Chapter 25.86 FLOOD PLAIN MANAGEMENT AND OVERLAY ZONES


Section 25.86.190 Definitions.

Unless specifically defined below, words or phrases used in this chapter shall be interpreted so as to give them the meaning they have in common usage and to give this chapter its most reasonable application.
    1. Base Flood. The flood having a one percent chance of being equaled or exceeded in any given year. (See 100-year flood).
    2. Basement. Any enclosed area of a building that has its floor or lowest level below ground level (subgrade) on all sides.  (Also see lowest floor).
    3. Development. Any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, fillings, grading, paving, excavation or drilling operations.
    4. Existing Construction. Any structure for which the “ start of construction”  commenced before August 1, 1979, the effective date of the city’ s Flood Insurance Rate Map. Also referred to as an “ existing structure.”
    5. Existing Factory-built Home Park or Subdivision.  A factory-built home park or subdivision for which the construction of facilities servicing the lots on which the factory-built homes are to be affixed (including at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed before the effective date of the flood plain management regulations adopted by the city of Sioux City.
    6. Expansion of Existing Factory-built Home Park or Subdivision.  The preparation for additional sites by the construction of facilities for servicing the lots on which the factory-built homes are to be affixed (including at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).
    7. Factory-built Home.  Any structure, designed for residential use, which is wholly or in substantial part, made, fabricated, formed, or assembled in manufacturing facilities for installation or assembly and installation, on a building site.  For the purpose of this chapter, factory-built homes include mobile homes, manufactured homes and modular homes and also includes “ recreational vehicles”  which are placed on a site for greater than 180 consecutive days or not fully licensed for and ready for highway use.
    8. Factory-built Home Park.  A parcel or contiguous parcels of land divided into two or more factory-built home lots for sale or lease.
    9. Flood.  A general and temporary condition of partial or complete inundation of normally dry land areas resulting from the overflow of streams or rivers or from the unusual and rapid runoff of surface waters from any source.
    10. Flood Elevation.  The elevation flood waters would reach at a particular site during the occurrence of a specific flood.  For instance, the 100-year flood elevation is the elevation of flood waters related to the occurrence of the 100-year flood.
    11. Flood Insurance Rate Map (FIRM).  The official map prepared as part of (but published separately from) the Flood Insurance Study which delineates both the flood hazard areas and the risk premium zones applicable to the community.
    12. Flood Plain.  Any land area susceptible to being inundated by water as a result of a flood.
    13. Flood Plain Management.  An overall program of corrective and preventive measures for reducing flood damages and promoting the wise use of flood plains, including but not limited to emergency preparedness plans, flood control works, floodproofing and flood plain management regulations.
    14. Floodproofing.  Any combination of structural and nonstructural additions, changes, or adjustment to structures, including utility and sanitary facilities, which will reduce or eliminate flood damage to such structures.
    15. Floodway.  The channel of a river or stream and those portions of the flood plains adjoining the channel, which are reasonably required to carry and discharge flood waters or flood flows so that confinement of flood flows to the floodway area will not cumulatively increase the water surface elevation of the base flood by more than one foot.
    16. Floodway Fringe.  Those portions of the flood plain, other than the floodway, which can be filled, leveed, or otherwise obstructed without causing substantially higher flood levels or flow velocities.
    17. Historic Structure.  Any structure that is:
        a. Listed individually in the National Register of Historic Places, maintained by the Department of Interior, or preliminarily determined by the Secretary of the Interior or the Iowa State Historic Preservation Officer as meeting the requirements for individual listing of the National Register;
        b. Certified or preliminarily determined by the Secretary of the Interior or the Iowa State Historic Preservation Officer as contributing to the historical significance of a registered historic district or a district preliminarily determined by the Secretary to qualify as a registered historic district; or
        c. Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified by either i) an approved state program as determined by the Secretary of the Interior or ii) directly by the Secretary of the Interior in states without approved programs.
    18.  Lowest Floor. The floor of the lowest enclosed area in a building including a basement except when all the following criteria are met:
        a. The enclosed area is designed to flood to equalize hydrostatic pressure during floods with walls or openings that satisfy the provisions of Section 25.86.120-2.d.(1), and
        b. The enclosed area is unfinished (not carpeted, drywalled, etc.) and used solely for low damage potential uses such as building access, parking or storage, and
        c.  Machinery and service facilities (e.g., hot water heater, furnace, electrical service) contained in the enclosed area are located at least one foot above the 100-year flood level, and
        d. The enclosed area is not a "basement" as defined in Chapter 25.04.
    In cases where the lowest enclosed area satisfies criteria a, b, c, and c above, the lowest floor is the floor of the next highest enclosed area that does not satisfy the criteria above.
    19. New Construction (new buildings, mobile home parks). Those structures or development, including but not limited to new structures and mobile home parks, for which the start of construction commenced on or after the effective date of the Flood Insurance Rate Map.
    20. New Factory-built Home Park or Subdivision.  A factory-built home park or subdivision for which the construction of facilities for servicing the lots on which the factory-built homes are to be affixed (including at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after the effective date of flood plain management regulations adopted by the community.
    21. One-hundred (100) Year Flood. A flood, the magnitude of which has a 1 percent chance of being equaled or exceeded in any given year or which, on the average, will be equaled or exceeded at least once every 100 years.
    22. Recreational vehicle.  A vehicle which is:
        a. Built on a single chassis;
        b. 400 square feet or less when measured at the largest projection;
        c. Designed to be self-propelled or permanently towable by a light-duty truck; and
        d. Designed primarily not for use as a permanent dwelling but as a temporary living quarters for recreational, camping, travel or seasonal use.
    23. Special Flood Hazard Area. The land within a community subject to the 100 year flood.  This land is identified as Zone A on the community’ s Flood Insurance Rate Map.
    24. Start of Construction. Includes substantial improvement, and means the date the development permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement, or other improvement, was within 180 days of the permit date.  The actual start means either the first placement or permanent construction of a structure on a site, such as pouring of a slab or footings, the installation of pile, the construction of columns, or any work beyond the stage of excavation; or the placement of a factory-built home on a foundation.  Permanent construction does not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footing, piers, or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings such as garages or sheds not occupied as dwelling units or not part of the main structure.  For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of the building, whether or not that alteration affects the external dimensions of the building.
    25. Structure. Anything constructed or erected on the ground or attached to the ground, including, but not limited to, buildings, factories, sheds, cabins, factory-built homes, storage tanks, and other similar uses.
    26. Substantial damage. Damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damage condition would equal or exceed 50% of the market value of the structure before the damage occurred.  
    27. Substantial improvement. Any improvement to a structure that satisfies either of the following criteria:
        a. Any repair, reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50% of the market value of the structure either (i) before the start of construction of the improvement, or (ii) if the structure has been substantially damaged as is being restored, before the damage occurred. . The term does not, however, include any alteration of an historic structure provided the alteration will not preclude the structure's continued designation as a "historic structure".
        b. Any addition that increases the original floor area of a building by 25 percent or more.  All additions constructed after August 1, 1979 shall be added to any proposed addition in determining whether the total increase in original floor space would exceed 25 percent.
    28. Variance.  A grant of relief by a community from the terms of the flood plain management regulations.
    29. Violation. A failure of a structure or other development to be fully compliant with the community’ s flood plain management regulations. (Ord. 2001-0415; 92/T-10572; 89/T-7348)