Vessel capsized.  E-6 responded for a person in the river at Longshore/Argo pond area, with attempts being made by bystanders to take the person out of river.  At this point dispatch reported victim was in the water and was pushed onto a rock, later moving to a log. Enroute dispatch notified that PD had a visual on victim at Swift and Pontiac trail, E-3 went to this location.  Called arrival and location to responding units, with water rescue (L-5) vehicler to Argo to launch boat if necessary.  Made contact with victim who was standing on a downed tree about 25ft into the river.  River current was moving fairly rapidly, victim unable to walk/swim to shore.  Two rescuers sent in near victim to stabilize his situation with throw ropes and PFD.  Victim was hypothermic (shivering), A0x3, no injuries.  E-4 crew sent down stream with throw ropes in case situation deteriorated.  A 24ft extension ladder was used to bridge over logs to give victim a stable walkway.  With R-1, E-6 FF's in water to guide him, and crawled to shore and was loaded into abmulance.
The victim's kayak overturned when it became caught on a downed tree in the river along with struggle against a swift current.  Details regarding the size of the kayak are unknown.