rapids

Rapids are sections of a river where the current is fast and the water's surface is often broken by obstructions. These areas are characterized by strong currents that keep the riverbed clear, contrasting with deeper pools where debris can accumulate.12

The term "rapids" is often used in the plural, and these sections are crucial for understanding riverine ecosystems, as they support life forms specifically adapted to these conditions. Rapids are also central to activities like wild-water racing, where competitors navigate swift-flowing, turbulent streams in kayaks or canoes. The difficulty of rapids is categorized into six classes, ranging from easy (Class I) to extremely dangerous (Class VI).23