Rivers are graded from Grade I to VI depending on the degree of difficulty they present in maneuvering a whitewater craft (Raft/Kayak/Cataraft) through it.
GRADE I: Easy, small waves. No obstacles.
GRADE II: Moderate difficulty with clear passages.
GRADE III: Difficult, high irregular waves, narrow passages. Requires precise maneuvering.
GRADE IV: Difficult, powerful waves. Very precise maneuvering required.
GRADE V: Extremely difficult, violent, and highly congested. Team of experts only.
GRADE VI: Not to be run.