The legislature of the state has, in (statutes) 82 O.S. §§ 1601—1618, as amended, chapter 23 delegated the responsibility of local governmental units to adopt regulations designed to minimize flood losses. Therefore, the city ordains the following.

(LDC 1991, § 12-801; Ord. No. 625(08), 7-21-2008)

1. The flood hazard areas of the city are subject to periodic inundation, which results in loss of life and property, health and safety hazards, disruption of commerce and governmental services, and extraordinary public expenditures for flood protection and relief, all of which adversely affect the public health, safety and general welfare.
2. These flood losses are created by the cumulative effect of obstructions in floodplains which cause an increase in flood heights and velocities, and by the occupancy of flood hazards areas by uses vulnerable to floods and hazardous to other lands because they are inadequately elevated, floodproofed or otherwise protected from flood damage.

(LDC 1991, § 12-802; Ord. No. 625(08), 7-21-2008)

It is the purpose of this article to promote the public health, safety and general welfare and to minimize public and private losses due to flood conditions in specific areas by provisions designed to:

1. Protect human life and health;
2. Minimize expenditure of public money for costly flood control projects;
3. Minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;
4. Minimize prolonged business interruptions;
5. Minimize damage to public facilities and utilities such as water and gas mains, electric, telephone and sewer lines, streets and bridges located in floodplains;
6. Help maintain a stable tax base by providing for the sound use and development of floodprone areas in such a manner as to minimize future flood blight areas; and
7. Ensure that potential buyers are notified that property is in a flood area.

(LDC 1991, § 12-803; Ord. No. 625(08), 7-21-2008)

In order to accomplish its purposes, this article uses the following methods:

1. Restrict or prohibit uses that are dangerous to health, safety or property in times of flood, or cause excessive increases in flood heights or velocities;
2. Require that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;
3. Control the alteration of natural floodplains, stream channels, and natural protective barriers, which are involved in the accommodation of floodwaters;
4. Control filling, grading, dredging and other development which may increase flood damage;
5. Prevent or regulate the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards to other lands.

(LDC 1991, § 12-804; Ord. No. 625(08), 7-21-2008)

The following words, terms and phrases, when used in this article, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning:

Accessory structure means a structure which is on the same parcel of property as the principle structure and the use of which is incidental to the use of the principle structure (such as garages and storage sheds).

Area of shallow flooding means a designated AO or AH zone on a community's flood insurance rate map (FIRM) with a one percent chance or greater annual chance of flooding to an average depth of one to three 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.

Area of special flood hazard means the land in the floodplain within a community subject to a one percent or greater chance of flooding in any given year. The area may be designated as Zone A on the flood hazard boundary map (FHBM). After detailed ratemaking has been completed in preparation for publication of the FIRM, Zone A usually is refined into Zones A, AE, AH, AO or A1—99.

Base flood means the flood having a one percent chance of being equaled or exceeded in any given year.

Base flood elevation means the elevation in feet above mean sea level of the base flood or one percent chance flood.

Basement means any area of the building having its floor sub-grade (below ground level) on all sides.

Board means the state water resources board.

Critical feature means an integral and readily identifiable part of a flood protection system, without which the flood protection provided by the entire system would be compromised.

Development means any manmade change in improved and unimproved real estate, including, but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials.

Elevated building means a non-basement building built, in the case of a building in Zones A1—30, AE, A, A99, AO, AH, B, C, X, and D, to have the top of the elevated floor adequately anchored so as not to impair the structural integrity of the building during a flood up to the magnitude of the base flood. In the case of Zones A1—30, AE, A, A99, AO, AH, B, C, X, and D, the term "elevated building" also includes a building elevated by means of fill or solid foundation perimeter walls with openings sufficient to facilitate the unimpeded movement of floodwaters.

Existing construction means, for the purposes of determining rates, structures for which the start of construction commenced before the effective date of the FIRM or before January 1, 1975, for FIRMs effective before that date. The term "existing construction" may also be referred to as "existing structures."

Existing manufactured home park or subdivision means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed before the effective date of the floodplain management regulations adopted by a community.

Expansion to an existing manufactured home park or subdivision means the preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).

Flood or flooding means a general and temporary condition of partial or complete inundation of normally dry land areas from:

1. The overflow of inland or tidal waters.
2. The unusual and rapid accumulation or runoff of surface waters from any source.

