Ga. Code § 8-3-31
An authority shall have the right to acquire by the exercise of the power of eminent domain any real property which it may deem necessary for its purposes under this article after the adoption by it of a resolution declaring that the acquisition of the real property described therein is necessary for such purposes. An authority may exercise the power of eminent domain in the manner provided in Title 22; or it may exercise the power of eminent domain in the manner provided by any other applicable statutory provisions for the exercise of the power of eminent domain. Property already devoted to a public use may be acquired, except that no real property belonging to the city, the county, the state, or any political subdivision thereof may be acquired without the consent of such city, county, state, or other political subdivision.
OCGA § 8-3-31