§ 16-4. - Definitions.
The following words, terms, and phrases, when used in this chapter, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning:
44 CFR means applicable subsections of Chapter 44 of the Code of Federal Regulations also referred to as the national Flood Insurance Program (NFIP).
Administrator/Floodplain Administrator means the person responsible for implementing the community's local floodplain ordinance and ensuring that the community is complying with minimum NFIP standards and enforcing any locally imposed higher standards. The Administrator shall review, and evaluate floodplain development permit applications, review elevation certificates for completeness and accuracy, review development plans and specifications for compliance with this chapter, inspect floodplain construction to verify location relative to the floodplain/floodway and ensure compliance with this chapter, educate community members and local officials about floodplain management, maintain documentation and records of floodplain activities, and investigate violations of this chapter and initiate corrective action.
Base Flood means the flood having a one percent chance of being equaled or exceeded in any given year commonly referred to as the 100-year frequency flood.
Base Flood Elevation (BFE) means the computed elevation to which the flood is anticipated to rise during the base flood.
Board means the Oklahoma Water Resources Board.
Bridge means a hydraulic structure that is constructed with abutments and a superstructure which are typically made of concrete, steel, or other materials. Since superstructures are not an integral part of the abutments and could therefore potentially move, the hydraulic criteria for bridges are different than for culverts.
Building (see Structure).
Channel means defined landforms, either natural or manmade or man improved, whereby stormwater is carried between points of origin and destination.
City means the City of Oklahoma City.
City Engineer means the professional engineer designated in Section 2-111 of the Oklahoma City Municipal Code.
Clearing means the process of manually or mechanically removing the vegetative and/or nonvegetative cover of any land.
Corps of Engineers (COE) 404 Permit means a permit issued by the United States Army Corps of Engineers pursuant to Section 404 of the Clean Water Act.
Construction includes, but is not limited to, land preparation such as clearing, grading, and filling; the installation of streets and/or walkways; excavation for a basement, footings, piers, or foundations or for the erection of temporary forms; and the installation on the property of building, accessory buildings, structures, or improvements, such as garages or sheds not occupied as dwelling units or not part of the main structure.
Culvert means a closed conduit for the passage of stormwater under an embankment, such as a road, railroad, or trail. Flow generally enters a closed conduit (culvert) by an open channel, generally at a similar elevation. The geometry of the culvert inlet is utilized in the determination of the required size and capacity of the culvert. (See DCM for calculating culvert capacity)
Detention means storage that reduces the rate of stormwater runoff, for a short period of time, to lower peak flows whereby controlling the discharge rate of release to the receiving stream, river, pipe, channel, or culvert.
Detention facility or detention pond means a constructed facility, improvement, or pond functioning to retain or attenuate stormwater flow or runoff.
Developer means a person or entity that owns the land upon which a development is made or is to be made, occupies, or has the right to occupy or use the land where a development is made or is to be made or contracts for a development to be made.
Development or development in floodprone areas means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavations, or drilling operations, and/or storage of equipment or materials.
Drainage Criteria Manual (DCM) means the manual providing design guidance for use by landowners, developers, architects and/or engineers, and/or their agents, in preparation of drainage plans for development within the City. It establishes rules and design standards and requirements and methods that must be consistently followed and will be enforced throughout the City's jurisdiction. The design methods presented in this manual are intended to provide minimum standards for determination of runoff rates, methods of storm water collection, conveyance, and detention. The DCM sets forth the technical details, provisions, standards, and requirements established by the City Engineer, as may be amended from time to time.
Driveway pipe means a culvert located under a driveway.
EPA means the United States Environmental Protection Agency.
Elevated building means, for insurance purposes, a non-basement building which has its lowest elevated floor raised above ground level by foundation walls, shear walls, posts, piers, pilings, or columns:
(1) 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, or in the case of a building in zones V1—30, VE, or V, to have the bottom of the lowest horizontal structure member of the elevated floor elevated above the ground level by means of pilings, columns (posts and piers), or shear walls parallel to the flow of the water.
