Const. Ian MacDonald said Abbotsford police responded to a 911 call from the popular park on Wednesday evening at about 8:30 p.m.
A group of three young men had been cooling off in a quiet part of the lake when they noticed that one of them was missing.
Police, fire and ambulance crews looked for the man until midnight, when they suspended the search because of darkness. The search resumed Thursday morning with the help of the RCMP diving team.
The body of the victim was recovered about an hour later close to where the group had been hanging out.
"A lot of people believe that drowning victims make a lot of noise and that they splash about and they call for help," said MacDonald. "I would suggest that's something that is perhaps seen more in movies than in reality."
Lake has sharp drop-off
MacDonald said none of the young men, aged 19, 20 and 21, knew how to swim. When their friend disappeared, they had to ask passers-by for help as they were unable to search for him in the water themselves.
Alcohol is not believed to have been a factor in the accident.
"What we suspect happened was that this 20-year-old probably took one step too many and went from a what was relatively shallow water into an area where it can be as deep as 40 feet," said MacDonald.
MacDonald said the victim's friends were "completely distraught" and "overwhelmed with both emotion and panic."
Police will continue to investigate but MacDonald said at the drowning is not believed to be suspicious.