§ 28-3-2. Flood Hazard (FH) District.

(a)

Purpose of the FH District. The FH District is established for the following purposes:

(1)

To reduce the hazards of floods in the interest of the public health, safety, and welfare;

(2)

To protect floodplain occupants from losses from flood damage;

(3)

To protect the public from the burden of extraordinary financial expenditures for flood control and relief; and

(4)

To protect the capacity of floodplain areas to absorb, transmit, and store runoff.

(b)

Authority for the FH District. The FH District is established in accordance with the provisions of RSA 674:41, Innovative Land Use Controls, and the National Flood Insurance Act of 1968. Wherever a conditional use permit is authorized in this Section, the authority to administer or grant conditional use permits shall be vested in the Planning Board.

(c)

Limits of the FH District. The FH District, as displayed on the Zoning Map pursuant to Section 28-2-3(b), The Zoning Overlay District Maps, of this ordinance [,] shall include the following areas within the City:

(1)

Floodway . Within the FH District, and as shown on the FIRM as the floodway, the area that includes the channel of the watercourse and adjacent land that must be reserved in order to discharge flood waters without increasing the water surface elevation.

(2)

One Hundred (100) Year Floodplains . Within the FH District, the area which will be subject to a flood that has a one (1) percent chance of being equaled or exceeded in any given year. The one hundred (100) year floodplain is designated as Special Flood Hazard Areas (SFHA) subject to inundation by the one (1) percent annual flood as shown on the FIRM.

(3)

Five Hundred (500) Year Floodplains . Within the FH District, and as shown on the FIRM as Zone X (Other Flood Areas), the area immediately adjacent to the one hundred (100) year floodplain which will be subject to a flood that has a two-tenths (0.2) of a percent chance of being equaled or exceeded in any given year.

(d)

Uses Prohibited in the FH District.

(1)

Uses Prohibited in the Floodway .

a.

Buildings;

b.

The above-ground or underground storage of buoyant, flammable, toxic, hazardous, or explosive chemicals or materials;

c.

The dumping of waste materials;

d.

The installation of a well intended as a source for potable water; and

e.

The installation of an on-site subsurface disposal system.

(2)

Uses Prohibited in the One Hundred (100) Year Floodplains .

a.

Any dwelling unit, or building or structure designed for residential purposes;

b.

The storage of toxic or hazardous materials;

c.

The dumping of waste materials; and

d.

The installation of a well intended as a source of potable water.

(3)

Uses Prohibited in the Five Hundred (500) Year Floodplains .

a.

The storage of toxic or hazardous materials.

(e)

Conditional Use Permits Required for Encroachments in the Floodway .

(1)

Circumstances Under Which a Permit May Be Granted. The Planning Board may grant a conditional use permit allowing construction of a structure not designed for human occupancy, or the placement of fill, or the placement of other encroachments in the floodway. In issuing a permit, the Planning Board may attach conditions to the permit including but not limited to restrictions on the size and location of structures, and the type, quantity, and location of the placement of fill material or of other encroachments. In addition to the requirements of Section 28-9-4(b), Conditional Use Permits, of this ordinance, an applicant for a conditional use permit shall provide adequate documentation in order for the Planning Board to make a finding that the proposed encroachment in the floodway meets the following conditions:

a.

There will be no adverse affect to the flood carrying capacity of the floodway or the flood heights along the floodway,

b.

There will be no increase in the base flood level or other adverse affect to the flood levels along the flood plain, and

c.

There will be no increased hazard to life and property.

(2)

Water Dependent Use or Structure. Where an application is for a water dependent use or structure, including but not necessarily limited to boathouses, beaches, docks, piers, and moorings, the granting of a conditional use permit shall require the receipt of a permit from NHDES in accordance with RSA 482-A, Fill and Dredge in Wetlands, as well as any and all other permits and approvals required by this ordinance.

(3)

Consultation with Experts and Preparation of Special Studies. In considering any application for a conditional use permit under this Section, the Planning Board may consult with the U.S. Army Corps of Engineers or such other experts as deemed necessary. The Planning Board may engage a licensed professional engineer, at the applicant's expense, to conduct such studies as may be necessary to assist the Board in making findings and reaching a decision.

