Understanding currents and eddies will help you stay safe as well as getting the most enjoyment out of your river outdoor swimming.
Currents are not always predictable, and will be stronger after higher rainfall. If you can’t swim upstream against the flow, then you will be unable to swim out of the way of objects downstream (e.g. bridges and trees).
You will be able to see the main current which is usually in the centre of a straight piece of river, or on the outside of a bend where the water runs fast and deep.
Shallow water tends to have a rippled surface, while deep water will usually have a smooth surface (still waters run deep).
It’s a simple and effective trick to throw a stick or leaf into different areas of the water and watch how it behaves. This will make it easy to spot areas of faster flow, but also to see where the eddies are. At normal flow levels, eddies can be the wild swimmer’s best friend.
Eddies are areas where water flows back upstream against the current. An eddy might be a good spot for entering and exiting the water safely, because you won’t have to deal with a strong current while clambering in and out.
You will often find an eddy downstream from a large rock, and this will enable you to swim upstream.
Eddies in white water are far from safe; often they’ll send you at speed into a strong current.
The force of water is hard to comprehend. **** never underestimate what a swimmer might be dealing with, especially in high flows.