J. Hillaby , H. Englund and E. Gruhs
Background
They don’t call it “Sucker” Creek for nothing: suckers are tolerant of warm water and low oxygen conditions, and often extend into areas not habitable by salmonids. Most of our Sucker Creek seems to be characterised by low flow, warm water, beaver dams and wetlands. Salmonids (cool water fish) may only inhabit the lower reaches. Usually, the time/space inflection point that separates fish populations frequently shifts.
In Sucker Creek we have at times seen long areas of completely dry stream channels. We also know that recent stream channel restoration has allowed juvenile coho salmon (and probably other species) to expand their habitat upstream by removing a culvert-related barrier at the Black Creek Road. If we know more about what is causing these dry stretches that slow or sublimate stream flow, isolate fish populations or contribute to stagnant warm areas, we can better assess the health of the watershed and what can be done about it. Is Sucker Creek in a stable, permanent condition or not?
Take home messages
It pays to look around the watershed. This culvert has obviously failed and contributed quite a bit of road material into the stream channel below. Surface water flow has carved a channel through the rubble.
The issue here is that while the culvert owner can restore the road and stream crossing, the bedload will remain in the stream and contribute to channel instability. Restoring a stream channel that is stable enough to support fish habitat is difficult and expensive – it also becomes a public cost. The road tenure owner is responsible for preventing these situations from developing.
In our two sample stations, we recorded water quality characteristics that reflect a generally healthy stream.
|
Attribute |
Stream mouth: Horsefly confluence (Oct 10th) |
Lower site (50m above Black Ck Rd) |
Upper site (at ~3km up Barker Ck Rd) |
Comments |
|
Water temperature |
Did not measure |
5.8 – 6.7 oC |
5.8 – 6.2 oC |
Healthy. Supports salmonids |
|
Dissolved oxygen |
Did not measure |
8.0 mg/, 82% saturated |
9.1 mg/l, 92% saturated |
Healthy. Supports salmonids |
|
pH/ORP (oxidation-reduction potential) |
Did not measure |
7.65/-27 |
7.68/-27 |
Optimum for most fish, but little pollution tolerance |
|
Conductivity |
Did not measure |
199 μs/sec or 100 mg/l |
95 μs/sec or 47 ppm |
Dissolved minerals, often vegetation |
|
Turbidity |
Did not measure |
Some, 30 JTUs |
None. Tea coloured, clear. |
Healthy |
|
Channel observations |
Elevated piles of cobble substrate. |
Disturbance: boulder patches within fine material. |
Bedload movement, deep plunge pool and elevated berms below culvert. |
Conditions vary, complex watershed. |
What’s next?
Please be cautious about reacting strongly to these images and data – this is only a piece of the puzzle. We will start with better mapping – the road network has changed re: expanded logging in the headwaters of both Sucker Creek and its neighbour, Gibbons Creek. This may involve a re-think of our sample site selection, timing and what we are testing for.
Next outing in 2 weeks time: Harper’s Lake streams, for water quality and channel comparisons. November 7th, be outside SAWS at 11 am.