Design of storm water detention facilities shall be based on a return period of once in 100 years. The storage volume and outflow rate shall be sufficient to handle storm water runoff from a critical duration storm, as defined in JCC 16.10.360 and 16.10.370. Rainfall depth-duration-frequency relationships and intensity-duration-frequency relationships shall be those given in Tables 5 and 5A (in JCC 16.10.500). [Ord. 12-1-97C § 15(B).]