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Table of Contents » Title 14 Zoning and Land Use Control » Chapter 4 Flood Damage Prevention Ordinance » § 14-405 Provisions for flood hazard reduction.
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14
Title 14
14-1
Title 14, Chapter 1
14-101
§ 14-101
Rockford
Title 14 : Zoning and Land Use Control
Chapter 4 : Flood Damage Prevention Ordinance

14-405 : Provisions for flood hazard reduction.

  1. General standards. In all flood-prone areas the following provisions are required:
    1. New construction and substantial improvements to existing buildings shall be anchored to prevent flotation, collapse or lateral movement of the structure;
    2. Manufactured homes shall be elevated and anchored to prevent flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors. This standard shall be in addition to and consistent with applicable state requirements for resisting wind forces;
    3. New construction and substantial improvements to existing buildings shall be constructed with materials and utility equipment resistant to flood damage;
    4. New construction or substantial improvements to existing buildings shall be constructed by methods and practices that minimize flood damage;
    5. All electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities shall be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;
    6. New and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system;
    7. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters;
    8. On-site waste disposal systems shall be located and constructed to avoid impairment to them or contamination from them during flooding;
    9. Any alteration, repair, reconstruction or improvements to a building that is in compliance with the provisions of this ordinance, shall meet the requirements of "new construction" as contained in this ordinance; and
    10. Any alteration, repair, reconstruction or improvements to a building that is not in compliance with the provision of this ordinance, shall be undertaken only if said nonconformity is not further extended or replaced.
  2. Specific standards. These provisions shall apply to all areas of special flood hazard as provided herein:

    1. Residential construction. Where base flood elevation data is available, new construction or substantial improvement of any residential building (or manufactured home) shall have the lowest floor, including basement, elevated no lower than one foot (1') above the base flood elevation. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate equalization of flood hydrostatic forces on both sides of exterior walls and to ensure unimpeded movement of floodwater shall be provided in accordance with the standards of § 14-405(2).

      Within unnumbered A Zones, where base flood elevations have not been established and where alternative data is not available, the administrator shall require the lowest floor of a building to be elevated or floodproofed to a level of at least three feet (3') above the highest adjacent grade (lowest floor and highest adjacent grade being defined in § 14-402 of this ordinance). All applicable data including elevations or floodproofing certifications shall be recorded as set forth in § 14-404(2).

    2. Non-residential construction. New construction or substantial improvement of any commercial, industrial, or non-residential building, when BFE data is available, shall have the lowest floor, including basement, elevated or floodproofed no lower than one foot (1') above the level of the base flood elevation.

      Within unnumbered A Zones, where base flood elevations have not been established and where alternative data is not available, the administrator shall require the lowest floor of a building to be elevated or floodproofed to a level of at least three feet (3') above the highest adjacent grade (lowest floor and highest adjacent grade being defined in § 14-402 of this ordinance). All applicable data including elevations or floodproofing certifications shall be recorded as set forth in § 14-404(2).

      Buildings located in all A Zones may be floodproofed, in lieu of being elevated, provided that all areas of the building below the required elevation are watertight, with walls substantially impermeable to the passage of water, and are built with structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. A registered professional engineer or architect shall certify that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions above, and shall provide such certification to the administrator as set forth in § 14-404(2).

