If you are relatively new to this whole crazy, masochistic endeavor we call steelhead fishing, you've undoubtedly heard the term "flat" thrown around in conversation. As a young steelheader in junior high, I often overheard the river veterans talking about catching steelhead on flats. Flats, flats, flats…I kept hearing about them but I wasn't totally sure just exactly what a flat was.
Eventually, I got up the nerve and asked one of the old guys if he'd show me what they were talking about. Much to my surprise, the grizzled ol' angler was happy to share a bunch of valuable information about flats and steelhead in general with the new kid—and my steelheading game got infinitely better thereafter.
So, for all you budding steelheaders who are in the same boat, let me be the old graybeard here and help you identify the most fishy of steelhead spots: Flats.
Anatomy of a Steelhead Flat
I know the term is a bit nebulous, but a flat simply refers to a spot where the gradient levels off after a rapid or steep riffle. The current speed slows down as it runs over a flat and that’s why the fish like to hang there—they can chill there without burning a bunch of calories. They are the preferred holding zones for steelhead and if you can figure out how to spot them, you are going to catch more fish.
The best way I can describe a flat is to think of a river like one of those big switchback style stairways you’ll find in a tall office building. As you walk up the first flight, you are like steelhead swimming upstream through the rapids. Then, you get to the level landing area halfway up the floor, where you can catch your breath and let your legs rest for a second before you head up the next flight. Flats in a river are just like that.
Ideally, a flat will be anywhere from two to eight feet deep, with a choppy surface. And that broken surface is a real key! When the surface of the water is choppy, the fish feel much more secure than they do when the river is glassy. Happy fish are biting fish while spooky, skittish fish are much more difficult to tempt. Another way to think about it is: Imagine standing on a dock looking down into a clear lake. Five feet down is a quarter lying on the bottom. When the wind is calm, you can easily see the coin. But as soon as the wind comes up and ruffles the surface, it's almost impossible to see it.
In a perfect world, the flat will have some nice-sized cobble and some boulders in it and will be flowing at about the speed of a brisk walk. Depending on water conditions, steelhead may sit anywhere in a flat, with the two main spots being: At the head, just below the fast water and down in the tailout where the flat breaks and the river again picks up speed.
The tailout is the shallow area at the end of a flat where the river bottom starts to tilt up before it breaks into the next fast-water section. The hydraulics of that slight rise in the bottom’s gradient are such that the fish get some “lift” from the current in the tailout, which helps them expend less energy.
Tailouts are also resting zones for fish that have just come up through tough stretches of heavy water. Even in low and clear water, it’s not uncommon to find steelies sitting in water that is extremely shallow—especially in the early morning hours or on dark days. One cloudy afternoon in British Columbia, I watched my buddy Ben hook a massive steelhead that was probably 25 pounds in about a foot of water at the very back end of a tailout. (Sad to report he lost the fish).
You’ll also find fish sitting at the head of a flat—the upstream portion of the run where the current is heaviest. Typically, steelhead will hold lower down in the "meat" of a flat early in the morning, when the sun’s off the water. Then they'll move into the faster water at the head as the day brightens. Again that choppy, fast water is where the feel most comfortable.
Head of the Flat
The head of the run really comes into play when you have low, clear water conditions. In that situation, a lot of the flat will be unusable to fish so they will seek out the fastest water they can—even if it’s only a foot deep.
There are, of course, exceptions to most fishing "rules" but one thing is for sure: If you learn how to properly identify flats, you are going to see your steelhead catch rate go way up. Good luck!
If you'd like to learn more, check out my huge new eBook, The Ultimate Guide to Steelhead Bank Fishing, available at Amazon.com