Common Whitewater Terminology

Boils: ascending currents that rise above surface level unpredictably.
Chute: a narrow constricted portion of the river.
Clean: free of obstructions; used to describe a route through a rapid.
Drop: a steep, sudden change in the level of the river bottom (6'+ drops called falls)
Eddy: a pocket of water downstream of an obstacle that flows upstream or back against the main current
Ferry: a maneuver used to move a raft back & forth across a river.
Gradient: the measurement of a river's descent in feet per mile or meters per kilometer
Hole: A swirling vortex of water where the river pours over an obstacle and drops toward the river bottom, leaving a pocket behind the obstacle into which an upstream surface current flows.
Hydraulics: a change in currents that causes surface features that can deflect, slow, or speed up a rafts descent (e.g., holes, waves, and eddies).
Keeper: a large hole or reversal that can keep and hold a raft or swimmer for a long period of time
Pool-drop: a type of river consisting of intermittent rapids followed by long, easy sections of calm water
Put-in: the place where a raft trip begins
Rapid: a place where the river leaves its two-dimensional state & enters a three-dimensional state with faster currents, rocks, & various types of liquid surface features
Scout: to walk along a bank to inspect the river
Section: a portion of river between two points
Strainer: an obstacle, such as a tree, that lets water flow freely through it but catches and entraps swimmers, rafts, & debris.
Take-out: the place where a raft trip ends
Technical: rapids containing many obstacles and requiring constant maneuvering
Throw bag: a bag that holds a long coiled rope, used as a rescue device to be tossed to swimmers.
Volume: the amount of water in a river

*these definitions as listed in The Complete Whitewater Rafter by Jeff Bennett, © 1996