The reservoir’s pool level Monday afternoon rose to 322.86 feet above sea level, representing a 7.41-foot gain since Dec. 31.
The lake’s normal full pool is 330 feet above sea level, but an extended drought has kept water levels low for almost two years.
According to the Army Corps of Engineers’ online database, the last time the lake reached or surpassed Monday’s level was on Sept. 24, 2011, when the pool was measured at 323.01.
Weekend rainfall totals averaged just over 2 inches throughout much of Columbia County, with higher levels in the upper end of the Savannah River Basin.
Monthly rainfall totals so far were 3.88 inches at Thurmond Lake, at 3.49 inches at Lake Russell and 3.77 inches in the Lake Hartwell region.
The lake is expected to rise about 3 more feet, to 326, by late June, according to corps projections.