The Viscous Flow

Greenalert

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Is there a distinct viscous flow anywhere in the below photo?

Minitube, please feel free to use any photos I have posted in order to demonstrate a viscous flow if indeed any of them do





 
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minitube

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Greenalert

I can see this is going to get complicated, very complicated. Here goes, IMHO a riffle or riffled type water is still all moving in one direction and is very similar to a viscous flow as it is not very turbulent or churning although it is chopped or riffled on the surface and if studied there is some localised movement, such as would cause micro drag on a dry fly or flutter plastic mini tubes about enticingly, however the overall downstream pace of the water or flow is much greater than any minor lateral movements. Therefore it holds fish and fish will rest and lie and take in suitable places along such water. i.e places of suitable depth to hold a fish.

The viscous flow is so steady however it is smooth or smoothed out. Constant steady. Undisturbed, generally free from even minor lateral variations.

James Joyce described a flow of tap water in Ulysses using two words or phrases together with opposite meanings correctly in the same sentence one immediately after the other.

He used the following phrase to describe the flow of tap water he was watching, he called it the never changing ever changing water. That would be a good description of the viscous flow.

The water in your photos all looks good to me, there is nowhere that does not look productive except perhaps the shallowest parts of the riffles.

I'm sure there are parts of the water photographed where there are viscous flows and it is a matter of looking at and focussing on one place and noting the constant never changing smooth flow there, caused due to the local geography of the riverbed mainly or a steady draw away of water such as in a glide. A glide is usually a good example of a viscous flow though such a flow can and does occur away from a glide.
 
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goosander

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When you put on an aqualung and go into a pool say a couple of feet down sometimes there is no current although the surface is moving quite fast.
 

minitube

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It was a well kent ghillie and the owner of another beat who constantly preached me to look at this massive river in sections and look for "taking water"....they referred to it as "waxy" or "dark" water.

I was told about it in the first place myself by some old hands, greased line fishers. They called it the smooth bits. A Fisheries Scientist, Alan Sullivan, explained that they were Viscous and Laminar flows.
 
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Greenalert

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Minitube, thank you for taking the time in submitting such a superb reply

The quote by Joyce is just stunning " the never changing ever changing water."

Thanks again
 

Ursus Nautilus

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Very interesting article !

Puts the words and the technicalities right in things "one knows", but hardly can describe. On beats nearby where I live, I prefer to take a look and even some photos when the river is very low. Makes it much easier to plan the fishing at high and medium river height.

As a boy/youngster I often dived (with a snorkel) in Gaula when the river was low. We were initially looking for lures and other things (25 to 50 lures/spoons in a day was "big money") , being lost at higher water. But watching where and how the fish was lying was often a big surprise. And it changed with the river height, just 1/2 foot sometimes made a big difference.

It's also interesting to spot salmon from bridges, cliffs or other high structures with polariods on. I'm surprised every time I see many fish lying tightly together in a big pool, or on a big,flat rock with heavy stream around while the fish hardly moves a muscle.

A very nice piece of work that article!:)

Ursus
 

Ciarán

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What an cracking read Mr Gillespie...

This is what this forum is about...disseminated knowledge.
 

silverleapers

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Those that can 'read water' hook a lot of fish; those that can't get lots of casting practice.

Agreed! And the surface doesn't always tell whats happening on the bottom (eg fishing laying slightly down stream of a flow breaking turbulent boil and in effect under the boil as it moves down river on an angle as it rises to the surface.....no mention of bumps and hollows on the surface water height for tell-tale structure. Eg bars make dips in surface water height directly over the bar, and the holes in front of shoals can be seen as bumps in the water surface by water being backed up by the bar. What is seen on the surface is counter intuitive at first glance (water rising over a hole and dropping as it passes over a more shallow bar) ...guess that is lesson number 2.;)

Good stuff!

there is a LOT to reading water!
 

Scanny

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Usually I avoid Wednesday Fluid mechanics lectures and instead opt to go fishing :)

Nicely tied in Mr Gillespie, a huge can of worms but nicely explained.
 
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The Viscous Flow???

In 1948 Bernard Venables wrote a book called "Mr.Crabtree Goes Fishing".In that book Mr.Crabtree called it...."Reading The River"
 

crispin

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What a wonderful book it is too, full of those beautiful illustrations!
 
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What a wonderful book it is too, full of those beautiful illustrations!

Crispin,I have a original copy on my bookcase & I'm looking at it as I type.
I bet I pick it up and flick through it every other night.It's timeless,instructional,nostalgic and it reminds me of my younger days when I fished on some of the Yorkshire rivers for Chub & Barbel as well as all the other species of fish.
Fishing books don't get much better.The halcyon days of real fishing.It's just not like that anymore!:(:(
 

Black lab

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I have read this thread a few times now and I can say it has made me look at my local river a lot differently. Being knew to salmon fishing I would realy like to see more threads like this . Thank You
 

miramichi

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This is a very interesting thread, and in fact the entire subject of what makes a good holding/taking spot whether as a lie or for running fish, and in what height of water is fascinating. On the Miramichi most beats are formed of a small number - in many cases one - large pool. We are often stuck right there and have to do our best to find places on that pool that we can catch a fish, regardless of water conditions.
In certain water heights a beat may hold no fish at all, though running fish can be caught in certain places in the pool, often places that later become good lies. As the water drops fish will start to hold. On many occassions the holding locations at different heights are the same and predictable, but this is by no means always true. Fish will hold in one set of lies with the water on the gauge at 1.5 meters, but another time they will run right through these lies and take up others nearby. As fishermen we like to believe that there is an understandable and perhaps predictable reason for these things, but I don't think that is always true.
I have to say that I found the idea of looking at a normally productive beat and declaring without fishing that it couldn't hold any fish in the height of water that day sounds a bit far fetched to me, unless the river was boiling brown from bank to bank.
 

inland

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Miramichi,

Your last point was the same as I was thinking. Sometimes we think we know too much. And to prove our 'self fulfilling prophecy' we don't even cast a line making certain we were right. I would rather fish through those tough conditions, if for nothing more than the possibility to learn something new.

William
 
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