Flood insurance rate map (FIRM) means an official map of a community, on which the Federal Emergency Management Agency has delineated both the areas of special flood hazards and the risk premium zones applicable to the community.

Flood insurance study is the official report provided by the Federal Emergency Management Agency. The report contains flood profiles, water surface elevation of the base flood, as well as the floodway width, section area and mean velocity.

Floodplain or floodprone area means any land area susceptible to being inundated by water from any source. See Flood or flooding.

Floodplain administrator means a person accredited by the board and designated by a floodplain board, to administer and implement laws and regulations relating to the management of the floodplains.

Floodplain management means the operation of an overall program of corrective and preventive measures for reducing flood damage, including, but not limited to, emergency preparedness plans, flood control works and floodplain management regulations.

Floodplain management regulations means zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as a floodplain ordinance, grading ordinance and erosion control ordinance) and other applications of police power. The term "floodplain management regulations" describes such state or local regulations, in any combination thereof, which provide standards for the purpose of flood damage prevention and reduction.

Flood protection system means those physical structural works for which funds have been authorized, appropriated, and expended and which have been constructed specifically to modify flooding in order to reduce the extent of the areas within a community subject to a special flood hazard and the extent of the depths of associated flooding. Such a system typically includes hurricane tidal barriers, dams, reservoirs, levees or dikes. These specialized flood modifying works are those constructed in conformance with sound engineering standards.

Floodproofing means any combination of structural and non-structural additions, changes, or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, structures and their contents.

Floodway (regulatory floodway) means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.

Functionally dependent use means a use that cannot perform its intended purpose unless it is located or carried out in close proximity to water. The term "functionally dependent use" includes only docking facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, but does not include long-term storage or related manufacturing facilities.

Highest adjacent grade means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

Historic structure means any structure that is:

1. Listed individually in the National Register of Historic Places (a listing maintained by the Department of Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register;
2. Certified or preliminarily determined by the Secretary of the Interior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the Secretary to qualify as a registered historic district;
3. Individually listed on a state inventory of historic places in states with historic preservation programs which have been approved by the Secretary of Interior; or
4. Individually listed on a local inventory or historic places in communities with historic preservation programs that have been certified either:
   1. By an approved state program as determined by the Secretary of the Interior; or
   2. Directly by the Secretary of the Interior in states without approved programs.

Levee means a manmade structure, usually an earthen embankment, designed and constructed in accordance with sound engineering practices to contain, control, or divert the flow of water so as to provide protection from temporary flooding.

Levee system means a flood protection system, which consists of a levee, or levees, and associated structures, such as closure, and drainage devices, which are constructed and operated in accordance with sound engineering practices.

Lowest floor means the lowest floor of the lowest enclosed area, including basement. An unfinished or flood resistant enclosure, usable solely for parking or vehicles, building access or storage in an area other than a basement area is not considered a building's lowest floor, provided that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirement of section 60.3 of the National Flood Insurance Program regulations.

Manufactured home means a structure transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. The term "manufactured home" does not include a recreational vehicle.

Manufactured home park or subdivision means a parcel or contiguous parcels of land divided into two or more manufactured home lots for rent or sale.

Mean sea level means, for purposes of the National Flood Insurance Program, the North American Vertical Datum (NAVD) of 1988 or other datum, to which base flood elevations shown on a community's flood insurance rate map are referenced.

New construction means, for the purpose of determining insurance rates, structures for which the start of construction commenced on or after the effective date of an initial FIRM or after December 31, 1974, whichever is later, and includes any subsequent improvements to such structures. For floodplain management purposes, the term "new construction" means structures for which the start of construction commenced on or after the effective date of a floodplain management regulation adopted by a community and includes any subsequent improvements to such structures.

New manufactured home park or subdivision means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after the effective date of floodplain management regulations adopted by a community.

Recreational vehicle means a vehicle which is:

1. Built on a single chassis;
2. 400 square feet or less when measured at the largest horizontal projections;
3. Designed to be self-propelled or permanently towable by a light duty truck; and
4. Designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.

Start of construction (for other than new construction or substantial improvements under the Coastal Barrier Resources Act (Pub. L. 97-348)) includes substantial improvement and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement, or other improvement was within 180 days of the permit date. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or the placement of a manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for basement, footings, piers or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure. For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.