(2) adequately anchored so as not to impair the structural integrity of the building during a flood of up to the magnitude of the base flood.
(3) 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 floodwaters.
(4) In the case of zones VI—30, VE, or V, "elevated building" also includes a building otherwise meeting the definition of "elevated building" even though the lower area is enclosed by means of breakaway walls if the breakaway walls meet the standards of Section 60.3(e)(5) of the National Flood Insurance Program regulations.
Engineer means a registered professional engineer licensed in the State of Oklahoma. The City Engineer and other City employees who are registered professional engineers licensed in the State of Oklahoma are not included in this definition.
Erosion means the process of gradual wearing away of land areas or masses or portions thereof.
Erosion and sediment control measures are methods used to reduce the amount of soil particles that are carried by stormwater, from a land area or mass and deposited in a receiving water, or stormwater conveyance facility or improvement.
Excavation means the process of removing earth, stone, land, soil, topsoil, or other materials.
FEMA Elevation Certificate (EC) means a document for the purpose of estimating the risk premium rates necessary to provide flood insurance for new or substantially improved structures in designated Special Flood Hazard Areas. It is to be used to provide elevation information necessary to ensure compliance with community floodplain management ordinances and this chapter, to determine the proper insurance premium rate and to support a request for a Letter of Map Amendment (LOMA) or Letter of Map Revision based on fill (LOMR-F). It is a technical document which must be prepared by a registered Land Surveyor, or Engineer, licensed in the State of Oklahoma.
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 waters; or
(2) the unusual and rapid accumulation, flow, or runoff of surface waters from any source.
Flood Elevation Study means an examination, evaluation, and determination of flood hazards and, if appropriate, corresponding water surface elevations, or an examination, evaluation, and determination of mudslide (i.e., mudflow) and/or flood-related erosion hazards.
Flood Insurance Rate Map (FIRM) means an official map of a community, on which the Administrator has delineated both the special hazard areas and the risk premium zones applicable to the community.
Flood insurance study (FIS) Flood Elevation Study.
Floodplain or Floodprone Area means any land area susceptible to being inundated by water from any source (see definition of flood or flooding). Floodprone areas are determined from FEMA Flood Insurance Rate Maps, USGS Oklahoma City Urbanized Study, and/or any individual study of an unnamed tributary by an Oklahoma Professional Engineer.
Floodplain activity permit means the permit required for development from which runoff or drainage flows through or into the boundaries of the delineated floodplain for a watercourse as shown on the official floodplain maps or an area deemed floodprone, through independent flood study, reviewed and approved by the City Engineer.
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, drainage improvements, stormwater detention, and land use and control measures.
Floodproofing means protective measures added to or incorporated in a building or structure that is not elevated above the base flood elevation to prevent or minimize flood damage. "Dry floodproofing" measures are designed to keep water from entering a building. "Wet floodproofing" measures minimize damage to a building or structure and its contents from water that is allowed into a building or structure.
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, detention ponds, levees, or dikes. These specialized flood modifying works are those systems constructed in conformance with sound engineering standards.
Floodway means the channel of a river or other watercourse and that portion of the adjacent floodplain that must remain open to permit passage of the base flood without cumulatively increasing the water surface elevation more than one foot.
Flows or discharges means City calculated urbanized stormwater discharges or FEMA calculated stormwater discharges, whichever is higher.
Freeboard means a factor of safety expressed in feet above a flood level for purposes of flood plain management. "Freeboard'" tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected frequency flood and floodway conditions, such as wave action, bridge openings, and the hydrological effect of urbanization of the watershed.
Frequency flood means all frequency flood(s) mentioned in this chapter shall refer to either FEMA calculated stormwater discharges or City calculated urbanized discharges, whichever is higher.
Grading means the cutting and/or filling of the land surface to a desired slope or elevation.
Grubbing means the process of removing vegetation, roots, stumps, brush, or any excess deleterious materials that cannot be used for sub-grade or structural soil.
