City of Tarkio, MO Article IV Provisions For Flood Hazard Reduction

Section 415.150 General Standards.

[Ord. No. 150-14 Art. 4 § A, 7-8-2014]

A. No permit for floodplain development shall be granted for new construction, substantial-improvements, and other improvements, including the placement of manufactured homes, within any unnumbered A zone unless the conditions of this Section are satisfied.

B. All areas identified as unnumbered A zones on the FIRM are subject to inundation of the 100-year flood; however, the base flood elevation is not provided. Development within unnumbered A zones is subject to all provisions of this Chapter. If Flood Insurance Study data is not available, the community shall obtain, review, and reasonably utilize any base flood elevation or floodway data currently available from Federal, State, or other sources.

C. All new construction, subdivision proposals, substantial-improvements, prefabricated buildings, placement of manufactured homes, and other developments shall require:

1. Design or adequate anchorage to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;

2. Construction with materials resistant to flood damage;

3. Utilization of methods and practices that minimize flood damages;

4. All electrical, heating, ventilation, plumbing, air-conditioning equipment, and other service facilities be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;

5. New or replacement water supply systems and/or sanitary sewage systems be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters, and on-site waste disposal systems be located so as to avoid impairment or contamination; and

6. Subdivision proposals and other proposed new development, including manufactured home parks or subdivisions, located within special flood hazard areas are required to assure that:

a. All such proposals are consistent with the need to minimize flood damage;

b. All public utilities and facilities, such as sewer, gas, electrical, and water systems are located and constructed to minimize or eliminate flood damage;

c. Adequate drainage is provided so as to reduce exposure to flood hazards; and

d. All proposals for development, including proposals for manufactured home parks and subdivisions, of five (5) acres or fifty (50) lots, whichever is lesser, include within such proposals base flood elevation data.

D. Agricultural Structures. Structures used solely for agricultural purposes in connection with the production, harvesting, storage, drying, or raising of agricultural commodities, including the raising of livestock, may be constructed at-grade and wet-floodproofed provided there is no human habitation or occupancy of the structure; the structure is of single-wall design; there is no permanent retail, wholesale, or manufacturing use included in the structure; a variance has been granted from the floodplain management requirements of this Chapter; and a floodplain development permit has been issued.

E. Accessory Structures. Structures used solely for parking and limited storage purposes, not attached to any other structure on the site, of limited investment value, and not larger than 400 square feet, may be constructed at-grade and wet-floodproofed provided there is no human habitation or occupancy of the structure; the structure is of single-wall design; a variance has been granted from the standard floodplain management requirements of this Chapter; and a floodplain development permit has been issued.

F. Critical Facilities.

1. All new or substantially improved critical nonresidential facilities including, but not limited, to governmental buildings, police stations, fire stations, hospitals, orphanages, penal institutions, communication centers, water and sewer pumping stations, water and sewer treatment facilities, transportation maintenance facilities, places of public assembly, emergency aviation facilities, and schools shall be elevated above the 500-year flood level or together with attendant utility and sanitary facilities, be floodproofed so that below the 500-year flood level the structure is water tight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. A registered professional engineer or architect shall certify that the standards of this Subsection are satisfied. Such certification shall be provided to the Floodplain Administrator as set forth in the National Flood Insurance Program (NFIP) regulations.

2. All critical facilities shall have access routes that are above the elevation of the 500-year flood.

G. Storage, Material, And Equipment.

1. The storage or processing of materials within the special flood hazard area that are in time of flooding buoyant, flammable, explosive, or could be injurious to human, animal, or plant life is prohibited.

2. Storage of other material or equipment may be allowed if not subject to major damage by floods, if firmly anchored to prevent flotation, or if readily removable from the area within the time available after a flood warning.

H. Hazardous Materials. All hazardous material storage and handling sites shall be located out of the floodplain.

I. Non-Conforming Use. A structure, or the use of a structure or premises that was lawful before the passage or amendment of the ordinance, but which is not in conformity with the provisions of this Chapter, may be continued subject to the following conditions:

1. If such structure, use, or utility service is discontinued for 24 consecutive months, any future use of the building shall conform to this Chapter.

