Five Tips for Fly Fishing Big Water aka the Kootenai River

It happened again. Another river, a large one, has managed to captivate my attention. Where to fish the Kootenai River, and why, are some questions that arise.

Why the Kootenai River and Tips to Fly Fish its "Big" Water

Like most big water, the Kootenai is tail water that is blessed by a constant supply of food and stable water temps. The river flows free on its journey to the Columbia, and we are lucky to have access to some of its most productive stretches here in North Idaho and Northwest Montana.

Why would you want to fish the Kootenai? Dreams. Dreams of big fish in bigger water come to me at night. Riffles so large you could spend an entire day probing their depths, and still not cover them all. Undercut banks that stretch for half a mile. Waterfalls with enough water to devour boats... and the monster trout lurking in the depths of the pools they carve out of the slate and granite.

As a wade angler, or even when fishing from a boat, it can be daunting trying to figure out where to cast a fly, or what methods to use. Below are five tips I have picked up along the way that lead to consistent results across a good variety of fishing styles.

Let's look at rods. Pro tip: Rig multiple rods. Anytime I am fishing large water I like to carry three rods.

What Three Rods do you Need to Rig for the "Big" Kootenai?

On the dry fly rig I fish a 5wt, WF fly line (sharkskin, because every extra foot of casting distance matters on big water) with a 14 tapered leader.

I like to vary my flies, but as a general rule of thumb my first play is big and bushy (used as an attractor to let you see your drift accurately and to take fish feeding on hoppers) and my second fly is my "match the hatch," often a caddis soft hackle, grasshopper, or other small varietal of dry that I would have a hard time seeing otherwise.

The second rod is the nymph rod, in large, powerful rivers you need to go heavy or go home, so rig with a leader (3 ft. of 30lb maxima, 3 feet of 12l b maxima, 1-3 split shot, swivel to 3x floro - stonefly or 4x floro match the hatch nymph) and enough weight to keep your fly in the zone. The indicator attaches to the 30 lb section and the split shot goes just above the swivel. Cast upstream, mend for the fly to sink, then stack mend it down the run. This setup will allow you to make 80ft drifts down a seam from a point, or tight line nymph a pocket 10 feet in front of you. I fish these nymph rigs with a WF floater and a 6wt single hander, preferably 9 or 10 foot fast action rod. Set your depth to that of the bottom with this rig, not the standard 1.5 times the depth.

The third rod should be a streamer rod. I prefer a 6wt spey rod with a Skagit head and T14 sink tip. Fish the river steelhead style, with a streamer on the front and a soft hackle on the trailer, or with a double streamer set up. Generally, I start with the dry fly rod, then nymph the run, and then make one more pass with a streamer. This helps to ensure you target all the water within your casting range and gives you a second and third shot at fish that may have refused a previous offering.

Ignore the Lies you Can't Reach & Focus on the Ones you Can

No matter how good of a caster you are, there will be perfect, prime lies that you are never going to reach. Ignore them, and break down the river in your casting range. A large river fishes exactly like a small stream, but with more exaggerated features. The farthest distance you can present a fly effectively becomes your far bank.

Wade DEEP

What is the point of fishing a 400 yard riffle if you can’t stand chest deep in the water about to be washed away. It’s summer after all. Consider swimming out to that rock and then fish it hard once you get there. A simple PFD can be a great tool for wade fishing a big river, allowing you to safely swim side channels to get onto islands or far away gravel bars.

Start in close, and work out further and further into the runs. It is important to not line fish on clear flowing tail waters. Even though the river is huge, it can pay to approach the river on your hands and knees and fish with as much stealth as possible. Wear clothing that is natural colors and with a broken pattern, to avoid fish detection.

Swing Soft Hackles

Seriously, there is no better way to cover the big riffles during an epic caddis hatch then fishing 2 or 3 soft hackles on the swing. Casting 80 feet out, swing it out, then take a step down stream. Hold on tight, takes are aggressive on swung soft hackles. The soft hackle rigs are also super good in large back eddies where drag free drifts are impossible do to powerful conflicting currents.

Bonus Tip for Fishing Large Bodies of Water

If the river is a tail water, especially a for bottom spill dams, nymph with a large chironomid as your dropper fly! Also consider a shrimp pattern, if they are present in the reservoir above. The other nymphs to consider below the dam on large tail waters would be scuds, dragonflies, and damsels. While the river may not support large populations of these insects, the reservoir surely will, and the amount of food washed through the turbines can be astonishing. The fish are sure to recognize these major still water patterns as a reliable food source.