Classification of rivers

Once all the necessary gear is bought/hired/borrow, it is important to know where one’s limits are. These limits are defined by knowledge of whitewater, knowledge of safety, skill-level, and ultimately, one’s state of mind. To make it possible for paddlers to know whether a certain stretch of whitewater is within their capabilities (once they know what they are capable of), rivers and rapids are classified according to an internationally accepted protocol.

The character of a river is influenced by two factors, namely the gradient and the volume of water. Four main categories can be derived from this: low gradient with small volume, low gradient with big volume, steep gradient with small volume and steep gradient with big volume. Rivers with steep gradients are known as creeks.

Rivers can consist of continuous rapids or short rapids with pools in between, dubbed pool-drop. The latter are more forgiving in the sense that it is easier to scout them and portage the rapids if necessary. The pools also make it possible to recover from whatever happens in the rapids. Continuous rapids demand more fitness and dedication, with a small margin allowed for error. Remember that a river that is pool-drop at a low level may become continuous at higher levels.

Rapids are graded on a scale of 1 to 6, taking two major factors into account. The technical difficulty is considered, as well as the consequences of misjudgement or technical failure.

The different routes in a rapid may have different gradings. Rapids are very complex, and this aspect makes it very difficult to grade some of them. Don’t stare blindly at the grading given to a rapid by someone else: decide for yourself whether you are capable of running it. That said, don’t get too relaxed when paddling “easy” rapids; they can be just as lethal when one lands at the wrong spot.

Class 1 – Moving water with few rocks and small waves. Small risk to swimmers and self-rescue is easy.

Class 2 – Easy rapids with small stoppers and small drops. The line down the rapid may require some manoeuvring, but is easy to read. Swimmers are seldom injured and group-rescue is easy, but seldom needed. Rapids at the upper end of the range are designated Class 2+.

Class 3 – High, irregular waves with numerous obstructions. Complex manoeuvring may be required. Scouting from the bank may be necessary. Swimmers are seldom injured and self-rescue is relatively easy, but group rescue may be required to avoid long swims. Rapids at the lower and upper end of the range are designated Class 3- and Class 3+ respectively.

Class 4 –Rapids are long and difficult, and require difficult manoeuvring. The water is very turbulent and stoppers are powerful. Scouting from the bank is often necessary. Rescue is difficult but essential, and a good Eskimo-roll is required. Rapids at the lower and upper end of the range are designated Class 4- and 4+ respectively.

Class 5 – The rapids are extremely difficult, long and very violent, with large drops, narrow passages and complex boulder fields. Scouting definitely necessary. Rescue is difficult, and one’s life is at risk if you mess up. A very reliable Eskimo-roll, proper equipment, extensive experience and practised rescue skills are essential. Class 5 is an open ended, multiple scale designated by Class 5.0, 5.1, 5.2, etc. This scale is necessary because kayakers continue to push the limits of the sport.

Class 6 – Danger to the utmost degree. You are risking your life if you shoot it, even if you are part of an expert team. Class 6 rapids are considered to be unrunnable. After a Class 6 rapid has been run a few times, it’s rating may be changed to an appropriate Class 5.x rating.

The classification of rivers is normally based on the grading of the majority of the rapids, together with a notion of the character of the river. In cases where most rapids are a class or two lower than the odd larger rapid, the river is graded according to the lower class with the more difficult rapids being pointed out as major obstacles or danger spots.

Bear in mind that the grading of the rivers covered in this book is totally subjective. Nevertheless, great care was taken to be consistent. It should also be pointed out that rapids change with time, especially during heavy floods.