How do I read water and find where trout are holding?

What is a trout actually looking for in a river?

Three things, simultaneously, and the third is the one anglers forget.

1. Food delivery. Current is a conveyor belt. A trout wants to sit where the belt passes close.
2. Shelter from the current. Holding in fast water burns more calories than the food is worth. A trout wants slow water immediately adjacent to fast water, not slow water somewhere else.
3. Cover from above. Ospreys, herons and otters hunt from above. Depth, broken surface, overhanging bank, a log, or shade all count.

Every productive lie on a river is a place where those three overlap. This is why a boulder in fast water holds a fish and an identical boulder in a dead backwater does not: the second one has shelter and cover but no food arriving.

Once you are looking for the overlap rather than for "good-looking water", the river gets much smaller and much easier to fish.

Where do trout hold? The eight lies worth casting to

If you fish nothing but seams and pool tails for a season, you will out-fish someone casting randomly into pretty-looking pools. The list above is roughly in order of reliability.

How do I fish a riffle?

A riffle is shallow, fast, cobbled water with a broken but not whitewater surface. It is the insect factory of a trout stream and, in summer, often the most densely populated water on the river. Anglers walk past them because they look too shallow to hold anything.

1. Start at the bottom and work up

   Fish rest facing upstream. Enter at the downstream end of the riffle and move up, so you are always approaching from behind the fish.

2. Fish the near water first

   Cover the water within 15 feet before you wade into it. The single most common error in riffle fishing is walking through catchable fish to reach a cast you cannot control.

3. Keep the drift short

   A 10 to 20 foot drift with the rod tip high and most of the line off the water beats a 40-foot cast with line lying across three current speeds. Short and clean, then take one step.

4. Get the fly down fast

   In two to three feet of moving water you have a couple of seconds before the drift is over. A tungsten bead or a split shot 12 to 18 inches above the fly buys you that depth immediately.

5. Grid it out

   Fan casts across the width in a systematic pattern, then step up three feet and repeat. Riffles hold fish spread across the whole width, not in one obvious spot.

In broken riffle water a trout has a fraction of a second to decide, which is why an impressionistic pattern like an Elk Hair Caddis works so well there and why exact imitation matters far less than it does in a flat pool.

How do I fish a seam?

Find the line where fast water meets slow. It will be visible as an edge in the surface texture, and often as a line of foam and bubbles tracking downstream. Trout sit just inside the slow side and move a few inches into the fast side to intercept food.

The cast goes into the fast water above the seam, so the fly drifts down the boundary. The problem is that your line lands across two current speeds, and the fast one drags the line downstream ahead of the fly. That drag is what makes seam fishing look easy and fish badly.

1. Position downstream and to the side

   Stand in the slow water, below the target, casting up and across into the faster lane.

2. Cast with slack

   Aim slightly high and stop the rod so the leader lands with a few gentle curves in it. That slack is your drift budget.

3. Mend immediately

   As soon as the line lands, flip the belly of the line upstream with a lift-and-roll of the rod tip. Do it before drag starts, not after.

4. Track with the rod tip

   Follow the fly downstream with the rod tip, lifting line off the fast water as it goes.

5. Let it swing out

   At the end of the drift, let the fly rise and swing. Takes on the swing are common and hard, and a soft hand keeps you from breaking off.

Where do the big fish hold?

Not usually where the numbers are. Large trout trade feeding efficiency for security, so they take the lies that combine heavy cover with a good food lane and then defend them.

• Undercut banks on the outside of a bend, where the current has dug depth right against overhead cover.
• Under and behind woody debris — log jams, root wads, a fallen tree. Difficult to fish, which is exactly why fish are there.
• The deepest slot of a pool head, in the fastest oxygenated water, especially in warm weather.
• Bridge and culvert shade, which offers permanent overhead cover in otherwise featureless water.

These lies punish sloppy approach. Fish them from further away than feels necessary, cast fewer and better casts, and expect to lose flies — if you are not occasionally hanging up in the timber, you are not fishing close enough to it. A weighted Pat's Rubber Legs bumped along the bottom against a log jam is a classic way to find out what actually lives in a river.

How does the season change where fish hold?

What is the one habit that improves this fastest?

Stop and watch before you cast. Two minutes, from a position where you are not silhouetted against the sky, looking at one section of river. You are collecting three pieces of information: where the current lanes actually run, whether anything is rising, and where you would sit if you were a fish.

The second habit: fish where you are standing before you stand there. Wading anglers push a pressure wave ahead of themselves that alerts every fish within twenty feet. The water you just walked through was the water you came to fish.

And when a piece of water looks perfect and produces nothing after a dozen good drifts, change depth before you change fly. Nine times out of ten the fly was fine and it was passing three feet above the fish. A Woolly Bugger that never reaches the bottom of the pool is not being refused — it is not being seen.