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 Oklahoma Administrative Code (Last Updated: March 11, 2021)
 TITLE 785. Oklahoma Water Resources Board
 Chapter 25. Dams and Reservoirs
 Subchapter 3. Responsibility, Classification and Design Standards

  SECTION 785:25-3-11. Minimum safety factors

Latest version.
  •   As a guide for use by the Board and by engineers designing new dams, assessing the condition of existing dams or proposing modifications to existing dams, the following safety factors shall be utilized for:
    (1)   Embankment dams:
       
    LOADING CONDITION
    MINIMUM FACTOR OF SAFETY*
    Steady seepage at emergency spillway crest
    1.5
    Rapid drawdown from principal spillway
    1.2
    Earthquake - reservoir at emergency spillway crest for downstream slope; reservoir at principal spillway for upstream slope
    1.0
    *The minimum factor of safety is calculated by the ratio of available shear strength to shear stress required for stable equilibrium.
       
    (2)   Concrete dams or concrete portions thereof:
         
    LOADING CONDITION
    MINIMUM FACTOR OF SAFETY** (by hazard classification of dam)
     
    High and Significant
    Low
    Principal spillway level
    2.25
    2.0
    Inflow design flood at maximum pool level
    1.75
    1.25
    Principal spillway level with earthquake
    greater than 1.0
    greater than 1.0
    **These minimum factors of safety apply to the calculation of stress and the shear friction factor of safety within the structure of the rock/concrete interface and foundation.
         
[Source: Amended at 11 Ok Reg 2931, eff 6-13-94]