Small, regular waves and easy riffles, with little or no rapid water. Suitable for a wide variety of craft.

Easy rapids and waves requiring some maneuvering. Suitable for sturdy river craft, preferably with added internal flotation.

Large waves, ledges, and other features requiring skilled maneuvering. Suitable only for whitewater-specific craft with substantial flotation or decking.

Powerful rapids, ledges, and hazardous features requiring precise maneuvering. Suitable for experienced groups using whitewater-specific craft and equipment.

Long, steep rapids with little respite, strong turbulence, and features requiring expert maneuvering around frequent obstacles. Near the limits of navigation. Suitable only for highly experienced groups using whitewater-specific craft and equipment.

Landscape : wild, scattered cabins, hunting and fishing clubs, or both

Human occupancy : less than 10%

Water : drinkable

Landscape : lightly wild, visible forestry operations, hydroelectric dams

Human occupancy : 10% to 50%

Water : questionable

Landscape : developed, major settlements, roads running along the body of water

Human occupancy : 50% and more

Water : polluted