§ 151.055  STREET, PARKING LOT AND UNDERGROUND STORAGE.
   The following design criteria shall be met where streets, parking lots and culverts are proposed to be used for stormwater detention or conveyance.
   (A)   Streets.  If streets are to be used as part of the major drainage system, ponding depths shall not exceed three inches at the street centerline and the street shall not remain flooded for more than eight hours for the 100-year frequency event.
   (B)   Parking lots.  The maximum ponding depth in parking facilities designed to store excess stormwater runoff shall not exceed 12 inches at the deepest point, and the duration of flooding shall not exceed eight hours for the 100-year frequency event. Storage in parking facilities shall only be allowed in the most remote, least-used areas of the parking facilities.
   (C)   Underground. Underground stormwater storage facilities must meet the following design criteria.
      (1)   Access to all chambers shall be provided in order to remove accumulated sediment and debris.
      (2)   Underground facilities shall be provided with a positive gravity outlet.
      (3)   Storage volume shall only be provided in the pipe. Void space volume of bedding material will not be considered as part of the detention volume.
(Ord. 07-02, passed 4-16-2007)