Hydraulic Grade Line is a line coinciding with the level of flowing water at any point along an open channel. In closed conduits flowing under pressure, the hydraulic grade line is the level to which water would rise in a vertical tube (open to atmospheric pressure) at any point along the pipe.
Highest adjacent grade means the highest natural elevation of the ground surface prior to grading or construction next to the proposed walls of a building or structure.
Historical runoff means, when utilized in the calculations of detention requirements, the runoff conditions existing prior to any new development, construction, or grading.
Impervious surface means any hard-surfaced areas which prevent or retard the entry of water into the soil in the manner or to the extent that such water entered the soil under natural conditions, or where water is caused to run off the surface in greater quantities or at an increased rate of flow than was present under natural conditions. Impervious surfaces shall include, but are not limited to, rooftops; sidewalks; paving; driveways; parking lots; walkways; patio areas; storage areas; and asphalt, concrete, gravel, oiled macadam, or other surfaces which similarly affect the natural infiltration or runoff patterns of real property in its natural state.
Levee means a man-made structure, usually an earthen embankment, designed and constructed in accordance with sound engineering practices to contain, control, or divert the flow of water 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).
(1) An unfinished or flood resistant enclosure, usable solely for parking of 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 building or structure in violation of the applicable non-elevation design requirements.
(2) Basements or underground storm shelters, shall be permitted to be constructed if an engineered plan illustrating that the lowest opening to any part of the basement or shelter is not less than one foot above the 100-year frequency, as determined by the FEMA maps or a flood study, which plan was prepared by an Engineer and submitted to and accepted approved by the City Engineer prior to construction.
(3) Specifically, for all new construction and substantial improvements to buildings or structures, fully enclosed areas below the lowest floor that are subject to flooding must be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters.
Major river channels mean the cross-sectional area of the North Canadian and Canadian Rivers at and below the elevation of the 100-year frequency flood limits as established by the City, the Federal Emergency Management Agency, and the U.S. Army Corps of Engineers.
Manufactured home means a building or 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 attached to the required utilities. The term "manufactured home"' does not include a "recreational vehicle".
Manufactured home park or subdivision means a parcel (or continuous parcels) of land divided into two or more manufactured homes, or lots for sale or rent.
Mean sea level means, for purposes of the National Flood Insurance Program, the North American Vertical Datum (NAVD 88) or, other City accepted datum, as the datum can be updated from time to time, to which base flood elevations shown on a community's flood insurance rate map are referenced.
Mechanical equipment or utility equipment means any electrical, heating, ventilation, plumbing, and air conditioning equipment or other service facilities associated with a building or structure.
New construction for floodplain management purposes means buildings or structures for which the "start of construction" commenced on or after the effective date of an initial Flood Insurance Rate Map (FIRM) or after December 31, 1974, whichever is later, including any subsequent improvements. For Floodplain Management Purposes: Buildings or 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 buildings or structures.
NPDES means National Pollutant Discharge Elimination System, EPA's program to control the discharge of pollutants to waters of the United States.
NPDES permit means an authorization, license, or equivalent control document issued by the EPA.
100-year floodplain area means river or stream flood hazard areas, and areas with a one percent or greater chance of flooding each year.
Primary drainage channels are all drainage channels, streams or creeks which drain an area of 500 acres or more, excluding those areas defined as major river channels.
Private stormwater facility means a stormwater facility other than a public stormwater facility.
Public stormwater facility means a stormwater facility in a public drainage or utility easement, dedicated to, and formally accepted by the City for public use and benefit if constructed as approved by the City Engineer and in accordance with this chapter and if accepted by specific formal action of the City by the City Council.
Public Works Director or Director means the person designated in Section 2-542 of the Oklahoma City Municipal Code.
Repetitive Loss (RL) property is any insurable building for which two or more claims of more than $1,000.00 were paid by the National Flood Insurance Program (NFIP) within any rolling ten-year period, since 1978.
Receiving water means a runoff process connected to a network of waterways that increase in size as the watershed area increases.
