The Legislature of the State of Oklahoma has in 82 O.S. §§ 1601—1618, as amended, delegated to local governmental units the responsibility to adopt regulations designed to minimize flood losses.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

(1)

The flood hazard areas of the City of Mustang 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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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 flood-prone 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.

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 flood waters;

(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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

Unless specifically defined below, words or phrases used in this article shall be interpreted to give them the meaning they have in common usage and to give this article its most reasonable application.

Accessory structure means structures which are 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, AH, or VO 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 Oklahoma 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, "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 flood waters.

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

Floodplain or flood-prone area means any land area susceptible to being inundated by water from any source (see definition of flooding).

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 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 nonstructural 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 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:

a.

By an approved state program as determined by the secretary of the interior; or

b.

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, "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)

Four hundred 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 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 requirement 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) 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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

This article shall apply to all areas of special flood hazard within the jurisdiction of the City of Mustang, Oklahoma.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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 Canadian County, Oklahoma and Incorporated areas" dated September 26, 2008, with accompanying Flood Insurance Rate Map (FIRM) are hereby adopted by reference and declared to be a part of this article. The current flood ordinances shall remain in effect until September 26, 2008. This article shall go into effect on September 26, 2008.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

A development permit shall be required to ensure conformance with the provisions of this article on floodplain management.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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 punished by fine or imprisonment, or both, as provided in section 1-8, and in addition shall pay all costs and expenses involved in the case. Nothing herein contained shall prevent the city from taking such other lawful action as is necessary to prevent or remedy any violation.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

The community development director or his/her designee is hereby designated the floodplain administrator 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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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 this article.

(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 this article.

(4)

Review permits for proposed development to assure 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 U.S.C. 1344) 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 Oklahoma 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)

Assure that the flood carrying capacity within the altered or relocated portion of any watercourse is maintained.

(8)

Shall require the applicant/developer to provide base flood elevation data for any proposed development in a special flood hazard area in order to administer the provisions of division 4 of this article.

(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 Chapter 1, Section 65.12, of the National Flood Insurance Program regulations, a community may approve certain development in zones A1-30, AE, 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, Chapter 1, Section 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 of Mustang determine if the residential and nonresidential structures and manufactured homes have been substantially damaged and enforce the substantial improvement requirement.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

(a)

Application for a development permit shall be presented to the floodplain administrator on forms furnished by him/her 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 subsection 50-92(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)

Maintain a record of all such information in accordance with subsection 50-72(1).

(b)

Approval or denial of a development permit by the floodplain administrator shall be based on all of the provisions of this article 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 flood waters 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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

(a)

The board of adjustment shall hear and render judgment on requests for variances from the requirements of this article.

(b)

The board of adjustment 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.

(c)

Any person or persons aggrieved by the decision of the board of adjustment may appeal such decision in the courts of competent jurisdiction.

(d)

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.

(e)

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 section.

(f)

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 50-73(2) have been fully considered. As the lot size increases beyond the one-half acre, the technical justification required for issuing the variance increases.

(g)

Upon consideration of the factors noted above and the intent of this article, the board of adjustment may attach such conditions to the granting of variances as it deems necessary to further the purpose and objectives of this article.

(h)

Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.

(i)

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.

(j)

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:

a.

Showing a good and sufficient cause;

b.

A determination that failure to grant the variance would result in exceptional hardship to the applicant; and

c.

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.

(k)

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 (a)—(i) 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.

(l)

Any person seeking a variance shall file a petition with the board of adjustment, accompanied by a filing fee in the amount set forth in subsection 42-122(e).

(m)

A copy of any variance issued shall be sent to the OWRB within in 15 days of issuance.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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 flood waters into the system;

(6)

New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the system and discharge from the systems into flood waters; and

(7)

On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

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 subsection 50-73(a) 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 at least one foot above the base flood elevation.

(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 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.

b.

The bottom of all openings shall be no higher than one foot above grade.

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.

Require that 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 least 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.

b.

Require that manufactured homes 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, be elevated on a permanent foundation such that the lowest floor 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.

c.

Require that manufactured homes be 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 (4) of this section 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. 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 180 consecutive days,

b.

Be fully licensed and ready for highway use, or

c.

Meet the permit requirements of subsection 50-73(a), and the elevation and anchoring requirements for "manufactured homes" in subsection (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.

a.

