A 23 year old man from Colfax drowned in the South Yuba River yesterday after getting caught in rocks, according to the Nevada County Sheriffa s office. Authorities have identified him as Mario Benassi. He was swimming with friends at about 3 PM in the river where highway 49 crosses when he submerged and was under water about 10 minutes. A group of people were on the bridge and witnessed the incident. An autopsy is planned for tomorrow.