How to Read a River for Fly Fishing

Optimize your time on the river by approaching the water with a keen eye and open mind.

Ask any experienced angler how to successfully "read a river" and they'll tell you it depends largely on the season, region and conditions of the water you are about to fish. But, they'll follow that reservation up with an admission that there are some general guidelines that they follow every time they get to the water and decide where to make their first cast.

I've gathered a lot of tips, guidelines and general advice about the skill of river reading, and they range from meticulously detailed to straight-forward and simple. But within this stream of advice emerged a pretty clear theme — "think like a trout." This river-reading mantra can be pared down to the two most basic needs of a trout.

The River-Reading Basics: Trout Need Food and Shelter to Survive

When forced to simplify the complicated process of reading a river, we can boil it down to two basic needs — food and shelter. As you look at the river, keep these two basic needs in mind.

Trout need food to survive.

Pretty simple, right? The complexity comes in what trout do in order to eat said food. They often conserve energy by finding a place in the water where slow water meets fast water, also known as a seam. They will "sit" in the slow water and take advantage of the food that is being carried by them in the fast water. So, when reading the river, ask yourself, "where does fast water meet slow water?" or "Where are the seams?"

  • Tailouts, or a shallow area at the edge of a deep, calm pool. The water spills into a riffle and makes a great place for trout to eat hatching insects as they float by.

  • Behind diversions like rocks and logs.

  • Edge of riffles, or rocky, shallow areas of the river

  • Inside river bends and indentations in the river bank.

  • Drop offs in the river bed, where depth changes quickly.

How to Read a River

Trout need shelter, rest and security.

When reading the river, ask yourself "where would a trout feel the most secure?"

  • Look for structures that could provide trout shelter, like trees, logs, boulders, submerged roots and undercut banks.

  • Keep conditions in mind when assessing the water; the risk of predation is higher in sunny conditions (better visibility for predators), so trout may stay in a deep pool, where they feel safer.

  • Approach the water quietly and carefully. Sound travels over four times faster in water than in air, and quick movements and sounds can scare fish off. Fishing is just like hunting in that you need to keep your presence unknown in order to be successful.

While the rules of reading the river can be complicated and variable, you'll get a long way by simply asking one question: "where are the trout's most basic needs being met?" If you ask yourself that question and adjust your location accordingly, you will surely find your next trout honey hole. Happy fishing!
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