(a) Public health standards.
(1) 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.
(2) New and replacement water supply systems, wells, sanitary sewer lines and on-site waste disposal systems may be permitted, provided that all manholes or other aboveground openings located below the flood protection elevation are water tight.
(3) Public utilities and facilities such as sewer, gas and electric shall be located and constructed to minimize or eliminate flood damage.
(4) 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.
(5) All other activities, defined as development, such as pools, fences, filling, paving, etc., shall be designed so as not to alter flood flows or increase potential flood damages, nonstructural fill within a coastal high hazard area (zone V, V1-30, or VE) or within a moderate wave action area shall be permitted only if an engineering report demonstrates that the fill will not cause wave runup, ramping, or deflection of floodwaters that cause damage to buildings.
(6) The use of fill for structural support of buildings within a coastal high hazard area (zone V, V1-30, or VE) or within a moderate wave action area is prohibited.
(7) Man-made alterations of sand dunes within a coastal high hazard area (zone V, V1-30, or VE) or within a moderate wave action area are prohibited unless an engineering report documents that the alterations will not increase potential flood damage by reducing the wave and flow dissipation characteristics of the sand dunes.
(8) Within a coastal high hazard area or within a moderate wave action area, bulkheads, seawalls, revetments, and other erosion control structures shall not be connected to the foundation or superstructure of a building, and shall be designed and constructed so as not to direct floodwaters or increase flood forces or erosion impacts on the foundation or superstructure of any building.
(b) Carrying capacity and notification. For all projects involving channel modification, fill or stream maintenance (including without limitation levees), the flood carrying capacity of the watercourse shall be maintained. In addition, the village shall notify adjacent communities in writing within 30 days prior to the issuance of a permit for the alteration or relocation of the watercourse.
(c) Protecting buildings.
(1) All buildings located within zones A, AO, AH, and AE shall be protected from flood damage below the flood protection elevation. Existing buildings located within a regulatory floodway also shall meet the more restrictive appropriate use standards included in § 9-99. These building protection criteria shall apply to the following situations:
A. Construction or placement of a new building;
B. A structural alteration to an existing building that either increases the first floor area by more than 20% or the building’s market value by more than 50%;
C. Substantial improvements, made to any existing building. If substantially improved, both the existing building and any addition must meet the flood protection standards of this section.
D. Substantially damaged building under repair. Substantial damage shall be figured cumulatively during a ten-year period by comparing the cost to repair the building to its pre- damage condition with the market value of the building immediately prior to the damage, for each event in which the building sustains damage, and adding the percentages of damage for each event. If substantially damaged, the entire building must meet the flood protection standards of this section.
E. Installation of 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; and
F. Installation of a travel trailer on a site for more than 180 days.
G. Repetitive loss to an existing building.
(2) Residential buildings. In zones A, AO, AH, and AE, the lowest floor, including basement of new construction of residential buildings, and substantially improved residential buildings, must be elevated to the FPE, and are subject to the more specific additional requirements below.
A. If fill, including grading to redistribute onsite material to alter existing topographv, is used as a means of elevation:
1. The fill shall be placed in lavers no greater than six inches before compaction and must extend at least 20 feet beyond the foundation before sloping below the FPE in lieu of a geotechnical report.
2. The fill shall be protected against erosion and scour during flooding by vegetative cover, riprap, or other structural measure.
3. The fill shall be composed of clean rock or soil and not include debris or refuse material.
4. The fill shall not adversely affect the flow of surface drainage from or onto neighboring properties.
B. If the building's lowest floor is elevated above ground level with an enclosed or unenclosed area below the lowest floor:
1. The building shall be elevated on piles, walls, columns, or other foundation that is permanently open to floodwaters.
2. All enclosed areas below the FPE shall provide for equalization of hydrostatic pressures by allowing the automatic entry and exit of floodwaters. A minimum of two permanent openings shall be provided on at least two walls located below the BFE and no more than one foot above finished 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, or the design must be certified by a registered P.E. as providing the equivalent performance in accordance with accented standards of practice. Refer to FEMA TB1, Openings in Foundation Walls and Walls of Enclosures, for additional guidance.
3. All electrical lines, switches, receptacles, and fixtures must be located above the FPE except to the minimum extent required by applicable building or life-safety codes. Any switches, receptacles, and/or fixtures required by applicable building or life-safety codes to extend below the FPE shall be rated, or located in enclosures rated, for prolonged submersion.
4. The building, foundation, and supporting members shall be adequately anchored to prevent flotation, collapse, or lateral movement of the building resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy, and be designed so as to minimize exposure to current, waves, ice, and floating debris.