(4)

Exemptions from Conditional Use Permits Requirements. Upon presentation to the Code Administrator of a copy of a permit from the New Hampshire Department of Environmental Services (NHDES), the construction within the floodway of dams; hydroelectric facilities; public water supply, sewage treatment, and stormwater drainage facilities; and other public utilities and appurtenances, shall be exempt from the requirements for a conditional use permit.

(f)

Development Standards in the FH District.

(1)

Resistance to, and Minimization of, Flood Damage. All new construction and substantial improvements, together with attendant utility and sanitary facilities, shall be:

a.

Designed and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;

b.

Constructed by methods and practices that minimize flood damages, and with materials resistant to flood damage; and

c.

Constructed with electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities at an elevation that is equal to or greater than the required elevation, as determined pursuant to Section 28-3-2(h), Determination of Required Elevations, of this ordinance, and which are designed and located so as to prevent water from entering or accumulating within the equipment and facilities during conditions of flooding.

(2)

Buildings or Structures in the One Hundred (100) Year Floodplain. Nonresidential buildings or structures may be constructed or improved within the one hundred (100) year floodplain provided that such buildings or structures are served by municipal water and sewer services, and subject to the following standards:

a.

The lowest floor, including any basement, shall be established at an elevation that is equal to or greater than the required elevation, as determined pursuant to Section 28-3-2(h), Determination of Required Elevations, of this ordinance; or

b.

The building or structure, shall be floodproofed so that below the required elevation, as determined pursuant to Section 28-3-2(h), Determination of Required Elevations, of this ordinance, the structure is watertight, with walls substantially impermeable to the passage of water, and has structural components capable of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy.

(3)

Buildings or Structures in the Five Hundred (500) Year Floodplain. Buildings or structures may be constructed or improved within the five hundred (500) year floodplain subject to the following standards:

a.

The lowest floor, including any basement, shall be established at an elevation that is equal to or greater than the required elevation, as determined pursuant to Section 28-3-2(h), Determination of Required Elevations, of this ordinance, for the closest, adjacent, upstream area of the one hundred (100) year floodplain; and

b.

All buildings or structures shall be served by municipal water and sewer services.

(4)

Storage of Flammable or Combustible Fuels. Flammable or combustible fuels may be stored in the FH District outside of the floodway when installed and stored in accordance with the most recently adopted version of the BOCA National Fire Prevention Code, to the satisfaction of the Code Administrator.

(5)

Storage of Buoyant Materials. Buoyant materials may be stored in the FH District outside of the floodway provided that the lowest elevation of the buoyant materials in storage is higher than the required elevation, as determined pursuant to Section 28-3-2(h), Determination of Required Elevations, of this ordinance. The buoyant materials shall be placed on the ground, on fill, or on supports that are suitably anchored and designed, so that no portion of the buoyant materials is located below the required elevation. The components of all structural support of a storage facility for buoyant materials shall have the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy.

(6)

Recreational Vehicles and Trailers. Certain recreational vehicles and trailers placed on sites within the FH District shall be on the site for fewer than one hundred eighty (180) consecutive days, and be fully licensed and ready for highway use. The recreational vehicles and trailers to which this Section applies are those that meet the following criteria:

a.

Are built on a single chassis;

b.

Are four hundred (400) square feet or less when measured at the largest horizontal projection;

c.

Are designed to be self-propelled or permanently towable by a light duty truck; and

d.

Are designed as temporary living quarters for recreational, camping, travel, or seasonal use, but not primarily for use as a permanent dwelling.

(g)

General Application Requirements within the FH District. The Code Administrator shall review all applications for permits and approval of new construction or substantial improvements to determine whether proposed building site is in the FH District and if so, to assure that proposed buildings, structures, and improvements will be reasonably safe from flooding and in accordance with the requirements of this Section. Within the FH District, the following plans, data, information, and certification shall be provided by an applicant to the Code Administrator:

(1)

The proposed elevation in relation to the North American Vertical Datum (NAVD) of the lowest floor, including any basement;

(2)

If the structure is proposed to be floodproofed, the elevation in relation to NAVD to which the structure is to be floodproofed;

(3)

Upon completion of floodproofing, the certification of a licensed professional engineer or architect that the design and methods construction or installation of floodproofing were completed in accordance with accepted standards of practice for the same;

(4)

Where replacement on-site subsurface disposal systems are proposed outside of the floodway in the FH District, the certification of a licensed professional engineer, assuring that new or replacement systems will be designed to minimize or eliminate infiltration of floodwaters into the systems, and to minimize or eliminate discharges from the systems into floodwaters, and that the systems will be located to avoid impairment to them or contamination from them during periods of flooding; and

(5)

Copies of all necessary permits 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.

