Title 18 - Unified Development Ordinance

18.360 Floodplain Management Ordinance

18.360.450 Provisions for Flood Hazard Reduction

A.
General Standards
1. 1.
  
  No floodplain development permit shall be granted for new construction, substantial-improvements, and other improvements, including the placement of manufactured homes, within Special Flood Hazard Areas unless the conditions of this Section are satisfied.
2. 2.
  
  Structures used solely for parking and limited storage purposes, not attached to any other structure on the site, of limited investment value, and not larger than 400 square feet, may be constructed at grade and wet flood-proofed provided there is no human habitation or occupancy of the structure; the structure is of single wall design; a floodplain variance has been granted from the standard floodplain management requirements of this Chapter; and a floodplain development permit has been issued. Provided, however, this 400 square foot limitation shall not apply to agricultural structures that require minimal investment, where the structure is used for temporary storage of equipment or crops, or temporary shelter for livestock, and only in circumstances where it can be demonstrated that such structures can be designed in a manner that flooding results in minimal damage to the structure and its contents and will create no additional threats to public safety.
3. 3.
  
  All areas identified as unnumbered A zones on the FIRM are subject to inundation of the 100-year flood; however, the Base Flood Elevation is not provided. Development within unnumbered A zones is subject to all provisions of this Chapter. If Flood Insurance Study data is not available or flood studies have not been completed, a professional engineer licensed in the State of Kansas shall obtain, review and reasonably utilize any base flood elevation or floodway data currently available from federal, state or other sources. Conclusive engineering data which establishes the Base Flood Elevations and floodway shall then be submitted by the professional engineer to the City for review.
4. 4.
  
  Until a floodway is designated, no new construction, substantial improvements, or other development, including fill, shall be permitted within the Special Flood Hazard Area unless it is demonstrated 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 (1) foot at any point. Additional conditions are established in Section 18.360.450 A. 5.
5. 5.
  
  Grading changes within the Flood Fringe must not cause an increase in the Base Flood Elevation unless the Floodplain Administrator has expressly issued a written waiver of this requirement and acknowledges the rise.
6. 6.
  
  The boundaries of the Floodway and Flood Fringe shall be determined by reviewing the Flood Insurance Rate Map (FIRM) and amendments thereto, the Flood Insurance Study (FIS) or other available data. Where interpretation is needed to locate the boundaries of the Floodway or Flood Fringe, the Floodplain Administrator may make the necessary interpretation when sufficient data is available. If the interpretation is contested, the applicant may apply to FEMA for a Letter of Map Change to clarify the location of the Floodway and/or Flood Fringe. If property near the Flood Fringe is lower than the Base Flood Elevation, this property shall be considered part of the Floodway or Flood Fringe for the purposes of this Chapter, regardless of the FIRM designation. If the FIRM indicates property is within the Floodway or Flood Fringe and such property is higher than the Base Flood Elevation, the FIRM designation shall establish the requirements of this Chapter until a Letter of Map Change revises the FIRM.
7. 7.
  
  The Floodplain Administrator is authorized to request a Letter of Map Change or Physical Map Revision for any work performed in the Special Flood Hazard Area in order to maintain proper records and assist in the notification process.
8. 8.
  All new construction, subdivision proposals, substantial-improvements, prefabricated structures, placement of manufactured homes, and other developments shall require:
  1. a.
    
    Design or adequate anchorage to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
  2. b.
    
    Construction with materials resistant to flood damage;
  3. c.
    
    Utilization of methods and practices that minimize flood damages;
  4. d.
    
    All electrical, heating, ventilation, plumbing, air-conditioning equipment, and other service facilities be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;
  5. e.
    
    New or replacement water supply systems and/or sanitary sewage systems be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters, and on-site waste disposal systems be located so as to avoid impairment or contamination from them during flooding; and
  6. f.
    
    All additions constructed outside the existing walls of a structure in the Special Flood Hazard Area shall be constructed with the lowest floor elevated two (2) feet above the B.F.E., except non-residential structures, excluding apartment buildings, are allowed to flood proof to two (2) feet above B.F.E. This includes minor additions and substantial improvements for pre-firm and post-firm structures.
  7. g.
    
    Subdivision proposals and other proposed new development, including manufactured home parks or subdivisions, located within Special Flood Hazard Areas are required to assure that:
    
    1.
    
    All such proposals are consistent with the need to minimize flood damage;
    
    2.
    
    All public utilities and facilities, such as sewer, gas, electrical, and water systems are located and constructed to minimize or eliminate flood damage;
    
    3.
    
    Adequate drainage is provided so as to reduce exposure to flood hazards;
    
    4.
    
    All proposals for development include within such proposals Base Flood Elevation data;
    
    5.
    
    New subdivision plats or rezonings which contain Special Flood Hazard Areas, cannot create a new lot within the Special Flood Hazard Area which would allow constructing a residential dwelling;
    
    6.
    