2. If any nonconforming use or structure is destroyed by any means, including flood, it shall not be reconstructed if the cost is more than 50 percent of the pre-damaged market value of the structure. This limitation does not include the cost of any alteration to comply with existing state or local health, sanitary, building, safety codes, regulations or the cost of any alteration of a structure listed on the National Register of Historic Places, the State Inventory of Historic Places, or local inventory of historic places upon determination.

J. Cumulative Improvement. A structure may be improved (remodeled or enlarged) without conforming to current requirements for elevation so long as the cumulative value of all work done within the last five calendar years does not exceed 50 percent of the structure's current market value. If the cumulative value of the improvement exceeds 50 percent of the structure's current market value, the structure must be brought into compliance with Article IV, Section 415.160(A) which requires elevation of residential structures to or above the base flood elevation or the elevation/floodproofing of non-residential structures to or above the base flood elevation.

Section 415.160 Specific Standards.

[Ord. No. 150-14 Art. 4 § B, 7-8-2014]

A. In all areas of special flood hazard, once base flood elevation data is obtained, as set forth in Article IV, Section 415.150(B), the following provisions are required:

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

[*The FEMA, Region VII office recommends elevating to one foot above the base flood elevation to accommodate floodway conditions when the floodplain is fully developed.]

2. Non-residential construction. New construction or substantial-improvement of any commercial, industrial, or other non-residential structure, including manufactured homes, shall have the lowest floor, including basement, elevated to one (1) foot above the base flood level or, together with attendant utility and sanitary facilities, be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall certify that the standards of this Subsection are satisfied. Such certification shall be provided to the Floodplain Administrator as set forth in Article III, Section 415.130(A)(7)(c).

[*The FEMA Region VII office recommends elevating to one foot above the base flood elevation to qualify for flood insurance rates based upon floodproofing.]

3. Require, for all new construction and substantial-improvements, that fully enclosed areas below lowest floor used solely for parking of vehicles, building access, or storage in an area other than a basement and that 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 minimum criteria:

a. 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; and

b. The bottom of all opening shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.

B. In all areas of special flood hazard, once floodway data is obtained, as set forth in Article IV, Section 415.150(B), the following provisions are required:

1. The designated floodway shall be based on the standard that the area chosen for the floodway must be designed to carry the waters of the base flood, without increasing the water surface elevation more than one foot at any point; and

2. The community shall prohibit any encroachments, including fill, new construction, substantial- improvements, and other development within the designated regulatory floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels within the community during the occurrence of the base flood discharge.

Section 415.170 Manufactured Homes.

[Ord. No. 150-14 Art. 4 § C, 7-8-2014]

A. All manufactured homes to be placed within special flood hazard areas shall be required to be installed using methods and practices that minimize flood damage. For the purposes of this requirement, manufactured homes must be elevated and 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.

B. Require manufactured homes that are placed or substantially improved within unnumbered A zones on the community's FIRM on sites:

1. Outside of manufactured home park or subdivision;

2. In a new manufactured home park or subdivision;

3. In an expansion to and existing manufactured home park or subdivision; or

4. In an existing manufactured home park or subdivision on which a manufactured home has incurred "substantial-damage" as the result of a flood,

be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to one (1) foot above the base flood level and be securely attached to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

C. Require that manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within unnumbered A zones on the community's FIRM, that are not subject to the provisions of Article IV, Section 415.170(B) of this Chapter, be elevated so that either:

1. The lowest floor of the manufactured home is one (1) foot above the base flood level; or

2. The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than thirty-six (36) inches in height above grade and be securely attached to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

[*The FEMA, Region VII office recommends elevating to one foot above the base flood elevation to accommodate floodway conditions when the floodplain is fully developed.]

Section 415.180 Recreational Vehicles.

[Ord. No. 150-14 Art. 4 § D, 7-8-2014]

A. Require that recreational vehicles placed on sites within unnumbered A zones on the community's FHBM or FIRM either:

1. Be on the site for fewer than one hundred eighty (180) consecutive days,

2. Be fully licensed and ready for highway use*; or

3. Meet the permitting, elevation, and the anchoring requirements for manufactured homes of this Chapter.

*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.