Floodplain Management Ordinance

Floodplain Management Ordinance

ARTICLE VI – DEVELOPMENT STANDARDS

All developments in areas of special flood hazard shall meet the following applicable standards:

  • A. All Development – All development shall:
    1. be designed or modified and adequately anchored to prevent flotation (excluding piers and docks), collapse or lateral movement of the development resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
    2. use construction materials that are resistant to flood damage;
    3. use construction methods and practices that will minimize flood damage; and,
    4. use electrical, heating, ventilation, plumbing, and air conditioning equipment, and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during flooding conditions.
  • B. Water Supply – All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the systems.
  • C. Sanitary Sewage Systems – All new and replacement sanitary sewage systems shall be designed and located to minimize or eliminate infiltration of flood waters into the system and discharges from the system into flood waters.
  • D. On Site Waste Disposal Systems – On site waste disposal systems shall be located and constructed to avoid impairment to them or contamination from them during floods.
  • E. Watercourse Carrying Capacity – All development associated with altered or relocated portions of a watercourse shall be constructed and maintained in such a manner that no reduction occurs in the flood carrying capacity of the watercourse.
  • F. Residential – New construction or substantial improvement of any residential structure located within Zone A shall have the lowest floor (including basement) elevated to at least one foot above the base flood elevation utilizing information obtained pursuant to Article III.H.1.; Article V.B; or Article VIII.D.
  • G. Non Residential – New construction or substantial improvement of any non-residential structure located within Zone A shall have the lowest floor (including basement) elevated to at least one foot above the base flood elevation utilizing information obtained pursuant to Article III.H.1.; Article V.B; or Article VIII.D., or together with attendant utility and sanitary facilities shall:
    1. be floodproofed to at least one foot above the base flood elevation utilizing information obtained pursuant to Article III.H.1.; Article V.B; or Article VIII.D., so that below that elevation the structure is watertight with walls substantially impermeable to the passage of water;
    2. have structural components capable of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy; and,
    3. be certified by a registered professional engineer or architect that the floodproofing design and methods of construction are in accordance with accepted standards of practice for meeting the provisions of this section. Such certification shall be provided with the application for a Flood Hazard Development Permit, as required by Article III.K. and shall include a record of the elevation above mean sea level to which the structure is floodproofed.
  • H. Manufactured Homes – New or substantially improved manufactured homes located within Zone A shall:
    1. be elevated such that the lowest floor (including basement) of the manufactured home is at least one foot above the base flood elevation utilizing information obtained pursuant to Article III.H.1.; Article V.B; or Article VIII.D.;
    2. be on a permanent foundation, which may be poured masonry slab or foundation walls, with hydraulic openings, or may be reinforced piers or block supports, any of which support the manufactured home so that no weight is supported by its wheels and axles; and,
    3. be securely anchored to an adequately anchored foundation system to resist flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to:
      • a. over-the-top ties anchored to the ground at the four corners of the manufactured home, plus two additional ties per side at intermediate points (manufactured homes less than 50 feet long require one additional tie per side); or by,
      • b. frame ties at each corner of the home, plus five additional ties along each side at intermediate points (manufactured homes less than 50 feet long require four additional ties per side).
      • c. all components of the anchoring system described in Article VI.H.3.a.& b. shall be capable of carrying a force of 4800 pounds.
  • I. Recreational Vehicles – Recreational Vehicles located within:
    1. Zone A shall either:
      • a. be on the site for fewer than 180 consecutive days,
      • b. be 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 utilities and security devices, and has no permanently attached additions; or,
      • c. be permitted in accordance with the elevation and anchoring requirements for “manufactured homes” in Article VI.H.1.
  • J. Accessory Structures – Accessory Structures, as defined in Article XIII, located within Zone A, shall be exempt from the elevation criteria required in Article VI.F. & G. above, if all other requirements of Article VI and all the following requirements are met. Accessory Structures shall:
    1. be 500 square feet or less and have a value less than $3000;