Structure means a walled and roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a manufactured home.

Substantial damage means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.

Substantial improvement means any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before start of construction of the improvement. This includes structures that have incurred substantial damage, regardless of the actual repair work performed. The term "substantial improvement" does not, however, include either:

1. Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary conditions; or
2. Any alteration of a historic structure provided that the alteration would not preclude the structure's continued designation as a historic structure.

Variance means a grant of relief to a person from the requirements of this article when specific enforcement would result in unnecessary hardship. A variance, therefore, permits construction or development in a manner otherwise prohibited by this article. (For full requirements see section 60.6 of the National Flood Insurance Program regulations.)

Violation means the failure of a structure or other development to be fully compliant with this community's floodplain management regulations. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in section 60.3(b)(5), (c)(4), (c)(10) or (d)(3) of the National Flood Insurance Program regulations is presumed to be in violation until such time as that documentation is provided.

Water surface elevation means the height, in relation to the National Geodetic Vertical Datum (NGVD) of 1929 (or other datum, where specified), of floods of various magnitudes and frequencies in the floodplains of coastal or riverine areas.

(LDC 1991, § 12-805; Ord. No. 625(08), 7-21-2008)

1. Lands to which this article applies. This article shall apply to all areas of special flood hazard within the jurisdiction of the city.
2. Basis for establishing the areas of special flood hazard. The areas of special flood hazard identified by the Federal Emergency Management Agency in a scientific and engineering report entitled, "The Flood Insurance Study for Cleveland County, Oklahoma and Incorporated areas," depicted and dated 40027C0157K (March 27, 2024: 40027C0160K (March 27, 2024); 40027C0170J (January 15, 2021); 40027C0180J (February 20, 2013); 40027C0190K (January 15, 2021); and 40027C0195J (February 20, 2013), with the accompanying flood insurance rate map (FIRM) are hereby adopted by reference and declared to be a part of this article.
3. Establishment of development permit. A development permit shall be required to ensure conformance with the provisions of this article.
4. Compliance. No structure or land shall hereafter be located, altered, or have its use changed without full compliance with the terms of this article and other applicable regulations.
5. Abrogation and greater restrictions. This article is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this article and any other ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail.
6. Interpretation. In the interpretation and application of this article, all provisions shall be:
   1. Considered as minimum requirements;
   2. Liberally construed in favor of the governing body; and
   3. Deemed neither to limit nor repeal any other powers granted under state statutes.
7. Warning and disclaimer or liability. The degree of flood protection required by this article is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. On rare occasions, greater floods can and will occur and flood heights may be increased by manmade or natural causes. This article does not imply that land outside the areas of special flood hazards or uses permitted within such areas will be free from flooding or flood damages. This article shall not create liability on the part of the community or any official or employee thereof for any flood damages that result from reliance on these regulations or any administrative decision lawfully made hereunder.

(LDC 1991, § 12-806; Ord. No. 625(08), 7-21-2008)

1. Designation of the floodplain administrator. The community development director or his designee shall hold the position as floodplain administrator for the city to administer and implement the provisions of this article and other appropriate sections of 44 CFR (National Flood Insurance Program Regulations) pertaining to floodplain management.
2. Duties and responsibilities of the floodplain administrator. Duties and responsibilities of the floodplain administrator shall include, but not be limited to, the following:
   1. Maintain and hold open for public inspection all records pertaining to the provisions of these regulations.
   2. Review permit application to determine whether proposed building site, including the placement of manufactured homes, will be reasonably safe from flooding.
      
