SECTION 785:25-3-3. Classification of size and hazard potential

(a)   All dams shall be classified as to size and for potential hazards as follows:

(1)   Size Classification of Dams. The size classification shall be based on the following:

(A)   Small. Small size dams are those which have a maximum storage of less than 10,000 acre feet and have a maximum height of less than 50 feet.

(B)   Intermediate. Intermediate size dams are those which have a maximum storage of between 10,000 and 50,000 acre feet and have a maximum height of between 50 and 100 feet.

(C)   Large. Large size dams are those which have a maximum storage of over 50,000 acre feet and have a maximum height of over 100 feet.

(2)    Hazard-Potential Classification of Dams. The hazard-potential classification of a dam is determined by the downstream risk in the event of a failure, without regard to the physical condition of the dam, as follows:

(A)   Low. Dams assigned the low hazard-potential classification are those where failure would result in no probable loss of human life and low economic losses.

(B)   Significant. Dams assigned the significant hazard-potential classification are those dams where failure would result in no probable loss of human life but can cause economic loss or disruption of lifeline facilities.

(C)   High. Dams assigned the high hazard-potential classification are those where failure will probably cause loss of human life.

(b)   Hazard-potential classification subject to regulation and change.

(1)   For dams which were inventoried in the National Safety of Dams program authorized under 33 U.S.C. 467 et seq., and for which "Phase I" reports pursuant to said inventory were prepared, the hazard classifications set forth in such "Phase I" reports shall be presumed accurate. If the owner of the dam disagrees with the hazard classification, the owner shall have the burden to show that such hazard classification is inaccurate and should be changed.

(2)   At the discretion of the Board, any proposed or existing dam considered to have classification of a high hazard-potential may be subject to regulation regardless of size or impounding capacity.

(3)   The hazard-potential classification may change as the area downstream from a dam develops and the dam may be reclassified from time to time under the provisions of 785:25-9-10 and 785:25-9-11.

[Source: Amended at 11 Ok Reg 2931, eff 6-13-94; Amended at 27 Ok Reg 1300, eff 5-27-10]