Our summer-long run-off has drawn to a close with the rivers and streams of the Roaring Fork Valley dropping to seasonal flows. Lower autumn and winter stream flows allow the wading angler a better opportunity to fish a stretch of the river more intimately than when floating. Whether you float or wade a river, having the skill to “read the water” will put you in front of more fish more frequently.
Learning to recognize where and how fish exploit their habitat will improve your fishing skill set. Reading the water is not complicated if you take into consideration that fish need three things for primary survival: a respite from the current, cover from above and an abundant food source. These three factors can give you a number of stream channel features at which to look. When you find a place with all three elements you have water worthy of fishing.
Respite from the current can come in a couple of forms -- physical obstructions and hydraulic dynamics. Trout prefer a current speed they can comfortably hold steady while expending the least amount of energy. Look for current speed from a stroll to a brisk walk and a depth of one to four feet. Fish will hold in much stronger or shallower currents if the bottom rubble is softball to bowling ball-sized. Low-pressure gradients are created on the downstream side of rocks -- much like how an airplane wing allows airflow -- which allows the fish to hold with minimal effort.
When looking for productive water, look for hydraulic features that funnel drifting material into bubble lanes. The best way to find these bubble lanes or current seams is to look for lines of bubbles drifting in single-file lines. Observe how the bubbles and foam always seem to take the same path as they get caught into micro-vortices. That is your indication that the currents are also gathering drifting food into a defined path akin to a conveyor belt.
Adding all three elements together is not hard to do. As you move from pool to pool, look for walking speed currents flowing over softball to bowling ball sized cobble that has observable bubble lanes. Then look for other clues as to where the fish might hold nearby while waiting to ambush drifting insects.
Remembering the three primary factors of Current, Cover and a Conveyor belt of food, while fishing will help guide you to fish more productive water.