Paramedics said the 28-year-old man was pulled from the water by witnesses before a water rescue boat arrived with a paramedic Thursday, and the man was transported to the Ottawa Hospital's Civic campus, the Canadian Broadcasting Corp. reported Friday.
The man told rescuers he had been attempting a frontal flip from a cliff when his head apparently hit the cliff during the fall. He said he could not remember anything in between his jump and being brought to shore.
The man was being treated for head injuries and possible neck and lower extremity injuries, officials said.
"They're just taking precautions not for everyone to get hurt. I guess that's the smart thing to do," Daniel Lacourciere said.