HYDROLOGIC SAFETY - IMPROVING PROBABLE MAXIMUM FLOOD ESTIMATES.

It is generally accepted practice in the United States to use the Probable Maximum Flood (PMF) to design structures whose failure consequences dictate holding flood failure risks to essentially zero. This paper briefly reviews current practice and outlines an approach for establishing a consistent standard for PMF determination for use in the design and evaluation of high-hazard dams based upon risk assessment. The discussion is limited to selection of natural events in contrast to computational procedure or operating assumptions.