(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 (FPE) unless such materials are stored in a floodproofed and anchored storage tank and certified by a professional engineer or floodproofed building constructed according to the requirements of division (C) of this section.
(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 flood waters into the systems and discharges from the systems into flood waters.
(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.
(5) All other activities defined as development shall be designed so as not to alter flood flows or increase potential flood damages.
(B) Carrying capacity and notification.
(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 city 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.
(1) All buildings located within a 100-year floodplain, also known as a SFHA, shall be protected from flood damage below the flood protection elevation. However, existing buildings located within a regulatory floodway shall also meet the more restrictive appropriate use standards included in §§ 159.40 through 159.42. This building protection criteria applies to the following situations:
(a) 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 or structural alterations made to an existing building that increase the floor area by more than 20% or equal or exceed the market value by 50%. Alteration shall be figured cumulatively. If substantially improved, the existing structure and the addition must meet the flood protection standards of this section;
(c) Repairs made to a substantially damaged building. These repairs shall be figured cumulatively. If substantially damaged the entire structure must meet the flood protection standards of this section;
(d) Installing a manufactured home on a new site or a new manufactured home on an existing site (the building protection requirements do not apply to 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 days per year; and
(f) Repetitive loss to an existing building as defined in § 159.02. This building protection requirement may be met by one of the following methods.
(2) A residential or non-residential building, when allowed, may be constructed on permanent land fill in accordance with the following:
(a) The lowest floor (including basement) shall be at or above the flood protection elevation; and
(b) Fill requirements:
1. The fill shall be placed in layers no greater than six inches deep before compaction and should extend at least ten feet beyond the foundation of the building before sloping below the flood protection elevation;
2. The top of the fill shall be above the flood protection elevation. 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;
3. The fill shall be protected against erosion and scour during flooding by vegetative cover, riprap or other structural measure;
4. The fill shall be composed of rock or soil and not incorporate debris or refuse materials; and
5. The fill shall not adversely affect the flow or surface drainage from or onto neighboring properties, and when necessary, stormwater management techniques such as swales or basins shall be incorporated.
(3) A residential or non-residential building may be elevated in accordance with the following:
(a) The building or improvements shall be elevated on crawl space, stilts, piles, walls, or other foundation that is permanently open to flood waters and not subject to damage by hydrostatic pressures of the base flood or 100-year frequency flood. Designs must include a minimum of two permanent openings, one on each wall, no more than one foot above existing grade. 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;
(b) 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;
(c) All areas below the flood protection elevation shall be constructed of materials resistant to flood damage:
1. 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; and
2. Water and sewer pipes, electrical and telephone lines, submersible pumps, and other waterproofed service facilities may be located below the flood protection elevation provided they are waterproofed;
(d) No area below the flood protection elevation shall be used for storage of items or materials;
(e) Manufactured homes, and travel trailers to be installed on a site for more than 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 Tie-Down Act issued pursuant to 77 Ill. Adm. Code Part 870 or any successor provisions. In addition, all manufactured homes shall meet the following elevation requirements:
1. In the case of manufactured homes placed or substantially improved outside of a manufactured home park or subdivision, in a new manufactured home park or subdivision, in an expansion to an existing manufactured home park or subdivision, or 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.
2. 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 36 inches in height above grade and supported by reinforced piers or other foundations of equivalent strength, whichever is less.
(f) Recreational vehicles or travel trailers shall be required to meet the elevation and anchoring requirements of this division (C)(3)(f) of this section unless:
1. They are on site for fewer than 180 consecutive days; and
2. 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.
(4) Only a non-residential building may be structurally dry floodproofed (in lieu of elevation) provided that:
(a) A licensed 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;
(b) 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; and
(c) 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 division).
(5) A building may be constructed with a crawlspace located below the flood protection elevation provided that the following conditions are met:
(a) 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;
(b) 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 above grade;
(c) The interior grade of the crawlspace below the flood protection elevation must not be more than two feet below the lowest adjacent exterior grade;
(d) The interior height of the crawlspace measured from the interior grade of the crawlspace to the top of the foundation wall must not exceed four feet at any point;
(e) 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;
(f) Portions of the building below the flood protection elevation must be constructed with materials resistant to flood damage; and
(g) Utility systems within the crawlspace must be elevated above the flood protection elevation.
(6) 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 base flood elevation shall be provided to all critical facilities.
(7) Existing buildings located within a designated floodway shall also meet the more restrictive appropriate use standards included in §§ 159.40 through 159.42. Non-conforming structures located in a designated floodway may remain in use and may only be enlarged, replaced or structurally altered in accordance with § 159.42. A non-conforming structure 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.
(D) Record drawings. For all developments in the SFHA, record drawings shall be submitted to the City Administrator or his designee, before occupancy permits will be issued. The record drawings shall be prepared by a registered land surveyor or the licensed professional engineer who prepared the design drawings. Three paper copies of these drawings, signed and sealed by the surveyor or engineer, and one electronic copy, are required. Electronic files shall be provided in Adobe Portable Document File ".pdf' formats.
(E) Timely construction. A development permit or approval shall become invalid unless the start of construction, for work authorized by such permit, is commenced within 180 days after its issuance, or if the work authorized is suspended or abandoned for a period of 180 days after the work commences. All permitted work shall be completed within (insert 12 months, 18 months or a local permit expiration period) after the date of issuance of the permit or the permit shall expire. Time extensions, of not more than 180 days each, may be granted, in writing, by the City Administrator or his designee. Time extensions shall be granted only if the original permit is compliant with this chapter and the FIRM and FIS in effect at the time the extension is granted.
(Ord. 2008-08-0196O, passed 8-12-2008; Am. Ord. 2019-10-0759O, passed 10-22-2019)