River Primer

Originally this article was titled “Why am I not catching fish?” After completion and reflection the title was changed as many anglers who do very well on lakes do not do so well on rivers. This is a beginner guide meant to help understand where the fish are and what they need. If you don’t already know this – it could be why you’re not catching fish…

Understand the water you’re fishing
Experienced fly fishers “read the water” they are about to fish by looking for water where rainbow trout will be. On big water like the Columbia River we have lots of different types of current. A sandy, flat bottom usually means the flow of water will be fairly uniform and even flowing. As the river widens it becomes slower and shallower, and as it narrows it gets fast and deep. Throw in some boulders or other obstacles to flow and you create turbulence. Mix narrow fast water with big boulders and you get rapids. Going from roughest to smoothest water you have rapids, riffles, runs, pools and flats.

Rapids: Fishing in fast water is generally not productive. As we will explain later, in rapids you want to look for calm pockets of water behind large boulders, corners and other obstacles.

Riffles: Fishing riffles can be very productive.  Riffles occur in relatively shallow water less than 4 feet deep with a moderate flow over a rocky bottom. The rocks act like a washboard agitating the water to create lots of surface ripples that oxygenate the water.  At these shallow depths there is lots of sunlight for photosynthesis of plankton and vegetation for aquatic insects to live. Riffles are the food factories of the Columbia River.

Runs: Fishing a run can also be productive.  Runs are deeper than riffles and are often downstream of a riffle or pool.  Because the water is deeper the surface is smoother.  There are still some aquatic insects and light penetration, but not to the extent of the riffles.

Pools: Pools are where the big trout tend to hang out to feed on baitfish and are often the deepest parts of a river.  Because of the depth the water is often slow and there is little light penetration and few aquatic insects.

Flats: Fishing flats can be very tricky.  This is where the water surface is very smooth and glasslike. Generally this is off the main channel of the river where it is wide and the bottom is smooth. Fish do feed in the flats, but with the clear, calm water the fish are very easily spooked.