Structure is low valued and represents a minimal investment.

b.

Structure shall be small and not exceed 600 square feet in size.

c.

Structure shall be unfinished on the interior.

d.

Structure can be used only for parking and limited storage.

e.

Structure shall not be used for human habitation (including work, sleeping, living, cooking, or restroom areas).

f.

Service facilities such as electrical and heating equipment must be elevated to or above the BFE or floodproofed.

g.

Structure is constructed and placed on building site so as to offer the minimum resistance to the flow of floodwaters.

h.

Structure is designed to have low flood damage potential, i.e., constructed with flood resistance materials.

i.

Structure is firmly anchored to prevent flotation, collapse, and lateral movement.

j.

Floodway requirements must be met in the construction of the structure.

k.

Openings to relieve hydrostatic pressure during a flood shall be provided below the BFE.

l.

Structure is to be located so as not to cause damage to adjacent and nearby structures.

(7)

Compensatory storage. Filling or development, which diminishes the flood storage capacity of any special flood hazard area delineated on the Canadian County Flood Insurance Rate Map, the volume of development, shall be compensated. The volume lost to flood waters shall be replaced by a land cut that must equal or exceed the space lost to the base flood elevation. Subsequent to filling or development, there shall be a zero increase in the surface elevation of BFE. Furthermore, the development shall be constructed so that it will not increase the frequency of flooding or the depth of inundation of structures.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

(a)

All subdivision proposals including the placement of manufactured home parks and subdivisions shall be consistent with sections 50-32, 50-33 and 50-34 of this article.

(b)

All proposals for the development of subdivisions including the placement of manufactured home parks and subdivisions shall meet development permit requirements of section 50-54; section 50-73; and the provisions of division 4 of this article.

(c)

Base flood elevation data shall be generated for subdivision proposals and other proposed developments 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 50-53 or subsection 50-72(9) of this article.

(d)

All subdivision proposals including the placement of manufactured home parks and subdivisions shall have adequate drainage provided to reduce exposure to flood hazards.

(e)

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.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

Located within the areas of special flood hazard established in section 50-53 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;

a.

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

b.

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.

(3)

A registered professional engineer or architect shall submit a certification to the floodplain administrator that the standards of this section, as proposed in subsection 50-73(a) are satisfied.

(4)

Require within zones AH or AO adequate drainage paths around structures on slopes, to guide floodwaters around and away from proposed structures.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

Floodways located within areas of special flood hazard established in section 50-53 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 (1) above is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of division 4 of this article.

(3)

Under the provisions of 44 CFR Chapter 1, Section 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 Chapter 1, Section 65.12.

(Ord. No. 1009, §§ 1, 2, 9-2-2008)

The regulations and standards of this division are intended to protect the various portions of the urban area from flooding, to provide clean and sanitary channels for runoff, to prevent pollution of watersheds, streams and natural drainage channels, to prevent the encroachment of buildings and 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 of the area. The regulations, policies and standards contained in this division shall apply to the area outlined on the comprehensive plan, which is made a part of this division. All subdivisions of land and all improvements of any character which affect drainage in any portion of the area contained on the comprehensive plan shall be subject to the provisions of this division.

(Code 1977, § 13.12.010)

(a)

Primary drainage channels shall be those rivers and other channels which have been so designated on the comprehensive plan.

(b)

Secondary drainage channels shall include all channels in the area set forth on comprehensive plan which are not classified as primary channels.

(c)

In general it is intended that channels which are designed as primary channels serve a drainage area of 640 acres or more. It is intended by this division to provide that the improvement of primary drainage channels will be the responsibility of the city primarily, since the whole city is benefited materially, except that the developer of the land containing the primary channel is expected to lay out, design and otherwise plan and carry out his improvements in a manner that will not interfere with or restrict the natural flow of water or materially change the conditions of runoff. Increased runoff and changes in primary channels which are created by improvements of an individual subdivision shall be the responsibility of the developer of the subdivision and shall be made in accordance with the provisions of this division. It is intended by this division that the improvement of secondary channels shall be the responsibility of the developer of the area served by the channel since the primary benefit is to the area served by the secondary channel and not to the city as a whole.

