Coquitlam Dam Seismic Upgrade Project ... - BC Hydro

2.2. AQUATIC RESOURCES
The Coquitlam River historically supported healthy populations of coho, chinook, sockeye, pink,
and chum salmon, steelhead trout and cutthroat trout, and Dolly Varden char (Decker 1996).
Sockeye were eradicated from the watershed in 1911 when the height of the dam was raised and
access to lake and upper river habitats was lost (Koop 1999). During the 1950’s and 1960’s,
gravel removal from the riverbed for the purposes of flood control and commercial development
resulted in severe loss of salmonid habitat through sedimentation, channelization, loss of suitable
spawning habitat and removal of woody debris. From the late 1960s to present, gravel mining
has been limited to areas outside the riverbed, however, sedimentation resulting from these
operations continues to be a problem (Riley et al., 1997).
Presently, coho, chum, steelhead and cutthroat are the most abundant salmonids. Longnose dace
are also abundant (Decker 1998). Table 2 lists the fish species present within the Coquitlam
River. Since the 1970s, a number of enhancement activities have been undertaken in an attempt
to improve salmonid populations and to re-establish chinook and pink salmon stocks. In
September 1997, adult pink salmon and chinook salmon were observed for the first time since
the 1950s (Foy pers. comm.).
Table 2. Fish species present in the Coquitlam River and tributaries.
Salmon and Trout Species Other Species
pink salmon longnose dace
chinook salmon Dolly Varden Char
chum salmon prickly Sculpin
coho salmon 3-spine stickleback
cutthroat tout largescale sucker
steelhead trout Pacific lamprey
rainbow trout
Grant’s Tomb is a 5,000 m 2 salmon enhancement area consisting of an inlet-spawning channel,
a rearing pond fed by a GVWD water supply line, and an outlet spawning channel. This habitat
enhancement project was completed in 1995 and was jointly funded by BC Hydro and Fisheries
and Oceans Canada. This enhancement project has proven to be very productive since its
construction.
Studies completed between 1996 and 2002 estimated the influence of off-channel habitat and
other enhancement on the abundance and distribution of salmonids in the Coquitlam River.
These studies have suggested that off-channel enhancement areas, particularly Grant’s Tomb,
have increased coho production in the upper reaches of the Coquitlam River (Decker, 1998).
During 1996-2000, mean annual estimates of coho density ranged from 22.0 to 58.5 smolts per
100 m 2 in off-channel sites compared to 1.4 to 5.2 smolts per 100 m 2 in the mainstem (Decker,
2000). Trout densities were also high with steelhead being the most common of the trout species
Coquitlam Dam Seismic Rehabilitation Page 9
Environmental Management Plan – Version 4
June 15, 2004