High temps - Low flows

[toolman]

River closures during High temps and low flows, right? Maybe not. Read on....

https://idfg.idaho.gov/blog/2022/06/some-perspective-trout-fishing-during-low-water-and-high-temperatures

[SilverDoctor]

Interesting study, thanks for posting.

[pokerfish]

very interesting, and gives some food for thought.   kinda contrary to conventional wisdom.  always good to test the assumptions.

 

[SilverDoctor]

Mind you from personal experience I have caught numerous trout more than once based on teh same marking which tend to be individual.

[FishnChips]

Toolman, thank you.

As I watched alpine snow melt delay further and further and start at least one month later than normal in the Bow Watershed, I observed the Upper Bow was much lower and greener in colour than normal. Its colour reminded me of the Cowichan River of my youth. Curious about the temperature I measured it at a surprising 11C in late May when it is normally 4C during run-off. Outside air temperatures in the Upper Bow Valley were slightly below average all spring so the water was not being warmed by the air as much. I have a personal theory (don't shoot me, I have no scientific training), that since the water was more clear and much more shallow than normal, that the river bottom was absorbing higher than normal amounts of incoming solar radiation  and thus the water is warmer. Thoughts fellow fisher folk?

[lad]

On 6/20/2022 at 11:51 AM, FishnChips said:

Toolman, thank you.

As I watched alpine snow melt delay further and further and start at least one month later than normal in the Bow Watershed, I observed the Upper Bow was much lower and greener in colour than normal. Its colour reminded me of the Cowichan River of my youth. Curious about the temperature I measured it at a surprising 11C in late May when it is normally 4C during run-off. Outside air temperatures in the Upper Bow Valley were slightly below average all spring so the water was not being warmed by the air as much. I have a personaly theory (don't shoot me, I have no scientific training), that since the water was more clear and much more shallow than normal, that the river bottom was absorbing higher than normal amounts of incoming solar radiation  and is thus the water is warmer. Thoughts fellow fisher folk?

Your theory sounds great. I have thought that the surface air temperature is 90 % radiated from the ground surface and 10% of the heat is directly from the sun. That is why temps cool when you increase altitude on a plane. Also why Newfoundland surface temp could be -30 but it could still be -5,  2 miles affshore. 

[FishnChips]

Thank you.

Yes ground (any land mass not covered by ice or snow which has high albedo or reflective properties) heats and cools much more rapidly than water (ocean or lake).