   3. Review, approve or deny all applications for development permits required by adoption of these regulations.
   4. Review permits for proposed development to ensure that all necessary permits have been obtained from those federal, state or local governmental agencies (including section 404 of the Federal Water Pollution Control Act Amendments of 1972, 33 USC 1334) from which prior approval are required.
   5. Where interpretation is needed as to the exact location of the boundaries of the areas of special flood hazards (for example, where there appears to be a conflict between a mapped boundary and actual field conditions), the floodplain administrator shall make the necessary interpretation.
   6. Notify, in riverine situations, adjacent communities and the state coordinating agency, the state water resources board, prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Emergency Management Agency.
   7. Ensure that the flood-carrying capacity within the altered or relocated portion of any watercourse is maintained.
   8. Require the applicant and/or developer to provide the base flood elevation data in order to administer the provisions of section 12-806.
   9. When a regulatory floodway has not been designated, the floodplain administrator must require that no new construction, substantial improvements, or other development, including fill, shall be permitted within Zones A1—30 and AE on the community's 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.
   10. Under the provisions of 44 CFR 65.12, of the National Flood Insurance Program regulations, a community may approve certain development in Zones A1—30, AE, and AH, on the community's FIRM which increases the water surface elevation of the base flood by more than one foot, provided that the community first complies with 44 CFR 65.12.
   11. Become accredited by the board in accordance with 82 O.S. §§ 1601—1618, as amended.
   12. After a disaster or other type of damage occurrence to structures in the city, determine if the residential and nonresidential structures and manufactured homes have been substantially damaged and enforce the substantial improvement requirement.
3. Permit procedures.
   1. Application for a development permit shall be presented to the floodplain administrator on forms furnished by him and may include, but not be limited to, plans in duplicate drawn to scale showing the location, dimensions, and elevation of proposed landscape alterations, existing and proposed structures, including the placement of manufactured homes, and the location of the foregoing in relation to areas of special flood hazard. Additionally, the following information is required:
      1. Elevation in relation to mean sea level, of the lowest floor, including basement, of all new and substantially improved structures;
      2. Elevation in relation to mean sea level to which any nonresidential structure shall be floodproofed;
      3. A certificate from a registered professional engineer or architect that the nonresidential floodproofed structure shall meet the floodproofing criteria of section 12-808(b)(2);
      4. Description of the extent to which any watercourse or natural drainage will be altered or relocated as a result of proposed development;
      5. A record of all such information in accordance with section 12-807(b)(1).
   2. Approval or denial of a development permit by the floodplain administrator shall be based on all of the provisions of these regulations and the following relevant factors:
      1. The danger to life and property due to flooding or erosion damage;
      2. The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner;
      3. The danger that materials may be swept onto other lands to the injury of others;
      4. The compatibility of the proposed use with existing and anticipated development;
      5. The safety of access to the property in times of flood for ordinary and emergency vehicles;
      6. The costs of providing governmental services during and after flood conditions, including maintenance and repair of streets and bridges, and public utilities and facilities such as sewer, gas, electrical and water systems;
      7. The expected heights, velocity, duration, rate of rise and sediment transport of the floodwaters and the effects of wave action, if applicable, expected at the site;
      8. The necessity to the facility of a waterfront location, where applicable;
      9. The availability of alternative locations, not subject to flooding or erosion damage, for the proposed use;
      10. The relationship of the proposed use to the comprehensive plan for that area.
4. Variance procedures.
   1. The appeal board as established by the community shall hear and render judgment on requests for variances from the requirements of this article.
   2. The appeal board shall hear and render judgment on an appeal only when it is alleged there is an error in any requirement, decision, or determination made by the floodplain administrator in the enforcement or administration of this article.
   3. Any persons aggrieved by the decision of the appeal board may appeal such decision in the courts of competent jurisdiction.
   4. The floodplain administrator shall maintain a record of all actions involving an appeal and shall report variances to the Federal Emergency Management Agency upon request.
   5. Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed on the National Register of Historic Places or the state inventory of historic places, without regard to the procedures set forth in the remainder of this article.
   6. Variances may be issued for new construction and substantial improvements to be erected on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level, providing the relevant factors in subsection (C)(2) of this section have been fully considered. As the lot size increases beyond the one-half acre, the technical justification required for issuing the variance increases.
   7. Upon consideration of the factors noted above and the intent of this article, the appeal board may attach such conditions to the granting of variances as it deems necessary to further the purpose and objectives of this article as identified in section 12-803.
   8. Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.
   9. Variances may be issued for the repair or rehabilitation of historic structures upon a determination that the proposed repair or rehabilitation will not preclude the structure's continued designation as a historic structure and the variance is the minimum necessary to preserve the historic character and design of the structure.
   10. Prerequisites for granting variances.
       1. Variances shall only be issued upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.
       2. Variances shall only be issued upon:
          1. Showing a good and sufficient cause;
          2. A determination that failure to grant the variance would result in exceptional hardship to the applicant; and
          3. A determination that the granting of a variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public, or conflict with existing local laws, regulations or ordinances.
       3. A written notice will be provided to any person granted a variance to build a structure below the base flood elevation. This notice will inform the variance applicant that the cost of flood insurance will be commensurate with the increased risk resulting from permitting the structure to be built lower than the base flood elevation.
   11. Variances may be issued by a community for new construction and substantial improvements and for other development necessary for the conduct of a functionally dependent use provided that:
       1. The criteria outlined in subsections (D)(1) through (9) of this section are met, and
       2. The structure or other development is protected by methods that minimize flood damages during the base flood and create no additional threats to public safety.
   12. Any person seeking a variance shall file a petition with the floodplain board, accompanied by a filing fee in an amount established in adopted fee schedule.
   13. A copy of any variance issued shall be sent to the board within in 15 days of issuance.

