On a warm sunny Central Otago day, there’s nothing more inviting than a dip in one of our many lakes and rivers. 

However, river and lake swimming can be as risky as any coastal location around New Zealand, a risk highlighted by two recent tragic drownings at Glenorchy.

Many people lack an understanding of or acknowledge the strength of river currents. It can be particularly deceitful when a river meets a larger body of water, such as a lake or reservoir.

Lake Dunstan

The two recent drownings near Glenorchy were close to where the Rees River flows into the head of Lake Wakatipu.

Swimming in a river presents many hazards; swimmers can be swept down river, dragged underwater, or pushed against an obstacle like a rock or log and trapped. 

Water Safety New Zealand’s river swimming safety tips warn that swimming in a river is not like swimming in a pool or in the sea: River water is much colder than pool or seawater, and you do not float as well in river water as you do in seawater. 

People should also be aware of river currents. The current can be strong even if the river looks calm and the water is slow-moving.

Check there is no risk of being swept into a fast-flowing part of the river.

If you are in a current and try to put your feet down, your foot could become trapped under rocks; you can become trapped against obstacles and strainers or be swept into rapids, waterfalls or weirs; and you will use a lot of energy to keep yourself afloat as you aim to get out of the river at the first safe exit.

People should also check the depth of the water (it may be deeper or shallower than you think), and what is beneath the water - there may be obstacles you can’t see washed into the swimming hole. You could get trapped on a submerged log or rubbish. 

Central Otago swimmers especially should check the water depth before leaping into rivers, as they can change daily.

Investigations into the two Glenorchy drowning incidents are still ongoing. The causes of the drownings will be revealed when the coroner reports are released.  

For more information on water safety please visit the Water Safety New Zealand website.