The combination of bank holidays and hot weather usually bring an annual influx of would-be swimmers at reservoirs such as Manvers Lake and Thrybergh Country Park.
The dangers of swimming in reservoirs or any open water include:
It is always very cold. The temperature will rarely rise much above 12C, even in summer. This is cold enough to take your breath away which can lead to panic and drowning or it will make your arms and legs go numb and limit the ability to swim. It can also lead to hypothermia - serious reduction in your body temperature - which can cause heart failure.
It can be deep.
There may be hidden obstacles beneath the surface.
The sides of reservoirs are very steep and slippery in places, making it difficult to climb out.
There might be blue green algae in the water which can produce toxins that cause skin rashes and stomach upsets.
Reservoirs are often in isolated places. No matter how quickly you call for help, it can take too long for help to reach you.
Swimming in reservoirs is extremely dangerous, no matter how strong a swimmer you are. Within minutes of a swimmer disappearing beneath the surface, it is often too late for the emergency services to help.
If you do want to swim, please use your local swimming pool. Many will provide swimming lessons and all will have lifeguards on duty to ensure your safety when swimming.