Mark Govier is from the Merthyr Tydfil Sailing Club, which uses the Pontsticill reservoir as its base for training.
An investigation is currently underway the reservoir after a man's body was recovered from the water.
Mr Govier says that while swimming in reservoirs can seem quite tempting, the cold water can be dangerous.
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It will become increasingly cloudy with some showery rain at times and heavier downpours by the early hours of the morning.
Russell Wadge, of Baglan Farm in Trimsaran, will appear before Haverfordwest Magistrates Court on Wednesday.
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