Secondary drainage channel requirements.
Oklahoma City Municipal Code § 16-7
in effect§ 16-7. - Secondary drainage channel requirements.
All secondary drainage channels which are located within an improvement, construction area, development, or subdivision, must be protected and/or improved by the developer in accordance with this chapter, the DCM and as follows:
(a) All land within a development having an elevation below the 100-year frequency flood elevation of the secondary drainage channel must be dedicated for the purpose of providing: containment of runoff and drainage flow in a drainage facility within a private drainage easement, or in a common area. Private drainage facilities and systems must be constructed, operated, and maintained by the developer, property owner, or Homeowners Association or Property Owners Association.
(b) Secondary drainage channels with a drainage area of 40 to 500 acres must be improved with a concrete lined channel or enclosed storm sewer system. Drainage areas between six to 40 acres shall have an improved closed storm sewer system, unless written approval has been given by the City Engineer for construction of a concrete lined channel. If the offsite drainage area entering the development is between zero and six acres, the flow may be intercepted and directed to a paved concrete channel and/or closed storm sewer. If the entire drainage area of zero to six acres is generated on site, enclosed storm sewer system shall be constructed.
(c) For purposes of maintenance, all closed storm sewer systems shall be constructed at the front of the lot, or between lots in any subdivision development. It shall not be constructed at the back of the lot, unless approved in writing by the City Engineer.
(d) Site drainage improvements must provide for the grading of all building pads to an elevation where all building pads will not be subjected to overflow from a 100-year frequency flood. Manufactured home placement pads must be elevated to one foot above the 100-year frequency flood elevation. Construction of new and substantial improvements to existing buildings and structures are subject to all regulations and requirements of this chapter, the DCM, and the following:
(1) New construction or substantial improvements of residential or nonresidential buildings and structures (including manufactured homes) must have the lowest floor (including basements) elevated to one foot above the level of the 100-year frequency flood.
(2) Nonresidential buildings and structures and accessory buildings may meet this requirement by floodproofing the buildings and structures, including above ground utility and sanitary facilities, up to one foot above the level of the 100-year frequency flood.
(3) Mechanical and utility equipment for residential or nonresidential buildings and structures must be elevated to one foot above the level of 100-year frequency flood.
(4) If a nonresidential building or structure is intended to be floodproofed, an Engineer must develop and/or review its structural design, specifications and plans for the construction, and must certify that the design and methods of construction are in accordance with the accepted standards of practice and meeting the elevation requirements of this chapter. A record of such certificates which includes the specific elevation (in relation to mean sea level) to which such buildings or structures are floodproofed must be submitted by an Engineer to the City Engineer for review as to compliance with this chapter and the DCM before any construction may commence.
(e) An open drainage channel may not be located in a street easement or utility easement except under the following conditions:
(1) Where a paved street surface of at least two lanes is provided on both sides of a paved channel to provide access to abutting properties.
(2) Where lots are platted to back up to the street right-of-way where the open drainage channel is located between the rear lot line and the paved street, and further provided that at no time in the future may access be allowed or constructed over the open drainage channel to the rear of a lot so platted. For the purpose of this chapter, 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 (e)(2) above is present, adequate space adjacent to the channel must be dedicated as right-of-way to provide for maintenance of the paved drainage channel and its bank, paved or unpaved.
(f) Open drainage channels must be improved by providing a paved section that will carry the runoff from a 100-year frequency rain event. Whenever an open improved channel is required or authorized for a secondary drainage channel under the provisions of this chapter and that channel crosses residential lots, or where the channel improvement is designed as a drainage area and will be privately maintained by a Property Owners Association or Home Owners Association, the City Engineer may modify the requirements of the first part of this provision to permit an alternate channel design, provided all hydraulic requirements to support the overflow resulting from a 100-year frequency rainfall are met to prevent flooding of all building pads, buildings, structures and accessory buildings.
(Ord. No. 27691, § 2, 9-24-24)
Source: City of Oklahoma City, Municipal Code and City Charter (Municode Library, library.municode.com)URL: https://library.municode.com/ok/oklahoma_city/codes/code_of_ordinances?nodeId=OKMUCO2020_CH16DRFLCO_S16-7SEDRCHREFetched: 10/28/2026