Oklahoma Administrative Code
Title 785 - Oklahoma Water Resources Board
Chapter 55 - Development on State Owned or Operated Property Within Floodplains and Floodplain Administrator Accreditation
Subchapter 3 - Development on State Owned or Operated Property Within the Floodplains
Section 785:55-3-3 - Development in delineated regulatory floodways

(a) Development where regulatory floodway delineated. In areas in which a regulatory floodway has been delineated, the following shall apply to development in such delineated regulatory floodways in addition to those in 785:55-3-1, 785:55-3-2 and 785:55-3-4.

(b) Regulatory floodway designation. The Board shall designate regulatory floodways based on the principle that the area chosen for the regulatory floodway must be designed to carry the waters of the base flood, without increasing the water surface elevation of that flood more than one foot at any point.

(c) Development or encroachments within regulatory floodway. Encroachments, including fill, new construction, substantial improvements, and other development within the designated regulatory floodway are prohibited 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.

(d) Increase in base flood elevations. Enroachments within the designated regulatory floodway that would result in an increase in the base flood elevation are prohibited unless the applicant first makes application to FEMA and receives a conditional letter of map revision or floodway revision.

(e) Modifications or additions. For modification or additions, the following shall apply: