In fast-water stretches, it pays to err on the side of too much tension on your nymphs.
Nymphing without an indicator can be a challenge, especially when you’re fishing turbulent water where micro currents are moving in different directions. Some currents may be moving straight downstream, while some are pulling to the side, some are pushing downward towards the stream bottom, and so on. Instead of having an indicator to suspend and control the drift of your nymphing presentation, you have to decide both the direction and speed the rod tip needs to travel to stay in touch with your nymphs. It can be difficult to determine how fast or how slow to lead the flies in this kind of water are because it’s constantly changing.
To “staying in touch” with your flies, you need the rod tip to be in a position that maintains some degree of tension between angler and fly. This tension allows the angler to detect a take (by feel or by sight) when a trout strikes. Often, the ideal amount of tension is enough allow the angler to see a strike the moment a fish takes, but not so much that the angler is dragging the nymph. Usually you don’t want to drag the nymphing rig too fast, since that may cause a trout to refuse the presentation for the same reason that it would refuse a dragging a dry fly on the surface. Of course, it’s easier to see drag in a dry-fly presentation. When your nymphs are out of sight below the surface, sometimes all you can do is guess. So what do you do when you’re not sure about the correct speed to lead the flies in fast water?
Pocket water often contains conflicting micro currents that make indicator fishing difficult.
Asked about the best course of action when faced with such dynamic currents, a top Czech competitive angler told me, “I would rather have too much drag than too much slack when nymphing fishing.” You can’t detect a strike if there’s too much slack in the line. Slack may help you achieve a natural drift, but but if you can’t detect the strike then what’s the use? Although the drift may not be as natural when you’ve got too much tension in the line, at least you’ll be able to feel the strike.
This makes perfect sense in fast, turbulent water—such as pocket water and heavy riffles—where a dragging presentation can be masked by the strong currents and where trout don’t have as much time to think about whether or not to eat. Finally, adding weight to the rig, in the form a heavier fly or shot can create an anchor and better keep the nymphing rig deeper the water column, while the angler leads the presentation under tension. This approach may not work in slower and clearer stretches where trout can really examine your offering. However, when in doubt, drag your nymphs in fast-moving water. You may not fool as many fish, but at least you’ll see the strike.