Lake Forrest Dam Repair

The Lake Forrest Dam is classified by the State Safe Dams Program of the Environmental Protection Division of the Georgia Department of Natural Resources (EPD) as a Category I, High Hazard dam.  In 2009, the dam was identified with several deficiencies impacting its structural integrity.  With safety a primary concern, the cities of Atlanta and Sandy Springs, through an Intergovernmental Agreement, have agreed to share jointly in addressing and implementing improvements, repairs and/or alterations or other long-term options to bring the dam into compliance with regulations. The cities monitor the dam regularly for safety and structural integrity.   

Lake Forrest Dam runs beneath Lake Forrest Drive on the Atlanta-Sandy Springs border.  Two smaller, private, dams are located upstream and have a direct impact on the integrity of the Lake Forrest Dam (the larger dam). Below is a chronological order of activity related to efforts to repair the Dam: 

Project Update 

September 2022:

Interim repairs have been implemented and disturbed areas stabilized. Two minor tasks remain. The first task is installation of a conduit for power cable scheduled for first week of October. The second item is field work for a limited “as-built survey” of the completed improvements arranged for October 7. Once the As-built survey drawing is ready, it will be submitted to GA EPD Safe Dams Program reporting and documenting the interim repairs as complete.

The interim repairs are designed to provide temporary improvements to the embankment and spillway conduit, as well as to maintain the lake at lowered elevation. The intent of work is to improve safety to the dam until long-term repair plans can be developed and implemented to bring the structure into compliance with the Georgia Safe Dams Act of 1978.

The temporary repair measures included:

• Initial clearing and grubbing of the work area
• Installation of erosion control measures
• Grouting of the upstream portion of the embankment near the 24-inch diameter corrugated metal pipe spillway conduit
• Partial lining of the existing principal spillway conduit
• Fish relocation
• Removal and replacement of the auxiliary over-flow conduit
• Dredging and haul off of silt and sediment
• Installation of filter ring and an electric pump to keep the lake level in lowered level
• CCTV inspection
• Stabilization of all disturbed areas using vegetative measures.

March 2022:

• Completed clearing undergrowth from the embankment and constructed access to the lakebed.
• Grouted the embankment and lined the principal spillway per approved plans.
• Replaced the over-flow conduit and stabilized the embankment.
• Lowered the lake level per plans and have been maintaining the lowered water level with use of a diesel pump.
• Delivered modified filter-ring design plans to GA EPD for review and approval.
• Requested GA Power to provide needed power for a planned electric pump.

August 2021:

• GA EPD final Consent Order issued on January 11, 2021.
• The Cities of Sandy Springs and Atlanta are jointly completing construction of Interim Repair Measures. The interim repairs include pipe lining, grouting, and ongoing pumping to maintain the lake at a lower level. Those repair measures have been coordinated with the Georgia Environmental Protection Division - Safe Dams Program.

October 2019: 

• Lake Forrest Dam Project Update October 1 2019

September 2019: 

• GA EPD first proposed Consent Agreement in negotiation

August 2019:

• Plans and specifications for temporary repair measures produced
• A Notice of Violation letter and a Draft Consent Agreement from GA EPD received by City of Atlanta (City of Sandy Springs letter enroute

March 2019:

• Mandatory biennial dam inspection performed - Engineer recommends temporary repair measures

January 2019:

• Dam Breach Analysis and sensitivity analysis studies performed

June 2018:

• Cost validation study prepared with independent contractors

April 2018:

• Peer-review of alternative analysis report performed by a third party consulting firm

December 2017: 

• Interim Emergency Action Plan prepared