In addition to the requirements found in sections 12-1-7-1, 12-1-7-2 and 12-1-7-3 of this chapter for development in flood fringes, designated floodways and SFHA or floodplains where no floodways have been identified (zones A, AO, AH, AE, A1-A30, A99, VO, V1-30, VE, V, M, E, or D), the following requirements shall be met:
A. Health Standards: Public health standards.
B. Storing Hazardous Materials: No developments in the SFHA shall include locating or storing chemicals, explosives, buoyant materials, animal wastes, fertilizers, flammable liquids, pollutants, or other hazardous or toxic materials below the flood protection elevation (FPE).
C. Minimizing Flood Damage: Public utilities and facilities such as sewer, gas and electric shall be located and constructed to minimize or eliminate flood damage. Public sanitary sewer systems and water supply systems shall be located and constructed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters. New and replacement water supply systems, wells, sanitary sewer lines and on site waste disposal systems may be permitted providing all manholes or other aboveground openings located below the FPE are watertight.
D. Carrying Capacity And Notification: For all projects involving channel modification, fill or stream maintenance (including levees), the flood carrying capacity of the watercourse shall be maintained. In addition, the city shall notify adjacent communities in writing thirty (30) days prior to the issuance of a permit for the alteration or relocation of the watercourse.
E. Protecting Buildings:
1. All buildings located within a 100-year floodplain, also known as an SFHA, and all buildings located outside the 100-year floodplain but within the 500-year floodplain, shall be protected from flood damage below the flood protection elevation. This building protection criteria applies to the following situations:
a. Construction or placement of a new building valued at more than one thousand dollars ($1,000.00) or seventy (70) square feet.
b. "Substantial improvement" to an existing building as defined in section 12-1-4 of this chapter, including an increase to the first floor area by more than twenty percent (20%). This alteration shall be figured cumulatively beginning with any alteration which has taken place subsequent to April 1, 1990.
c. Installing a manufactured home on a new site or a new manufactured home on an existing site. This building protection requirement does not apply to returning a mobile home to the same site it lawfully occupied before it was removed to avoid flood damage.
d. Installing a travel trailer on a site for more than one hundred eighty (180) days per year.
e. "Substantial damage" to an existing building as defined in section 12-1-4 of this chapter. This alteration shall be figured cumulatively beginning with any alteration which has taken place subsequent to April 1, 1990.
f. "Repetitive loss" to an existing building as defined in section 12-1-4 of this chapter.
2. This building protection requirement may be met by one of the following methods:
a. A residential or nonresidential building, when allowed, may be constructed on permanent landfill in accordance with the following:
(1) Lowest Floor: The lowest floor (including basement) shall be at or above the flood protection elevation.
(2) Fill Requirements:
(A) The fill shall be placed in layers no greater than one foot (1') deep before compaction and should extend at least ten feet (10') beyond the foundation of the building before sloping below the flood protection elevation.
(B) The top of the fill shall be above the flood protection elevation. However, the ten foot (10') minimum may be waived if a structural engineer certifies an alternative method to protect the building from damages due to hydrostatic pressures.
(C) The fill shall be protected against erosion and scour.
(D) The fill shall not adversely affect the flow or surface drainage from or onto neighboring properties.
b. A residential or nonresidential building may be elevated in accordance with the following:
(1) The building or improvements shall be elevated on crawl space, stilts, piles, walls or other foundation that is permanently open to floodwaters and not subject to damage by hydrostatic pressures of the base flood or 100-year frequency flood. The openings must have 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.
(2) 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.
(3) All areas below the flood protection elevation shall be constructed of materials resistant to flood damage.
(A) 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 flood protection elevation.
(B) Water and sewer pipes, electrical and telephone lines, submersible pumps, and other waterproofed service facilities may be located below the flood protection elevation.
(4) The areas below the flood protection elevation may only be used for the parking of vehicles, building access or storage in an area other than a basement and not later modified or occupied as habitable space.
