POTENTIAL PROBLEMS CREATED BY THE NEW CDA INFLOW DESIGN FLOOD DETERMINATION METHODOLOGY

摘要

In 2007, the Canadian Dam Association (CDA) published revised dam safety guidelines that included a new methodology for deriving the inflow design flood (IDF) for dams belonging to different Incremental Consequence Classification (ICC) categories. The aim of this new method was to provide some flexibility in the selection of the required spillway capacity for dams with different ICCs.Experience over the past three years has indicated that there are some issues in applying the new methodology as a result of the use of two different "anchors" stipulated for deriving the IDF. The frequency based 1:1000 year event at the lower end and the deterministically based PMF (with no assigned return frequency) at the upper end.This paper describes some of the experiences encountered and practical difficulties in applying this new methodology.