Town of Putnam, CT Article V Provisions for Flood Hazard Reduction

§ 211-17 General standards.

In all areas of special flood hazard, the following provisions are required:

A. New construction, substantial improvements, and repair to structures that have sustained substantial damage shall be anchored to prevent flotation, collapse or lateral movement of the structure, resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.

B. New construction, substantial improvements, and repair to structures that have sustained substantial damage shall be constructed with materials and utility equipment resistant to flood damage and conform to the provisions of FEMA Technical Bulletin 2, Flood Damage-Resistant Material Requirements. This includes, but is not limited to, flooring, interior and exterior walls, wall coverings and other materials installed below the base flood elevation plus one foot.

C. New construction or substantial improvements shall be constructed by methods and practices that minimize flood damage.

D. The bottom of all electrical, heating, plumbing, ventilation and air-conditioning equipment, appliances, fixtures and components, HVAC duct work and duct systems, and any other utility service equipment, facilities, machinery, or connections servicing a structure shall be elevated at least one foot above the base flood elevation (BFE). This includes, but is not limited to, furnaces, oil or propane tanks, air conditioners, heat pumps, hot water heaters, ventilation duct work, washer and dryer hookups, electrical junction boxes, and circuit breaker boxes. Connections or other equipment that must be located below the BFE plus one foot elevation are permitted only when no other elevation alternative is available and provided they are designed and installed to prevent water from entering or accumulating within the components and to resist hydrostatic and hydrodynamic loads and stresses, including the effects of buoyancy, during the occurrence of the base flood event. Electrical wiring systems that must be located below the BFE plus one foot shall conform to the standards for wet locations.

E. New and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system.

F. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system and discharges from the system into floodwaters.

G. On-site waste disposal systems shall be located and constructed to avoid impairment to them or contamination from them during flooding.

H. Manufactured homes.

(1) All manufactured (mobile) homes to be newly placed, undergoing a substantial improvement or repaired as a result of substantial damage in areas of special flood hazard, shall be elevated so that the bottom of the frame is located one foot above the base flood elevation. The manufactured home must also meet all the construction standards as per § 211-17. The foundation and anchorage of manufactured homes to be located in floodways shall be designed and constructed in accordance with ASCE 24. This includes areas of special flood hazard located outside a manufactured home park or subdivision, in a new manufactured home park or subdivision, in an existing manufactured home park or subdivision, in an expansion to an existing manufactured home park or subdivision, or on a site in an existing manufactured home park in which a manufactured home has incurred substantial damage as a result of a flood;

(2) They shall be placed on a permanent foundation which itself is securely anchored and to which the structure is securely anchored so that it will resist flotation, lateral movement, and hydrostatic and hydrodynamic pressures. Anchoring may include, but not be limited to, the use of over-the-top or frame ties to ground anchors;

(a) They shall be installed using methods and practices which minimize flood damage: Adequate access and drainage should be provided.

(b) Elevation construction standards include piling, foundations placed no more than 10 feet apart, and reinforcement for piers more than six feet above ground level.

(3) In any portion of a watercourse which is altered or relocated, the flood-carrying capacity shall be maintained;

(4) Recreational vehicles placed on sites within areas of special flood hazard shall either be on the site for fewer than 180 consecutive days, and be fully licensed and ready for highway use, or meet all the general standards of § 211-17 and the elevation and anchoring requirement of § 211-17H. 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; and

(5) A structure already in compliance with the provisions of this chapter shall not be made noncompliant by any alteration, repair, reconstruction or improvement to the structure.

I. Underground tanks shall be anchored to prevent flotation, collapse and lateral movement under conditions of the base flood. The bottom of aboveground storage tanks which are located outside or inside of a structure must be elevated one foot above the base flood elevation or shall be securely anchored to prevent flotation, collapse or lateral movement under conditions of the base flood. Where elevated on platforms, the platforms shall be cantilevered from or knee braced to the building or shall be supported on elevated foundations that conform to the standards for the particular flood zone as described in § 211-8. Anchored tanks must have the top of the fill pipe located at least one foot above the BFE and have a screw fill cap that does not allow for the infiltration of floodwater.

J. New construction, substantial improvements and repair to structures that have sustained substantial damage cannot be constructed or located entirely or partially over water unless they are a functionally dependent use or facility.