    New subdivision plats with only one public street for access during any phase of platting, shall meet one of the following:
    
    a.
    
    The public street, including the street’s intersection to existing streets, shall be constructed outside the Special Flood Hazard Areas; or
    
    b.
    
    The depth of storm water for public streets constructed in the Special Flood Hazard Area shall meet the City’s most current storm water design criteria, including the street’s intersection to existing streets, or a deviation from the City’s design criteria for storm water depths in public streets must be approved by the Fire Department; or
    
    c.
    
    A secondary emergency access route is provided, as approved by the Fire Department.
    
    7.
    
    Critical Facilities:
    
    a.
    
    All new or substantially improved critical nonresidential facilities including, but not limited, to governmental buildings, police stations, fire stations, hospitals, orphanages, penal institutions, communication centers, water and sewer pumping stations, water and sewer treatment facilities, transportation maintenance facilities, emergency aviation facilities, and schools shall be protected from the 0 .2 percent annual chance flood event, also referred to as the 500-year flood event, by either:
    
    1.
    
    Elevating the structure, along with its attendant utility and sanitary facilities, above the 500-year flood level or,
    
    2.
    
    Flood proofing the structure and its attendant utility and sanitary facilities below the 500-year flood level. Habitable spaces must be constructed so the structure is water tight 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 a space is non-habitable, other means of flood proofing may be accomplished provided the contents of the structure cannot be damaged by storm water. A professional engineer or registered architect shall certify that the standards of this subsection are satisfied. Certification shall be provided to the Floodplain Administrator as set forth in Section 18.360.440 C 7-9.
    
    b.
    
    All critical facilities shall have access routes that are above the elevation of the 500-year flood.
    
    c.
    
    No critical facilities shall be constructed in any designated floodway, except sanitary sewer and water supply facilities.
9. 9.
  Storage, Material, and Equipment
  1. a.
    
    The storage or processing of materials within the Special Flood Hazard Area that are in time of flooding buoyant, flammable, explosive, or could be injurious to human, animal, or plant life is prohibited.
  2. b.
    
    Storage of other material or equipment may be allowed if not subject to major damage by floods, if firmly anchored to prevent flotation, or if readily removable from the area within the time available after a flood warning.
10. 10.
  Nonconforming Use
  A structure, or the use of a structure or premises that was lawful before the passage or amendment of the Chapter, but which is not in conformity with the provisions of this Chapter, may be continued subject to the following conditions:
  1. a.
    
    If such structure, use, or utility service is discontinued for 6 consecutive months, any future use of the building shall conform to this Chapter.
  2. b.
    
    No such use or substantial improvement of that use shall be expanded, changed, enlarged or altered in any way which increases the nonconformity. Provided, however, substantial improvements to existing buildings are permissible provided that the building be modified to comply with Section 18.360.450 B - F inclusively, that the footprint of the building is not increased, the total floor area is not increased, and except for any accessory structures, an access path is available for emergency vehicles meeting the requirements of Section 18.360.450.A.8.g.6.a through 18.360.450.A.8.g.6.c inclusively.
  3. c.
    
    If any nonconforming use or structure is destroyed by any means, including flood, it shall not be reconstructed if the cost is more than fifty (50) percent of the pre-damaged market value of the structure except as provided under Section 18.360.450 A.10.b. This limitation does not include the cost of any alteration to comply with existing state or local health, sanitary, building, safety codes, regulations or the cost of any alteration of a structure listed on the National Register of Historic Places, the State Inventory of Historic Places, or local inventory of historic places upon determination.
B.
Specific Standards
In all areas identified as numbered and unnumbered A zones, AE, and AH Zones (also known as the Special Flood Hazard Areas), where Base Flood Elevation data have been provided, as set forth in Section 18.360.450 A.3., the following provisions are required:
1. 1.
  
  Residential Construction
  New construction or substantial-improvement of any residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated a minimum of two (2) feet above Base Flood Elevation. Mechanical and HVAC equipment servicing the building shall be elevated or floodproofed to the same level as the lowest floor. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.
  
  In addition, new construction of any residential structure shall have the lowest adjacent grade a minimum of one (1) foot above the energy grade line of the base flood for fully developed conditions upstream.
2. 2.
  
  Non-Residential Construction
  New construction or substantial-improvement of any commercial, industrial, or other non-residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated a minimum of two (2) feet above the Base Flood Elevation or, together with attendant utility and sanitary facilities, be floodproofed to a minimum of two (2) feet above the Base Flood Elevation so the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall certify that the standards of this subsection are satisfied. Mechanical and HVAC equipment servicing the building shall be elevated or floodproofed to the same level as the lowest floor. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer. Such certification shall be provided to the Floodplain Administrator as set forth in Section 18.360.440 C 7-9.
3. 3.
  Require for all new construction and substantial-improvements that fully enclosed areas below the lowest floor are used solely for parking vehicles, building access or storage in an area other than a basement and that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood waters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria:
  1. a.
    