    3. Elevated building. All new construction or substantial improvements to existing buildings that include any fully enclosed areas formed by foundation and other exterior walls below the base flood elevation, or required height above the highest adjacent grade, shall be designed to preclude finished living space and designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls.
      1. Designs for complying with this requirement must either be certified by a professional engineer or architect or meet the following minimum criteria:
        1. Provide a minimum of two (2) openings having a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding;
        2. The bottom of all openings shall be no higher than one foot (1') above the finish grade; and
        3. Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwaters in both directions.
      2. Access to the enclosed area shall be the minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment used in connection with the premises (standard exterior door) or entry to the elevated living area (stairway or elevator); and
      3. The interior portion of such enclosed area shall not be partitioned or finished into separate rooms in such a way as to impede the movement of floodwaters and all such partitions shall comply with the provisions of § 14-405(2) of this ordinance.
    4. Standards for manufactured homes and recreational vehicles.
      1. All manufactured homes placed, or substantially improved on:
        1. Individual lots or parcels;
        2. In expansions to existing manufactured home parks or subdivisions; or
        3. In new or substantially improved manufactured home parks or subdivisions, must meet all the requirements of new construction, including elevations and anchoring.
      2. All manufactured homes placed or substantially improved in an existing manufactured home park or subdivision must be elevated so that either:
        1. When base flood elevations are available the lowest floor of the manufactured home is elevated on a permanent foundation no lower than one foot (1') above the level of the base flood elevation; or
        2. Absent base flood elevations the manufactured home chassis is elevated and supported by reinforced piers (or other foundation elements) at least three feet (3') in height above the highest adjacent grade.
      3. Any manufactured home, which has incurred "substantial damage" as the result of a flood or that has substantially improved, must meet the standards of § 14-405(2)(d) of this ordinance.
      4. All manufactured homes must be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement.
      5. All recreational vehicles placed on identified flood hazard sites must either:
        1. Be on the site for fewer than one hundred eighty (180) consecutive days;
        2. Be fully licensed and ready for highway use. A recreational vehicle is ready for highway use if it is licensed, on its wheels or jacking system, attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached structures or additions.
        3. The recreational vehicle must meet all the requirements for new construction, including the anchoring and elevation requirements of this section above if on the site for longer than one hundred eighty (180) consecutive days.
    5. Standards for subdivisions.
      1. Subdivisions and other proposed new developments, including manufactured home parks, shall be reviewed to determine whether such proposals will be reasonably safe from flooding. If a subdivision proposal or other proposed new development is in a flood-prone area, any such proposals shall be reviewed to ensure that:
        1. All subdivision proposals shall be consistent with the need to minimize flood damage;
        2. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize or eliminate flood damage;
        3. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood hazards;
        4. Base flood elevation data shall be provided for subdivision proposals and other proposed developments (including manufactured home parks and subdivisions) that are greater than fifty (50) lots and/or five (5) acres in area.
  3. Standards for areas of special flood hazard with established base flood elevations and with floodways designated. Located within the areas of special flood hazard established in § 14-403(2) are areas designated as floodways. A floodway may be an extremely hazardous area due to the velocity of floodwaters, debris or erosion potential. In addition, the area must remain free of encroachment in order to allow for the discharge of the base flood without increased flood heights and velocities. Therefore, the following provisions shall apply:
    1. Encroachments are prohibited, including earthen fill material, new construction, substantial improvements or other developments within the regulatory floodway. Development may be permitted however, provided it is demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practices that the cumulative effect of the proposed encroachments or new development, when combined with all other existing and anticipated development, shall not result in any increase the water surface elevation of the base flood level, velocities or floodway widths during the occurrence of a base flood discharge at any point within the community. A registered professional engineer must provide supporting technical data and certification thereof.
    2. New construction or substantial improvements of buildings shall comply with all applicable flood hazard reduction provisions of § 14-405.
  4. Standards for areas of special flood hazard Zones AE with established base flood elevations but without floodways designated. Located within the areas of special flood hazard established in § 14-403(2), where streams exist with base flood data provided but where no floodways have been designated, (Zones AE) the following provisions apply:
    1. No encroachments, including fill material, new structures or substantial improvements shall be located within areas of special flood hazard, unless certification by a registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot (1') at any point within the community. The engineering certification should be supported by technical data that conforms to standard hydraulic engineering principles.
    2. New construction or substantial improvements of buildings shall be elevated or floodproofed to elevations established in accordance with § 14-405(2).
  5. Standards for streams without established base flood elevations or floodways (A Zones). Located within the areas of special flood hazard established in § 14-403, where streams exist but no base flood data has been provided (A Zones), or where a floodway has not been delineated, the following provisions shall apply:
    1. When base flood elevation data or floodway data have not been provided in accordance with § 14-403, then the administrator shall obtain, review and reasonably utilize any scientific or historic base flood elevation and floodway data available from a federal, state or other source, in order to administer the provisions of § 14-405. Only if data is not available from these sources, then the following provisions ((b) and (c)) shall apply:
    2. No encroachments, including structures or fill material, shall be located within an area equal to the width of the stream or twenty feet (20'), whichever is greater, measured from the top of the stream bank, unless certification by registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot (1') at any point within the community. The engineering certification should be supported by technical data that conforms to standard hydraulic engineering principles.
    3. In special flood hazard areas without base flood elevation data, new construction or substantial improvements of existing shall have the lowest floor of the lowest enclosed area (including basement) elevated no less than three feet (3') above the highest adjacent grade at the building site. Openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with the standards of § 14-405(2), and "Elevated Buildings."
  6. Standards for areas of shallow flooding (AO and AH Zones). Located within the areas of special flood hazard established in § 14-403(2) are areas designated as shallow flooding areas. These areas have special flood hazards associated with base flood depths of one to three feet (1' – 3') where a clearly defined channel does not exist and where the path of flooding is unpredictable and indeterminate; therefore, the following provisions apply:
    1. All new construction and substantial improvements of residential and non-residential buildings shall have the lowest floor, including basement, elevated to at least one foot (1') above the flood depth number specified on the Flood Insurance Rate Map (FIRM), in feet, above the highest adjacent grade. If no flood depth number is specified, the lowest floor, including basement, shall be elevated, at least three feet (3') above the highest adjacent grade. Openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with standards of § 14-405(2), and "Elevated Buildings."
    2. All new construction and substantial improvements of non-residential buildings may be floodproofed in lieu of elevation. The structure together with attendant utility and sanitary facilities must be floodproofed and designed watertight to be completely floodproofed to at least one foot (1') above the specified FIRM flood level, with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. If no depth number is specified, the lowest floor, including basement, shall be floodproofed to at least three feet (3') above the highest adjacent grade. A registered professional engineer or architect shall certify that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions of this ordinance and shall provide such certification to the administrator as set forth above and as required in § 14-404(2).
    3. Adequate drainage paths shall be provided around slopes to guide floodwaters around and away from proposed structures.
    4. The administrator shall certify the elevation or the highest adjacent grade, where applicable, and the record shall become a permanent part of the permit file.
  7. Standards for areas protected by flood protection system (A-99 Zones). Located within the areas of special flood hazard established in § 14-403 are areas of the 100-year floodplain protected by a flood protection system but where base flood elevations and flood hazard factors have not been determined. Within these areas (A-99 Zones) all provisions of §§ 14-404 and 14-405(1) shall apply.
  8. Standards for unmapped streams. Located within Rockford, Tennessee are unmapped streams where areas of special flood hazard are neither indicated nor identified. Adjacent to such streams the following provisions shall apply:
    1. In areas adjacent to such unmapped streams, no encroachments including fill material or structures shall be located within an area of at least equal to twice the width of the stream, measured from the top of each stream bank, unless certification by a registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot (1') at any point within the locality.
    2. When new elevation data is available, new construction or substantial improvements of buildings shall be elevated or floodproofed to elevations established in accordance with § 14-404. (as added by Ord. #071207, Aug. 2007)