(Code 1977, § 13.12.020)

The maximum condition of rainfall for a 100-year interval shall be used for the purposes of determining all runoff for the sizing of drainage channels and structures, unless otherwise specified in this division. Values used in formulas for runoff and size of drainage structures shall reflect and shall not be less than the degree of urbanization set forth in the projected land use plan contained in the general plan. The following formulas and values shall be used for calculating all stream flow and runoff for the policies and regulations established this division:

(1)

Runoff from all drainage areas shall be determined by rational formula:

Q = AIR

In which:

(2)

The size of closed storm sewers, open channels, culverts and bridges shall be determined using the Manning formula:

Q = 1,486 / n  r ^2/3 s ^1/2

(Code 1977, § 13.12.030)

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

(1)

All land having an elevation below the 100-year maximum flood elevation and not protected by levees or dikes shall be dedicated to the city for the purpose of providing drainage and for public park and utility easement use.

(2)

The existing channel lying within or immediately adjacent to the subdivision 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 beyond the limits of the dedicated drainage area.

(3)

Site improvement shall provide for the grading of all building sites and streets to an elevation where all lots, building areas and streets will not be subject to overflow and in a manner that will provide for the rapid runoff of all rainfall; however, such improvements shall be carried out in a manner that will preserve and protect large trees and attractive physical features of the area.

(4)

Whenever channel improvement is carried out, sodding, backsloping, cribbing and other bank protection shall be designed and constructed to control erosion for all the anticipated conditions of flow for the segment of channel involved.

(5)

A drainage channel shall not be located in a street easement unless it is placed in an enclosed storm sewer, or unless a paved street surface is provided on both sides of a paved channel to give access to abutting properties.

(6)

Culverts, bridges and other drainage structures shall be constructed in accordance with the specifications of the city at all locations where drainage channels intersect with continuous streets or alleys.

(Code 1977, § 13.12.040)

(a)

All secondary drainage channels which are located within or immediately adjacent to an improvement or a subdivision, and all surface drainage conditions, shall be protected and improved as follows:

(1)

Secondary drainage channels which have a primary function of collecting surface water from adjacent properties or intercepting and diverting side hill drainage shall be provided with an improved open channel.

(2)

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 an improved open channel or closed storm sewer. 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.

(3)

A drainage channel shall not be located in a street easement unless it is placed in a closed storm sewer, or unless a paved street surface is located on both sides of a paved drainage channel to give access to abutting properties.

(4)

Site grading shall be carried out in such a manner that surface water from each lot shall flow directly to a storm sewer, improved channel or paved street without crossing more than two adjacent lots.

(5)

Surface water collected on streets shall be diverted to storm drains at satisfactory intervals to prevent overflow of six-inch-high curbs during a 100-year frequency rain for the area and grades involved; provided, however, that in no case shall the drainage area served by one street exceed 20 acres, regardless of the amount of flow.

(6)

Drainage easements of satisfactory width to provide working room for construction and maintenance shall be provided for all storm sewers. In no case shall the total easement be less than 20 feet.

(7)

Open channels shall be improved by providing a paved section that will carry the runoff from a rain of 50-year frequency and a sodded section to carry the runoff from a rain of 100-year frequency. The design of the channel improvements shall be in accordance with the standards set forth on figure B or figure C of Ordinance No. 168, on file in the office of the city clerk.

(b)

Whenever an open improved channel is required or authorized for a secondary drainage channel under the provisions of this division and the channel crosses residential lots 80 percent or more of which have a width of not less than 90 feet and an area of not less than 13,500 square feet and the channel improvement is to be designed as an integral part of the landscaping of the area that will be maintained by the property owners of the area, then the planning commission may modify the requirements of this section to permit a channel improvement design in accordance with figure D of Ordinance No. 168, on file in the office of the city clerk. The developer may elect to provide a paved section to accommodate runoff from a rain of 100-year frequency, provided that sodding shall be carried out to the extent necessary to protect paved surfaces.

(Code 1977, § 13.12.050)

(a)

Bridges or culverts shall be provided where watercourses cross continuous streets or alleys.

(b)

Bridges and culverts shall be sized to accommodate a 50-year frequency rain, based on the drainage area involved.

(c)

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 to serve a 50-year frequency rain for the drainage area involved.

(d)

Open-paved storm drainage channels shall be constructed in accordance with city specifications.