    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 shall be provided; and
  2. b.
    
    The bottom of all opening shall be no higher than one (1) foot above grade. Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of flood waters.
C.
Manufactured Homes
1. 1.
  
  All manufactured homes to be placed within the Special Flood Hazard Area on the City's FIRM shall be required to be installed using methods and practices that minimize flood damage. For the purposes of this requirement, manufactured homes must be elevated and anchored to resist 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 requirement is in addition to applicable state and City anchoring requirements for resisting wind forces.
2. 2.
  Require manufactured homes that are placed or substantially improved within the Special Flood Hazard Areas on the City's FIRM on sites:
  1. a.
    
    Outside of a manufactured home park or subdivision;
  2. b.
    
    In a new manufactured home park or subdivision;
  3. c.
    
    In an expansion to and existing manufactured home park or subdivision; or
  4. d.
    
    In an existing manufactured home park or subdivision on which a manufactured home has incurred substantial-damage as the result of a flood;

be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated a minimum of two (2) feet above the Base Flood Elevation and be securely attached to an adequately anchored foundation system to resist flotation, collapse, and lateral movement. Mechanical and HVAC equipment servicing the building shall be elevated or floodproofed to the same level as the lowest floor. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.

1. 3.
  
  Require that manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within the Special Flood Hazard Area on the City's FIRM, that are not subject to the provisions of Section 18.360.450 C.2. of this Chapter, be elevated so that the lowest floor of the manufactured home is a minimum of two (2) feet above the Base Flood Elevation. Mechanical and HVAC equipment servicing the building shall be elevated or floodproofed to the same level as the lowest floor. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.

D.
Areas of Shallow Flooding (AO and AH zones)
Located within Special Flood Hazard Areas described in Section 18.360.430 A. are areas designated as AO zones. These Special Flood Hazard Areas have special flood hazards associated with base flood depths of one (1) to three (3) feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and indeterminate. The following provisions apply:
1. 1.
  AO Zones
  1. a.
    
    All new construction and substantial-improvements of residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated above the highest adjacent grade at least two (2) feet higher than the depth number specified in feet on the City's FIRM (at least four (4) feet if no depth number is specified). Mechanical and HVAC equipment servicing the building shall be elevated or floodproofed to the same level as the lowest floor. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.
  2. b.
    
    All new construction and substantial-improvements of any commercial, industrial, or other non-residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the City FIRM (at least two (2) feet if no depth number is specified) or together with attendant utilities and sanitary facilities be completely floodproofed to that so that the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. Mechanical and HVAC equipment servicing the building shall be elevated or floodproofed to the same level as the lowest floor. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.
  3. c.
    
    Adequate drainage paths shall be required around structures on slopes, in order to guide floodwaters around and away from proposed structures.
2. 2.
  AH Zones
  1. a.
    
    The specific standards for all Special Flood Hazard Areas where Base Flood Elevation has been provided shall be required as set forth in Section 18.360.450 B.
  2. b.
    
    Adequate drainage paths shall be required around structures on slopes, in order to guide floodwaters around and away from proposed structures.
E.
Floodway
Located within Special Flood Hazard Areas established in Section 18.360.430 A., are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters that carry debris and potential projectiles, the following provisions shall apply:
1. 1.
  
  The City shall select and adopt a floodway based on the principle that the area chosen for the floodway must be designed to carry the waters of the base flood without increasing the water surface elevation of that flood more than one (1) foot at any point.
2. 2.
  
  The City shall prohibit any encroachments, including fill, new construction, substantial improvements, and other development within the adopted floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels within the City during the occurrence of the base flood discharge.
3. 3.
  
  If Section 18.360.450 E.2., is satisfied, all new construction and substantial-improvements shall comply with all applicable flood hazard reduction provisions of Section 18.360.450.
4. 4.
  
  In unnumbered A zones, the City shall obtain, review, and reasonably utilize any Base Flood Elevation or floodway data currently available from federal, state, or other sources as set forth in Section 18.360.450 A.3.
F.
Recreational Vehicles

Recreational vehicles placed in compliance with Chapter 7.22 (Vehicle Use, Parking and Storage) on sites within the Special Flood Hazard Area on the City’s FIRM shall either:
1. 1.
  
  Be on the site for fewer than 180 consecutive days; or
2. 2.
  
  Be fully licensed and ready for highway use*; or
3. 3.
  
  Meet the permitting, elevation, and anchoring requirements for manufactured homes of this Chapter.

*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 utilities and security devices, and has no permanently attached additions.

(History: Ord. ZRR-2812 §11, 2009; ZRR-2450 §7, 2003)

Effective on: 1/1/1901