Work on the Lake Forrest Dam will require a Lake Forrest Drive lane closure Aug. 29 through Sept. 4, 9 a.m. to 9 p.m.

The 60-year-old dam on the Atlanta-Sandy Springs border is undergoing examination for possible repairs. The lane closure is needed for “geotechnical sampling” of the dam, according to a joint Atlanta-Sandy Springs press release.

The fence recently installed atop the Lake Forrest Dam. (Photo John Ruch)

The lane closure will affect Lake Forrest Drive between Forrest Lake Drive and Barbara Lane. Flaggers will be in place and residents will be able to access driveways.

Atlanta and Sandy Springs are splitting the cost on figuring out possible safety issues and repair alternatives for the earthen dam. The dam is categorized as “high-hazard” by the state Safe Dams Program, meaning that if it were to fail, the flood likely would kill people downstream. The “high-hazard” category is not a rating of the dam’s current condition. But previous state and city-commissioned inspections have said the trees atop the dam are a problem, as is an apparently leaking pipe inside it.