K. If any portion of a structure lies within the area of special flood hazard, the entire structure is considered to be located within the area of special flood hazard and must meet the construction requirements of the flood zone. The structure includes any structurally attached additions, garages, decks, porches, sunrooms, patios or any other structure attached to the main structure.

L. If a structure lies within two or more flood zones, the construction standards of the most restrictive zone apply to the entire structure (i.e., structure must be built to the highest base flood elevation). The structure includes any structurally attached additions, garages, decks, porches, patios, sunrooms, or any other structure attached to the main structure.

M. Compensatory storage. The water holding capacity of the floodplain, except those areas which are tidally influenced, shall not be reduced. Any reduction caused by filling, new construction or substantial improvements involving an increase in footprint to the structure, shall be compensated for by deepening and/or widening of the floodplain. Storage shall be provided on-site, unless easements have been gained from adjacent property owners; it shall be provided within the same hydraulic reach and a volume not previously used for flood storage; it shall be hydraulically comparable and incrementally equal to the theoretical volume of floodwater at each elevation, up to and including the 100-year flood elevation, which would be displaced by the proposed project. Such compensatory volume shall have an unrestricted hydraulic connection to the same waterway or water body. Compensatory storage can be provided off-site if approved by the municipality.

N. Equal conveyance. Within the floodplain, except those areas which are tidally influenced, as designated on the Flood Insurance Rate Map (FIRM) for the community, encroachments resulting from filling, new construction or substantial improvements involving an increase in footprint of the structure, are prohibited unless the applicant provides certification by a registered professional engineer demonstrating, with supporting hydrologic and hydraulic analyses performed in accordance with standard engineering practice, that such encroachments shall not result in any (0.00 feet) increase in flood levels (base flood elevation). Work within the floodplain and the land adjacent to the floodplain, including work to provide compensatory storage shall not be constructed in such a way so as to cause an increase in flood stage or flood velocity.

§ 211-18 Standards for streams without established base flood elevations.

Any base flood elevation and floodway data available from a federal, state or other source, including data developed pursuant to § 211-16K of this chapter, shall be obtained, reviewed and reasonably utilized as criteria for requiring that new construction, substantial improvements, or other development in Zone A on the Community's FIRM meets the standards in § 211-19 and Article VI.

A. In A Zones where base flood elevations have been determined, but before a floodway is designated, no new construction, substantial improvement, or other development (including fill) shall be permitted which will increase base flood elevations more than one foot at any point along the watercourse when all anticipated development is considered cumulatively with the proposed development.

B. Should data be requested and/or provided, a regulatory floodway shall be adopted based on the principal that the floodway must be able to convey the waters of the base flood without increasing the water surface elevation more than one foot at any point along the watercourse.

§ 211-19 Specific standards.

A. In all areas of special flood hazard, Zones A and AE, where base flood elevation data has been provided, as set forth in § 211-7 or § 211-16K, the following provisions are required:

(1) Residential construction. New construction or substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to at least one foot above the base flood elevation.

(2) Nonresidential construction.

(a) New construction or substantial improvement of any commercial, industrial, or nonresidential structure located in Zone A and AE shall have the lowest floor, including basement, elevated to at least one foot above the level of the base flood elevation; or

(b) Nonresidential structures located in Zone A and AE may be dry floodproofed in lieu of being elevated, provided that, together with all attendant utilities and sanitary facilities, the area of the structure below the base flood elevation plus one foot level is watertight with walls substantially impermeable to the passage of water, and structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy are used. A registered professional engineer or architect shall review and/or develop structural design, specifications, and plans for the construction, and shall certify that the design and methods of construction are in accordance with acceptable standards of practice for meeting the provisions of this subsection. Such certification shall be provided to the Building Official as set forth in § 211-15A(2)(a).

B. Elevated buildings. All new construction, substantial improvements, or repair to structures that have sustained substantial damage, whether residential or nonresidential, that include fully enclosed areas formed by a foundation and other exterior walls shall have the lowest floor elevated to one foot above the base flood elevation (BFE). The elevated building shall be designed to preclude finished living space below the lowest floor and be designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls (wet floodproofing). Designs for complying with this requirement must either be certified by a registered professional engineer or architect as meeting the requirements of ASCE 24 Section 2.6.2.2, or meet the following minimum criteria listed in Subsection B(1) through (8) below:

