This article, adopted pursuant to the authority of RSA 674:16,
shall be known as the "City of Rochester Floodplain Development Ordinance."
The regulations in this article shall overlay and supplement the regulations
in the City of Rochester Zoning Ordinance and shall be considered
part of the Zoning Ordinance for purposes of administration and appeals
under state law. If any provision of this article 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 in this article shall apply to all
lands designated as special flood hazard areas by the Federal Emergency
Management Agency (FEMA) in its Flood Insurance Study, Strafford County,
New Hampshire, together with the associated Flood Insurance Rate Maps
dated May 17, 2005, which are declared to be a part of this article
and are hereby incorporated by reference.
As used in this article, the following words and phrases shall
have the following meanings:
A designated AO or AH Zone on a community's Flood Insurance
Rate Map (FIRM) with a one-percent or greater annual chance of flooding
to an average depth of one to three feet where a clearly defined channel
does not exist, where the path of flooding is unpredictable, and where
velocity flow may be evident. Such flooding is characterized by ponding
or sheet flow.
The land in the floodplain within a community subject to
a one-percent or greater chance of flooding in any given year. The
area may be designated as Zone A on the FHBM. After detailed ratemaking
has been completed in preparation for publication of the FIRM, Zone
A usually is refined into Zone A, AO, AH, A1-30, AE or A99.
The flood having a one-percent chance of being equaled or
exceeded in any given year.
Any area of the building having its floor subgrade (below
ground level) on all sides.
A wall that is not part of the structural support of the
building and is intended through its design and construction to collapse
under specific lateral loading forces without causing damage to the
elevated portion of the building or supporting foundation.
See "structure."
Any man-made change to improved or unimproved real estate,
including but not limited to buildings or other structures, mining,
dredging, filling, grading, paving, excavation, or drilling operations.
The Federal Emergency Management Agency.
An official map of the community on which the Federal Emergency
Management Agency has delineated the regulatory floodway. This map
should not be used to determine the current flood hazard zone or base
flood elevation; the Flood Insurance Rate Map (FIRM) will be used
to make determinations of flood hazard zones and base flood elevations.
An examination, evaluation and determination of flood hazards
and, if appropriate, corresponding water surface elevations, or an
examination, evaluation, and determination of mudslide (i.e., mudflow)
and/or flood-related erosion hazards.
An official map of a community, issued by the Federal Emergency
Management Agency, where the boundaries of the flood, mudslide (i.e.,
mudflow), and related erosion areas having special hazards have been
designated as Zone A.
An official map of a community on which the Federal Emergency
Management Agency has delineated both the special hazard areas and
the risk premium zones applicable to the community.
See "Flood Elevation Study."
A general and temporary condition of partial or complete
inundation of normally dry land areas from:
Any land area susceptible to being inundated by water from
any source.
Any combination of structural and nonstructural additions,
changes, or adjustments to structures which reduce or eliminate flood
damage to real estate or improved real property, water and sanitary
facilities, structures, and their contents.
See "regulatory floodway."
A use which cannot perform its intended purpose unless it
is located or carried out in close proximity to water. The term includes
only docking and port facilities that are necessary for the loading/unloading
of cargo or passengers and ship building/repair facilities but does
not include long-range storage or related manufacturing facilities.
The highest natural elevation of the ground surface prior
to construction next to the proposed wall of a structure.
Any structure that is:
Listed individually on the National Register of Historic Places
(a listing maintained by the Department of Interior) or preliminarily
determined by the Secretary of the Interior as meeting the requirements
for individual listing on the National Register;
Certified or preliminarily determined by the Secretary of the
Interior as contributing to the historical significance of a registered
historic district or a district preliminarily determined by the Secretary
to qualify as a registered historic district;
Individually listed on a state inventory of historic places
in states with historic preservation programs which have been approved
by the Secretary of the Interior; or
Individually listed on a local inventory of historic places
in communities with historic preservation programs that have been
certified either:
The lowest floor of the lowest enclosed area (including basement).
An unfinished or flood-resistant enclosure, usable solely for parking
of vehicles, building access or storage, in an area other than a basement
area is not considered a building's lowest floor, provided that such
enclosure is not built so as to render the structure in violation
of the applicable non-elevation design requirements of this article.
A structure, transportable in one or more sections, which
is built on a permanent chassis and is designed for use with or without
a permanent foundation when connected to the required utilities. For
floodplain management purposes the term "manufactured home" also includes
park trailers, travel trailers, and other similar vehicles placed
on a site for greater than 180 consecutive days. For insurance purposes
the term "manufactured home" does not include park trailers, travel
trailers, and other similar vehicles.
A parcel (or contiguous parcels) of land divided into two
or more manufactured home lots for rent or sale.
