In all SFHAs, the following provisions are required for all new construction and substantial improvements:
(1) 
Designed (or modified) and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
(2) 
Constructed by methods and practices that minimize flood damage;
(3) 
Constructed with materials resistant to flood damage;
(4) 
Constructed with electrical, heating, ventilation, plumbing, and air-conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;
(5) 
Designed to minimize or eliminate infiltration of floodwaters into the system;
(6) 
Designed to minimize or eliminate infiltration of floodwaters into wastewater systems and discharge from the systems into floodwaters; and
(7) 
On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
(Ordinance 6691 adopted 2/5/2024)
In all areas of special flood hazards where base flood elevation data has been provided as set forth in section 3.12.007, section 3.12.042(8) or section 3.12.074(c), the following provisions are required:
(1) 
Residential construction.
(A) 
New construction and substantial improvement of any residential structure shall have the lowest floor (including basement) elevated to two (2) feet above the base flood elevation. A registered professional engineer, architect, or land surveyor shall submit a certification to the floodplain administrator that the standards proposed in section 3.12.043(b)(1)–(4) are satisfied.
(B) 
Any fill dirt required for improvements in the 1% annual chance (100-year) floodplain shall come from the lot that the proposed improvements are to be placed on. It shall be unlawful to bring into the 1% annual chance (100-year) floodplain, with the exception of sand necessary to construct an approved foundation that meets the requirements of this section, any fill materials. A registered professional engineer, architect, or land surveyor shall submit a certification to the floodplain administrator that the standard of this subsection as proposed in section 3.12.043(b)(1) is satisfied.
(2) 
Nonresidential construction.
(A) 
New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest floor (including basement) elevated to at least two (2) feet above the base flood level or, together with attendant utility and sanitary facilities, be designed 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 develop and/or review structural design, specifications, and plans for the construction, and shall certify that the design and methods of construction are in accordance with accepted standards of practice as outlined in this subsection. A record of such certification which includes the specific elevation (in relation to mean sea level) to which such structures are floodproofed shall be maintained by the floodplain administrator.
(B) 
Any fill dirt required for improvements in the 1% annual chance (100-year) floodplain shall come from the lot that the proposed improvements are to be placed on. It shall be unlawful to bring into the 1% annual chance (100-year) floodplain, with the exception of sand necessary to construct an approved foundation that meets the requirements of this section, any fill materials. A registered professional engineer, architect, or land surveyor shall submit a certification to the floodplain administrator that the standard of this subsection as proposed in section 3.12.043(b)(1) is satisfied.
(3) 
Enclosures.
New construction and substantial improvements, with fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or 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 minimum criteria:
(A) 
A minimum of two (2) openings on separate walls having a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding shall be provided;
(B) 
The bottom of all openings shall be no higher than one (1) foot above grade; and
(C) 
Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.
(4) 
Manufactured homes.
(A) 
All manufactured homes to be placed within zone A on a community's FHBM or FIRM shall be installed using methods and practices which 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.
(B) 
No development permit shall be issued for the construction of the following structures within the 1% annual chance (100-year) floodplain: hospitals, nursing or convalescent homes, sanitariums, homes for the aged or infirm, mental or penal institutions, refugee centers or camps, halfway houses.
(C) 
Manufactured homes along with attending utilities that are placed or substantially improved within zones A1-30, AH, and AE on the community's FIRM on sites:
(i) 
Outside of a manufactured home park or subdivision;
(ii) 
In a new manufactured home park or subdivision;
(iii) 
In an expansion to an existing manufactured home park or subdivision; or
(iv) 
In an existing manufactured home park or subdivision on which a manufactured home has incurred "substantial damage" as a result of a flood; must be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to at least three (3) feet above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
(D) 
Require that manufactured homes along with attending utilities be placed or substantially improved on sites in an existing manufactured home park or subdivision within zones A1-30, AH and AE on the community's FIRM that are not subject to the provisions of subsection (4) of this section be elevated so that either:
(i) 
The lowest floor of the manufactured home is at least three (3) feet above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement; or
(ii) 
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 anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
(5) 
Recreational vehicles.
Require that recreational vehicles placed on sites within zones A1-30, AH, and AE on the community's FIRM either:
(A) 
Be on the site for fewer than one hundred eighty (180) consecutive days;
(B) 
Be fully licensed and ready for highway use; or
(C) 
Meet the permit requirements of section 3.12.043(b)(1)–(4), and the elevation and anchoring requirements for "manufactured homes" in subsection (4)(A) of this section. A recreational vehicle is ready for highway use if it is:
(i) 
On its wheels or jacking system;
(ii) 
Is attached to the site only by quick disconnect-type utilities and security devices, and
(iii) 
Has no permanently attached additions.
