Fraser River environmental watch report July 30, 2018

Fraser River Environmental Watch Report [PDF]

Ten-day daily forecasts of lower Fraser River temperature and flow conditions as well as current conditions throughout the Fraser basin are updated bi-weekly from roughly late-June until mid-August. These short-range forecasts are generated using river temperature and river flow forecast models (Hague and Patterson 2014).

The latest research on Pacific salmon fresh water migration suggests there are population-specific differences in temperature and flow tolerance thresholds (Eliason et al. 2011). These differences likely relate back to the variability in the average river environmental conditions experienced by salmon beginning their river migration at different times of the year and along different paths (Farrell et al. 2008). Despite these differences, there are also species-wide thresholds that will result in migration difficulties for most populations of Fraser River sockeye salmon. We provide species-level thresholds as a guide to interpreting the potential effect of current and forecasted river temperature and flow conditions on returning salmon. However, in general, fish historically returning to the Fraser River in the mid-summer will be more tolerant of higher temperatures than those fish returning in the early or late summer or early fall.

Current Temperatures
July 29, 2018 Daily Mean Historic Mean
Chilcotin River at Big Creek 16.5 15.5
Fraser River at Hope 18.8 17.4
Fraser River at Marguerite 20.3 N/A
Fraser River at Shelley 17.1 15.1
Fraser River at Texas Creek 18.7 18.2
Nautley River at Fort Fraser N/A 19.0
Nechako River at Isle Pierre 20.3 19.1
Nechako River at Vanderhoof 19.2 17.2
North Thompson River at McLure 18.2 14.4
Quesnel River at Quesnel 17.2 15.7
South Thompson River at Chase 18.9 19.1
Stellako River at Glenannan 19.8 17.7
Stuart River at Fort St. James 19.2 18.6
Thompson River at Ashcroft 18.8 17.5
Thompson River at Spences Bridge 19.7 18.3

Fraser River discharge at Hope

Critical Levels for Fish Passage through Fraser Canyon:

Mean Daily Discharge (m3/s)

Fraser River water temperatures at Hope

Mean Daily Water Temparature oC