Detention.
Oklahoma City Municipal Code § 16-10
in effect§ 16-10. - Detention.
(a) For all new developments, detention facilities shall be installed providing a developed discharge rate not to exceed the historical runoff rate prior to development for the 2-, 5-, 10-, 25-, 50- and 100-year frequency storms. All private on-site detention facilities shall be constructed in a private drainage easement or common area, and the private drainage easement should include at a minimum the Q100 floodplain, outlet structures, and riprap.
(b) On-site detention facilities require signed and sealed plans and drainage calculations by an Engineer and must be provided to the City Engineer for review and must comply with this chapter and the DCM before the filing of a final plat or applying for a building permit on un-platted property. Approval of plans neither relieves the developer or property owner or the Engineer of responsibility or liability for the plan nor creates responsibility or liability for the City or the City Engineer. Detention pond facilities are reviewed, approved, and inspected by Public Works Engineering. Inspection fee as set forth in Chapter 60, the General Schedule of Fees, must be paid for each inspection trip and must be paid prior to scheduling of the inspection trip.
(c) The required maximum volume for stormwater detention must be calculated by the Engineer in accordance with the DCM.
(d) If the developer or engineer submits to the City Engineer alternative methods of protecting downstream properties that can be accomplished without causing substantial detriment to the public good, safety or welfare of surrounding or downstream properties, the City Engineer may accept a waiver of on-site detention facilities requirements. The developer's petition must include all the plans and calculations, as produced by an Engineer, that the City Engineer may need or request to demonstrate compliance with this chapter and the DCM and to support the developer's request for a waiver of on-site detention.
(1) All applications for a waiver of on-site detention facilities requirements must show no adverse impact to downstream structures or streets, and must be submitted to the City Engineer with the following information for review:
a. Site plan drawn to scale showing surveyed location, property dimensions, grade and elevations, and proposed construction or development including all impervious surfaces.
b. A summary showing total impervious surfaces in square feet, historic site runoff calculations, and proposed site runoff calculations.
c. Runoff from the proposed developed site must discharge directly to a public or private street or stormwater system in accordance with this chapter and the DCM.
d. Discharge onto an adjacent property will not be allowed, unless an analysis is provided by an engineer to demonstrate such developed discharges cause no negative impact to adjacent property and such analysis is approved by the City Engineer.
The City Engineer may approve or conditionally approve a waiver of on-site detention facilities or may deny the application and require on-site detention facilities or other improvements or modifications of the stormwater control system. Any significant change to the proposed construction or development or any failure to meet the requirements or standards in this chapter or the DCM shall void the waiver and will require either compliance with this chapter and the DCM or a new application for a waiver.
(2) Impervious surfaces installed or constructed as a part or portion of a public street or public sidewalk in the public street right-of-way shall not be included as a part of the on-site impervious area.
(3) Whenever a property upon which an impervious surface is installed or constructed lies within two different watersheds, detention shall be provided based upon the amount of increased impervious surface within each watershed.
(4) It is unlawful for any person to erect, construct, install, enlarge, alter, repair, move, improve, make, put together, or convert any building, structure, improvement, facility, or impervious surface within the City, or cause the same to be done, without providing on-site detention facilities, or request for waiver, as required by this section.
(5) If the City Engineer has record of any flooding within one-half mile of the proposed development, a waiver of the on-site detention requirement will not be considered.
(6) Single lot residential shall be excluded from the detention pond requirement in this chapter.
(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_S16-10DEFetched: 10/28/2026