Wahleach Project Water Use Plan Wahleach Reservoir ... - BC Hydro

4.6 Spawner Surveys
The number of kokanee spawners has increased over the study period, where
cumulative numbers range from approximately 1,800 in 2004 to over 8,000 in 2006
(Fig. 16). Escapement is approaching values found in 2001, when over 9,000
spawners were recorded. Given that Jones Creek was not enumerated in 2005, the
actual number of spawners were likely higher than 3,900 but given the high
interannual variability it is difficult to estimate the number of spawners in Jones
Creek. For instance, Boulder Creek accounted for 53% of total spawners in 2006
but only 11% in 2004.
Kokanee spawners
10000
8000
6000
4000
2000
0
1973
1979
1994
1995
1996
1997
1998
1999
2000
250
* * * * *
2001
2002
267
2003
237
* * *
Figure 16. Total number of kokanee spawners in Wahleach Reservoir, 1973-2006.
The numbers above the bars are mean fork lengths (mm) of spawners and the star
(*) indicates years of kokanee stocking.
During 2006, minimal large woody debris was observed in Boulder Creek and crown
closure was limited at 5%. In the lower reaches of Boulder Creek the substrate was
a mixture of gravel and fine sediments that may provide some spawning habitat for
kokanee salmon. In Flat Creek, coarse woody debris was present throughout the
channel. The creek has large sections of fine sediments and few spawning gravels
generally located in tail-out pools within 1 km from Flat Creek’s confluence with
Wahleach Reservoir. Throughout the 1 km study site, there is medium crown
closure providing both shady and open sections. In Wahleach/Jones Creek, course
woody debris was present throughout the creek. The confluence with the reservoir
Wahleach Reservoir Fertilization Project, 2004-2006.
2004
255
2005
242
2006
29