(Ordinance 6691 adopted 2/5/2024)
All subdivision plats embracing proposed development of portions of any area officially identified as having special flood hazards must be approved prior to the start of construction. Subdivisions or other proposed new development shall be required to be consistent with the need to minimize flood damage, locate, elevate, and construct all public utilities and facilities, such as sewer, gas, electrical and water systems, to minimize or eliminate flood damage and to provide adequate drainage so as to reduce exposure to flood hazards; as a part of subdivision plat approval, water supply and sanitary sewer systems shall be designed and installed to minimize or eliminate infiltration of floodwaters into water systems and discharges from sewer systems into floodwaters. Plats with planned on-site waste disposal systems shall be approved only where the systems can be designed, located, and constructed so as to avoid impairment of these or contamination from these during flooding. Official floodplain delineations and delineations of floodways denoting limits of permissible flood flow restricting development shall be clearly shown on all plats submitted for approval wherever such contain floodplain and floodway segments.
(Ordinance 6691 adopted 2/5/2024)
(a) 
All subdivision proposals, including the placement of manufactured home parks and subdivisions, shall be consistent with the provisions of this article.
(b) 
All proposals for the development of subdivisions, including the placement of manufactured home parks and subdivisions, shall meet floodplain development permit requirements of this article.
(c) 
Base flood elevation data shall be generated for subdivision proposals and other proposed development, including the placement of manufactured home parks and subdivisions, which is greater than fifty (50) lots or five (5) acres, whichever is lesser, if not otherwise provided pursuant to this article.
(d) 
Base flood elevation data, with the establishment of a floodway, shall be generated by a detailed engineering study for all zone A areas, within one hundred (100) feet of the contour lines of zone A areas, and other streams not mapped by, indicated on the community's FIRM.
(e) 
All subdivision proposals, including the placement of manufactured home parks and subdivisions, shall have adequate drainage provided to reduce exposure to flood hazards.
(f) 
All subdivision proposals, including the placement of manufactured home parks and subdivisions, shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize or eliminate flood damage.
(Ordinance 6691 adopted 2/5/2024)
Located within the areas of special flood hazard established in section 3.12.007 are areas designated as shallow flooding. These areas have special flood hazards associated with flood depths of one (1) to three (3) feet where a clearly defined channel does not exist, where the path of flooding is unpredictable, and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply:
(1) 
All new construction and substantial improvements of residential structures have the lowest floor (including basement) elevated to at least two (2) feet above the base flood elevation or the highest adjacent grade at least as high as the depth number specified in feet on the community's FIRM (at least two (2) feet if no depth number is specified). The minimum lowest floor elevation shall be two (2) feet above the flood elevation if flood elevation data is available.
(2) 
All new construction and substantial improvements of nonresidential structures shall:
(A) 
Have the lowest floor (including basement) elevated to at least two (2) feet above the base flood elevation or the highest adjacent grade at least as high as the depth number specified in feet on the community's FIRM (at least two (2) feet if no depth number is specified); the minimum lowest floor elevation shall be at least two (2) feet above the flood elevation if flood elevation data is available; or
(B) 
Be designed so that the structure and attendant utility and sanitary facilities are watertight (substantially impermeable to the passage of water and structurally capable of resisting hydrostatic and hydrodynamic loads or effects of buoyancy) below the base specified flood depth in an AO zone, or below the base flood elevation in an AH zone, as well as attendant utility and sanitary facilities.
(C) 
A registered professional engineer or architect shall submit a certification to the floodplain administrator that the standards of this section, as proposed in section 3.12.043(b)(1), are satisfied.
(D) 
Require within zones AH or AO adequate drainage paths around structures on slopes, to guide floodwaters around and away from proposed structures.
(Ordinance 6691 adopted 2/5/2024)
Located within areas of special flood hazard established in section 3.12.007 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles and erosion potential, the following provisions shall apply:
(1) 
Encroachments are prohibited, including fill, new construction, substantial improvements and other development unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice by a licensed engineer registered in the state that the proposed encroachment would not result in any increase in flood levels within the city during the occurrence of the base flood discharge.
(2) 
If subsection (1) above is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this division.
(3) 
Under the provisions of 44 CFR chapter 1, section 65.12 of the NFIP regulations, a community may permit encroachments within the adopted regulatory floodway that would result in an increase in base flood elevations, provided that the community first completes all of the provisions required by section 65.12 of the NFIP regulations.
(Ordinance 6691 adopted 2/5/2024)