(h)

Determination of Required Elevation in the FH District. The Code Administrator shall determine the required elevation for development outside of the floodway in the FH District within the Merrimack River floodplain by adding two (2) feet to the base flood elevation on the FIRM. The Code Administrator shall determine the required elevation for development outside of the floodway within the floodplains of surface waters other than the Merrimack River by adding one foot to the base flood elevation on the FIRM. The flood reference elevations on the FIRM shall be determined in the following order of precedence according to the data available:

(1)

In Zone AE by reference to the base flood elevation data in the FIS and accompanying FIRM;

(2)

In Zone A with no base flood elevation shown in the FIS or FIRM:

a.

The Flood Plain Administrator shall obtain, review, and reasonably utilizing any one hundred (100) year flood elevation data available from federal, state, or other sources including data submitted pursuant to development applications;

b.

Where a base flood elevation is not available or not known, the base flood elevation shall be determined to be at least two (2) feet above the highest adjacent grade;

c.

For developments greater than five (5) acres, the applicant shall develop a base flood elevation based on a hydrologic and/or hydraulic study.

(i)

Appeals to the Zoning Board of Adjustment (ZBA) in the FH District.

(1)

Any appeal of a determination or decision made pursuant to this Section, other than a determination or decision related to a conditional use permit, shall be made in accordance with Section 28-9-3, Decisions by the Zoning Board of Adjustment (ZBA), of this ordinance.

(2)

A record of all variance actions in the FH District shall be included in the City's regular reports to the Federal Insurance Administrator at the Federal Emergency Management Agency (FEMA).

(j)

Substantial Improvements to Existing Residential Structures Within the 100-Year and 500-Year Floodplains. Substantial improvements to existing residential structures may only occur within the 100-year floodplain and the 500-year floodplain subject to the following provisions:

(1)

The lowest floor, including any basement, shall be established at an elevation that is equal to or greater than the required elevation, as determined pursuant to Section 28-3-2(h), Determination of Required Elevations, of this ordinance.

(2)

Fully enclosed areas subject to flooding shall only be used for parking, storage and building access provided that the area is not a basement, the enclosed area is unfinished or flood resistant, and the areas are designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwater. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet or exceed the following criteria: A minimum of two (2) openings having a total net area of not less than one square inch of for every square foot of enclosed area subject to flooding shall be provided. The bottom of the openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers or other coverings provided that they permit the automatic entry and exit of floodwater.

(k)

Definitions for Flood Plan Management Purposes Only.

(1)

Development means any manmade changes to improved or unimproved real estate, including, but not limited to, buildings and structures, mining, dredging, filling, grading, paving, excavating, or drilling operation, or the storage of equipment or materials.

(2)

Manufactured home means 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" includes park trailers, travel trailers and other similar vehicles placed on site for more than one hundred eighty (180) consecutive days.

(3)

New construction means, for the purposes of determining insurance rates, structures for which the "start of construction" commenced on or after March 4, 1980, effective date of the initial FIRM. For floodplain management purposes, new construction means structures for which the start of construction commenced on or after the effective date of floodplain management regulation adoption by the City of Concord on August 12, 1974, and includes any subsequent improvements to such structures. "Substantial damage" means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.

(4)

Substantial damage means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed fifty (50) percent of the market value of the structure before the damage occurred.

(5)

Substantial improvement means any combination of repairs, reconstruction, alteration, or improvements to a structure in which the cumulative cost equals or exceeds fifty (50) percent of the market value of the structure. The market value of the structure should equal:

a.

The appraised value prior to the start of the initial repair or improvement, or

b.

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 that 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".

(6)

Violation means the failure of a structure to be fully compliant with the community's floodplain regulations. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in 44 CFR 60.3(b)(5), (c)(4), (c)(10), (d)(3), (e)(2), (e)(4), or (e)(5) is presumed to be in violation until such time as that documentation is provided.

(Ord. No. 2784, § II, 3-8-10; Ord. No. 2798, §§ I, II, 7-12-10; Ord. No. 3030, §§ III—VIII, 2-11-19)