(LDC 1991, § 12-807; Ord. No. 625(08), 7-21-2008)

1. General standards. In all areas of special flood hazards the following provisions are required for all new construction and substantial improvements:
   1. All new construction or substantial improvements shall be 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. All new construction or substantial improvements shall be constructed by methods and practices that minimize flood damage;
   3. All new construction or substantial improvements shall be constructed with materials resistant to flood damage;
   4. All new construction or substantial improvements shall be 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. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system;
      
   6. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system 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.
2. Specific standards. In all areas of special flood hazards the following provisions are required:
   1. Residential construction. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated at least one foot above the base flood elevation. 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 (D)(1) of this section is satisfied.
   2. Nonresidential construction. New construction and substantial improvements of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to 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. The floodplain administrator shall maintain a record of all floodproofing certifications that includes the specific elevation (in relation to mean sea level) to which each structure has been floodproofed.
   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:
      1. 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.
      2. The bottom of all openings shall be no higher than one foot above grade.
      3. 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.
      1. All manufactured homes to be placed within Zone A on a community's FHBM or FIRM shall be installed using methods and practices that minimize flood damage and have the bottom of the I-beam elevated at one foot above the base flood elevation. 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 and a licensed installer shall install the home and place the required placard on the dwelling.
      2. Manufactured homes that are placed or substantially improved within Zones A1—30, AH, and AE on the community's FIRM on sites:
         1. Outside of a manufactured home park or subdivision;
         2. In a new manufactured home park or subdivision;
         3. In an expansion to an 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 a result of a flood;
         are required to be elevated on a permanent foundation such that the I-beam of the manufactured home is elevated at least one foot above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement. Also, a licensed installer shall install the home.
      3. Manufactured homes placed or substantially improved on sites in an existing manufactured home park or subdivision with Zones A1—30, AH and AE on the community's FIRM that are not subject to the provisions of subsection (B)(4) of this section are required to be elevated so that the bottom of the I-beam of the manufactured home is at least one foot above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement support the manufactured home chassis and also installed by a licensed installer that complies with state law.
   5. Recreational vehicles. Recreational vehicles placed on sites within Zones A1—30, AH, and AE on the community's FIRM are required to either:
      1. Be on the site for fewer than 180 consecutive days;
      2. Be fully licensed and ready for highway use; or 
         