For purposes of the National Flood Insurance Program, the
National Geodetic Vertical Datum (NGVD) of 1929 or other datum to
which base flood elevations shown on a community's Flood Insurance
Rate Map are referenced.
See "base flood."
The channel of a river or other watercourse and the adjacent
land areas that must be reserved in order to discharge the base flood
without cumulatively increasing the water surface elevation more than
one foot at any point. These areas are designated as floodways on
the Flood Boundary and Floodway Map.
Relating to, formed by, or resembling a river (including
tributaries), stream, brook, etc.
An area having special flood, mudslide (i.e., mudflow) and/or
flood-related erosion hazards, and shown on an FHBM or FIRM as Zones
A, AO, A1-30, A99, and AH. (See "area of special flood hazard.")
Includes substantial improvement and means the date the building
permit was issued, provided the actual start of construction, repair,
reconstruction, placement, or other improvement was within 180 days
of the permit date. The actual start means either the first placement
of permanent construction of a structure on a site, such as the pouring
of a slab or footings, the installation of piles, the construction
of columns, or any work beyond the stage of excavation, or the placement
of a manufactured home on a foundation. Permanent construction does
not include land preparation, such as clearing, grading, and filling;
nor does it include the installation of streets and/or walkways; nor
does it include excavation for a basement, footings, piers, or foundations
or the erection of temporary forms; nor does it include the installation
on the property of accessory buildings, such as garages, or sheds
not occupied as dwelling units or not part of the main structure.
For floodplain purposes, a walled and roofed building, including
a gas or liquid storage tank, that is principally above ground, as
well as a manufactured home.
Damage by any origin sustained by a structure whereby the
cost of restoring the structure to its before-damaged condition would
equal or exceed 50% of the market value of the structure before the
damage occurred.
Any combination of repairs, reconstruction, alteration, or
improvements to a structure in which the cumulative cost equals or
exceeds 50% of the market value of the structure. The market value
of the structure should equal the appraised value prior to the start
of the initial repair or improvement or, in the case of damage, the
value of the structure prior to the damage occurring. For the purposes
of this definition, "substantial improvement" is considered to occur
when the first alteration of any wall, ceiling, floor, or other structural
part of the building commences, whether or not that alteration affects
the external dimensions of the structure. This term includes structures
which have incurred substantial damage, regardless of actual repair
work performed. The term does not, however, include any project for
improvement of a structure required to comply with existing health,
sanitary, or safety code specifications which are solely necessary
to assure safe living conditions or any alteration of a historic structure,
provided that the alteration will not preclude the structure's continued
designation as a historic structure.
The height, in relation to the National Geodetic Vertical
Datum (NGVD) of 1929 (or other datum, whether specified), of floods
of various magnitudes and frequencies in the floodplains of coastal
or riverine areas.
The following regulations, as well as the regulations contained in appropriate sections of this chapter, shall apply to the regulatory floodway zone as delineated in § 275-13.2 above:
A.
All proposed development in any special flood hazard areas shall
require a permit.
B.
The Director of Building, Zoning, and Licensing Services shall review
all building permit applications for new construction or substantial
improvements to determine whether proposed building sites will be
reasonably safe from flooding. If a proposed building site is in a
flood-prone area, all new construction and substantial improvements
shall:
(1)
Be 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)
Be constructed with materials resistant to flood damage;
(3)
Be constructed by methods and practices that minimize flood
damage; and
(4)
Be constructed with 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 conditions of flooding.
C.
The placement of a manufactured housing unit is prohibited within
the designated regulatory floodway, except in existing manufactured
housing parks.
D.
Within the regulatory floodway, any development or encroachment (including
fill) which would result in any increase in flood levels during the
base flood discharge is prohibited.
E.
Where new and replacement water and sewer systems (including on-site
systems) are proposed in flood-prone areas, the applicant shall provide
the Director of Building, Zoning, and Licensing Services with assurance
that new and replacement sanitary sewage systems will be designed
to minimize or eliminate infiltration of floodwaters, and on-site
waste disposal systems will be located to avoid impairment to them
or contamination from them during periods of flooding.
F.
The Director of Building, Zoning, and Licensing Services shall maintain
for public inspection, and furnish upon request, any certification
of floodproofing and the as-built elevation (in relation to mean sea
level) of the lowest floor (including basement) of all new or substantially
improved structures, and include whether or not such structures contain
a basement. This information must be furnished by the applicant.
[Amended at time of adoption of Code (see Ch. 1, General
Provisions, Art. II)]
G.
The Director of Building, Zoning, and Licensing Services shall review
proposed developments to assure 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.
H.
Watercourses.