(e)

Side slopes above the paved section shall be shaped and sodded on a slope of four horizontal to one vertical or flatter.

(f)

Fences shall not be erected below the shoulder of the sodded section, and in no case shall fences be closer than six feet (measured horizontally) to the edge of the paved section.

(Code 1977, § 13.12.060)

(a)

The city reserves the right to require improvements, provision of drainage easements and provision of agreements beyond the boundaries of the subdivision to facilitate the flow of water through the addition, to avoid the probability of lawsuits based on damage from changed runoff in the subdivision, and to provide continuous improvement of the overall storm sewer system.

(b)

Requirements outside the addition may include the following:

(1)

Improvements may be required in channels or storm sewers flowing to or from the addition, or in channels or storm sewers located in adjacent areas that are affected by flow of water from the addition.

(2)

The following kinds of improvements may be required:

a.

Enlargement or replacement of undersized drainage structures to provide free flow.

b.

Removal of obstructions.

c.

Straightening of the channel.

d.

Widening or deepening of the channel.

e.

Construction of erosion control structures.

f.

Backsloping, sodding and/or riprapping of the bank.

g.

Construction of closed or open-paved storm sewers for purposes of closing gaps or continuation of the overall storm sewer system.

(3)

Easements, where required, shall conform to section 50-133.

(4)

Property owner agreements, where required, shall be designed to protect the city from probable lawsuits for damage caused by changed runoff conditions.

(Code 1977, § 13.12.070)

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

Base flood and 100-year flood mean the flood having a one percent chance of being equalled or exceeded in any given year.

Detention means the temporary storage and controlled release of stormwater runoff.

Detention facility means a facility that provides temporary storage of stormwater runoff and controlled release of this runoff.

Development.

(1)

The following activities shall constitute development: any manmade change to improved or unimproved real estate, including but not limited to:

a.

Buildings or other structures.

b.

Mining, dredging, filling, grading, paving, excavation or drilling operations.

(2)

The following activities shall not constitute development:

a.

Lawn and yard care.

b.

Gardening.

c.

Tree care and maintenance.

d.

Removal of trees or other vegetation damaged by natural forces.

e.

Agricultural activities.

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 one foot.

Historic means pre-development or existing conditions at the time of development for all storm frequencies.

Stormwater runoff means that portion of the rainfall that is drained into the stormwater drainage system.

(Code 1977, § 13.14.020)

Cross reference— Definitions generally, § 1-2.

Any violation of the provisions of this division is punishable as provided in section 1-8.

(Code 1977, § 13.14.100)

(a)

It is the intent of this division to protect the general health, safety and welfare of the public from the dangers arising from improper drainage and unwise diversion, use and obstruction of drainage channels, to protect natural scenic areas, and to provide for the conservation of the natural resources of 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 this division.

(b)

The provisions of this division shall apply to and be binding upon every person who seeks to develop, redevelop, grade, regrade, excavate, landfill, berm or dike land subject to the jurisdiction of the city.

(Code 1977, § 13.14.010)

In the interpretation and application of this division and the city's drainage standards, all provisions shall be:

(1)

Considered as minimum requirements;

(2)

Liberally construed in favor of the city council; and

(3)

Deemed neither to limit nor repeal any other powers granted under state statutes.

(Code 1977, § 13.14.090)

The standard drainage policy, as may be amended from time to time, is hereby adopted and shall be used for all runoff flow and sizing for the regulations established in this division. The current standard drawing and details shall be used.

(Code 1977, § 13.14.030)

Editor's note— The city's "Standard Drainage Policy for the City of Mustang" is on file with the city clerk.

(a)

It shall be the goal of the owner/developer to limit the storm runoff leaving his property to the so-called historic value (before development). To achieve this, the developer/owner shall provide stormwater management for the increased stormwater runoff resulting from his development.

(b)

Where a developer/owner proposes development or use of only a portion of the property, provision for stormwater runoff control shall be required for that portion of the property proposed for immediate development or use.

(c)

The development shall provide a sufficient stormwater drainage system for the conveyance of existing stormwater runoff received from upstream and from the subject property, with specific allowance having been made for the continued conveyance of stormwater runoff from properties adjacent to the proposed development which may develop in the future.