5. All building components below the FPE shall be constructed of materials resistant to flood damage.
6. Water and sewer pipes, electrical and telephone lines, submersible pumps, and other service facilities may be located below the FPE provided they are waterproofed.
7. The area below the FPE shall be used solely for parking, storage, or building access and not later modified or occupied as habitable space.
(3) Nonresidential buildings. In zones A, AO, AH, and AE, the lowest floor (including basement) of new construction of nonresidential buildings, and substantial improvement of nonresidential buildings, must either (1) be elevated to or above the FPE, subject to the more specific additional requirements of subsections 9-101(c)(2)(A) through 9-101(c)(2)(B) above; or (2) be structurally dry-floodproofed, provided a registered P.E. or architect has developed and/or reviewed the structural design, specifications, and plans for construction, and the registered P.E. or architect submits a FEMA floodproofing certificate, certifying that the design and methods of construction are in accordance with accepted standards of practice for meeting the requirements of ASCE 24-14, and the following conditions:
A. Below the FPE, the building and attendant utility and sanitary facilities shall be watertight with walls substantially impermeable to the passage of water and structural components capable of resisting hydrostatic and hydraulic loads and the effects of buoyancy.
B. The building design accounts for flood velocities, duration, rate of rise, hydrostatic and hydrodynamic forces, the effects of buoyancy, and impact from debris and ice.
C. Floodproofing measures will be incorporated into the building design and operable without human intervention and without an outside source of electricity.
D. The building, utility, and sanitary facilities' design and construction will prevent the effect of sewer backup into the building.
E. Levees, berms, floodwalls, and similar works are not considered floodproofing for the purpose of this article XIV.
(4) Manufactured homes. In zones A, AO, AH, and AE, all placement or substantial improvement of manufactured homes and permanent installation of travel trailers on site for more than 180 consecutive days, shall be:
A. Elevated with the lowest floor at or above the FPE using a support and anchoring system, designed by a P.E. pursuant to 77 Ill. Adm. Code § 870.110.
B. Anchored to resist flotation, collapse, or lateral movement by being tied down in accordance with the rules and regulations for the Illinois Mobile Home Tie-Down Act issued pursuant to 77 Ill. Adm. Code § 870.220.
(5) Recreational vehicles. In zones A, AO, AH, and AE, travel trailers and recreational vehicles, on site for more than 180 consecutive days, shall meet the elevation requirement and anchoring requirements of subsection 9-101(c)(4) unless the following conditions are met:
A. The vehicle must be either self-propelled or towable by a light duty truck.
B. The vehicle must not be attached to any permanent additions or external structures, such as decks and porches.
C. The vehicle must be designed solely for recreation, camping, travel, or seasonal use rather than as a permanent dwelling.
D. The vehicles having a total area not exceeding 400 square feet when measured at the largest horizontal projection.
E. The vehicle's wheels must remain on axles and have inflated tires.
F. Any air conditioning units must be attached to the frame so as to be safe for movement out of the floodplain.
G. The vehicle must be attached to a site only by quick disconnect type utilities and security devices. Utility connections include, but are not limited to, propane tanks, electrical and sewage.
H. The vehicle must be licensed and titled as a recreational vehicle or park model, be entirely supported by jacks, or have a hitch jack permanently mounted, have the tires touching the ground and be supported by block in a manner that will allow the block to be easily removed by use of the jacks/hitch jack.
(6) Accessory structures. In zones A, AO, AH, and AE, detached accessory structures may be constructed with the lowest floor below the FPE provided the following conditions are met:
A. The building must be non-habitable, must not include areas intended or used for cooking, and must not include bathrooms, toilet rooms, or shower rooms.
B. All areas below the BFE shall be constructed with flood-resistant materials.
C. The building must be used only for the storage and parking and cannot be modified later into another use.
D. The building shall be located outside of the designated floodway unless the building can be constructed and placed on a building site so as not to block flood flows nor reduce floodway storage (§ 9-99). can also meet the appropriate use criteria of § 9-99, and all other applicable requirements of this article XIV.
E. All electrical lines, switches, receptacles, and fixtures must be located above the FPE except to the minimum extent required by applicable building or life-safety codes. Any switches, receptacles, and/or fixtures required by applicable building or life-safety codes to extend below the FPE shall be rated, or located in enclosures rated, for prolonged submersion.
F. No plumbing, heating, or air conditioning shall be permitted in accessory structures allowed under this subsection to be wet floodproofed in lieu of elevation.
G. The structure must have at least two permanent openings on at least two walls not more than one foot above grade and below the BFE, with one square inch of opening for every one square foot of floor area.
