information requirements for each of these agencies are briefly discussed. This document has been written to reflect the regulatory information requirements at the time of publication. It does not address draft or proposed acts, Codes of Practice, guidelines or policies.
Table 2.1 provides a quick summary checklist of the regulatory framework and the appropriate contacts.
Since the regulatory requirements are complex and continually changing across the country, the responsibility to ensure that all requirements are met falls on the proponent. Project planners should confirm with the appropriate agencies that the necessary permit applications are made and the regulatory requirements have been identified. Proponents should consult with regulatory authorities early in the planning process to ensure they understand the regulatory requirements.
2.1 Federal Jurisdictions
2.1.1 Fisheries Act The Fisheries Act was enacted to protect fish, fish habitat and water frequented by fish and to provide for sustainable fisheries in Canada. Responsibility for the Fisheries Act rests with the Minister of Fisheries and Oceans (MFO). Fisheries and Oceans Canada (DFO) administers the habitat protection provisions (Section 35) of the Fisheries Act, while Environment Canada, under a 1985 Memorandum of Understanding with DFO, administers those provisions of the Fisheries Act dealing with the control of pollution (Section 36).
In cases where it is not possible to protect fish habitat by mitigation or project design, a Subsection 35(2) Authorization may be issued. In accordance with DFO’s policy, an Authorization will stipulate the conditions necessary to achieve "no net loss" of productive capacity of fish habitat (i.e., compensation measures).
Authorizations may not be issued in all cases.
The Navigable Waters Protection Act (NWPA) provides a legislative mechanism for the protection of the public right of marine navigation on all navigable waterways in Canada. This is accomplished through permitting of the construction of works built or placed in, over, through or across navigable waterways and through a legal framework to deal with obstacles and obstructions to navigation. The NWPA is administered by the Navigable Waters Protection Program (NWPP) of Transport Canada (TC).