(A) Public health and other standards.
(1) No developments in the floodplain shall include locating or storing chemicals, explosives, buoyant materials, animal wastes, fertilizers, flammable liquids, pollutants, or other hazardous or toxic materials below the FPE unless such materials are stored in a floodproofed and anchored storage tank and certified by a P.E. or floodproofed building constructed according to the requirements of § ________of this chapter.
(2) Public utilities and facilities such as sewer, gas and electric shall be located and constructed to minimize or eliminate flood damage.
(3) 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.
(4) New and replacement water supply systems, wells, sanitary sewer lines and on-site waste disposal systems may be permitted providing all manholes or other above ground openings located below the FPE are watertight. New and replacement on-site sanitary sewer lines or waste disposal systems shall be located and constructed to avoid impairment to them or contamination from them during flooding.
(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.
(B) Carrying capacity and notification of adjacent communities.
(1) For all projects involving channel modification, fill, or stream maintenance (including levees), the flood carrying capacity of the watercourse shall be maintained.
(2) In addition, the village shall notify adjacent communities in writing 30 days prior to the issuance of a permit for the alteration or relocation of the watercourse.
(C) Protecting buildings.
(a) New construction or placement of a new building or alteration or addition to an existing building valued at more than $1,000 or 70 square feet.
(b) Substantial improvements, including any combination of alteration, repair, rehabilitation, reconstruction, addition, or other improvements made to an existing building that equal or exceed the market value by 50%, or that increase the floor area by more than 20%. Alteration shall be figured cumulatively ten-year period. If substantially improved, the existing building and the addition must meet the flood protection standards of this section.
(c) Any repairs made to a substantially damaged building. Substantial damage shall be figured cumulatively 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.
(d) Installing a manufactured home on a new site or a manufactured home on an existing site. (The building protection requirements do not apply when returning a manufactured home to the same site it lawfully occupied before it was removed to avoid flood damage).
(e) Installing a travel trailer or recreational vehicle on a site for more than 180 consecutive days; and
(f) Repetitive loss to an existing building as defined in § 152.02.
(2) The lowest floor (including basement) of new construction of residential buildings, and substantially improved residential buildings, must be elevated to the FPE, subject to the more specific additional requirements in § 152.24 below.
(a) If fill, including grading to redistribute onsite material to alter existing topography, is used as a means of elevation:
1. The lowest floor (including basement) shall be at or above the FPE.
2. The fill shall be placed in layers no greater than six inches before compaction and must extend at least ten feet beyond the foundation before sloping below the FPE.
3. The top of the fill shall be above the FPE. However, the ten-foot minimum may be waived if a structural engineer certifies an alternative method to protect the building from damages due to hydrostatic pressures.
4. The fill shall be protected against erosion and scour during flooding by vegetative cover, riprap, or other structural measure.
5. The fill shall be composed of clean rock or soil and not include debris or refuse material.
6. 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, crawlspace, 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. Each wall must have a minimum of one permanent opening that is 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 below the BFE, or the design must be certified by a registered P.E., as providing the equivalent performance in accordance with accepted standards of practice. Refer to FEMA TBI, Openings in Foundation Walls and Walls of Enclosures, for additional guidance.
3. All electrical, heating, ventilating, plumbing, and air conditioning equipment and utility meters shall be located at or above the FPE.
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 or building access and not later modified or occupied as habitable space.
(c) If the floor of any area of a building below the lowest floor is proposed to be below grade on all sides, typical for crawlspace construction, the building shall meet the requirements of this chapter and FEMA TB 11 Crawlspace Construction for Buildings Located in Special Flood Hazard Areas. The building, while NFIP compliant, will be considered to have a basement for NFIP insurance purposes.
1. The building shall be designed and adequately anchored to resist flotation, collapse, and lateral movement of the building resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.
