Welcome to the Orvis Fly Fishing Guide podcast with Tom Rosenbauer, bringing you tips, tricks and techniques to help you get the most from your time on the water.

Here's acclaimed fly fishing author and lifelong fly fishing

enthusiasts Tom Rosenbauer.

This is part two of reading the water and the Orvis Fly Fishing Guide the last time we talked a little bit about trout and what they need to feed and how they

feed.

And now I'd like to introduce the topic of hydraulics, it's kind of a scary subject, but it's not really because you just

need a basic understanding of hydraulics.

So to start an understanding of hydraulics, imagine water flowing through a pipe and the pipe is maybe 45 degrees,

angling downhill.

And the water flowing through that pipe, it looks like the flow is linear.

It looks like it's all going at the same speed but actually depending on the

the roughness of the surface of that pipe

There is a there's a boundary of slower water right along the edges of the pipe.

If the pipe is smooth, the boundary is microscopic.

If the surface of the inside surface of the pipe is really rough, then there might be quite a bit bigger

boundary around the edge of the pipe.

And that's what happens in a trout stream.

Trout can't live in a pool or a piece of water with a perfectly smooth bottom because they would

exhaust themselves trying to swim against the current.

What they do is they use a little bit of a protected

piece of water and lie in that and then dart into the faster water or kind of

slide into the faster water,

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