Repairs Approved For Lake Forrest Dam Deemed 'High Hazard'

SANDY SPRINGS, GA — The Sandy Springs City Council has approved a contract with Schnabel Engineering to move forward with the final engineering design to repair Lake Forrest Dam. In 2009, the Georgia Environmental Protection Division (GAEPD) reclassified the dam, which is at least 60-years-old, as a Category I (high hazard) structure. Schnabel performed preliminary engineering evaluations for the City and presented several options for repair.

The municipal boundary between the City of Atlanta and the City of Sandy Springs splits Lake Forrest Dam. GAEPD identified the dam owners who are responsible for bringing the dam into compliance with the Georgia Safe Dams program: City of Atlanta, City of Sandy Springs, Three Lakes Corporation and individual property owners in Sandy Springs.

Through an Intergovernmental Agreement, the cities of Atlanta and Sandy Springs agreed to share jointly in addressing and implementing improvements, repairs and/or alternations or other long-term options to bring the dam into compliance with state regulations. Where any contribution is sought from other dam owners, it will be determined at a later date.

Among the deficiencies with Lake Forrest Dam:

• Inappropriate vegetation on the embankment
• Steep downstream slope
• Existing conduits in the dam, which are leaking and have likely exceeded the design life
• Inadequate spillway capacity

The City of Sandy Springs engaged Schnabel Engineering as Engineer of Record in 2012. In 2015 and 2016, the primary lake was drained to reduce its hazard potential, with regular inspections ongoing.

In 2017, design alternatives were presented to dam property owners and Ga. EPD for review. The review of design alternatives included consideration of cost-effectiveness, environmental and property impacts, regulatory requirements, safety, time, and traffic impacts. The proposed design includes remediation of the existing dam, creation of a Labyrinth spillway or drop box spillway under Lake Forrest Drive, and returning the lake to full pool level. As Lake Forrest Drive is situated on top of the dam, the road will need to close during construction.

The $756,800 contract with Schnabel includes soil testing and supplemental subsurface exploration; Phase I and II roadway, utility and dam design services, and preparation of construction plans. The cities of Atlanta and Sandy Springs will share payment of the fees.

The work is expected to take at least eight months to complete.

For more information about the City of Sandy Springs, visit www.sandyspringsga.gov, or call the Citizen Response Center at 770-730-5600.