“His body was found floating in the water,” Major Thulani Zwane said.
Dennis, 30, went missing on Saturday during the Midmar Mile swimming race north of Pietermaritzburg. He was found in the dam on Tuesday morning around 7am.
An inquest docket was opened, Zwane said.
After Dennis went missing on Saturday, his brother Tarquin Dennis swam on Sunday, starting and finishing the race in honour of his brother who was missing at the time.
Midmar Mile water safety liaison Brad Glasspoole said Tarquin had insisted on swimming and did so for his brother who had gone missing on the opening day of the annual open water swimming event near Howick in the KwaZulu-Natal Midlands.
“Dennis was swimming in the company relay race and entered the water at 11:22:35,” the Midmar Mile organisers said on Saturday.
Concerned friends, who were swimming with him, alerted officials after waiting for more than an hour for him to emerge from the water.
Glasspoole said it was protocol to initiate a search mission after Dennis had been missing for a lengthy amount of time and that no one had spotted him going under.
The South African Police Service’s Search and Rescue unit, under the command of Lieutenant Jack Haskins, took over command of the search.
Zwane said they had a k9 unit on scene as well as divers in the water.
He added that the search and rescue unit was operating while the raced continues with swimmers still in the water.
In 2014, 43-year-old Herman van Straaten went missing last year. His body was found five days later after surfacing around 800m from the finish, while in 2011, 45-year-old Nick Mellet went missing and his body was found four days later.