; and (II) that the structure is not located in— (aa) a designated regulatory floodway; (bb) an area riverward of a levee or other flood control structure; or (cc) an area subject to high velocity wave action or seaward of flood control structures. (iii) In the case of existing structures— (I) if such structure is substantially damaged or in need of substantial repairs or improvements, such official has determined that neither floodproofing nor elevation to the base flood elevation is practicable