Tom Rosenbauer’s latest podcast covers reading high- and low-water conditions in trout streams, saltwater tide conditions, food availability and current flows. “When the water is really low, you want to look for the main flow in the stream, the thalweg. If you trace the main flow of water through the stream. And you can find that line by looking for a debris line or foam line — all the bubbles that trace a line down the thalweg. So the fish are going to be closer to that current because that’s where the food is.”
Rosenbauer’s recent revision of his classic Orvis Guide to Prospecting for Trout goes into great detail on all aspects of trout hunting.