When hope of any more strikes was well and truly exhausted, I waded into the vortex and began probing the winning spots. Several things surprised me. First, the water was far shallower than I had assumed, no doubt due to dropping stream levels. I also discovered large rocks that acted as current buffers or somehow changed the hydraulics of the flow, making it easier for the fish to hold there. And the water was cooler, which meant it was better oxygenated. That had me a bit stumped, but later I realized there was that subtle "cover," provided by the broken surface water.