H. The structure must be no more than one story in height and no more than 600 square feet in size.
I. The building shall be anchored to resist floatation and overturning.
J. All flammable or toxic materials (gasoline, paint, insecticides, fertilizers, etc.) shall be stored above the FPE.
K. The lowest floor elevation should be documented, and the owner advised of the flood insurance implications of building with the lowest floor below the BFE.
(7) In floodplain zones AD and AD, drainage paths shall be provided to guide water around and away from the buildings.
(8) The repair, remodeling, or maintenance of existing buildings located within a designated floodway, built before November 18, 1987, are exempt from 17 Ill. Adm. Code Part 3708, including the more restrictive appropriate use standards. Such buildings are not exempt from subsection 9-101(c)(1). including substantial damage and substantial improvement requirements, and if enlarged, replaced, or structurally altered must meet the requirements of 17 Ill. Adm. Code Part 3708.
(9) A. New construction or substantial improvement of critical facilities within the floodplain or the 0.2% annual chance flood elevation when defined, shall have the lowest floor (including basement) elevated or structurally dry floodproofed to the 0.2% annual chance flood elevation or three feet above the BFE, whichever is greater. Adequate parking shall be provided for staffing of the critical facilities at or above the BFE or 0.2% chance flood, when defined. Access routes to all critical facilities should be reviewed and considered when permitting. Access routes should be elevated to or above the level of the BFE.
B. Floodproofing and sealing measures may also be used to provide protection, as described in § 9-101(c)(7), and must be taken to ensure that toxic substances will not be displaced by or released into floodwaters.
(10) In a coastal high hazard area (zone VE) and in any area of zone AE designated as a moderate wave action area, the building protection requirements of this § 9-101 must be met according to the following criteria:
A. All new construction and substantial improvements shall be elevated on pilings or columns so that the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated to or above the FPE, and the pile or column foundation and structure attached thereto is anchored to resist flotation, collapse, and lateral movement due to the effects of wind and water loads acting simultaneously on all building components.
1. Water loading values used shall be those associated with the base flood.
2. Wind loading values shall be those defined according to American Society of Civil Engineers 7-16 Minimum design loads and associated criteria for buildings and other structures, or other equivalent standard.
B. A registered professional engineer or architect shall develop or review the structural design, specifications and plans for the construction, and shall certify that the design and methods of construction to be used are in accordance with accepted standards of practice for meeting the provisions of § 9-101(c)(10)A.
C. All new construction and substantial improvements shall have the space below the lowest floor either free of obstruction or constructed with non-supporting breakaway walls, open wood lattice-work, or insect screening intended to collapse without causing collapse, displacement, or other structural damage to the elevated portion of the building or supporting foundation system.
1. For the purpose of § 9-101(c)(10)C., a breakaway wall shall have a design safe loading resistance of not less than ten and no more than 20 pounds per square foot.
2. Use of breakaway walls which exceed a design safe loading resistance of 20 pounds per square foot (either by design or where so required by local or state codes) may be permitted only if a registered professional engineer or architect certifies that the designs proposed meet all of the following conditions:
a. Breakaway wall collapse shall result from a water load less than that which would occur during the base flood;
b. The elevated portion of the building and supporting foundation system shall not be subject to collapse, displacement or other structural damage due to the effects of wind and water loads acting simultaneously on all building components (structural and non-structural). Water loading values shall be those associated with the base flood. Wind loading values shall be those defined according to American Society of Civil Engineers 7-16 Minimum design loads and associated criteria for buildings and other structures, or equivalent standard; and
c. All space enclosed by breakaway walls, open wood lattice-work, or insect screening below the lowest floor shall be used solely for parking of vehicles, building access, or storage.
(11) When construction of a building following a LOMR based on fill is requested, the condition where a site in the floodplain is removed due to the use of fill to elevate the site above the BFE, the applicant may not apply for a permit from the village to construct the lowest floor of a building below the BFE in the floodplain.
(d) Compensatory storage.
(1) Whenever any portion of a riverine floodplain is authorized for use, the volume of space which will be occupied by the authorized fill or structure below the BFE shall be compensated for and balanced by a hydraulically equivalent volume of excavation taken from below the BFE.
(2) The excavation volume shall be at least equal to 1.5 times the volume of storage lost due to the fill or structure.
(3) In the case of streams and watercourses, such excavation shall be made opposite or adjacent to the areas so filled or occupied.
(4) All floodplain storage lost below the existing 10% annual chance flood elevation shall be replaced below the proposed 10% annual chance flood elevation. All floodplain storage lost above the existing 10% annual chance flood elevation shall be replaced above the proposed 10% annual chance flood elevation. All such excavations shall be constructed to drain freely and openly to the watercourse.
(Ord. No. 2021-16-3512; Ord. No. 2021-17-3513)