Gordon County, GA Environmental Rules: Stormwater Management (2026)

Chapter 6 of the Gordon County Unified Land Development Code, Section 6.04.00, sets drainage and stormwater standards for development in unincorporated Gordon County, Georgia. Section 6.04.01 is the general rule. Stormwater management structures shall be provided by the developer as required in the County floodplain regulations and soil erosion sedimentation ordinance. They shall be designed and certified by an appropriate state approved professional and are subject to the approval of the County. The design storm is a 25-year storm event, while all cross drain pipes under streets carrying live streams and all bridges shall be designed for a 100-year storm event. Energy dissipation devices are required at all discharge points of storm drains, with rip rap at least six times the pipe diameter in length and two times the pipe diameter in width. If the exit velocity exceeds ten feet per second, rip rap set in concrete, stilling basins, baffle wall basins, impact blocks or other County approved devices are required.

The detailed standards follow. Section 6.04.02 sets catch basin spacing by grade: 500 feet up to seven percent, 400 feet from seven to ten percent, and 250 feet over ten percent. Section 6.04.03 requires pipes in a County right-of-way to be at least eighteen inches in diameter, and it limits the maximum velocity for unlined ditches to five feet per second design flow. The maximum continuous pipe length is three hundred feet for pipes less than forty-two inches.

Section 6.04.06 governs detention. When an independent state approved professional finds it necessary, a development must submit a certified hydrology study showing that drainage will not adversely affect downstream property owners. If the study shows the development will increase runoff by more than seven cfs for a 100-year storm, storage and release can be required, and no building permit shall be granted unless storage and release is provided for the water volume generated by a 100-year storm. Detention ponds with steep sides and more than two feet of standing water one hour after the storm need a fence at least five feet high with a ten foot gate, and the owner and successors must maintain detention and retention facilities.