Watch non-swimmers closely
Shallow water can deepen suddenly. If you, your children or your friends cannot swim, make sure you scout out the extent of the shallows, set clear boundaries and keep constant supervision. Remember that even shallow sections of fast-flowing water can knock you off your feet. Be careful with inflatables, which can create a false sense of security and float off into deep sections or burst. Buy a good quality buoyancy aid for non-swimmers and, best of all, learn to swim.
Slipping on rocks
One of the most common dangers in outdoor swimming. Rocks are very slippery when wet and you don’t want to hit your head. Never run. Go barefoot to get a better grip or wear shoes with a rubber sole.
Hypothermia and cold-shock
Outdoor swimming in cold water saps body heat. Shivering and teeth-chattering are the first stages of mild hypothermia, so get out of the water and warm up with a combination of warm, dry clothes and activity. Press-ups, star-jumps and running up a nearby hill are the quickest! Wear a wetsuit if you want to stay in for more than a quick dip. ‘Cold-shock’ is the involuntary gasp and rise in heart rate that occurs as the body enters very cold water. Test the temperature and wade in slowly unless you are already acclimatised to outdoor swimming.
Jumping and diving
Always check the depth of the water, even if you visit the same spot regularly. Depths can vary and new underwater obstructions (sand, rocks, branches, rubbish) may have been brought downstream or tipped in. A broken neck from a diving accident could paralyse you for life.
Cramps and solo-swimming
Swimming cramp can occur in the calf or foot and tends to be caused by overexertion, over-stretching and tiredness. Cramp is not more likely after eating but dehydration, or a poor diet in general, can make you especially prone. If you get a leg cramp, shout for help, lie on your back and paddle back to shore with your arms. Swimming alone in deep water is foolish but, if you must, wear a life jacket or trail a float behind you on a cord.
Most common in slow, warm lowland river swimming and lake swimming, weeds are quite easy to see and, while one or two aren’t such a problem, a spaghetti-like forest can entangle a swimmer’s legs. Try to avoid them. If you do encounter some, slow your swim speed right down, don’t kick or thrash, and either float on through using your arms to paddle, or turn around slowly.
Moving water and fast currents
Lots of our best water moves, and river swimming in and against a current can be fun, just like swimming in seaside surf. However, you generally want to avoid being taken downstream in an uncontrolled manner. Even shallow water, if it’s moving fast enough, can knock you over and carry you away. Always consider: if I do lose my footing or get swept downstream, where will I get out? Identify your emergency exits before getting in and scout around for any downstream hazards (obstructions, waterfalls or dams).
When judging flow rates remember the basics: the shallower or narrower the river bed becomes, the faster the water must flow to pass through, and vice versa. That’s why ‘still waters run deep’. Throw a stick in the water to judge flow speed and avoid anything moving faster than you can swim. In tidal estuaries there can also be counter-flows, with seawater moving in and river water moving out. In deep rivers or gorges the water in the surface layer may be flowing more slowly than the water beneath. These confused waters aren’t necessarily dangerous or outdoor swmiming – you’re not going to be sucked under – but they can be disorientating and may take you out into deeper water or close to an obstruction. You can generally feel what’s happening under the water with your feet and body. Large eddies and surface ‘simmering’ also suggest something more powerful is happening beneath. Be particularly cautious in these unpredictable waters.
Currents can be especially powerful directly under large waterfalls or dams. As with breaking waves, the water can be flowing in two directions, with some water exiting from the fall downstream while some creates a ‘rip-tide’ that is circulating to the back of the fall. Semi-circular or ‘box’ dams, which have three sides, create particularly dangerous re-circulating currents in the confined space within their walls. In a large plunge pool you’ll generally feel the currents long before you are in danger of being pulled under the waterfall but if you are foolish enough to swim into the tumult, and are taken down, it’s like being caught in a wave’s undertow. Keep calm, hold your breath, hope you don’t get dragged along a rocky bottom and wait a few seconds until you are spat out.