    2. have unfinished interiors and not be used for human habitation;
    3. have hydraulic openings, as specified in Article VI.K.2., in at least two different walls of the accessory structure;
    4. be located outside the floodway;
    5. when possible be constructed and placed on the building site so as to offer the minimum resistance to the flow of floodwaters and be placed further from the source of flooding than is the primary structure; and,
    6. have only ground fault interrupt electrical outlets. The electric service disconnect shall be located above the base flood elevation and when possible outside the Special Flood Hazard Area.
  • K. Floodways – Encroachments, including fill, new construction, substantial improvement, and other development shall not be permitted in a floodway which, in Zone A riverine areas, is the channel of the river or other water course and the adjacent land areas to a distance of one-half the width of the floodplain as measured from the normal high water mark to the upland limit of the floodplain, unless a technical evaluation certified by a registered professional engineer is provided demonstrating that the cumulative effect of the proposed development, when combined with all other existing development and anticipated development:
    1. will not increase the water surface elevation of the base flood more than one foot at any point within the community; and,
    2. is consistent with the technical criteria contained in Chapter 5 entitled “Hydraulic Analyses,” Flood Insurance Study – Guidelines and Specifications for Study Contractors, (FEMA 37/ January 1995, as amended).
  • L. Enclosed Areas Below the Lowest Floor – New construction or substantial improvement of any structure in Zone A that meets the development standards of Article VI, including the elevation requirements of Article VI, paragraphs F, G, or H and is elevated on posts, columns, piers, piles, “stilts,” or crawlspaces may be enclosed below the base flood elevation requirements provided all the following criteria are met or exceeded:
    1. Enclosed areas are not “basements” as defined in Article XIII;
    2. Enclosed areas shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood water. Designs for meeting this requirement must either:
      • a. be engineered and certified by a registered professional engineer or architect; or,
      • b. meet or exceed the following minimum criteria:
        • (1) a minimum of two openings having a total net area of not less than one square inch for every square foot of the enclosed area;
        • (2) the bottom of all openings shall be below the base flood elevation and no higher than one foot above the lowest grade; and,
        • (3) openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the entry and exit of flood waters automatically without any external influence or control such as human intervention, including the use of electrical and other non-automatic mechanical means;
    3. The enclosed area shall not be used for human habitation; and,
    4. The enclosed areas are usable solely for building access, parking of vehicles, or storage.
  • M. Bridges – New construction or substantial improvement of any bridge in Zone A shall be designed such that:
    1. when possible, the lowest horizontal member (excluding the pilings, or columns) is elevated to at least one foot above the base flood elevation utilizing information obtained pursuant to Article III.H.1.; Article V.B; or Article VIII.D.; and
    2. a registered professional engineer shall certify that:
      • a. the structural design and methods of construction shall meet the elevation requirements of this section and the floodway standards of Article VI.J.; and
      • b. the foundation and superstructure attached thereto are designed to resist flotation, collapse and lateral movement due to the effects of wind and water loads acting simultaneously on all structural components. Water loading values used shall be those associated with the base flood.
  • N. Containment Walls – New construction or substantial improvement of any containment wall located within Zone A shall:
    1. have the containment wall elevated to at least one foot above the base flood elevation utilizing information obtained pursuant to Article III.H.1.; Article V.B.; or Article VIII.D.
    2. have structural components capable of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy; and
    3. be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions of this section. Such certification shall be provided with the application for a Flood Hazard Development Permit, as required by Article III.K.
  • O. Wharves, Piers and Docks – New construction or substantial improvement of wharves, piers, and docks are permitted in Zone A in and over water and seaward of the mean high tide if the following requirements are met:
    1. wharves, piers, and docks shall comply with all applicable local, state, and federal regulations; and
    2. for commercial wharves, piers, and docks, a registered professional engineer shall develop or review the structural design, specifications, and plans for the construction.