Eddy

An eddy is a pocket of water that flows upstream, or simply sits calmer than the surrounding current, forming just downstream of an obstacle like a rock, bridge piling, or riverbank point. As the main current is forced around the obstacle, water fills in behind it and often circulates back upstream, creating a patch of slower or reverse-flowing water right next to the faster current beside it.

River paddlers use eddies deliberately, ferrying across the current into an eddy to rest, regroup, or scout what is downstream before committing to the next section. The boundary between the main current and an eddy, called the eddy line, can be sharp enough to grab a hull and spin the boat if crossed at the wrong angle, which is part of why eddy turns are practiced as a specific skill rather than picked up by accident.

Reading where eddies form, behind visible obstacles and along the inside of bends, is a core part of reading rivers generally, and it applies even on milder moving water, not just whitewater. Paddling in current, including using and crossing eddies, carries real risk from features like eddy lines, strainers, and changing water levels, and is best learned with a qualified instructor rather than from a written description alone.