What’s wrong with the dam running beneath Lake Forrest Drive, and how bad is the problem? Answers are finally on the horizon, but still at least a half-year of study away, the Sandy Springs City Council was told Aug. 2.

“I’d say we have enough data to say we have a problem,” Sandy Springs Public Works Director Garrin Coleman told the council about the Lake Forrest Dam, which appears to have some sort of leak in an internal pipe. But Sandy Springs and the city of Atlanta are just starting to review a six-month scope of work from an engineering firm to nail down answers and suggest alternative fixes, he said.

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

Meanwhile, a chain link fence topped with barbed wire went up atop the dam in July. And, Coleman said, the city and engineers are investigating reports of “downstream sediment” reported by a resident.

The earthen dam, running under the 4600 block of Lake Forrest Drive on the Atlanta-Sandy Springs border, is rated “high-hazard” by the state, meaning that if it fails, the flood likely would kill people. Since 2009, the state Safe Dams Program has said the 60-year-old dam has obvious issues, like trees growing atop it. It was last inspected by the state in February, but the official report is still not available, according to Safe Dams Program manager Tom Woosley.

Sandy Springs is taking the lead on studying and repairing the dam while splitting the costs with Atlanta. Sandy Springs has budgeted $1.91 million for its half of the fixes.

The firm Schnabel Engineering has proposed a study—including soil testing to look for moisture levels within the dam and drawing up possible solutions—that is now under review by the two cities, Coleman said. Depending on what is found, city officials previously said, the options range from dam repairs, to building a retention pond upstream, to simply breaching the embankment permanently to make it a culvert instead of a dam.

Schnabel has been prepping the dam for examination for over 18 months, including draining most of the lake and relocating fish to another pond.