§ 151.43  STANDARDS FOR AREAS OF SHALLOW FLOODING (AO/AH ZONES).
   Located within the areas of special flood hazard established in § 151.08, are areas designated as shallow flooding. These areas have special flood hazards associated with flood depths of one to three feet where a clearly defined channel does not exist, where the path of flooding is unpredictable, and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply.
   (A)   All new construction and substantial improvements of residential structures have the lowest floor (including basement) elevated to three feet above the base flood elevation where FEMA Flood Insurance Study data exists or two feet above the base flood elevation as determined by a study using fully urbanized hydrology or the highest adjacent grade at least as high as the depth number specified in feet on the community’s FIRM (at least three feet if no depth number is specified).
   (B)   All new construction and substantial improvements of non-residential structures:
      (1)   Have the lowest floor (including basement) elevated to three feet above the base flood elevation where FEMA Flood Insurance Study data exists or two feet above the base flood elevation as determined by a study using fully urbanized hydrology or the highest adjacent grade at least as high as the depth number specified in feet on the community’s FIRM (at least two feet if no depth number is specified); or
      (2)   Together with attendant utility and sanitary facilities be designed so that below the base specified flood depth in an AO Zone, or below the Base Flood Elevation in an AH Zone, level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads of effects of buoyancy.
   (C)   A registered professional engineer or architect shall submit a certification to the Floodplain Administrator that the standards of this section, as proposed in § 151.27 are satisfied.
   (D)   Require within Zones AH or AO adequate drainage paths around structures on slopes, to guide flood waters around and away from proposed structures.
(Ord. OR-1871-13, passed 4-8-13)