Riverine means of or produced by a river.
Riverine floodplains are a floodplain of or produced by a river having readily identifiable channels.
Rural subdivision shall include any subdivision of land:
(1) Within an AA Agricultural District; or
(2) Under the RA Single-Family Rural Residential District provisions set forth in the Planning and Zoning Code; or
(3) Under the Planned Unit Development provisions set forth in the Planning and Zoning Code; or
(4) Within the Garber-Wellington Aquifer Recharge Area, regardless of the uses allowed by zoning.
Secondary drainage channels are all drainage channels, streams, and creeks which drain an area of less than 500 acres, excluding those areas defined as major river channels or Primary Drainage Channels.
Sediment means soil, sand, and minerals transported by wind offsite or washed from land into water, usually after rain.
Soil means the unconsolidated mineral and organic material on the surface of the earth that serves as a natural medium for growth of plants.
Soil disturbance/soil disturbing activities mean any moving or removing by manual or mechanical means of the vegetative and/or nonvegetative cover or soil mantle, including but not limited to grading, excavations, and mining.
Special flood hazard map means an official map provided through FEMA administration, having special flood, mudslide, or flood-related erosion hazards, and shown on a Flood Hazard Boundary Map (FHBM) or FIRM as Zone A, AO, A1—30, AE, AR, AR/A1—30, AR/AE, AR/AO, AR/AH, AR/A, A99, AH, VO, V1—30, VE, V, M, or E.
Stockpiling means the storing of soil or other fill or excavated material.
Stormwater system means any improved open channel, closed conduit, natural stream, creek, or swale, that acts to collect, deliver, discharge, and release any stormwater, improved or unimproved, across a specific development site or tract of land.
Structure means a walled and roofed building, other than a gas or liquid storage tank, principally above ground and permanently affixed to a site as well as a manufactured home on a permanent foundation.
Substantial improvement means any repair, reconstruction, or improvement of a building or structure, the cost of which equals or exceeds 50 percent of the market value of the building or structure either (1) before the improvement or repair is started, or (2) if the building or structure has been damaged and is being restored, before the damage occurred. For the purpose of this definition "substantial improvement" is considered to commence when the first alteration of any wall, ceiling, floor, or other structural part of the structure commences, whether or not that alteration affects the external dimensions of the building or structure. The term does not, however, include either (1) any project for improvement of a building or structure to comply with such existing State or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions, or (2) any alteration of a building or structure listed on the National Register of Historic Places or an official State of Oklahoma inventory of historic places.
Sump areas means low elevations which collect water.
Surface means the upper most boundary of either standing or flowing water and that elevation of said surface boundary equals the Water Surface Elevation.
Surveyor's Certificate means a document prepared by a qualified engineer/surveyor, licensed in the State of Oklahoma, which provides information on elevation of a building or structure relative to flood elevations, building or structure type, and as-built finished floor elevation established by independent flood study approved by the City.
Urbanized discharge means FEMA/USGS (USGS Open File Report 83-26) historical "urbanized" information for the City studies for streams and rivers, or new hydrology for unstudied FEMA drainage basins for portions of the City; prepared, signed, sealed, and submitted to the City Engineer by an Engineer.
Vegetative cover means vegetative growth shielding the soil surface from erosion.
Violation means act or omission in violation of this chapter, the DCM or any other referenced applicable requirement or the failure of a structure, building, improvement, or other development to be fully compliant with this chapter, the DCM, or any other referenced applicable requirement. A structure, building, improvement or other development without the elevation certificate, other required certifications, or other evidence of compliance required in 44 CFR 60.3(b)(5), (c)(4), (c)(10), (d)(3), (e)(2), (e)(4) or (e)(5) is presumed to be in violation until such time as that documentation is provided.
Water surface elevation means the heights in relation to mean sea level expected to be reached by floods of various magnitudes and frequencies at pertinent points in the floodplains or riverine areas.
(Ord. No. 27691, § 2, 9-24-24)
