Dam safety modification decision process

The United States Bureau of Reclamation's dam safety modification decision process is described. Each dam is considered unique, requiring its own quantitative evaluation to determine treatment needs. The quantitative evaluation needs consist of a determination of the dam's failure potential; whether the dam's failure would produce significant incremental consequences; and the best corrective action alternative. Key considerations in making decisions on modification of a dam include the following. Historical failure rates need to be understood and compared to potential structural failures anticipated for the existing structure, considering the comparative soundness of the structure to the condition of those that have failed. The incremental impact resulting from the potential dam failure in terms of downstream damages, lost benefits, and potential loss of life, versus those losses which occur from successful performance of the dam (no failure but high discharge) must be determined. The corrective action study should include consideration of all viable structural and non-structural corrective actions, and combinations of these. The viability of a warning system to reduce loss of life needs to be examined for each case. 2 figs., 4 tabs