      3. Meet the permit requirements of section 12-807(C), and the elevation and anchoring requirements for manufactured homes in subsection (B)(4) of this section.
      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.
   6. Accessory structure. Requirements for accessory structures are as follows:
      1. Structure is low valued and represents a minimal investment.
      2. Structure shall be small and not exceed 600 square feet in size.
      3. Structure shall be unfinished on the interior.
      4. Structure can be used only for parking and limited storage.
      5. Structure shall not be used for human habitation (including work, sleeping, living, cooking, or restroom areas).
      6. Service facilities such as electrical and heating equipment must be elevated to or above the BFE or floodproofed.
      7. Structure is constructed and placed on building site so as to offer the minimum resistance to the flow of floodwaters.
      8. Structure is designed to have low flood damage potential (i.e., constructed with flood resistance materials).
      9. Structure is firmly anchored to prevent flotation, collapse, and lateral movement.
      10. Floodway requirements must be met in the construction of the structure.
      11. Openings to relieve hydrostatic pressure during a flood shall be provided below the BFE.
      12. Structure is to be located so as not to cause damage to adjacent and nearby structures.
3. Standards for subdivision proposals.
   1. All subdivision proposals including the placement of manufactured home parks and subdivisions shall be consistent with this section.
   2. All proposals for the development of subdivisions including the placement of manufactured home parks and subdivisions shall meet development permit requirements of section 12-807(C), subsection (C) of this section and the provisions of section 12-806(b).
   3. 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 50 lots or five acres, whichever is lesser, if not otherwise provided pursuant to section 12-807(B), or 12-807(B)(8).
   4. All subdivision proposals including the placement of manufactured home parks and subdivisions shall have adequate drainage provided to reduce exposure to flood hazards.
   5. 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.
4. Standards for areas of shallow flooding (AO/AH zones). Located within the areas of special flood hazard established in section 12-806 (B), are areas designated as shallow flooding. 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 where velocity flows 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 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).
   2. All new construction and substantial improvements of nonresidential structures:
      1. 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); or
      2. Together with attendant utility and sanitary facilities, shall 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 of effects of buoyancy.
   3. A registered professional engineer or architect shall submit a certification to the floodplain administrator that the standards of this section are satisfied.
   4. Require within Zones AH and AO adequate drainage paths around structures on slopes, to guide floodwaters around and away from proposed structures.
5. Floodways. Located within areas of special flood hazard established in section 12-806(B), are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters that 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 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 community during the occurrence of the base flood discharge.
   2. If subsection (E)(1) of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this section.
   3. Under the provisions of 44 CFR 65.12, of the National Flood Insurance 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 complies with all of 44 CFR 65.12.
6. Severability. If any section, clause, sentence, or phrase of this article is held to be invalid or unconstitutional by any court of competent jurisdiction, then said holding shall in no way affect the validity of the remaining portions of this article.

(LDC 1991, § 12-808; Ord. No. 625(08), 7-21-2008)

No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this article and other applicable regulations. Violation of the provisions of this article by failure to comply with any of its requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Any person who violates this article or fails to comply with any of its requirements shall, upon conviction thereof, be fined in accordance with the city schedule of fines for each violation, and in addition shall pay all costs and expenses involved in the case. Nothing herein contained shall prevent the city council or the city attorney from taking such other lawful action as is necessary to prevent or remedy any violation.

(LDC 1991, § 12-809; Ord. No. 625(08), 7-21-2008)

It is the intent of this article to protect the general health, safety and welfare of the public from the hazards and damages of flooding from the various drainage areas in the city, to provide clean and sanitary channels for runoff; to prevent pollution of watershed, streams and natural drainage channels; to prevent the encroachment of buildings or improvements on natural drainage channels; to equitably apportion the cost of improvements; to protect natural scenic areas; and to provide for the conservation of the natural resources in the area. All subdivisions of land and all developments or improvements of any character which affect drainage in any portion of the city shall be subject to the provisions of these regulations.

(Prior Code, § 10-16; LDC 1991, § 12-821; Ord. No. 5(91), 11-18-1991)

The following words, terms and phrases, when used in this article, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning:

Developer means the owner of property or his agent engaged in the subdivision or improvement of, or the construction of, structures upon land within the city.

Primary drainage channels mean all drainage channels, streams or creeks which drain an area of 500 acres or more.

Secondary drainage channels means all drainage channels, streams and creeks which drain an area of less than 500 acres.

(Prior Code, § 10-17; LDC 1991, § 12-822; Ord. No. 5(91), 11-18-1991)

It is intended by this article that improvements of primary drainage shall be the long range responsibility of the developer and the community as a whole, since the developer and the whole community is benefited materially. The developer of land or improvements within an area containing a primary drainage channel shall design, plan and carry out his developments in a manner that will not interfere with or restrict the natural flow of water or materially change the condition of runoff within the calculated area below the 100-year maximum flood elevation. Increased runoff and changes in primary channels which are created by such developments within primary drainage areas shall be the planning responsibility of the developer and shall be made in accordance with the provisions of this article. The improvement of secondary drainage channels shall be the responsibility of the developer, since the primary benefit is to the area served by the secondary channel and not to the community as a whole.

