Classification of whitewater

        The most widely used grading system in the International Grading System, where whitewater (either an individual rapid, or the entire river) is classed in six categories from class I ( the easiest and safety) to class VI (the most difficult and most dangerous).

• Grade 1 - Easy Fast moving water, ripples and small waves. Few obstructions, all obvious. Easily rescued.
• Grade 2 - Novice Straight forward rapid with wide clear channel evident without scouting. Rocks and medium sized waves easily missed by trained paddlers. Easily rescued.
• Grade 3 - Intermediate  Rapids with moderate and irregular waves. Strong eddies and powerful current, particularly on large volume rivers. Good boat control is required in tight passages and around ledges. Scouting is advisable. Rescue is possible.
• Grade 4 - Advanced Intense powerful but predictable rapids. May feature large unavoidable waves and holes or constricted passages demanding fast maneuvering under pressure. Scouting is necessary first times. Difficult rescued may be possible.
• Grade 5 - Expert Extremely long, obstructed or violent rapids which expose a paddler to above average danger. Drops may contain large unavoidable waves and holes. Rapids may continue for long distances between pools, requiring a level of fitness. Scouting is essential but difficult. Difficult and painful rescue may be possible.
• Grade 6 - Extreme These runs exemplify extremes of difficulty and danger. For teams of experts only, at favorable water levels and after close study and taking all precautions. NO RESCUE POSSIBLE !

Whitewater's Grade in Thailand.

• Pai River, Mae Hong Son : Grade 1-4
• Mae Taeng River, Chiang Mai : Grade 2-5
• Keg River, Phetchabun : Grade 1-5
• Kang Luang Nam Wah (Lower stream), Nan : Grade 1-3
• Kang Luang Nam Wah (Middle stream), Nan : Grade 1-5
• Koh Roi, Kamphaeng Phet : Grade 2-3
• Mae Wong, Kamphaeng Phet and Nakhon Sawan : Grade 2-3
• Mae La Mao, Tak : Grade 2-3
• Umphang Klee, Tak : Grade 2-4
• Mae Klong (Umphang-Thi Lo Jau-Thi Lo Su), Tak : Grade 2-3
• Mae Klong (Umphang-Thi Lo Jau-Thi Lo Su), Tak : Grade 3-4
• Mae Tuen, Tak : Grade 2-3

Spacial Thanks : tat.or.th