|
<br />Appendix B. Selected National Flood Insurance Program (NFIP)
<br />Minimum Requirements for New Construction and Substantial Improvements;
<br />NFIP Subdivision Requirements; NFIP Glossary
<br />
<br />!\.rTIP A1illimut11 Requiremcnts
<br />
<br />Community floodplain management ordinances require that all
<br />new construction and substantial improvements of residential and
<br />nonresidential structures be elevated to or above the identified 100-
<br />year flood elevation. Nonresidential structures can also be
<br />floodproofed (made watertight) to that elevation.
<br />Specific criteria that apply to new construction can be found in 44
<br />Code of Federal Regulations (CFR) 60.3 (0)(3), (c)(3), (c)(2), (e)(7),
<br />(c)(10), (d)(3), (e)(3), (e)(4), and (e)(7). A listing of these
<br />requirements follows.
<br />
<br />(a)(3) Review all permit applications to determine whether
<br />proposed building sites will be reasonably safe from flooding.
<br />If a proposed building site is in a flood-prone area, all new
<br />construction and substantial improvements shall:
<br />i) be designed (or modified) and adequately anchored to
<br />prevent flotation, collapse, or lateral movement of the
<br />structure resulting from hydrodynamic and hydrostatic
<br />loads, including the effects of buoyancy;
<br />ii) be constructed with materials resistant to flood damage;
<br />hi) be constructed by methods and practices that minimize
<br />flood damages; and
<br />iv) be constructed Mth electrical, heating, ventilation,
<br />plumbing, and air conditioning equipment and other
<br />service facilities that are designed and/or located so as
<br />to prevent water from entering or accumulating Mthin
<br />the components during conditions of flooding.
<br />
<br />(c)(2) Require that all new construction and substantial
<br />improvements of residential structures within Zones AI-30,
<br />AE, and AH zones on the community's FIRM have the lowest
<br />floor (including basement) elevated to or above the base flood
<br />level, unless the community is granted an exception by the
<br />Administrator for the allowance of basements in accordance
<br />with Sec. 60.6 (b) or (c).
<br />
<br />(c)(3) Require that all new construction and substantial
<br />improvements of nonresidential structures within Zones AI-
<br />30, AE, and AH on the community's FIRM:
<br />i) have the lowest floor (including basement) elevated to or
<br />above the base flood level or,
<br />ii) together \\'ith attendant utility and sanitary facilities, be
<br />designed so that, below the base flood level, the structure is
<br />watertight with walls substantially impermeable to the
<br />passage of water and with structural components having
<br />the capability of resisting hydrostatic and hydrodynamic
<br />loads and effects of buoyancy.
<br />
<br />(c)(7) Require that, Mthin any AO zone on the community's
<br />FIRM, all new construction and substantial improvements of
<br />residential structures have the lowest floor (including
<br />basement) elevated above the highest adjacent grade at least
<br />
<br />as high as the depth number specified in feet on the
<br />community's FIRM (at least two feet if no depth number is
<br />specified).
<br />
<br />(c)OO) Require that, until a regulatory floodway is designated,
<br />that no new construction, substantial improvements, or other
<br />development (including fill) shall be permitted within Zones
<br />AI-3D and AE on the community's FIRM unless it is
<br />demonstrated that the cumulative effect of the proposed
<br />development, when combined with all other existing and
<br />anticipated development, will not increase the water surface
<br />elevation of the base flood more than one foot at any point
<br />within the community.
<br />
<br />(d)(3) Prohibit encroachments, including fill, new
<br />construction, substantial improvements, and other
<br />development within the adopted regulatory floodway unless
<br />it has been demonstrated through hydrologic and hydraulic
<br />analyses performed in accordance with standard engineering
<br />practice that the proposed encroachment would not result in
<br />any increase in flood levels Mthin the community during the
<br />occurrence of the base flood discharge.
<br />
<br />(e)(3) Provide that all new construction within Zones VI-3D,
<br />VE, and V on the community's FIRM is located landward of
<br />the reach of mean high tide.
<br />
<br />(e)(4) Provide that all new construction and substantial
<br />improvements in Zones VI-30, VE, and V, if base flood
<br />elevation data is available, on the community's FIRM, are
<br />elevated on pilings and columns so that:
<br />i) the bottom of the lowest horizontal structural member of
<br />the lowest floor (excluding the pilings or columns) is
<br />elevated to or above the base flood level; and
<br />ii) the pile or column foundation and structure attached
<br />thereto is anchored to resist flotation, collapse, and
<br />lateral movement due to the effects of wind and water
<br />loads acting simultaneously on all building components.
<br />
<br />Water loading values used shall be those associated with
<br />the base flood. Wind loading values shall be those required by
<br />applicable state or local building standards. A registered
<br />professional engineer or architect shall develop or review the
<br />structural design, specifications, and plans for the
<br />construction, and shall certify that the design and methods of
<br />construction to be used are in accordance with an accepted
<br />standard of practice for meeting the provisions of paragraphs
<br />(e)(4)(;) and (ii).
<br />
<br />(e)(7) Prohibit man-made alteration of sand dunes and mangrove
<br />stands within Zones VI-30, VE, and V on the community's FIRM
<br />that would increase potential flood damage.
<br />
<br />"JI.lFIP Subdivision Regulati011S
<br />
<br />NFIP has placed primary reliance on building standards to
<br />minimize flood damages. In the early days of the program, most
<br />participating communities did not have comprehensive subdivision
<br />regulations or the sophistication to develop such regulations. In
<br />addition, there were hundreds of thousands of lots that were already
<br />subdivided. However, NFIP criteria do include some general
<br />performance standards for subdivision proposals.
<br />
<br />. The installation of adequate drainage facilities
<br />. The mapping of flood hazard areas on the plat
<br />. The prohibition of encroachment of structures into the floodway
<br />that would result in any increase in flood levels during a flood
<br />
<br />. Filling of a portion of each lot to elevate the house's pad above
<br />base flood elevation
<br />
<br />51
<br />
|