Authors: R.D. Zhou and R. Donnelly
Canadian Dam Association Annual Conference, British Columbia, October 3-8, 2009
Abstract
In any dam safety assessment, it is necessary to establish the inflow design flood (IDF) to ensure that the dam has adequate capacity to handle flood flows up to a point where there is no unacceptable risk to the public if the dam should fail. In Ontario, and many other areas in Canada and USA, the inflow design flood may be generated either by high intensity summer storm events or, more commonly, by rain on snowmelt (or simply snowmelt) events depending on the size and location of watershed, local meteorological conditions and other hydrological parameters. In order to determine the critical flood generating mechanism for a dam site, a detailed hydrological model is usually needed in order to simulate both types of flood events. Based on the simulation model, the higher flood generated is selected as the inflow design flood. This procedure can require a significant amount of effort and, therefore, cost.
This paper provides details of a simple, but effective, methodology based on hydrological principles commonly used in dam safety assessments to accurately identify the critical flood generating mechanism for a given dam site using watershed and local meteorological characteristics without going through the detailed hydrological modeling processes. This procedure will allow hydrologists and hydro-technical engineers to focus on the evaluation of the critical flood generating events leading to reduced time and efforts in the performance of hydrological analyses of accurate and reliable dam safety assessments.
