§ 27-552. Provisions for flood hazard reduction.

(a)

General standards.

(1)

No permit for floodplain development shall be granted for new construction, substantial improvements, and other improvements, including the placement of manufactured homes, within any numbered or unnumbered A zones, AE, AO, and AH zones, unless the conditions of this section are satisfied.

(2)

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 subdivision. 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.

(3)

Until a floodway is designated, no new construction, substantial improvements, or other development, including fill, shall be permitted within any unnumbered or numbered A zones, or AE zones 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.

(4)

All new construction, subdivision proposals, substantial improvements, prefabricated structures, placement of manufactured homes, and other developments shall require:

a.

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;

b.

Construction with materials resistant to flood damage;

c.

Utilization of methods and practices that minimize flood damages;

d.

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;

e.

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 from them during flooding; and

f.

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

1.

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

2.

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

3.

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

4.

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

(5)

Storage, material, and equipment.

a.

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.

b.

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.

(6)

Nonconforming uses. A structure, or the use of a structure or premises that was lawful before the passage or amendment of this subdivision, but which is not in conformity with the provisions of this subdivision, may be continued subject to the following conditions:

a.

If such structure, use, or utility service is discontinued for 18 consecutive months, any future use of the building shall conform to this subdivision.

b.

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.

(b)

Specific standards.

(1)

In all areas identified as numbered and unnumbered A zones, AE, and AH zones, where base flood elevation data have been provided, as set forth in subsection 27-552(a)(2), the following provisions are required:

a.

Residential construction . New construction, substantial improvement, or substantial damage of any residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated a minimum of 18 inches above base flood elevation. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer. Substantial improvement or substantial damage is applied when the combined total of improvements or repairs made to the structure in the calendar year exceeds 50 percent of the structure's market value.

All electrical, heating, ventilation, plumbing, air-conditioning equipment, and other service facilities be designed to be elevated to a minimum of 18 inches above the base flood elevation and in accordance with section 27-552.

When fill is used, the top layer shall be above the BFE and in accordance with adopted building code standards. Fill shall not adversely affect the flow or surface drainage from or onto neighboring properties.

Retrofitting a pre-firm single family residence 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 may be retrofitted to meet the design standards for insurance ratings as specified in FEMA flood insurance manual, lowest floor guide. Owners may voluntarily choose to wet floodproof. Any mechanical, electrical, or other utility equipment must be located 18 inches above the base flood elevation. Designs for meeting this requirement must either be certified by a registered professional engineer or architect and meet or exceed the following minimum criteria National Flood Insurance Program (NFIP) opening requirements. If wet floodproofing techniques are utilized, a certificate of wet floodproofing shall be provided by a registered professional engineer or architect.

Pre-firm accessory structure in a single family residential zoned district, that are subject to flooding may be retrofitted to meet the design criteria for automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood waters. Owners may voluntarily choose to wet floodproof an accessory structure to reduce potential flood damage. Designs for meeting this requirement must either be certified by a registered professional engineer or architect and meet or exceed the following minimum criteria National Flood Insurance Program (NFIP) opening requirements.

b.

Non-residential construction . New construction, substantial improvement or substantial damage of any commercial, industrial, or other non-residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated a minimum of 18 inches above the base flood elevation or, together with attendant utility and sanitary facilities in accordance with section 27-552, be dry floodproofed to a minimum of 18 inches above the base flood elevation. A registered professional engineer and/or architect shall certify that the standards of this subsection are satisfied. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer. Such certification shall be provided to the floodplain administrator as set forth in subsections 27-551(c)(7)—(9). Substantial improvement or substantial damage is applied when the combined total of improvements or repairs made to the structure in the calendar year exceeds 50 percent of the structure's market value.

When fill is used, the top layer shall be above the BFE and in accordance with adopted building code standards. Fill shall not adversely affect the flow or surface drainage from or onto neighboring properties.

c.

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 flood waters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria:

1.

The structure must provide one square inch of venting for every square foot of enclosed area;

2.

The structure must provide at least two vents located on different sides of the structure, with one being located on the upstream side of the structure, if possible;

3.

The bottom of required vents must be no higher than one foot above grade;

4.

The required vents must be freely open with no human interventions required and be equipped with screens, louvers, valves, or other coverings or devices provided that they permit automatic entry and exit of floodwaters;

5.

The area below the base flood elevation must be unfinished and constructed of flood-resistant materials as the same are defined by FEMA. Sheetrock or drywall used for fire protection is permitted in unfinished areas;

6.

All ductwork, heating, ventilation and air conditioning systems, electrical and hot water heaters included as part of the structure must be elevated a minimum of 18 inches above the base flood elevation;

7.

All of the above required features must be shown on the plan submitted for the floodplain development permit;

8.

An elevation certificate must document the venting features included in a structure and be filed with the floodplain administrator before the structure is occupied.

(c)

Manufactured homes.

(1)

All manufactured homes to be placed within all unnumbered and numbered A zones, AE, and AH zones, on the community's FIRM 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. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.

(2)

Require manufactured homes that are placed or substantially improved within unnumbered or numbered A zones, AE, and AH zones, on the community's FIRM on sites:

a.

Outside of a manufactured home park or subdivision;

b.

In a new manufactured home park or subdivision;

c.

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

d.

