River Terms

CFS– Cubic feet per second is a volume of water measure, which is commonly used to describe most rivers. It is measured by a water gauging device.

Eddy – Protected from the main current, these smooth sections of water are found behind obstacles (e.g., boulders or bends in the river).

Hole, hydraulic or reversal – When water falls over an object (e.g., a rock or ledge), the falling water creates a depression. Surrounding surface water then rushes to fill in the depression and forms a hole.

Strainer – An obstacle in the river that allows water to pass through, but not a person or boat (e.g., a tree with its limbs partially submerged).

Wave Train – A series of standing waves perpendicular to the main current.

Whitewater Scale – Whitewater is classified on a scale from one to six. A description of this scale is given below.

Class I – Easy, flat water. No problem. Take your grandmother.

Class II – Small rapids with clear, wide channels. Take a timid friend.

Class III – Good-sized rapids with waves and boulders. Chances of maneuvers inside the rapids are great. Get a guide!

Class IV – Intense rapids. Plan on maneuvers, hazards, big waves and tight boulders. For those seeking a challenge.

Class V – Intense and violent water. Long rapids, drops, extremely tight channels, and hazards. Get a good guide!

Class VI – Don’t do it. If you do, say your final prayers first.


Call us at (800) 858-6808 for more information or to reserve your whitewater rafting trip. You can also book a trip using our online booking agent. Click here for more information on group discounts and making reservations.