Even a tropical storm can’t get Lake Lanier to anywhere near full pool.
The lake’s water level is only up 5 inches since Tropical Storm Irma passed over the Chattahoochee River basin that feeds Lake Lanier on Sept. 11 and Sept. 12.
Before the storm hit, National Weather Service forecasts called for as much as 6 inches of rain to fall on Cumming and Forsyth County, but that figure decreased as Irma neared North Georgia. With the storm passed, just more than 4 inches inches of rain fell on Cumming on Monday and Tuesday, according to National Oceanic and Atmospheric Administration records.
The storm brought the wind but left the rain in Florida.
Lake Lanier’s water level is severely down since the start of 2016, when it swelled to more than 1,075 feet above sea level. By January 2017, the lake had drained 15 feet, and the normal winter refilling period never happened. In May, Lake Lanier was at about 1,063 feet.
A wet summer has helped the lake enough to lead the state of Georgia to call off its drought restrictions in early September, but the lake still only sits at 1,065.6 feet above sea level.
As of Monday, that’s about 5 inches higher than it was on Sept. 10 before Tropical Storm Irma hit Forsyth County.
It takes time for rainfall to work its way into Lake Lanier. As a relatively narrow body of water fed by many streams and tributaries, the lake catches rain from a narrow band of land stretching northward from Buford.
Rain that falls into the area saturates the soil and eventually drains into the lake, but the lake level on Monday is likely the best it’s going to get after Tropical Storm Irma.
Dale Caldwell, a Gainesville-based watershed protection specialist with the Chattahoochee Riverkeeper, said Monday that the lake is likely seeing the full effects of the rainfall during the storm.
In the lowlands of South Georgia and Florida, the effects of a heavy rainfall can be seen for days and weeks, but much of the Chattahoochee River watershed passes through the North Georgia mountains, which quickly drain water into streams and rivers.