The Uncertain Future of Fraser River Sockeye - Publications du ...

Cohen Commission of Inquiry into the Decline of Sockeye Salmon in the Fraser River • Volume 2
Dr. Tschaplinski said that provincial field assessments
had not yet shown increased clear-cutting in
riparian areas. 49 However, Mr. Miller stated that, under
the salvage operation under way, it is reasonable
to expect larger clear-cuts in the future. 50 A University
of British Columbia study examined the impacts of
the mountain pine beetle on channel morphology
and woody debris in riparian areas. 51 It found that,
in the riparian areas surveyed, there were relatively
small volumes of pine. The study concluded that
woody debris transferred to the streams in the next
25 years is likely to be relatively small and within the
range of typical conditions. 52
Given the unknowns about the future impact of
the mountain pine beetle on fish–forestry interactions,
Dr. Tschaplinski recommended researching
large-scale clear-cutting impacts on fishery values. 53
Surface water withdrawals and
groundwater extraction
Dr. Michael Bradford is a research scientist with
DFO and Simon Fraser University, and during the
hearings he was qualified as an expert in aquatic
habitat ecology. 54 He testified that the impact of
removing water from a stream, for any purpose, is
to reduce the magnitude of flow. 55 Low stream flows
have the potential to affect salmon in various ways,
for example, by limiting access to spawning and
rearing habitat, interrupting the passage of adults to
spawning grounds, and contributing to the problem
of high water temperatures during the summer
migration period. 56 In some parts of the BC interior,
extensive water withdrawals occur in the summer
for irrigation, at a time when streams have naturally
lower flows and maximum temperatures. 57
However, impacts from water withdrawals may
be less of a concern for sockeye as compared with
other species of salmon because major sockeye-producing
areas such as the Adams River are generally
located downstream of large lakes, which provide
a buffering influence on stream flows. 56 Water
withdrawals may have some effect on sockeye in the
Shuswap Basin, although Dr. Bradford did not think
it is as big a problem for sockeye as for coho. 59
According to Jason Hwang, area manager, BC
Interior office, Oceans, Habitat and Enhancement
Branch (OHEB), his staff have generally not
observed any impact to sockeye related to water
withdrawals. 60 However, he said that water
withdrawals could become a concern in the future
as demand for water increases. 61 Dr. Bradford
agreed that population growth, particularly in the
drier Okanagan and Cariboo areas, could have
impacts on sockeye in the future. 62
Dr. Steve MacDonald, a research scientist with
both DFO and Simon Fraser University, testified as
an expert in aquatic habitat ecology. He described
how groundwater has a number of functions that
may contribute to the survival of salmon, which
may be affected by extraction. Groundwater delivers
ions and nutrients to streams and generally has
a moderating influence on stream temperatures.
In winter, particularly in the northern parts of the
Fraser River watershed, it prevents streams from
freezing and anchor ice from forming. In summer,
groundwater provides a cooling influence on the
spawning grounds, which is important in areas
such as the Nechako watershed. Groundwater may
also have a cooling influence on streams, which
are used by adult sockeye as “thermal refugia” en
route to the spawning grounds. 63
Dr. Bradford indicated that groundwater
extraction is potentially a concern for Cultus Lake
sockeye. 64 Dr. Craig Orr, executive director of the
Watershed Watch Salmon Society and qualified at
the hearings as an expert in behavioural ecology
with a specialty in salmon habitat ecology, said
that, to maintain the Early Stuart sockeye stocks,
something has to be done to protect groundwater.
65 He also said that groundwater is the “key to
resilience of the salmon habitat.” 66
Independent power projects
DFO has identified a number of potential impacts of
independent power projects (IPPs) on fish and fish
habitat, including the following:
• Construction and installation of powerhouses,
intakes, and other hydro infrastructure may
cause a harmful alteration, disruption, or
destruction of fish habitat (a HADD, which is
prohibited by section 35 of the Fisheries Act).
• Operating requirements of a facility may alter
natural flow regimes and cause a flow-related
HADD (where instream flows are insufficient
for the protection of fish and fish habitat).
• Entrainment in pen stocks and turbines may
lead to mortality of fish. 67
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