(5) Manufactured homes, and travel trailers to be installed on a site for more than one hundred eighty (180) days, shall be elevated to or above the flood protection elevation; and, shall be anchored to resist flotation, collapse, or lateral movement by being tied down in accordance with the rules and regulations for the Illinois mobile home tiedown act issued pursuant to 77 Illinois administrative code part 870. In addition, all manufactured homes shall meet the following elevation requirements:
(A) In the case of manufactured homes placed or substantially improved: 1) outside of a manufactured home park or subdivision, 2) in a new manufactured home park or subdivision, 3) in an expansion to an existing manufactured home park or subdivision, or 4) in an existing manufactured home park or subdivision on which a manufactured home has incurred substantial damage from a flood, the top of the lowest floor shall be elevated to or above the flood protection elevation.
(B) In the case of manufactured homes placed or substantially improved in an existing manufactured home park or subdivision, the manufactured home shall be elevated so that either the top of the lowest floor is above the base flood elevation or the chassis is at least thirty six inches (36") in height above grade and supported by reinforced piers or other foundations of equivalent strength, whichever is less.
(6) Recreational vehicles or travel trailers shall be required to meet the elevation and anchoring requirements of subsection E2b(5) of this section unless:
(A) They are on site for fewer than one hundred eighty (180) consecutive days; and
(B) They are fully licensed, ready for highway use, and used only for recreation, camping, travel or seasonal use rather than as a permanent dwelling. A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utility and service devices, and has no permanently attached additions.
c. Only a nonresidential building may be structurally dry floodproofed (in lieu of elevation) provided that:
(1) A registered professional engineer or architect shall certify that the building has been structurally dry floodproofed below the flood protection elevation, the structure and attendant utility facilities are watertight and capable of resisting the effects of the base flood or 100-year frequency flood.
(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 (levees, berms, floodwalls and similar works are not considered floodproofing for the purpose of this subsection).
d. A building may be constructed with a crawl space located below the flood protection elevation provided that the following conditions are met:
(1) The building must be designed and adequately anchored to resist flotation, collapse, and lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy; and
(2) Any enclosed area below the flood protection elevation shall have openings that equalize hydrostatic pressures by allowing for the automatic entry and exit of floodwaters. A minimum of one opening on each wall having a total net area of not less than one square inch per one square foot of enclosed area. The openings shall be no more than one foot (1') above grade; and
(3) The interior grade of the crawl space below the flood protection elevation must not be more than two feet (2') below the lowest adjacent exterior grade; and
(4) The interior height of the crawl space measured from the interior grade of the crawl space to the top of the foundation wall must not exceed four feet (4') at any point; and
(5) An adequate drainage system must be installed to remove floodwaters from the interior area of the crawl space within a reasonable period of time after a flood event; and
(6) Portions of the building below the flood protection elevation must be constructed with materials resistant to flood damage; and
(7) Utility systems within the crawl space must be elevated above the flood protection elevation.
e. Critical facilities shall be protected to the 500-year flood elevation. In addition, all ingress and egress from any critical facility must be protected to the 500-year flood elevation.
f. Toolsheds, detached garages, and other minor accessory structures on an existing single-family platted lot, may be constructed with the lowest floor below the flood protection elevation in accordance with the following:
(1) The building is not used for human habitation.
(2) All areas below the base flood or 100-year frequency flood elevation shall be constructed with waterproof material. Structures located in a designated floodway shall be constructed and placed on a building site so as not to block the flow of floodwaters and shall also meet the appropriate use criteria of section 12-1-7-2 of this chapter. In addition, all other requirements of sections 12-1-7-1, 12-1-7-2 and 12-1-7-3 of this chapter must be met.
(3) The structure shall be anchored to prevent flotation.
(4) Service facilities such as electrical and heating equipment shall be elevated or floodproofed to the flood protection elevation.
(5) The building shall be valued at less than ten thousand dollars ($10,000.00) and be less than five hundred (500) square feet in floor size.
(6) The building shall be used only for the storage of vehicles or tools and may not contain other rooms, workshops, greenhouses or similar uses.
(7) The building shall meet the permanent opening criteria of subsection E2b(1) of this section.
g. Existing buildings located within a designated floodway shall also meet the more restrictive appropriate use standards included in section 12-1-7-2 of this chapter. Nonconforming structures located in a designated floodway may remain in use and may only be enlarged, replaced or structurally altered in accordance with subsection 12-1-7-2C of this chapter. A nonconforming structure damaged by flood, fire, wind or other natural or manmade disaster may be restored unless the damage exceeds fifty percent (50%) of its market value before it was damaged, in which case it shall conform to this chapter. (Ord. O-20-2008, 6-16-2008)