Myburgh said Enock was with a group of about 12 pupils on the home-made raft before it overturned.
“It seems like the currents were quite strong and the last time the boy was seen is when some of his friends saw the raft overturn and the kids fell off into the water,” Myburgh said.
Myburgh said the incident happened at about 3pm on Wednesday.
Gauteng education department MEC Panyaza Lesufi said the camp had been cancelled.
Lesufi joined Mpianzi’s parents at the lodge on Friday morning.