(Prior Code, § 10-18; LDC 1991, § 12-823; Ord. No. 5(91), 11-18-1991)

The maximum condition of rainfall for a 50-year frequency shall be used for the purpose of determining all runoff for the sizing of drainage channels and structures, unless otherwise specified herein. The following formula and values shall be used for calculating all stream flow and runoff for the policies and regulations established herein:

1. Runoff from drainage areas of 500 acres or less shall be determined by the rational formula:
   
   Q = AIR
   
   Where:
   
   Q = Flow in cubic feet per second.
   A = Area to be drained in acres, determined by field surveys for areas less than 100 acres, and by latest government quadrangle maps for larger areas.
   I = Percent of imperviousness of the area; may vary between 50 percent and 95 percent. Coefficients lower than these indicated values may be used; however, in such instances individual block calculations will be submitted with plans.
   R = Rate of rainfall over entire drainage area in inches per hour, based on time for concentration and latest government records for area.
2. Runoff from drainage areas greater than 500 acres will be determined by use of accepted engineering principles as approved by the community development director.
3. The size of closed storm sewers, open channels, culverts and bridges shall be determined by using the Manning Formula which may be modified for use with runoff determined by the rational formula to:
   
   Q = 1.486 r2/3 s½ A / n
   
   Where:
   
   Q = Discharge in cubic feet per second.
   A = Cross-sectional area of water in conduit in square feet.
   r = Hydraulic radius in feet.
   s = Mean slope of hydraulic gradient in feet of vertical fall per foot of horizontal distance.
   n = Roughness coefficient.

(Prior Code, § 10-19; LDC 1991, § 12-824; Ord. No. 5(91), 11-18-1991)

All primary drainage channels which are located within, or immediately adjacent to, an improvement, development or subdivision, shall be protected and improved by the developer as follows:

1. All land having an elevation below the 100-year maximum flood elevation for the final improved channel and not protected by levees or dikes shall be dedicated for the purpose of providing drainage for public park and/or utility easement use;
2. The existing channel lying within or immediately adjacent to the subdivision or parcel of land proposed for development or redevelopment shall be cleaned to provide for the free flow of water, and the channel shall be straightened, widened and improved to the extent required to prevent overflow, resulting from a 50-year frequency rainfall;
3. Site improvement shall provide for the grading of all building pads to an elevation above the highwater elevation from a 100-year frequency flood and in a manner that will provide for the rapid runoff of stormwater;
4. Whenever channel improvements are carried out, sodding, blacksloping, cribbing and other bank protection shall be designed and constructed to control erosion for the anticipated conditions and flow resulting from a 50-year frequency rainfall;
   
5. A drainage channel shall not be located in a street easement unless it is placed in an enclosed storm sewer except under the following conditions:
   1. Where a paved street surface at least two lanes wide is provided on both sides of a paved channel so as to provide access to abutting properties;
   2. Where lots are platted to back up to the street right-of-way where the drainage channel is located between the rear lot line and the paved street, provided that there is no access to the rear of the lot from the street, and further provided that at no time in the future shall access be allowed or constructed over the open drainage channel to the rear of a lot so platted. For the purpose of these regulations, a lot which sides to a public street is not considered to back up to the street right-of-way;
   3. When a condition outlined in either subsection (E)(1) or (2) of this section is present, adequate space shall be dedicated as right-of-way to provide for maintenance of the paved drainage channel and its unpaved bank;
6. Culverts, bridges and other drainage structures shall be constructed in accordance with the specifications and design criteria of the city when the city shall have present or future maintenance responsibility.

(Prior Code, § 10-20; LDC 1991, § 12-825; Ord. No. 5(91), 11-18-1991)

All secondary drainage channels which are within, or immediately adjacent to, an improvement, development or subdivision shall be protected and improved by the developer as follows:

1. All land having an elevation below the 100-year maximum flood elevation for the final improved channel and not protected by levees or dikes shall be dedicated for the purpose of providing drainage for public park or utility easement use;
2. Secondary drainage channels which have a primary function of collecting surface water from adjacent properties or intercepting and diverting side hill drainage shall be improved open channels;
3. Secondary drainage channels which have a primary function of transporting water through the block or collecting water from cross channels and which have a drainage area of less than 40 acres shall be improved with closed storm sewers; and where the secondary drainage channel has a drainage area of greater than 40 acres, an improved open channel or closed storm sewer shall be provided. When the unit area to be drained is less than four acres, the city engineer may modify the requirements of the first part of this provision to permit a paved open channel, designed to serve any common recreation or open space, public or private;
   
