Your county has a guide posted on their website that will probably explain what you need, I linked it below. Without knowing your situation, you are probably required to have some version of a Stormwater Discharge permit. Here in Iowa they are handled by the state but other jurisdictions might handle locally.



Building or Renovating a Pond in Georgia A Pond Guide for Citizens

https://www.carrollcountyga.com/DocumentCenter/View/2634/pond_guide