GMSMON-17 WILLISTON RESERVOIR TRIBUTARY - BC Hydro

3.2.1 Spawner surveys
3.2.1.1 First site visit (9 to 18 May, 2011)
May 22, 2012
Report No. 1114920016-R-Rev0-2000 15
GMSMON-17 WILLISTON RESERVOIR TRIBUTARY HABITAT
REVIEW
The timing of this field session corresponded closely with the timing of the lowest elevation of the reservoir
(Figure 3); therefore, impediments to fish movement into the tributaries should have been evident; however,
none were noted at any of the trial tributary locations. Six Mile and Lamonti creeks did display some braiding of
the channel across the drawdown zone (particularly at Six Mile Creek); however, there was no apparent barrier
to upstream fish passage. Factor Ross Creek did not have large woody debris (LWD) blockage at its mouth,
contrary to what was expected, though some LWD was present in the vicinity which may have contributed to
blockages in the past. Ole Creek did have a large accumulation of LWD at the mouth but fish passage through
the accumulation seemed likely (see Photographs 14, 16, and 18 in Appendix B). Although water levels in the
streams appeared to be relatively low during the survey period (with the exception of Factor Ross and Ole
creeks during the end of the survey when water levels were on the rise), each creek appeared to provide
adequate depths and velocities for passage of fish species such as Arctic Grayling, Rainbow Trout, and suckers.
Rainy weather on the large snow pack may have resulted in higher than average water levels in the creeks
during early spring 2011 but there were no signs of recent high flow events that would have flushed out debris at
the creek mouths. Freshet conditions were not experienced during the survey, although creek flows were
increasing by 17 May, when crews were departing the site.
Fish were not observed or captured in any of the four streams during May. Potential spawning habitat was
mapped with a GPS. Water temperatures ranged between 0 and 3.5°C (see Table 1, Appendix D).
3.2.1.2 Second site visit (7 to 8 June, 2011)
Fish were not observed in either of the 2 visited streams (Six Mile and Lamonti). Potential spawning habitat that
was mapped with a GPS during the first survey was visited and a kick net was deployed to sample for fish eggs.
Six kick net samples were collected in Lamonti where suitable spawning gravels were noted, and 2 were
conducted in Six Mile Creek as high water and velocity precluded safe execution of additional sampling in this
stream. Eggs were not found. Water temperatures were between 3 and 5°C, below the optimum range for
Rainbow Trout but within the optimum range for Arctic Grayling (although late in the spring) (McPhail 2009).
There did not appear to be any impediments to fish passage up Six Mile and Lamonti creeks. Water levels in the
streams appeared to be relatively high during the survey period. Each creek appeared to provide adequate
depths and velocities for passage of fish species such as Arctic Grayling, Rainbow Trout, and suckers. Rainy
weather on the large snow pack may have resulted in higher than average water levels in the creeks during late
spring 2011. Near freshet conditions were experienced during the survey but water temperatures were still quite
low.
3.2.2 Juvenile and Small-Bodied Fish Surveys (8 to 18 August, 2011)
Water temperatures in the creeks ranged from 6 to 12°C at the time of sampling (Table 1, Appendix D). Flows
were categorized as medium for all creeks. Catch rates of fish by electrofishing in all four study creeks were
generally characterized by low species diversity and small numbers of fish (Tables 2 and 3, Appendix D).
Rainbow Trout were caught and observed in Six Mile and Lamonti creeks but not in Ole or Factor Ross creeks.
Arctic Grayling were not caught or observed in any of the creeks. Other fish species caught were Mountain