Columbia County Coroner Vernon Collins identified the boy as Jonathan Tyler Thomas of the 1900 block of Diane Drive in Augusta.
Pam Tucker, director of the Columbia County Emergency Management Agency, said the boy was reported missing at 4:20 p.m. Sunday in the West Dam area. She said the child was wading with his mother in water about 1.5 feet deep when he encountered a sudden drop.
The drowning was the fourth at Thurmond Lake this season. Three have happened at West Dam and one at Lake Springs, Ms. Tucker said.