10.0 Floodplain Conservation District

The regulations in the Town of Wilton Zoning Ordinance shall be considered part of the zoning Ordinance for purposes of administration and appeals under state law. If any provision of this ordinance differs or appears to conflict with any provision of the zoning Ordinance or other ordinance or regulation, the provision imposing the greater restriction or more stringent standard shall be controlling.

The following regulations shall apply to all lands designated as special flood hazard areas by the Federal Emergency Management Agency (FEMA) in its "Flood Insurance Study for the Town of Wilton, N.H." together with the associated Flood Insurance Rate Maps (FIRM) and Flood Boundary and Floodway Maps of the Town dated April 15, 1980, which are declared to be a part of this ordinance and are hereby incorporated by reference.

10.1 Definitions.

The following definitions shall apply only to this Floodplain Development Ordinance and shall not be affected by the provisions of any other ordinance of the Town of Wilton.

10.1.1

(Deleted)(March, 2007)

10.2 Permit Required.

All proposed development in any special flood hazard area shall require a permit. The building inspector shall review all building permit applications for new construction or substantial improvements to determine whether proposed building sites will be reasonably safe from flooding.

The Building Inspector will not issue a building permit until the applicant certifies that all necessary permits have been received from those governmental agencies from which approval is required by federal or state law, including Section 404 of the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. 1334. It shall be the responsibility of the applicant to certify these assurances to the Building Inspector.

In addition, the applicant shall supply the Building Inspector with the following information for all new or substantially improved structures:

1. the as-built elevation (in relation to NGVD) of the lowest floor (including the basement) and include whether or not the structure contains a basement;
2. if the structure has been floodproofed, the as-built elevation (in relation to NGVD) to which the structure was floodproofed; and
3. any certification of floodproofing.

The Building Inspector shall maintain this information for public inspection and furnish it upon request.

10.3 Location of the 100-Year Flood Elevation.

In special flood hazard areas the Building Inspector shall determine the 100-year flood elevation in the following order of precedence according to the data available:

1. In Zone AE, refer to the elevation data provided in the communities Flood Insurance Study and accompanying FIRM; (Amended March, 2007)
2. in unnumbered A zones the Building Inspector shall obtain, review, and reasonably utilize any 100-year flood elevation data available from any federal, state, or other source including data submitted to the Town for development proposals (i.e. subdivisions, site approvals).

10.4 Construction Standards.

1. All new construction or substantial improvements within a flood prone area shall be:
   1. designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
   2. constructed with materials resistant to flood damage;
   3. constructed by methods and practices that minimize flood damages; and
   4. constructed with electrical, heating, ventilation, plumbing, 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 conditions of flooding.
2. Any new construction or substantial improvement within the A and AE Zones shall meet the following criteria that: (Amended March, 2007)
   1. all new construction or substantial improvement of residential structures have the lowest floor (including the basement) elevated to or above the 100-year flood elevation;
   2. all new construction or substantial improvement of non-residential structures have the lowest floor (including the basement) elevated to or above the 100-year flood level; or together with attendant utility and sanitary facilities, shall:
      1. be floodproofed so that below the 100-year flood elevation the structure is watertight will 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 design and methods of construction are in accordance with accepted standards of practice for meeting the provisions of this section;
3. all manufactured homes to be placed or substantially improved within special flood hazard areas shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the base flood level and securely 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 local anchoring requirements for resisting wind forces;
4. Recreational vehicles placed on sites within Zone AE shall either: (i) be on the site for fewer than 120 consecutive days; (ii) be fully licensed and ready for highway use; or (iii) meet all standards of Section 60.0 (b) (1) of the National Flood Insurance Program Regulations and the elevation and anchoring requirements for manufactured homes in Paragraph (c) (6) of Section 60.3. (Amended March 1994.) (Amended March, 2007)
5. for all new construction and substantial improvements, fully enclosed areas below the lowest floor that are subject to flooding are permitted provided they meet the following requirements:
   1. the enclosed area is unfinished or flood resistant, usable solely for the parking of vehicles, building access of storage;
   2. the area is not a basement;
   3. the area shall be designed to automatically equalize hydrostatic flood forces or exterior walls by allowing for the entry and exit of floodwaters. 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 minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided;
      2. the bottom of all openings shall be no higher than one foot above grade; and
      3. openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters; and
6. where new or replacement water and sewer systems (including on-site systems) are proposed in floodprone areas the applicant shall provide the Building Inspector with assurance that these systems will be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters, and that on-site waste disposal systems will be located to avoid impairment to them or contamination from them during periods of flooding.

10.5 Alteration of Water Courses.

Any development involving the alteration of a watercourse shall meet the following requirements.

1. Prior to the alteration or relocation of a watercourse the applicant for such authorization shall notify the Wetlands Bureau of the New Hampshire Department of Environmental Services and submit copies of such notification to the Building Inspector, in addition to the copies required by RSA 483-A:3. Further, the applicant shall be required to submit copies of said notification to those adjacent communities as determined by the Building Inspector. (Amended March 2000) (Amended March 2007)
2. The applicant shall submit to the Building Inspector, certification provided by a registered professional engineer, assuring that the flood carrying capacity of an altered or relocated watercourse can and will be maintained.
3. Along watercourses with a designated Regulatory Floodway no encroachments, including fill, new construction, substantial improvements, and other development are allowed within the floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practices that the proposed encroachment would not result in any increase in flood levels within the community during the base flood discharge. (Amended March, 2007)
4. Until a Regulatory Floodway is designated along watercourses, no new construction, substantial improvements or other development (including fill) shall be permitted within Zone AE on the FIRM, unless it is demonstrated by the applicant that the cumulative effect of the proposed development, when combined with all existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot at any point within the community. (Amended March, 2007)

5. The Building Inspector shall obtain, review, and reasonably utilize any floodway data available from Federal, State, or other sources as criteria for requiring that all development located in Zone A meet the following floodway requirement:

   "No encroachments, including fill, new construction, substantial improvements, and other development are allowed within the floodway that would result in any increase in flood levels within the community during the base flood discharge." (Adopted March, 2007)

10.6 Variances and Appeals.

Any order, requirement, decision or determination of the Building Inspector made under this ordinance may be appealed to the Zoning Board of Adjustment as set forth in RSA 676:5.

If the applicant, upon appeal, requests a variance as authorized by RSA 674:33, I (b), in addition to the usual variance standards under state law the applicant shall show that:

1. the variance will not result in increased flood heights, additional threats to public safety or extraordinary public expense;
2. if the requested variance is for activity within a designated regulatory floodway, it will not result in any increase in flood levels during the base discharge; and
3. considering flood hazard, the variance is necessary to afford relief.

The Zoning Board of Adjustment shall notify the applicant in writing that:

1. the issuance of a variance to construct below the base flood level will result in increased premium rates for flood insurance up to amounts as high as $25 for $100 of insurance coverage; and
2. construction below the bases flood level increases risks to life and property.

The notification shall be maintained with a record of all variance actions.

The Town shall maintain a record of all variance actions, including the justification for their issuance, and report the issuance of any variance to the FEMA's Federal Insurance Administrator in its annual or biennial report.