(1) Provide a minimum of two openings (hydraulic flood vents) having a total net area of not less than one square inch for every one square foot of enclosed area subject to flooding. The enclosed area is measured on the exterior of the enclosure walls. These hydraulic openings must be located on at least two different exterior walls of each enclosed area. If the structure has more than one enclosed area, openings must be installed in the exterior walls of each enclosed area so that floodwaters can enter directly from the outside;

(2) The bottom of all openings shall be no higher than one foot above the higher of either the final interior grade or floor elevation, or the finished exterior grade adjacent to the outside of the foundation wall. At least one side of the structure's fully enclosed area must be at or above grade. Fill placed around the foundation walls must be graded so that the elevation inside the enclosed area is equal to or higher than the adjacent outside elevation on at least one side of the building. The finished floor of the enclosed area shall be no lower than the bottom of the foundation openings. The foundation slab of a residential structure, including the slab or a crawlspace, must be set equal to the outside finished grade on at least one side of the building;

(3) The openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic entry and exit of floodwaters in both directions without any external influence or control such as human intervention, including the use of electrical and other nonautomatic mechanical means. These coverings must not block or impede the automatic flow of floodwaters into and out of the enclosed area. Other coverings may be designed and certified by a registered professional engineer or approved by the Building Official;

(4) Openings shall not be less than three inches in any direction in the plane of the wall;

(5) The area cannot be used as finished living space. Use of the enclosed area shall be the minimum necessary and shall only be used for the parking of vehicles, building access or limited storage. Access to the enclosed area shall be the minimum necessary to allow for the parking of vehicles (garage door) or limited storage of maintenance equipment used in connection with the premises (standard exterior door) or entry to the living area (stairway or elevator). The enclosed area shall not be used for human habitation;

(6) All interior walls, floor, and ceiling materials located below the base flood elevation plus one foot elevation shall be unfinished and resistant to flood damage-resistant in accordance with FEMA Technical Bulletin 2, Flood Damage-Resistant Requirements.

(7) Electrical, plumbing, HVAC ductwork, machinery or other utility equipment and connections that service the structure (including, but not limited to, furnaces, oil or propane tanks, air conditioners, heat pumps, hot-water heaters, ventilation, washers and dryer hookups, electrical junction boxes, circuit breaker boxes and food freezers) are prohibited in the fully enclosed area below the base flood elevation plus one foot elevation. Utilities or service equipment located in this enclosed area, even if elevated one foot above the base flood elevation in the space, will subject the structure to increased flood insurance rates.

(8) A residential building with a structurally attached garage having the floor slab below the base flood elevation is considered an enclosed area below the base flood elevation and must meet the standards of § 211-19B(1) through (7). A garage attached to a residential structure, constructed with the garage floor slab below the base flood elevation, must be designed to allow for the automatic entry and exit of floodwaters in both directions. Flood openings or vents are required in the exterior walls of the garage or in the garage doors. Garage doors that must be manually opened do not meet the flood vent opening requirements in § 211-19B(1) through (3). In addition to the automatic entry of floodwaters, the areas of the garage below the base flood elevation plus one foot must be constructed with flood damage-resistant materials per the requirements of FEMA Technical Bulletin 2. Garages attached to nonresidential structures must also meet the aforementioned requirements or be dry floodproofed as per the requirements of § 211-19A(2).

C. Floodways. Located within areas of special flood hazard are areas designated as floodways on the community's Flood Insurance Rate Map. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and has erosion potential, the following provisions shall apply:

(1) Encroachments, including fill, new construction, substantial improvements, repairs to substantially damaged structures and other developments, shall be prohibited unless certification (with supporting technical data) by a registered professional engineer is provided demonstrating, through hydrologic and hydraulic analyses performed in accordance with standard engineering practice, that encroachments shall not result in any (0.00 feet) increase in flood levels during occurrence of the base flood discharge published by FEMA. Buildings and structures meeting the standard above and located in whole or in part in the floodway shall be designed and constructed in accordance with ASCE 24. Fences in the floodway must be aligned with the flow and be of an open design. A permit may be given which allows encroachments resulting in increases in base flood elevations provided the community first obtains a conditional floodway revision by meeting the requirements of C.F.R. 44, Chapter 1, Subsection 65.12.[1]

[1] Editor's Note: See 44 C.F.R. § 65.12.

D. In Zones AE along watercourses that have not been designated as a regulatory floodway, no new construction, substantial improvement, or other development shall be permitted; unless it is demonstrated that the cumulative effect of the proposed development will not increase the water surface elevation of the base flood more than one foot at any point within the community.