ARKANSAS CANOE CLUB

International Scale of River Difficulty Teaching Notes

The International Scale of River Difficulty is only a general guideline and is not exact. Regional and individual interpretations often cause misunderstandings. Rivers change quickly due to water level, downed trees, or many other factors.

The difficulty rating indicates the Boat Control needed combined with the advisability for Scouting, plus the danger to or rescue of a Swimmer.

Excerpts from Scale of River Difficulty

• Class I:
  • Fast moving water with riffles and small waves.
  • Few obstructions, all obvious and
  • easily missed with little training.
     
  • Risk to swimmers is slight; self-rescue is easy.
  • Class I features are very common in Arkansas and usually not named. Nearly all of the drops on Buffalo River from Pruitt to Rush at "ample" levels are Class I.
  
   
• Class II:
  • Straight forward rapids, wide, clear channels, evident without scouting.
  • Occasional maneuvering required, easy for trained paddlers.
     
  • Swimmers are seldom injured, rescue assistance is seldom needed.
  • Examples of Class II rapids on the Mulberry between 2.5 to 4.0 include Chainsaw Jungle, Sacroiliac, and Hamm Falls.

   

• Class III:
  • Rapids with moderate, irregular waves that may be difficult to avoid
  • Strong eddies and powerful current effects are present
  • Complex maneuvers in fast current and good boat control is required;
  • Large waves or strainers may be present but are easily avoided.
  • Scouting is advisable.
     
  • Injuries while swimming are rare, self-rescue easy but long without assistance
  • Standard Example: Nantahala Falls, N.C. @ 3.25 Local Example:The Esses and Falls on the Cossatot @ 4.0 feet
  
   
• Class IV:
  • Intense, powerful but predictable rapids requiring precise boat handling in turbulent water.
  • May feature large, unavoidable waves and holes or constricted passages
  • Demands fast maneuvers under pressure and "must" moves above hazards.
     
  • Scouting may be necessary
  • Risk of injury to swimmers is moderate to high, self-rescue is difficult.

   

• Class V:
  • Extremely long, obstructed, or very violent rapids which add risk.
  • Drops may contain large, unavoidable waves and holes or steep, congested chutes with complex, demanding routes.
     
  • Scouting Recommended but difficult.
  • Swims are dangerous, and rescue is often difficult even for experts.
  
   
• Class VI:
  • Almost never been attempted, extremes of difficulty, unpredictability and danger.
     
  • Only after close personal inspection
  • Consequences are very severe and rescue maybe not possible.

Please refer to Safety Code of American Whitewater for full description of the six difficulty classes and the list of standard rated rapids.

Secondary Reference Materials:

• Catch Every Eddy Surf Every Wave, pages 35-36 . Foster & Kelly, 1995
• ACA Kayak and Canoe Instruction Manual, pages 80-92, Guillion, 1987