(A) New buildings adjacent to the SFHA and within shaded Zone X shall be elevated to the FPE. Dry floodproofing for new buildings is not permitted in lieu of compliance with the FPE requirements.
(B) Accessory structures, such as tool sheds, which are not substantial improvements on an existing single-family lot, may be constructed with the lowest floor below the FPE in accordance with all of the following criteria.
(1) The building shall not be used for human habitation, nor have water or sanitary sewer service.
(3) The structure shall be anchored to prevent flotation and movement.
(4) Service facilities such as electrical and heating equipment shall be elevated or floodproofed to the FPE.
(5) The building shall be no greater than 600 square feet in floor size. The building shall meet permanent opening criteria as established by the Will County Stormwater Ordinance.
(6) The building shall be used only for the storage of vehicles or tools and may not contain basements or other rooms, workshops, greenhouses, storage of hazardous materials, or similar uses.
(7) If located in a designated floodway, the structure shall be constructed and placed on a building site so as not to block flood flows nor reduce floodway storage and shall also meet the appropriate use criteria of § 152.028(B)(6) and all other applicable requirements of this chapter.
(C) Any modification to an existing structure with dry floodproofing shall provide the following:
(1) A registered professional engineer or structural engineer shall certify that the building has been structurally dry floodproofed below the FPE; the elevation to which the structure was floodproofed, and the structure and attendant utility facilities are watertight and capable of resisting the effects of the BFE. Fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and are subject to flooding, shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following criteria: A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided. The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
(2) 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 or ice.
(3) Floodproofing measures shall be operable without human intervention and without an outside source of electricity.
(4) Levees, berms, flood walls and similar works are not considered floodproofing for the purpose of this section.
(D) Construction of new or substantially improved critical facilities shall be located outside the limits of the floodplain. Construction of new critical facilities shall be permissible within the floodplain if no feasible alternative site is available. Critical facilities constructed within the SFHA shall have the lowest floor (including basement) elevated or structurally dry floodproofed to the 500-year flood frequency elevation or three feet above the level of the 100-year flood frequency elevation, whichever is greater. Floodproofing and sealing measures must be taken to ensure that toxic substances will not be displaced by or released into floodwaters. Access routes elevated to or above the level of the BFE shall be provided to all critical facilities.
(Ord. 3187, passed 1-22-19) Penalty, see § 152.999