Around 12:30 pm Friday, deputies learned Ricardo Perez Diaz was unconscious after being pulled from the water at Skaggs Bridge Park in Kerman.
Deputies say the 24-year-old was in the river but did not know how to swim.
Diaz was not wearing a life jacket
The sheriff's office says he was wading through knee-high water when he fell into a deeper section of the river bed.
They say it took him two to three minutes to resurface, and friends tried to help.
First responders performed CPR, but Diaz died at the scene.
Deputies are urging people to be safe in waterways.