Buildings located in Zones A, AO, AH or AE that are subject to Section 16-6-060 must meet the protection requirements described in this section.
(a) If a building is constructed on a permanent landfill:
(i) The fill shall be placed in layers no more than six inches deep before compaction and shall extend at least ten feet beyond the outside of the wall of the existing or proposed building;
(ii) The fill shall be protected against erosion and scour by vegetative cover, riprap or other structural measure;
(iii) The fill shall be homogeneous and isotropic;
(iv) The fill shall not adversely affect the flow of surface drainage from or onto the property;
(v) The foundation and supporting members shall be anchored and aligned in relation to flood flows and adjoining structures so as to minimize exposure to known hydrodynamic forces such as current, waves, ice and floating debris;
(vi) All areas below the F.P.E. shall be constructed of materials resistant to flood damage. The lowest floor (including basement) and all electrical, heating, ventilating, plumbing and air conditioning equipment and utility meters shall be located at or above the F.P.E. water and sewer pipes, electrical and telephone lines, submersible pumps and other waterproofed service facilities may be located below the F.P.E.
(b) If a building is elevated:
(i) The building improvements shall be elevated on posts, piers, piles, walls, or other foundation that is permanently open to flood waters.
(ii) The foundation and supporting members shall be anchored and aligned in relation to flood flows and adjoining structures so as to minimize exposure to known hydrodynamic forces such as current, waves, ice and floating debris;
(iii) All areas below the F.P.E. shall be constructed of materials resistant to flood damage. The lowest floor (including basement) and all electrical, heating, ventilating, plumbing and air conditioning equipment and utility meters shall be located at or above the F.P.E. water and sewer pipes, electrical and telephone lines, submersible pumps and other waterproofed service facilities may be located below the F.P.E.
(iv) If walls are used, all enclosed areas below the flood protection elevation shall address hydrostatic pressures by allowing the automatic entry and exit of floodwaters. Designs must either be certified by a registered professional engineer or by having a minimum of one permanent opening on at least two different walls no more than one foot above grade. The openings shall provide a total net area of not less than one square inch for every one square foot of enclosed area subject to flooding below the base flood elevation.
(v) Any area below the F.P.E. shall be used solely for parking, building access or storage and shall not later be converted to habitable space or other uses.
(c) A nonresidential building not built on permanent landfill and not elevated shall be floodproofed in accordance with the following:
(i) A registered professional engineer shall certify that the building has been designed so that below the F.P.E., the structure and attendant utility facilities are watertight and capable of resisting the effect of the base flood. The building design shall take into account flood velocities, duration, rate of rise, hydrostatic and hydrodynamic forces, the effects of buoyancy, and impacts from debris and ice;
(ii) Floodproofing measures shall be operable without human intervention and without an outside source of electricity.
(d) A recreational vehicle is to be installed on a site for more than 180 days, or a manufactured home, shall be elevated at or above the F.P.E. and anchored to resist flotation, collapse or lateral movement by being tied down in accordance with the rules and regulations issued pursuant to the Illinois Home Tie-Down Act, as amended.
(Added Coun. J. 6-28-91, p. 2766; Amend Coun. J. 6-29-05, p. 51811, § 1; Amend Coun. J. 7-21-21, p. 33505, § 6)