2004 – Towards Increasing Objectivity in the Probable Maximum Flood

R.J. Nathan and P.E. Weinmann

Selected aspects of the guidelines dealing with the estimation of dam safety floods are being
considered for revision as part of a larger overhaul of “Australian Rainfall and Runoff”. One section
that warrants attention is the guidance provided on estimation of the Probable Maximum Flood
(PMF). The section of the current guidelines that deals with this issue received little attention in the
last revision as the focus was on estimating floods for risk-based design, that is on floods of known
annual exceedance probability. However, it is now common to jointly consider both risk-based and
standards-based components in the design process, and this has highlighted problems associated with the manner in which the PMF is defined and estimated. This paper examines the current problems involved with estimation of the PMF, and presents concepts and practical estimation approaches that could be considered for incorporation in the guidelines. The purpose of this paper is to promote discussion and elicit feedback from industry to aid the revision process.

Buy this resource