Dancing with the Dragon 101: How to Recognize Whitewater Features
Boating is the art of dancing the tango with a fire breathing dragon. The goal is to only get singed every now and then. How do you accomplish this? By learning the language of water. Water is the most honest thing on the planet, it will always tell you what it’s going to do before exactly what it is going to do before it does it, you just have to know how to understand. First step to this is learning how to recognize whitewater features and understanding how these features are formed.
Current
It’s the strongest down river “pull”. This can be identified by a bubble line- in most rivers. The bubble line will often indicate the strongest line of current. In a river that is glacially fed, bubble lines may not be present. Bubble lines are caused by the byproducts of the decay of organic plant material. Glacial rivers tend to be colder and have large amounts of fine silt. These conditions mean less plant material and less bubbles. Another way to identify the current, is to look for conveyer belt like chunks of current. Currents will, generally, move in a straight line.
Eddy
Patch of current going in the opposite direction of the main current. Eddies are caused by the current backfilling an open space. These could be caused the shape of the riverbank, and rocks.
Whirlpools
Are formed when 2 opposing currents meet.
Hole
A hole is an eddy but, in the vertical plain. This happens when water goes over a rock, or a ledge. This creates a hole- no pun intended- that the river refills, creating a circular current.
Pillow
This is a pad of water on the top of a rock. This is important to note because it will let you know- ON SMALL ROCKS, NOT POUR OVERS– there’s enough water to go over (sometimes).
Wave Train
A series of waves that are close together in a line. The way to identify a wave train vs. a hole is that waves have friends, holes do not. Sometimes a hole can hide in a wave train.
Water Depth
There’s no real way to know the depth of the water, however; you can see were the water gets shallow. The surface texture of the water changes compared to surrounding water.
Boils
Looks like it sounds, caused by water being forced up. Boils at the on the downstream side of a pour over and or a hole can indicate where the hydraulic jump of the hole has ended. When boils pop up, they can stop the momentum of the boat.
HAZARDS
The river is an inherently dangerous environment. Learning to recognize these hazards will prepare you to plan routes through rapids that will allow you minimize the risk posed by them.
Horizon Lines (Not always a Hazard, but can be!)
Indicate a drop in water level, usually happens at the top of the rapid. This could also indicate a low head dam, which is a death trap. Please, please, do your homework, make sure you are aware of all low head dams on the section of river you are running and portage around them. Here are a few videos that talk about hydraulic jumps and low head dams. This one is shorter and my personal favorite for this topic. This one is very through and has great data.
Undercuts
Often happen in rock faces the meet the water. These are often sneaky because the water undercuts the rock face and can trap body.
Pour Overs
Think of Niagara Falls, or the water feature in your backyard. Basically, it’s a mini waterfall in the middle of the river. This is probably NOT something you want to go over.
Strainers
Think about a tree, and tip it on it’s side and put it in the water. These are dangerous because the strength of the current can pin/ trap a person, or a boat in or on the branches.
Sieve or Siphon
A pile of rocks that water can go through, but people and boats cannot. These are extremely dangerous because the current can trap a person, and extraction can almost be impossible without a drop in water level.
These are some of the basic features in a river. Practice identifying them in small streams and creeks, not just the rivers you plan on boating. The more you practice, the more you will see.