A retention pond shall be defined as a permanent pool with sufficient capacity to store excess run-off and shall incorporate the following design criteria:
(A) Shall be designed so that a significant flush occurs in a five-year storm;
(B) Approaching slopes are a maximum five to one (5:1) or flatter;
(C) The pond shall have a shelf area along the sides, a minimum of three feet in width and a depth of no more than one foot before the pond pool area;
(D) The pond area shall be a minimum of three feet in depth;
(E) A two-stage weir shall be incorporated. First stage to allow flushing of the pond and second stage to limit the outflow for detention. Pond size shall be designed so that a significant flush occurs in a five-year storm;
(F) The pond shall incorporate an emergency overflow able to pass the inflow that would occur in a 100-year storm;
(G) The pond shall be designed so that as much flow as possible shall enter the pond through grass swales or sheet flow across grass areas;
(H) Developer shall submit a maintenance plan for sediment removal and water quality control; and
(I) A structure capable of dewatering the pond within 48 hours shall be incorporated into the pond design.
(2007 Code, § 34-6-44)