(d)

All roofs, paved areas, yards, courts and courtyards, other than one-family or two-family residential structures, shall drain into an existing or improved storm sewer system or to an approved place of disposal, not generally including streets. Release of stormwater onto arterial (section line) streets may be considered acceptable if:

(1)

Present street flow does not exceed four inches in depth at the face of the curb during a 50-year storm event; or

(2)

The release of stormwater when added to existing street flow does not increase the depth of flow at the face of the curb above four inches in depth during a 50-year storm.

Release of stormwater onto all other classifications of streets may be considered acceptable if the depth of flow does not exceed six inches in depth at the face of the curb during a 100-year storm event. The addition of off-site stormwater improvements may be waived by the city council if, in the opinion of the city council, the addition of storm sewers would cause extreme hardship on the developer, in which case the council will address alternative methods of disposal.

(e)

In the case of one-family and two-family residential structures, stormwater may be discharged onto flat areas such as streets or lawns if drainage is provided so that the stormwater will flow away from the building and if the requirements of the city drainage standards are met.

(f)

The owner/developer shall provide for the construction, operation and perpetual maintenance of stormwater detention systems acceptable to the city, except as provided in section 50-168(2). No conveyance of the responsibility for the detention system is allowed or implied by the issuance of building permits. Stormwater detention systems shall be considered a priority during construction. All stormwater drainage systems, erosion control and sedimentation control shall be constructed as one of the first items of a development, and shall be constructed prior to any change in the stormwater runoff of the development.

(Code 1977, § 13.14.040)

(a)

In any development or improvement of property, the developer/owner may be required to provide, at his own expense, a preliminary drainage study for the total area to be ultimately developed. It shall be the responsibility of the city engineer to determine whether the need exists for a preliminary drainage study, and, if required, the study shall be submitted to the city engineer for review prior to his acceptance of any preliminary plat or construction plans for the development or any increment thereof.

(b)

The city reserves the right to require improvements to preclude any backup of tailwater inundating any areas outside of the development as a result of the base flood.

(c)

All developments shall be designed, constructed and completed in a manner which minimizes the removal of vegetation and existing tree cover.

(d)

Development activities shall begin and continue only if appropriate sedimentation facilities are installed and maintained throughout the construction period.

(e)

The building pad for all proposed buildings shall be a minimum of one foot above the base flood or 100-year flood elevation.

(Code 1977, § 13.14.050)

Ownership and maintenance of stormwater detention storage facilities shall remain with the private sector unless such areas are in a development that has no neighborhood or homeowners' association or the like to regulate such facilities. Other drainage facilities provided for in this division may be dedicated to the public and maintained by the public unless such facilities are an integral usable part of the development, in which case the ownership and maintenance of the facilities shall remain with the private sector. Prior to the acceptance of any drainage or detention facility for maintenance by the city, the developer shall be in compliance with the following:

(1)

The developer shall have completed construction of all required facilities and erosion controls in accordance with approved plans, and this shall be certified by the community development director, or shall provide a sufficient surety bond, cash escrow or letter of credit approved by the city council and city attorney guaranteeing the construction of all required facilities and erosion controls as approved by the city engineer and community development director within one year.

(2)

In the case of public ownership, the developer shall pay a sum to the city as set forth in section 42-50, multiplied by the number of acres dedicated for the detention facility, multiplied by seven years, to cover the cost of maintenance. All funds received shall be maintained in a separate account to be used for the maintenance of detention ponds.

(Code 1977, § 13.14.060)

Prior to approval of any plat or plan, the developer's consulting engineer shall submit backwater profiles and stream flow and runoff calculations as may be required by the city engineer under the terms of this division. A building permit or occupancy permit shall not be issued for any structure in the subject area until:

(1)

The required improvements have been completed and accepted by the city engineer and community development director, with approved maintenance bonds on file; or

(2)

A development bond or irrevocable letter of credit approved by the city attorney and accepted by the city council, guaranteeing the required improvements, is on file with the city clerk.

(Code 1977, § 13.14.070)

The owner/developer understands and agrees by his submitting of a drainage system plan that approval by the city does not relieve him or his successors or assigns of an obligation to revise, improve and/or change any or all of the drainage system if the original proposal does not function as intended by the approved site or development plan.

(Code 1977, § 13.14.080)