§ 12.39 - Evaluation of spillway adequacy.

§ 12.39 Taking corrective measures after the report.

(a) Corrective plan and schedule.

(1) Not later than 60 days after the report of the independent consultant is filed with the Regional Engineer, the licensee must submit to the Regional Engineer three copies of a plan and schedule for designing and carrying out any corrective measures that the licensee proposes.

(2) The plan and schedule may include any proposal, including taking no action, that the licensee considers a preferable alternative to any corrective measure recommended in the report of the independent consultant. Any proposed alternative must be accompanied by the licensee's complete justification and detailed analysis and evaluation in support of that alternative.

(b) Carrying out the plan. The licensee must complete all corrective measures in accordance with the plan and schedule submitted to, and approved or modified by, the Regional Engineer.

(c) Extension of time. For good cause shown, the Regional Engineer may extend the time for filing the plan and schedule required by this section.

Evaluation of spillway adequacy.

The adequacy of any spillway must be evaluated, as part of a comprehensive assessment or as otherwise requested by the Regional Engineer, by considering hazard potential which would result from failure of the project works during normal and flood flows.

(a) If failure would present a hazard to human life or cause significant property damage, the independent consultant team must evaluate the following for floods up to and including the probable maximum flood:

(1) The ability of project works to withstand the loading or overtopping which may occur during floods;

(2) The capacity of spillways to prevent the reservoir from rising to an elevation that would endanger the project works; and

(3) The potential for misoperation of; failure to operate; blockage of; or debilitating damage to a spillway and its appurtenances (including but not limited to structural, mechanical, and electrical components of gates, valves, chutes, and training walls); and the effect thereof on the maximum reservoir level and potential for surcharged loading or overtopping to occur during floods.

(b) If failure would not present a hazard to human life or cause significant property damage, spillway adequacy may be evaluated by means of a design flood of lesser magnitude than the probable maximum flood provided that the most recent comprehensive assessment report required by § 12.38 provides a detailed explanation of and rationale for the finding that structural failure would not present a hazard to human life or cause significant property damage.