As the Current Flows
Learning the art of reading trout and salmon rivers leads to a lifetime of angling satisfaction.

The mystery and beauty of flowing water is unmatched by a still lake or pond. The way water flows around rocks, plunges over falls, sneaks along a bank, or disappears under a log-jam always intrigues. Rivers are living things, sometimes swollen and discoloured, other times thin and anaemic. Spend enough time around a particular river, you learn to read its moods, like a spouse reads a partner.

Mix in mercurial fish such as steelhead, salmon, or brook and brown trout, and a river takes on yet another layer of mystery. Where are the fish? What makes them hold in a certain spot? A river is an endlessly fascinating, sometimes confounding, and always challenging place for an angler to spend a day. Yet, when you learn to identify parts of a river that consistently hold fish, the mystery becomes easier to solve. This skill is called reading water, and most consistently successful river anglers have it down pat. Learning it is not difficult, but takes on-the-water practice. Starting with the basic chapters will help you reveal the hidden characters.

The Pool
A pool is the most obvious piece ofany river’s fish-holding water. Generally, a pool is below rapids or at the base of a falls. A pool will also form in a river bend or where a beaver dam or other obstruction allows water to accumulate. Pools are generally deeper than other sections of a river. They provide sanctuary from predators and respite from bright light. Migratory trout and salmon rest in pools, before using the deep water to launch themselves over the falls or obstruction.

Pools come in all shapes and sizes, but generally have a head, middle, and tail-out. Fish in pools normally hold tight to bottom where the current is less swift. Depending on water temperature, current speed, and the attitude of the fish, trout and salmon can be found in any portion of a pool.

Fish in tail-outs seem to be the most willing to strike. Fish at the head of a pool can be feeding, as well, but are just as likely to be moving or hiding. This said, I’ve caught some of my largest brookies at the head of pools, often on drifted flies. This position likely allows dominant fish first crack at dislodged insects and minnows in the current.

The middle or belly of a pool usually holds fish at some point, too. Getting down to fish holding deep in the centre of it, though, can be difficult, as surface current can blow away lures and other terminal tackle. Heavy weights or sinking lines help solve the problem, but are unwieldy to use. Heavy spoons and spinners can also get down to fish in some of these holes.

When the water is cold, back eddies in pools hold fish. Current in these eddies flows in reverse. They generally form at the sides of a pool, but occasionally at the head, especially if there’s a falls, and behind obstructions.

Back eddies are difficult to fish, but floats can be used to naturally present baits and flies. Back eddies are always worth a try, particularly when you’re after migrating fish.

Runs
A run is a long, swift section of water that might be between a set of rapids or two pools or at the top of a falls. Runs are generally not as deep as a pool, although they can be. Runs can also be slow or incredibly fast, depending on the height and incline of the river. A good run is not always as obvious as a pool, but can be an extraordinary place to catch fish. Migratory fish use runs to move slowly up a river, stopping from time to time to rest behind a boulder or in a small depression.

Runs are also great places for trout to set up during an insect hatch. The relatively smooth surface of a run allows fish to more easily see emerging insects. Since runs tend to have an almost constant rate of flow, this also allows fish to feed without fighting the changing shapes and water speed of a pool or rapid.

Runs might be associated with undercut banks or log-jams, which provide excellent cover and security for both migratory and resident fish. Brown trout, in particular, tuck beneath undercut banks, coming out only for an especially big daytime meal or to prowl at night.

In some rivers, a long run doubles as a resting pool. A river I fish on Lake Superior has a swift run bookended by wild chutes of white water. Migratory steelhead, coho salmon, and coaster brookies set up in the same way they would as if it was a pool. They hold at the tail-out, in the belly, and at the head. Fish stay tight to bottom and use any boulder, log, or sandbar to break the current. It’s a prime spot to intercept fish.

Riffles
Riffles flow swiftly and are usually shallow, anywhere from a few inches to several feet deep. As often as not, they’re immediately above a pool or run. Riffles are magnets for stream trout at first and last light and at night. Trout enter riffles to grab minnows, insects, and other food. Riffles are also where most salmonids spawn, and stray eggs are also picked off as food items.

Fish can be just aboutanywhere in a riffle, often in incredibly shallow water. Small depressions in a riffle are almost always productive, as both migratory and resident fish will pick off food items as they go by overhead.

Alligator Water
In cold water, slow runs (sometimes called "alligator water") below rapids and other heavy current can often hold a large number of migratory fish. Steelhead, for instance, often run upstream when water temperature approaches 40°F. In such frigid flows, deep, slow runs allow the fish to set up without expending much energy.

In some rivers, alligator water holds steelhead over winter. On warm early spring days, these hold-overs can become active. Alligator water is a great place for float or fly anglers willing to take their time and wait for fish to start hitting.

These are just the basics of reading a river. As is so often the case in fishing, you need to learn the rule book before you throw it out. As you become proficient at reading water and start to explore different rivers, you will discover they’re full of more mysteries and surprises. Each one really is a different story.