(1)
In riverine situations, prior to the alteration or relocation
of a watercourse, the applicant for such authorization shall notify
the Wetlands Board of the New Hampshire Environmental Services Department
and submit copies of such notification to the Director of Building,
Zoning, and Licensing Services. Further, the applicant shall be required
to submit copies of said notification to those adjacent communities
as determined by the Director.
(2)
Within the altered or relocated portion of any watercourse,
the applicant shall submit to the Director of Building, Zoning, and
Licensing Services certification provided by a registered professional
engineer assuring that the flood-carrying capacity of the watercourse
has been maintained.
(3)
Along watercourses that have a designated regulatory floodway,
no encroachments, including fill, new construction, substantial improvements,
and other development, are allowed within the designated regulatory
floodway that would result in any increase in flood levels within
the community during the base flood discharge. In Zone A, the Director
of Building, Zoning, and Licensing Services shall obtain, review,
and reasonably utilize any floodway data available from a federal,
state, or other source as criteria for requiring that development
meet the floodway requirements of this article.
(4)
Along watercourses that have not had a regulatory floodway designated,
no new construction, substantial improvements, or other development
(including fill) shall be permitted within Zones A1-30 on the FIRM,
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 foot at any point within the community.
A.
In special flood hazard areas the Director of Building, Zoning, and
Licensing Services shall determine the one-hundred-year flood elevation
in the following order of precedence according to the data available:
(1)
In Zones A1-30 and AH, refer to the elevation provided in the
community's Flood Insurance Study and accompanying FIRM or FHBM.
(2)
In unnumbered A Zones, the Director of Building, Zoning, and
Licensing Services shall obtain, review, and reasonably utilize any
one-hundred-year flood elevation data available from federal, state,
development proposals submitted to the community (example: subdivisions,
site approvals, etc.) or other source.
(3)
In Zone AO, the one-hundred-year flood elevation is determined
by adding the elevation of the highest adjacent grade to the depth
number specified on the FIRM or, if no depth number is specified on
the FIRM, at least two feet.
B.
The Director of Building, Zoning, and Licensing Services' one-hundred-year
flood elevation determination will be used as criteria for requiring
in Zones A1-30, AE, AH, AO and A that:
(1)
All new construction and substantial improvements of residential
structures have the lowest floor (including basement) elevated to
or above the one-hundred-year flood level.
(2)
All new construction and substantial improvements of nonresidential
structures have the lowest floor (including basement) elevated to
or above the one-hundred-year flood level or, together with attendant
utility and sanitary facilities, shall:
(a)
Be floodproofed so that below the one-hundred-year flood elevation
the structure is watertight with walls substantially impermeable to
the passage of water;
(b)
Have structural components capable of resisting hydrostatic
and hydrodynamic loads and the effects of buoyancy; and
(c)
Be certified by a registered professional engineer or architect
that the design and methods of construction are in accordance with
accepted standards or practice for meeting the provisions of this
article.
(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 be 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. Recreational
vehicles placed on sites within Zones A, A1-30, AH and AE on the City's
FIRM must either:
(4)
New construction and substantial improvements.
(a)
For all new construction and substantial improvements, fully enclosed
areas below the lowest floor that are subject to flooding are permitted
provided the enclosed areas meet the following requirements:
[1]
The enclosed area is unfinished or flood-resistant, usable solely
for parking of vehicles, building access or storage;
[2]
The area is not a basement; and
[3]
Shall be designed to automatically equalize hydrostatic flood forces
on exterior walls by allowing for the entry and exit of floodwaters.
(b)
Designs for meeting this requirement must either be certified by
a registered professional engineer or architect or must meet or exceed
the following minimum criteria:
[1]
A minimum of two openings have 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.
[3]
Openings may be equipped with screens, louvers, or other coverings
or devices provided that they permit the automatic entry and exist
of floodwaters.
(5)
Proposed structures to be located on slopes in special flood
hazard areas, Zones AH and AD, shall include adequate drainage paths
to guide floodwaters around and away from the proposed structures.
A.
Any order, requirements, decision or determination of the Building
Inspector made under this article may be appealed to the Zoning Board
of Adjustment as set forth in RSA 676:5.
B.
If the applicant, upon appeal, requests a variance as authorized
by RSA 674:33, I(b), the applicant shall have the burden of showing,
in addition to the usual variance standards under state law, 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, no increase in flood levels during the base flood
discharge will result.
(3)
The variance is the minimum necessary, considering the flood
hazard, to afford relief.
C.
The Zoning Board of Adjustment shall notify the applicant in writing
that 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 twenty-five dollars ($25.) for one hundred dollars
($100.) of insurance coverage and such construction below the base
flood level increases risks to life and property. Such notification
shall be maintained with a record of all variance actions.
D.
The community shall maintain a record of all variance actions, including
their justification for their issuance, and report such variances
issued in its annual or biennial report submitted to FEMA's Federal
Insurance Administrator.
