(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).
(2) 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.
(3) Larger area roof and lot drainage. Drainage from roofs and paved parking or other areas larger than 40,000 square feet along any street shall be stored temporarily on the premises, in retention ponds, on roofs or at ground level or otherwise, which storage areas shall be equipped with outlets that may be set or regulated to empty slowly the stored runoff water into storm sewers or surface channels according to their ability to handle the flow safely.
(4) Roof drainage disposal on lawns. Roof drainage through downspouts or otherwise shall not be connected directly to any street or public sewer (storm, sanitary or combined) but shall be directed away from the building onto the lawn or yard or into a seepage well.
(5) Foundation footing drainage. Foundation footing drainage shall not be disposed of in a street or public sanitary or combined sewer, but may be disposed of in a seepage well or pumped out away from the building onto the lawn or yard.
(B) 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 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. All buildings located within a 100-year floodplain also known as a 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:
(1) Construction or placement of a new building;
(2) Substantial improvement to an existing building as defined in § 154.02, including an increase to the first floor area by more than 20%. This alteration shall be figured cumulatively beginning with any alteration which has taken place subsequent to April 1, 1990;
(3) Installing a manufactured home on a new site or a new manufactured home on an existing site. This building protection requirements does not apply to returning a mobile home to the same site it lawfully occupied before it was removed to avoid flood damage; and
(4) Installing a travel trailer on a site for more than 180 days.
(D) This building protection requirement may be met by one of the following methods.
(1) 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.
(b) Fill requirements. The fill shall be placed in layers no greater than one foot deep before compaction and should extend at least ten feet beyond the foundation of the building before sloping below the flood protection elevation. 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. The fill shall be protected against erosion and scour. The fill shall not adversely affect the flow or surface drainage from or onto neighboring properties.
(2) 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. The permanent openings shall be no more than one foot above existing grade, and consists of a minimum of two openings. 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. 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. Water and sewer pipes, electrical and telephone lines, submersible pumps, and other waterproofed service facilities may be located below the flood protection elevation.
(d) 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.
(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. 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 division (C)(2)(e) of this section unless:
1. They are on site for fewer than 180 consecutive days.
2. They are fully licensed and ready for highway use. 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.
3. Only a non-residential building may be structurally dry floodproofed (in lieu of elevation) provided that: a registered professional engineer 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. 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. 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).
4. Existing buildings located within a designated floodway shall also meet the more restrictive appropriate use standards included in § 154.53. Non-conforming structures located in a designated floodway may remain in use and may only be enlarged, replaced or structurally altered in accordance with § 154.53(D). 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.
(Ord. 801, passed 7-26-05) Penalty, see § 154.99