28-5.03   Standards for Streams Without Established Base Flood Elevation (Unnumbered A Zones and/or Floodways).
   Located within the special flood hazard areas established this Chapter, where streams exist but where no base flood data has been provided or where base flood data has been provided without floodways, the following provisions apply:
   a.   No encroachments, including fill material or structures, shall be located within special flood hazard areas unless certification by a registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot at any point within the City.  The engineering certification should be supported by technical data that conforms to standard hydraulic engineering principles; and,
   b.   New construction or substantial improvements of structures shall be elevated or flood proofed to elevations established in accordance with this Chapter.