An afternoon trip to the San Joaquin River turned deadly.
Deputies say a 47-year-old Fresno man drowned just after 5 p.m. on Friday at the Skaggs Bridge County Park, located near Highway 145 and Barstow.
Deputies say the man and three family members were enjoying the park.
Deputies believe the man took a dip in the water to cool off, and never resurfaced.
Jose Reyes, who was at the park with his family, said he saw the 47-year-old man's family searching for him in the water.
Witnesses say when members of the Fresno County Fire Department Dive Team found the 47-year-old, he had been under water for more than 30 minutes.
Fire fighters say the man did not know how to swim. He was found in the middle of the river where the floor drops off some 10 feet.
Emergency crews say the river may look calm but below the surface it is filled with debris and even large logs, the current moves much faster
Despite warning signs notifying visitors of hazardous water conditions, several children were still playing in the water.
Emergency crews and visitors say far too many drowning happen at the park.
Some believe the county should consider hiring lifeguards.
Visitor Andrea Lizarraga says, "The river is really deep on this side and I know my friend don't let his kids swim and there is no supervision at all."
Deputies say an autopsy will be performed on the 47-year-old.
Right now, deputies say it does not appear alcohol played a role in the drowning.