§ 141-18. Specific standards., Chapter 141. Flood Damage Prevention, Part II. General Legislation, Code of Ordinances, Rocky Hill

Residential construction.

(1)

New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to two feet of freeboard or above base flood elevation.

(2)

All manufactured homes (except those to be placed in an existing manufactured home park/subdivision where the repair, reconstruction or improvement of the streets, utilities and pads is less than 50% of the value before the repair, reconstruction or improvement has commenced) shall have the lowest floor elevated to or above the base flood level. They shall be placed on a permanent foundation which itself is securely anchored and to which the structure is securely anchored.

Nonresidential construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to the level of the base flood elevation or, together with attendant utility and sanitary facilities, shall:

(1)

Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water.

(2)

Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.

(3)

Be certified by a registered professional engineer or architect that the standards of this subsection are satisfied. Such certifications shall be provided to the official as set forth in § 141-13C(2).

For new construction or substantial improvements: require that fully enclosed areas below the lowest floor that are usable solely for the parking of vehicles, building access, or limited storage in an area other than a basement, and which are subject to flooding, shall be designed to automatically equalize hydrostatic flood forces on 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 criteria: 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. The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, valves, or other coverings or devices, provided they permit the automatic entry and exit of floodwaters.

Compensatory storage. The water holding capacity of the floodplain, except those areas that 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 one-hundred-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.

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.

Aboveground oil tanks. Aboveground storage tanks (oil, propane, etc.) which are located outside or inside of the structure must either be elevated above the base flood elevation (BFE) on a concrete pad or be securely anchored with tie-down straps to prevent flotation or lateral movement, have the top of the fill pipe extended above the BFE, and have a screw fill cap that does not allow for the infiltration of floodwater.

Portion of structure in flood zone. If any portion of a structure lies within the Special Flood Hazard Area (SFHA), the entire structure is considered to be in the SFHA. The entire structure must meet the construction requirements of the flood zone. The structure includes any attached additions, garages, decks, sunrooms, or any other structure attached to the main structure. Decks or porches that extend into a more restrictive flood zone will require the entire structure to meet the standards of the more restrictive zone.

Structures in two flood zones. 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., V Zone is more restrictive than A Zone; structure must be built to the highest BFE). The structure includes any attached additions, garages, decks, sunrooms, or any other structure attached to the main structure. (Decks or porches that extend into a more restrictive zone will require the entire structure to meet the requirements of the more restrictive zone.)

No structures entirely or partially over water. New construction, substantial improvements and repair to structures that have sustained substantial damage cannot be constructed or located entirely or partially over water.