(A) New construction, substantial improvements, and all other development, including fill, shall be prohibited within zones numbered A1-30 on the FIRM, except where it is demonstrated to the Zoning Administrator that the cumulative effect of the proposed development when combined with all other existing and anticipated development will not harmfully increase the water surface elevation of a base flood. In determining whether a harmful increase will occur, compliance with Public Act 245 of 1929, being M.C.L.A. §§ 323.1 - 323.12, as amended by Public Act 167 of 1968, being M.C.L.A. §§ 323.1 - 323.5b, shall be required, provided that the allowable increase shall not exceed 1 foot. The provisions of this section shall not apply within the regulatory floodway. The provisions of subsection (B) shall be applied to land situated within the regulatory floodway.
(B) All development occurring within the regulatory floodway shall comply with the following standards:
(1) Encroachments, including fill, new construction, substantial improvements, and other development shall be prohibited. Exception to this prohibition shall only be made upon certification by a registered professional engineer or the Department of Natural Resources that the development proposed will not result in any increases in flood levels during a base flood discharge, and compliance with Public Act 245 of 1929, being M.C.L.A. §§ 323.1 - 323.12, as amended by Public Act 167 of 1968, being M.C.L.A. §§ 323.1 - 323.5b;
(2) The placement of mobile homes shall be prohibited except in mobile home parks and subdivisions which exist at the time this section is adopted; and
(C) The uses of land permitted in an underlying zoning district shall not be construed as being permitted within the regulatory floodway, except upon compliance with the provisions in this section.