4. Site improvement shall provide for the grading of all building pads to an elevation above the high water elevation from a 100-year frequency flood and in a manner that will provide for the rapid runoff of stormwater;
5. A drainage channel shall not be located in a street easement unless it is placed in an enclosed storm sewer except under the conditions as set out in section 8-825(e);
6. In single-family residential, duplex or mobile home development, site grading shall be carried out in such a manner that surface water from each dwelling lot will flow directly to a storm sewer, improved channel, sodded swale or paved street without crossing more than four adjacent lots;
7. Surface water collected on streets shall be diverted to storm drains at satisfactory intervals to prevent overflow of six-inch-high curbs during a 25-year frequency rain for the area and grades involved. Drainage area allowed for surface flow on streets at point of diversion shall not exceed 20 acres, regardless of flow;
8. Drainage easement of satisfactory width to provide working room for construction and maintenance shall be provided for all storm sewers;
9. Open channels shall be improved by providing a paved section that will carry the runoff from a rain of 25-year frequency within the concrete lined section and a sodded section to carry the additional runoff from a rain of 50-year frequency. Whenever an open improved channel is required or authorized for a secondary drainage channel under the provisions of these regulations and the channel crosses residential lots which have been developed under the community unit plan of development or where the channel improvement is to be designed as an area that will be maintained by a property owners' association, the community development director may modify the requirements of the first part of this provision to permit a channel improvement design in keeping with landscaping architectural plans, providing all hydraulic requirements to support the overflow resulting from a 100-year frequency rainfall are met in such a manner as to prevent flooding of all building pads.

(Prior Code, § 10-21; LDC 1991, § 12-826; Ord. No. 5(91), 11-18-1991)

All flow of water across continuous streets or alleys shall be through culverts or bridges. Bridges and culverts shall be sized to accommodate a 50-year frequency rain. Structural design of bridges and culverts shall conform to the state highway department's standards and/or design criteria. Construction shall comply with city specifications.

(Prior Code, § 10-23; LDC 1991, § 12-827; Ord. No. 5(91), 11-18-1991)

Closed storm sewers shall be constructed of precast or prefabricated pipe or built in place of closed box design to conform with city construction specifications. Sizing shall be calculated by the Manning Formula, provided that storm sewers carrying runoff from streets may be designed to serve a ten-year frequency rain for the drainage area involved except that in sump areas the storm sewer shall be designed to serve a 50-year frequency rain with a concrete flume being constructed over the storm sewer to ensure that overflow from a 100-year frequency rain can reach a suitable outlet without inundating any building pad.

(Prior Code, § 10-24; LDC 1991, § 12-828; Ord. No. 5(91), 11-18-1991)

1. Open paved storm drainage channels shall be constructed in accordance with the city's specifications. Side slopes above the paved section shall be shaped and sodded on a slope of four horizontal to one vertical (4:1) or flatter. Fences shall not be erected within the limits of open channel easements except upon application for and receipt of a permit issued by the community development director.
2. The community development director will establish a procedure to confirm the following requirements prior to the issuance of such permits:
   1. The control or erosion of side slopes above the paved section with grass sod or by other means have been established;
   2. Channel siltation has been eliminated or minimized by established ground cover of the area drained by the channel;
   3. The location of the fence with respect to the paved section will be prescribed by the permit with due consideration being given to the problem of maintenance as evidenced by the condition and effectiveness of the channel improvement at the time of application for the permit. Fences erected in violation of these requirements are subject to removal or damage by the city maintenance operations without recourse by the owner.

(Prior Code, § 10-25; LDC 1991, § 12-829; Ord. No. 5(91), 11-18-1991)

The city reserves the right to require improvements to preclude any backup of tail water inundating any areas outside of the dedicated drainage easements in the subdivision as a result of a 50-year frequency flood.

(Prior Code, § 10-26; LDC 1991, § 12-830; Ord. No. 5(91), 11-18-1991)

Prior to authorization of any building permit by the building official, the community development director shall review and approve all such stream flow and runoff calculations as he may require of a developer under the terms of this article, and the community development director shall have final authority of engineering interpretations of all required 50- and 100-year flood elevations necessary to this article.

(Prior Code, § 10-27; LDC 1991, § 12-831; Ord. No. 5(91), 11-18-1991)