A vocabulary of landscape — a landscape of words 975 entries

seam

SEEM
The visible boundary where fast current meets slow current — a line on the water’s surface where two different speeds of flow run side by side. Fish position themselves on the slow side of a seam and dart into the fast side to intercept food. For anglers, seams are the most consistently productive water on any river.
Etymology
Old English sēam, a joining or junction. The same word used for the stitched junction of two pieces of fabric. On a river, the seam is where two fabrics of current are sewn together.