Ch Insp for Newark, Clive Collings, said: “This is a tragic incident and our thoughts are solely with this young man’s family.
“We recognise this will be very upsetting for the local community and we encourage people to access support if they need it.
“During hot weather we know people want to keep cool but open waters are exceptionally dangerous as there is no way of telling what’s beneath the surface.”
Nottinghamshire Fire and Rescue Service said on Thursday one man got out of the water and crews rescued another man – who police confirmed died on Saturday.
Group manager Charlotte Weatherall-Smith, from the fire service, said: “I would like to extend our deepest sympathies and heartfelt condolences to the family, friends and loved ones of this young man at this incredibly difficult time.
“This is a tragic incident, and our thoughts remain with everyone affected.
“Incidents like this are a stark reminder of the dangers that open water can present.
“Even on warm and sunny days, water temperatures can be much colder than they appear, and entering the water can lead to cold water shock, which can be sudden, severe and potentially fatal.
“If you see someone in difficulty in the water, call 999 immediately and ask for the fire service.
“Encourage the person to float on their back to help them stay calm and conserve energy. For your own safety, please do not enter the water or attempt a rescue yourself, as this can put additional lives at risk.”