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 a minimum of 18 inches above the base flood elevation and be securely attached to an adequately anchored foundation system to resist flotation, collapse, and lateral movement. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.

(3)

Require that manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within all unnumbered and numbered A zones, AE and AH zones, on the community's FIRM, that are not subject to the provisions of subsection 27-551(c)(2) of this subdivision, be elevated so that either:

a.

The lowest floor of the manufactured home is a minimum of 18 inches above the base flood level; or

b.

Reserved.

c.

The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely attached to an adequately anchored foundation system to resist flotation, collapse, and lateral movement. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.

(d)

Appurtenant structure/accessory structure. Agriculture structure, or accessory structure with two or less outside rigid walls and a fully secured roof, or an accessory structure used solely for parking and limited storage purposes, not attached to any other structure on the site, and of limited investment value may be constructed at-grade and wet-floodproofed (flood vents and flood openings) provided there is no human habitation or occupancy of the structure; 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 flood waters. Accessory structure shall be in conformance with section 27, article VIII, zoning and accessory uses. Designs for meeting this requirement must either be certified by a registered professional engineer or architect and meet or exceed the following minimum criteria National Flood Insurance Program (NFIP) opening requirements.

In order to minimize flood damages during the 100-year flood and the threat to public health and safety, the following conditions shall be included for agricultural structures and accessory structures that are constructed at grade and wet-floodproofed.

(1)

Use of the accessory structures must be solely for parking and limited storage purposes in zones A, AE, AO, and AH only as identified on the community's flood insurance rate map (FIRM).

(2)

For any new or substantially damaged accessory structures, the exterior and interior building components and elements (i.e., foundation, wall framing, exterior and interior finishes, flooring, etc.) below the base flood elevation, must be built with flood resistant materials. If floodproofing techniques are utilized, a certificate of floodproofing shall be provided by a registered professional engineer or architect.

(3)

The accessory structures must be adequately anchored to prevent flotation, collapse, or lateral movement of the structures. All of the building's structural components must be capable of resisting specific flood related forces including hydrostatic, buoyancy, and hydrodynamic and debris impact forces.

(4)

Any mechanical, electrical, or other utility equipment must be located 18 inches above the base flood elevation.

(5)

The accessory structures must meet all National Flood Insurance Program (NFIP) opening requirements. The NFIP requires that enclosure or foundation walls, subject to the 100-year flood, contain openings that will permit the automatic entry and exit of floodwaters. If wet floodproofing techniques are utilized, a certificate of floodproofing shall be provided by a registered professional engineer or architect.

(6)

Reserved.

(7)

Equipment, machinery, or other contents must be protected from any flood damage and in accordance with subsections 27-522(5)(a) and (b). Equipment such as scales, may be floodproofed so that they are contained within a watertight, floodproofed enclosure that is capable of resisting damage during flood conditions. If floodproofing techniques are utilized, a certificate of floodproofing shall be provided by a registered professional engineer or architect.

(8)

Reserved.

(9)

All of the above required features must be shown on the plan submitted for the floodplain development permit.

(10)

An elevation certificate must document the features included in a structure and be filed with the floodplain administrator before the structure is occupied.

(e)

Areas of shallow flooding (AO and AH zones). Located within the areas of special flood hazard as described in subsection 27-550(a) are areas designated as AO zones. These areas have special flood hazards associated with base flood depths of one to three feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and indeterminate. The following provisions apply:

(1)

AO zones.

a.

All new construction and substantial improvements of residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the community's FIRM (at least two feet if no depth number is specified).

b.

All new construction and substantial improvements of any commercial, industrial, or other non-residential structures, including manufactured homes, shall have the lowest floor, including basement, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the community FIRM (at least two feet if no depth number is specified) or together with attendant utilities and sanitary facilities be completely floodproofed to that level so that 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.

c.

Adequate drainage paths shall be required around structures on slopes, in order to guide floodwaters around and away from proposed structures.

(2)

AH zones.

a.

The specific standards for all areas of special flood hazard where base flood elevation has been provided shall be required as set forth in subsection 27-552(b).

b.

Adequate drainage paths shall be required around structures on slopes, in order to guide floodwaters around and away from proposed structures.

(f)

Floodway. Located within areas of special flood hazard established in subsection 27-550(a) are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters that carry debris and potential projectiles, the following provisions shall apply:

(1)

The unified government shall select and adopt a regulatory floodway based on the principle that the area chosen for the regulatory floodway must be designed to carry the waters of the base flood without increasing the water surface elevation of that flood more than one foot at any point.

(2)

The unified government shall prohibit any encroachments, including fill, new construction, substantial improvements, and other development within the adopted 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 city during the occurrence of the base flood discharge.

(3)

If subsection 27-552(e)(2), is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of section 27-552.

(4)

In unnumbered A zones, the unified government shall obtain, review, and reasonably utilize any base flood elevation or floodway data currently available from federal, state, or other sources as set forth in subsection 27-552(a)(2).

(g)

Recreational vehicles. Require that recreational vehicles placed on sites within all unnumbered and numbered A zones, AE, AH, and AO zones on the city's FIRM either:

(1)

Be on the site for fewer than 180 consecutive days, or

(2)

Be fully licensed and ready for highway use ; or

(3)

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

(Ord. No. O-41-15 , § 1, 7-30-2015)