The following criteria shall be followed when designing a storm water management facility.
(A) Design storm. Storm water management facilities shall be designed to retain the difference in the pre-development and post-development, twenty-five year, 24-hour storm event. The effect of the 100-year storm must be considered and documented in the design of all storm water management facilities. Any detention basin located in a parking lot shall not be designed to hold water more than six inches deep.
(B) Design calculation. Design calculations submitted must include, but are not limited to, the following:
(1) Drainage area. Indicate if pre-development and post-development areas differ;
(2) List area drainage types and run-off coefficient numbers for predevelopment and post-development conditions;
(3) Stage - Storage curve for the proposed storm water management facility;
(4) Stage - Discharge curve for the outlet structure of the proposed storm water management facility;
(5) Inflow and outflow hydrographs for pre-development and post- development conditions; and
(6) Emergency spillway design calculations.
(Ord. 2017-07, passed 11-27-2017; Ord. 2020-06, passed 6-22-2020)