The slow-motion effort to repair and evaluate the Lake Forrest Dam has reached a new step that could take many weeks more: Watching the lake dry up.

An earthmover rests atop the Lake Forrest Dam on Lake Forrest Drive May 11. (Photo John Ruch)

An earthmover rests atop the Lake Forrest Dam on Lake Forrest Drive May 11. (Photo John Ruch)

The 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 dam has obvious issues, like trees growing atop it.

But it’s an open question whether it has internal structural problems and if so, what the solutions might be. The only way to find out is to drain the “lake”—a pond—behind the dam so workers can dig in. The city of Sandy Springs kicked off a study and repair process more than a year ago.

For months, workers have slowly drained the lake, removing boatloads of live fish. Now the lake has been drained as much as possible, and a new outflow pipe was installed over the past month, according to Sandy Springs City Attorney Wendell Willard, who is coordinating the dam work. A large earthmover is still on the site, where new grading work on the embankment has been underway.

“The purpose is to let the lake dry out,” Willard said. Officials have previously said that could take weeks or months.

Depending on what is found, the options range from dam repairs, to building a retention pond upstream, to simply breaching the dam permanently. The latter option might not be popular with homeowners who have used the pond for boating and enjoying wildlife. Ducks and baby Canada geese were using the shallow remnant of the pond earlier this week.

Tom Woosley, program manager of the Safe Dams Program, said that inquiries from city officials indicate they’re leaning toward permanently draining the lake. Instead of a drainpipe, a large culvert would be cut through the dam. In that arrangement, “this would no longer be a dam and hold water, but rather be considered a roadway embankment and thus no longer regulated by this office,” Woosley said.

“No decision has been made,” and won’t be until the post-dry-out examination happens, Willard said. “The structure will be there. Whether it will be a dam or not [is still a question]…That’s not being highly touted, but it’s an option.”

The cities of Atlanta and Sandy Springs have agreed to split the costs of any Lake Forrest Dam work, with Sandy Springs taking the lead on supervising it.

In February, the Safe Dams Program inspected the dam. Woosley said the inspection report has not yet been issued.

Lake Forrest Dam is one of many “high-hazard” dams in the area that often have ownership and maintenance issues and are little-known to the general public.

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