This week I found myself faced with a somewhat unusual situation of not having the right weight of fly to meet my tactical angling needs. I have been dredging the depths of rivers for so long looking for the largest fish a stream might hide that I completely overlooked stocking my boxes with lightly weighted flies. My tactical focus became locked in on presenting heavily weighted nymphs in deep slots and thus ignored having a good plan for low water conditions.
The Rivers in Western Colorado are currently flowing below average for this time of year. With our rivers so low, the pools that I frequently fish are now shallow, which causes a significant change to the hydraulics. This change in the hydrology moves fish out of the reliable pools and into other locations within the stream channel, generally, in pockets behind boulders or riffles. My attempt at drifting dense stonefly patterns into those locations was an exercise in futility. Fishing densely weighted patterns in shallow water may require more effort in maintaining a good drift, and in fact, it can be tricky.
I am re-tooling many of my favorite spring fly patterns to be lighter to make low water tactical angling manageable. I am tying Perdigon nymphs with smaller than usual beads for gently sinking into shallow pockets behind boulders and soft hackled stoneflies for drifting just above the cobble in riffles. I even added a few smaller streamers that I can fish with my thirty-foot French leaders.
While it is necessary to match the prevailing benthic macroinvertebrates that are present in your trout waters with our pattern selection, it is also vital to match the conditions as well. This year's low water will require an adjustment in tying lighter weight nymphs, so they will slowly reach the bottom without immediately banging into or getting snagged in the rocks. Brass beads are a lighter alternative to using tungsten beads can offer the solution for this requirement.
Besides bead selection, color is also an essential factor to consider. Somber hued, less flashy patterns are less likely to turn off the fish in low water conditions. Leave the bright hot spotted attractor patterns at home until it rains. Choose materials such as pheasant tail fibers, hares ear fur and partridge. These materials are buggy and dull lending to a natural looking fly. If using reflective materials such as tinsel, do so in a judicious manner. A little glint in a fly pattern can make them more attractive to fish, but just a dash too much can ruin it.