The river slowly declined until recent rains raised the river level and clouded the lower Eagle River. The slow drop in water level illustrates the importance of microstructure to fly anglers. A wide approach is often applied when fly anglers hit the river. But the careful wader finds increased success when focusing on breaking down a stretch of river into smaller river formations. By focusing on key components during low water, anglers focus on the microstructure.
In a normal stretch of river, anglers will encounter a variety of conditions. Dissecting the river helps anglers choose a productive approach to fishing a specific part of the structure, whether it is deep water, rapids, pocket water, or a boulder field. Combining a specific fly fishing technique allows anglers to focus on similar conditions when wading through a stretch.
As water levels drop, small variations in river depth become more significant. When the river was flowing at around 800 cubic feet per second (CFS) in early July, shallow rock fields were covered with a few feet of water. Until a few days ago, the drop in levels had uncovered rocks, thinned the water depths and created small spots for fish to concentrate.
River bottom footprints that can only drop 6, 8, or 10 inches are irrelevant when CFS are high. But when we start to feel the effects of lower water levels and less CFS, these shallow depth changes possess the ability to hold fish. This is an example of a microstructure.
Dry fly anglers will primarily fish in pocket water or shallow rapids. Lower water levels make every rock a piece of microstructure. The cushion at the front of the boulder, another example of a microstructure, is a feeding position that deserves special attention. The trout rides the push, watching the conveyor belt of food as it approaches.
The whirlpool behind a rock is always a target area for dry fly anglers. The current of the river will scour the pocket behind a rock. This creates a resting area where the trout can grab food from the current as it passes the rock and reposition themselves immediately behind the rock breaking the current. This type of microstructure deserves great attention. Depending on the depth, anglers can fish this pocket first with a dry fly, then with a dry dropper, and again with a shallow water nymph rig.
Wading anglers have the advantage of a slower, more focused approach to microstructure. Anglers can repeatedly present their flies to a single piece of microstructure, unlike float anglers who typically get a single shot at the structure.
The shallow rapids are faster sections, but they contain very difficult to discern underwater structure. Fish that are actively feeding in shallow rapids will become a well-managed dry fly, eat nymph dropper after larger dry fly, or even feed on a nymph rig in shallow water. The riffle becomes the microstructure the fly fisherman wants to draw attention to, rather than a piece of concrete structure like a rock or log. The moving water in the shallow riffle creates a unique winding situation that can produce large numbers of fish.
Breaking the river down into manageable chunks of smaller structure and devoting a focused approach to each chunk will maximize the angler’s success. A shallow water nymph rig is a finesse nymph rig that can be extremely productive when water levels drop.
A pair of pupae tied in tandem and placed no more than a few feet deep is an effective way to introduce subterranean insects to any type of microstructure. Keystroke indicators should be light and responsive. A fish feeding in a shallow riffle may spin a single indicator rather than submerge the tool. It is a very difficult bite to detect. The shallow water angler who uses a pair of pinch indicators on the shore, however, detects the slightest movement.
The pair of indicators will rotate and change their relationship, indicating a eat. Palse-style pinch-on foam indicators are also easy to sink.
Separate each piece of microstructure with a well-placed casting. Proper repair is the key to selling it, no matter which approach an angler chooses. Dry fly, dropper or nymph fishing in shallow water allows the fly fisherman to dissect the river for maximum success. Having the ability to select a productive microstructure when the water level drops will improve your angling experience.