A: To get to the other side!
A rescuer’s ability to wade through swiftwater depends on three main parameters. They are:
- Depth – Assuming that the rescuer is wearing a pfd, he or she will float at some point. If you are floating you are not wading. Depth can also can be thought of in terms of the height of the rescuer.
- Flow – A channel doesn’t have to be deep to make crossing difficult. Even channels that look shallow can have enough force to knock a rescuer down. Flow deals with volume, and is usually measured in cubic feet / second or cubic meters / second.
- Friction – This parameter has two meanings. The first focuses on the surface of the channel bottom. For example, gravel and sand have more friction than smooth bedrock or concrete. The second aspect deals with the amount of friction you are putting in contact with the channel bottom. More people = more feet touching the surface = more friction. It is important to understand these parameters before you get in the water.
There are numerous methods people use to cross streams and wade. In our courses at Sierra Rescue, we spend time refining crossing techniques and trying a variety of methods. Each technique is slightly different, but consistent to the majority of them, is one central theme: use the current don’t fight it. In line-astern, line abreast, and the pyramid group crossing techniques, each rescuer uses the eddy formed by the rescuer in front (upstream) of them thus minimizing the force of friction.
A few more tips that will help your crossing technique:
- Channel crossing methods are effective when you have no downstream momentum. Realizing this is very important and helps to avoid foot entrapments.
- Communicate! A breakdown in communication can lead to a breakdown in the group.
- Avoid movement in unison since you will reduce friction and can de-stabilize drastically. Using random steps for larger groups works well.
- If you get swept off your feet you become a swimmer. DON’T TRY TO REGAIN FOOTING. YOU ARE NOW A SWIMMER. SWIM!!!
- In group crossings the most up-stream rescuer is ideally taller and preferably streamlined (wetsuit vs drysuit). He or she often uses a paddle (inverted) or pole to make a trip-pod.
- Work to keep the group oriented upstream to the current vector, not the riverbank. If a group gets pointed in the wrong direction, then they are exposed to much greater current force.
- Keep the spacing between rescuers tight and increase friction by pulling each other down (to the bottom surface).
- Know the hazards downstream and have downstream safety for your wading group, as well as an upstream spotter.
There’s a time and place for wading. Don’t spend all your time trying to wade unsuccessfully. Often shallow water crossing and wading are fast and simple methods to Access and Transport, but they are not always the only ones available. Test your limits in a safe environment and know the parameters that you as a rescuer are capable of wading before you get in the water.
Train Hard. Stay Safe.