2. All enclosed areas below the FPE shall provide for equalization of hydrostatic pressures by allowing the automatic entry and exit of floodwaters. Each wall must have a minimum of one permanent opening that is 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 below the BFE, or the design must be certified by a registered P.E. as providing the equivalent performance in accordance with accepted standards of practice. Refer to FEMA TB 1, Openings in Foundation Walls and Walls of Enclosures, for additional guidance.
3. Per FEMA TB 11, the crawlspace shall be designed so that:
A. The interior grade of the crawlspace floor below the FPE must not be more than two feet below the lowest adjacent grade.
B. The interior height of the crawlspace measured from the interior grade of the crawl to the top of the foundations wall must not exceed four feet at any point.
C. An adequate drainage system must be installed to remove floodwaters from the interior area of the crawlspace within a reasonable period of time after a flood event.
D. The velocity of floodwater at the site shall not exceed five feet per second.
4. Portions of the building below the FPE must be constructed with materials resistant to flood damage.
5. Utility systems within the crawlspace must be elevated above the FPE.
(3) 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 this section; or (2) be structurally dry-floodproofed (in lieu of elevation), provided a registered P.E. or architect submits a FEMA floodproofing certificate, documenting that the registered P.E. or architect developed and/or reviewed the structural design, specifications, and plans for construction, and that the engineer or architect certifies 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 requirements listed below:
(a) Below the FPE, the building and attendant utility and sanitary facilities are 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) Flood proofing 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 flood proofing for the purpose of this chapter.
(4) All placement of manufactured homes and or travel trailers, to be permanently installed on site for more than 180 consecutive days, shall be:
(a) Elevated to 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) Travel trailers and recreational vehicles, on site for more than 180 consecutive days, shall meet the elevation requirement and anchoring requirements of division (C)(4) above 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 measured when all horizontal projections are fully expanded.
(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, and must either be entirely be 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) Garages, sheds or other minor accessory structures constructed ancillary to an existing residential use may be constructed with the lowest floor below the FPE provided the following conditions are met:
(a) The building must be not be constructed and used for habitation, must not include areas intended or used for living, sleeping, eating, or 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 of vehicles and tools 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 (§ 152.21), can also meet the appropriate use criteria of § 152.21 and all other applicable requirements of this chapter.
(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 garages, sheds, or other minor accessory structures allowed to be wet floodproofed under this section in lieu of elevation.
(g) The building must have at least one permanent opening on each wall below the BFE and not more than one foot above the finished, outside grade with one square inch of opening for every one square foot of floor area.
(h) The building must be less than $15,000 in market value or replacement cost whichever is greater or less than 576 square feet (24 feet x 24 feet).
(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 flood below the BFE.
(7) In floodplain Zones AO and AH, drainage paths shall be provided around buildings on sloped ground to guide water away from the buildings.
(8) Existing buildings located within a designated floodway shall also meet the more restrictive appropriate use standards included in § 152.21. Non-conforming buildings located in a designated floodway may remain in use and may only be enlarged, replaced or structurally altered in accordance with § 152.21. A non-conforming building damaged by flood, fire, wind or other natural or man-made disaster may be restored unless the damage exceeds 50% of its market value before it was damaged, in which case it shall conform to this chapter.
(9) (a) New construction or substantial improvement of 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 0.2% chance flood elevation or three feet above the BFE whichever is greater.
(b) 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. As necessary, adequate parking, at or above the BFE, shall be provided for staffing of the critical facilities during a flood. Critical facilities may include: emergency services facilities (such as fire and police stations), schools, sewage treatment plants, water treatment plants, sanitary pumping stations, hospitals, retirement homes, senior care facilities, major roads and bridges, critical utility sites (telephone switching stations or electrical transformers), and hazardous material storage facilities (chemicals, petrochemicals, hazardous or toxic substances).
(Ord. 93-O-048, passed 6-22-93; Am. Ord. 2000-O-103, passed 11- 7-00; Am. Ord. 2019-O-003, passed 2-5-19; Am. Ord. 2019-O-054, passed 9-17-19)